0.9.17.8:
[sbcl.git] / src / runtime / gencgc.c
index b8df9f4..6902759 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * GENerational Conservative Garbage Collector for SBCL x86
+ * GENerational Conservative Garbage Collector for SBCL
  */
 
 /*
 #include "thread.h"
 #include "genesis/vector.h"
 #include "genesis/weak-pointer.h"
+#include "genesis/fdefn.h"
 #include "genesis/simple-fun.h"
+#include "save.h"
 #include "genesis/hash-table.h"
+#include "genesis/instance.h"
+#include "genesis/layout.h"
+
+#ifdef LUTEX_WIDETAG
+#include "genesis/lutex.h"
+#endif
 
 /* forward declarations */
-long gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed);
-static void  gencgc_pickup_dynamic(void);
+page_index_t  gc_find_freeish_pages(long *restart_page_ptr, long nbytes,
+                                    int unboxed);
 
 \f
 /*
  * GC parameters
  */
 
-/* the number of actual generations. (The number of 'struct
- * generation' objects is one more than this, because one object
- * serves as scratch when GC'ing.) */
-#define NUM_GENERATIONS 6
+/* Generations 0-5 are normal collected generations, 6 is only used as
+ * scratch space by the collector, and should never get collected.
+ */
+enum {
+    HIGHEST_NORMAL_GENERATION = 5,
+    PSEUDO_STATIC_GENERATION,
+    SCRATCH_GENERATION,
+    NUM_GENERATIONS
+};
 
 /* Should we use page protection to help avoid the scavenging of pages
  * that don't have pointers to younger generations? */
 boolean enable_page_protection = 1;
 
-/* Should we unmap a page and re-mmap it to have it zero filled? */
-#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__sun)
-/* comment from cmucl-2.4.8: This can waste a lot of swap on FreeBSD
- * so don't unmap there.
- *
- * The CMU CL comment didn't specify a version, but was probably an
- * old version of FreeBSD (pre-4.0), so this might no longer be true.
- * OTOH, if it is true, this behavior might exist on OpenBSD too, so
- * for now we don't unmap there either. -- WHN 2001-04-07 */
-/* Apparently this flag is required to be 0 for SunOS/x86, as there
- * are reports of heap corruption otherwise. */
-boolean gencgc_unmap_zero = 0;
-#else
-boolean gencgc_unmap_zero = 1;
-#endif
-
 /* the minimum size (in bytes) for a large object*/
-unsigned large_object_size = 4 * PAGE_BYTES;
+unsigned long large_object_size = 4 * PAGE_BYTES;
 
 \f
 /*
  * debugging
  */
 
-
-
 /* the verbosity level. All non-error messages are disabled at level 0;
  * and only a few rare messages are printed at level 1. */
 #ifdef QSHOW
-unsigned gencgc_verbose = 1;
+boolean gencgc_verbose = 1;
 #else
-unsigned gencgc_verbose = 0;
+boolean gencgc_verbose = 0;
 #endif
 
 /* FIXME: At some point enable the various error-checking things below
  * and see what they say. */
 
 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
- * Set verify_gens to NUM_GENERATIONS to disable this kind of check. */
-int verify_gens = NUM_GENERATIONS;
+ * Set verify_gens to HIGHEST_NORMAL_GENERATION + 1 to disable this kind of
+ * check. */
+generation_index_t verify_gens = HIGHEST_NORMAL_GENERATION + 1;
 
 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
 boolean pre_verify_gen_0 = 0;
@@ -128,6 +124,19 @@ boolean gencgc_enable_verify_zero_fill = 0;
 /* Should we check that free pages are zero filled during gc_free_heap
  * called after Lisp PURIFY? */
 boolean gencgc_zero_check_during_free_heap = 0;
+
+/* When loading a core, don't do a full scan of the memory for the
+ * memory region boundaries. (Set to true by coreparse.c if the core
+ * contained a pagetable entry).
+ */
+boolean gencgc_partial_pickup = 0;
+
+/* If defined, free pages are read-protected to ensure that nothing
+ * accesses them.
+ */
+
+/* #define READ_PROTECT_FREE_PAGES */
+
 \f
 /*
  * GC structures and variables
@@ -140,9 +149,15 @@ unsigned long auto_gc_trigger = 0;
 
 /* the source and destination generations. These are set before a GC starts
  * scavenging. */
-long from_space;
-long new_space;
+generation_index_t from_space;
+generation_index_t new_space;
 
+/* Set to 1 when in GC */
+boolean gc_active_p = 0;
+
+/* should the GC be conservative on stack. If false (only right before
+ * saving a core), don't scan the stack / mark pages dont_move. */
+static boolean conservative_stack = 1;
 
 /* An array of page structures is statically allocated.
  * This helps quickly map between an address its page structure.
@@ -153,25 +168,19 @@ struct page page_table[NUM_PAGES];
  * is needed. */
 static void *heap_base = NULL;
 
-#if N_WORD_BITS == 32
- #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
-#elif N_WORD_BITS == 64
- #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
-#endif
-
 /* Calculate the start address for the given page number. */
 inline void *
-page_address(long page_num)
+page_address(page_index_t page_num)
 {
     return (heap_base + (page_num * PAGE_BYTES));
 }
 
 /* Find the page index within the page_table for the given
  * address. Return -1 on failure. */
-inline long
+inline page_index_t
 find_page_index(void *addr)
 {
-    long index = addr-heap_base;
+    page_index_t index = addr-heap_base;
 
     if (index >= 0) {
         index = ((unsigned long)index)/PAGE_BYTES;
@@ -186,19 +195,19 @@ find_page_index(void *addr)
 struct generation {
 
     /* the first page that gc_alloc() checks on its next call */
-    long alloc_start_page;
+    page_index_t alloc_start_page;
 
     /* the first page that gc_alloc_unboxed() checks on its next call */
-    long alloc_unboxed_start_page;
+    page_index_t alloc_unboxed_start_page;
 
     /* the first page that gc_alloc_large (boxed) considers on its next
      * call. (Although it always allocates after the boxed_region.) */
-    long alloc_large_start_page;
+    page_index_t alloc_large_start_page;
 
     /* the first page that gc_alloc_large (unboxed) considers on its
      * next call. (Although it always allocates after the
      * current_unboxed_region.) */
-    long alloc_large_unboxed_start_page;
+    page_index_t alloc_large_unboxed_start_page;
 
     /* the bytes allocated to this generation */
     long bytes_allocated;
@@ -227,21 +236,25 @@ struct generation {
      * prevent a GC when a large number of new live objects have been
      * added, in which case a GC could be a waste of time */
     double min_av_mem_age;
+
+    /* A linked list of lutex structures in this generation, used for
+     * implementing lutex finalization. */
+#ifdef LUTEX_WIDETAG
+    struct lutex *lutexes;
+#else
+    void *lutexes;
+#endif
 };
-/* the number of actual generations. (The number of 'struct
- * generation' objects is one more than this, because one object
- * serves as scratch when GC'ing.) */
-#define NUM_GENERATIONS 6
 
 /* an array of generation structures. There needs to be one more
  * generation structure than actual generations as the oldest
  * generation is temporarily raised then lowered. */
-struct generation generations[NUM_GENERATIONS+1];
+struct generation generations[NUM_GENERATIONS];
 
 /* the oldest generation that is will currently be GCed by default.
- * Valid values are: 0, 1, ... (NUM_GENERATIONS-1)
+ * Valid values are: 0, 1, ... HIGHEST_NORMAL_GENERATION
  *
- * The default of (NUM_GENERATIONS-1) enables GC on all generations.
+ * The default of HIGHEST_NORMAL_GENERATION enables GC on all generations.
  *
  * Setting this to 0 effectively disables the generational nature of
  * the GC. In some applications generational GC may not be useful
@@ -250,13 +263,13 @@ struct generation generations[NUM_GENERATIONS+1];
  * An intermediate value could be handy after moving long-lived data
  * into an older generation so an unnecessary GC of this long-lived
  * data can be avoided. */
-unsigned int  gencgc_oldest_gen_to_gc = NUM_GENERATIONS-1;
+generation_index_t gencgc_oldest_gen_to_gc = HIGHEST_NORMAL_GENERATION;
 
 /* The maximum free page in the heap is maintained and used to update
  * ALLOCATION_POINTER which is used by the room function to limit its
  * search of the heap. XX Gencgc obviously needs to be better
  * integrated with the Lisp code. */
-static long  last_free_page;
+page_index_t last_free_page;
 \f
 /* This lock is to prevent multiple threads from simultaneously
  * allocating new regions which overlap each other.  Note that the
@@ -265,7 +278,9 @@ static long  last_free_page;
  * seized before all accesses to generations[] or to parts of
  * page_table[] that other threads may want to see */
 
-static lispobj free_pages_lock=0;
+#ifdef LISP_FEATURE_SB_THREAD
+static pthread_mutex_t free_pages_lock = PTHREAD_MUTEX_INITIALIZER;
+#endif
 
 \f
 /*
@@ -275,9 +290,9 @@ static lispobj free_pages_lock=0;
 /* Count the number of pages which are write-protected within the
  * given generation. */
 static long
-count_write_protect_generation_pages(int generation)
+count_write_protect_generation_pages(generation_index_t generation)
 {
-    long i;
+    page_index_t i;
     long count = 0;
 
     for (i = 0; i < last_free_page; i++)
@@ -290,13 +305,13 @@ count_write_protect_generation_pages(int generation)
 
 /* Count the number of pages within the given generation. */
 static long
-count_generation_pages(int generation)
+count_generation_pages(generation_index_t generation)
 {
-    long i;
+    page_index_t i;
     long count = 0;
 
     for (i = 0; i < last_free_page; i++)
-        if ((page_table[i].allocated != 0)
+        if ((page_table[i].allocated != FREE_PAGE_FLAG)
             && (page_table[i].gen == generation))
             count++;
     return count;
@@ -306,10 +321,11 @@ count_generation_pages(int generation)
 static long
 count_dont_move_pages(void)
 {
-    long i;
+    page_index_t i;
     long count = 0;
     for (i = 0; i < last_free_page; i++) {
-        if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
+        if ((page_table[i].allocated != FREE_PAGE_FLAG)
+            && (page_table[i].dont_move != 0)) {
             ++count;
         }
     }
@@ -320,12 +336,13 @@ count_dont_move_pages(void)
 /* Work through the pages and add up the number of bytes used for the
  * given generation. */
 static long
-count_generation_bytes_allocated (int gen)
+count_generation_bytes_allocated (generation_index_t gen)
 {
-    long i;
+    page_index_t i;
     long result = 0;
     for (i = 0; i < last_free_page; i++) {
-        if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
+        if ((page_table[i].allocated != FREE_PAGE_FLAG)
+            && (page_table[i].gen == gen))
             result += page_table[i].bytes_used;
     }
     return result;
@@ -333,7 +350,7 @@ count_generation_bytes_allocated (int gen)
 
 /* Return the average age of the memory in a generation. */
 static double
-gen_av_mem_age(int gen)
+gen_av_mem_age(generation_index_t gen)
 {
     if (generations[gen].bytes_allocated == 0)
         return 0.0;
@@ -343,37 +360,42 @@ gen_av_mem_age(int gen)
         / ((double)generations[gen].bytes_allocated);
 }
 
-void fpu_save(int *);           /* defined in x86-assem.S */
-void fpu_restore(int *);        /* defined in x86-assem.S */
 /* The verbose argument controls how much to print: 0 for normal
  * level of detail; 1 for debugging. */
 static void
 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
 {
-    int i, gens;
-    int fpu_state[27];
+    generation_index_t i, gens;
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+#define FPU_STATE_SIZE 27
+    int fpu_state[FPU_STATE_SIZE];
+#elif defined(LISP_FEATURE_PPC)
+#define FPU_STATE_SIZE 32
+    long long fpu_state[FPU_STATE_SIZE];
+#endif
 
     /* This code uses the FP instructions which may be set up for Lisp
      * so they need to be saved and reset for C. */
     fpu_save(fpu_state);
 
-    /* number of generations to print */
+    /* highest generation to print */
     if (verbose)
-        gens = NUM_GENERATIONS+1;
+        gens = SCRATCH_GENERATION;
     else
-        gens = NUM_GENERATIONS;
+        gens = PSEUDO_STATIC_GENERATION;
 
     /* Print the heap stats. */
     fprintf(stderr,
-            "   Gen Boxed Unboxed LB   LUB  !move  Alloc  Waste   Trig    WP  GCs Mem-age\n");
+            " Gen StaPg UbSta LaSta LUbSt Boxed Unboxed LB   LUB  !move  Alloc  Waste   Trig    WP  GCs Mem-age\n");
 
     for (i = 0; i < gens; i++) {
-        int j;
-        int boxed_cnt = 0;
-        int unboxed_cnt = 0;
-        int large_boxed_cnt = 0;
-        int large_unboxed_cnt = 0;
-        int pinned_cnt=0;
+        page_index_t j;
+        long boxed_cnt = 0;
+        long unboxed_cnt = 0;
+        long large_boxed_cnt = 0;
+        long large_unboxed_cnt = 0;
+        long pinned_cnt=0;
 
         for (j = 0; j < last_free_page; j++)
             if (page_table[j].gen == i) {
@@ -400,13 +422,19 @@ print_generation_stats(int verbose) /* FIXME: should take FILE argument */
         gc_assert(generations[i].bytes_allocated
                   == count_generation_bytes_allocated(i));
         fprintf(stderr,
-                "   %1d: %5d %5d %5d %5d %5d %8ld %5ld %8ld %4ld %3d %7.4f\n",
+                "   %1d: %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %8ld %5ld %8ld %4ld %3d %7.4f\n",
                 i,
-                boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
+                generations[i].alloc_start_page,
+                generations[i].alloc_unboxed_start_page,
+                generations[i].alloc_large_start_page,
+                generations[i].alloc_large_unboxed_start_page,
+                boxed_cnt,
+                unboxed_cnt,
+                large_boxed_cnt,
+                large_unboxed_cnt,
                 pinned_cnt,
                 generations[i].bytes_allocated,
-                (count_generation_pages(i)*PAGE_BYTES
-                 - generations[i].bytes_allocated),
+                (count_generation_pages(i)*PAGE_BYTES - generations[i].bytes_allocated),
                 generations[i].gc_trigger,
                 count_write_protect_generation_pages(i),
                 generations[i].num_gc,
@@ -417,9 +445,70 @@ print_generation_stats(int verbose) /* FIXME: should take FILE argument */
     fpu_restore(fpu_state);
 }
 \f
-/*
- * allocation routines
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+void fast_bzero(void*, size_t); /* in <arch>-assem.S */
+#endif
+
+/* Zero the pages from START to END (inclusive), but use mmap/munmap instead
+ * if zeroing it ourselves, i.e. in practice give the memory back to the
+ * OS. Generally done after a large GC.
  */
+void zero_pages_with_mmap(page_index_t start, page_index_t end) {
+    int i;
+    void *addr = (void *) page_address(start), *new_addr;
+    size_t length = PAGE_BYTES*(1+end-start);
+
+    if (start > end)
+      return;
+
+    os_invalidate(addr, length);
+    new_addr = os_validate(addr, length);
+    if (new_addr == NULL || new_addr != addr) {
+        lose("remap_free_pages: page moved, 0x%08x ==> 0x%08x", start, new_addr);
+    }
+
+    for (i = start; i <= end; i++) {
+        page_table[i].need_to_zero = 0;
+    }
+}
+
+/* Zero the pages from START to END (inclusive). Generally done just after
+ * a new region has been allocated.
+ */
+static void
+zero_pages(page_index_t start, page_index_t end) {
+    if (start > end)
+      return;
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+    fast_bzero(page_address(start), PAGE_BYTES*(1+end-start));
+#else
+    bzero(page_address(start), PAGE_BYTES*(1+end-start));
+#endif
+
+}
+
+/* Zero the pages from START to END (inclusive), except for those
+ * pages that are known to already zeroed. Mark all pages in the
+ * ranges as non-zeroed.
+ */
+static void
+zero_dirty_pages(page_index_t start, page_index_t end) {
+    page_index_t i;
+
+    for (i = start; i <= end; i++) {
+        if (page_table[i].need_to_zero == 1) {
+            zero_pages(start, end);
+            break;
+        }
+    }
+
+    for (i = start; i <= end; i++) {
+        page_table[i].need_to_zero = 1;
+    }
+}
+
 
 /*
  * To support quick and inline allocation, regions of memory can be
@@ -473,7 +562,7 @@ struct alloc_region boxed_region;
 struct alloc_region unboxed_region;
 
 /* The generation currently being allocated to. */
-static int gc_alloc_generation;
+static generation_index_t gc_alloc_generation;
 
 /* Find a new region with room for at least the given number of bytes.
  *
@@ -501,10 +590,11 @@ static int gc_alloc_generation;
 static void
 gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
 {
-    long first_page;
-    long last_page;
+    page_index_t first_page;
+    page_index_t last_page;
     long bytes_found;
-    long i;
+    page_index_t i;
+    int ret;
 
     /*
     FSHOW((stderr,
@@ -516,7 +606,8 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
     gc_assert((alloc_region->first_page == 0)
               && (alloc_region->last_page == -1)
               && (alloc_region->free_pointer == alloc_region->end_addr));
-    get_spinlock(&free_pages_lock,(long) alloc_region);
+    ret = thread_mutex_lock(&free_pages_lock);
+    gc_assert(ret == 0);
     if (unboxed) {
         first_page =
             generations[gc_alloc_generation].alloc_unboxed_start_page;
@@ -574,11 +665,11 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
     /* Bump up last_free_page. */
     if (last_page+1 > last_free_page) {
         last_free_page = last_page+1;
-        SetSymbolValue(ALLOCATION_POINTER,
-                       (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
-                       0);
+        /* do we only want to call this on special occasions? like for boxed_region? */
+        set_alloc_pointer((lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES));
     }
-    release_spinlock(&free_pages_lock);
+    ret = thread_mutex_unlock(&free_pages_lock);
+    gc_assert(ret == 0);
 
     /* we can do this after releasing free_pages_lock */
     if (gencgc_zero_check) {
@@ -590,11 +681,26 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
                  * (long) in code like this, so that it is less likely to
                  * break randomly when running on a machine with different
                  * word sizes. -- WHN 19991129 */
-                lose("The new region at %x is not zero.", p);
+                lose("The new region at %x is not zero.\n", p);
             }
+        }
+    }
+
+#ifdef READ_PROTECT_FREE_PAGES
+    os_protect(page_address(first_page),
+               PAGE_BYTES*(1+last_page-first_page),
+               OS_VM_PROT_ALL);
+#endif
+
+    /* If the first page was only partial, don't check whether it's
+     * zeroed (it won't be) and don't zero it (since the parts that
+     * we're interested in are guaranteed to be zeroed).
+     */
+    if (page_table[first_page].bytes_used) {
+        first_page++;
     }
-}
 
+    zero_dirty_pages(first_page, last_page);
 }
 
 /* If the record_new_objects flag is 2 then all new regions created
@@ -614,9 +720,9 @@ gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
  * scavenge of a generation. */
 #define NUM_NEW_AREAS 512
 static int record_new_objects = 0;
-static long new_areas_ignore_page;
+static page_index_t new_areas_ignore_page;
 struct new_area {
-    long  page;
+    page_index_t page;
     long  offset;
     long  size;
 };
@@ -626,9 +732,9 @@ long max_new_areas;
 
 /* Add a new area to new_areas. */
 static void
-add_new_area(long first_page, long offset, long size)
+add_new_area(page_index_t first_page, long offset, long size)
 {
-    unsigned new_area_start,c;
+    unsigned long new_area_start,c;
     long i;
 
     /* Ignore if full. */
@@ -653,7 +759,7 @@ add_new_area(long first_page, long offset, long size)
     /* Search backwards for a prior area that this follows from. If
        found this will save adding a new area. */
     for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
-        unsigned area_end =
+        unsigned long area_end =
             PAGE_BYTES*((*new_areas)[i].page)
             + (*new_areas)[i].offset
             + (*new_areas)[i].size;
@@ -698,13 +804,14 @@ add_new_area(long first_page, long offset, long size)
 void
 gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
 {
-    long more;
-    long first_page;
-    long next_page;
-    long bytes_used;
+    int more;
+    page_index_t first_page;
+    page_index_t next_page;
+    int bytes_used;
     long orig_first_page_bytes_used;
     long region_size;
     long byte_cnt;
+    int ret;
 
 
     first_page = alloc_region->first_page;
@@ -715,7 +822,8 @@ gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
 
     next_page = first_page+1;
 
-    get_spinlock(&free_pages_lock,(long) alloc_region);
+    ret = thread_mutex_lock(&free_pages_lock);
+    gc_assert(ret == 0);
     if (alloc_region->free_pointer != alloc_region->start_addr) {
         /* some bytes were allocated in the region */
         orig_first_page_bytes_used = page_table[first_page].bytes_used;
@@ -819,7 +927,9 @@ gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
         page_table[next_page].allocated = FREE_PAGE_FLAG;
         next_page++;
     }
-    release_spinlock(&free_pages_lock);
+    ret = thread_mutex_unlock(&free_pages_lock);
+    gc_assert(ret == 0);
+
     /* alloc_region is per-thread, we're ok to do this unlocked */
     gc_set_region_empty(alloc_region);
 }
@@ -830,15 +940,17 @@ static inline void *gc_quick_alloc(long nbytes);
 void *
 gc_alloc_large(long nbytes, int unboxed, struct alloc_region *alloc_region)
 {
-    long first_page;
-    long last_page;
-    long orig_first_page_bytes_used;
+    page_index_t first_page;
+    page_index_t last_page;
+    int orig_first_page_bytes_used;
     long byte_cnt;
-    long more;
+    int more;
     long bytes_used;
-    long next_page;
+    page_index_t next_page;
+    int ret;
 
-    get_spinlock(&free_pages_lock,(long) alloc_region);
+    ret = thread_mutex_lock(&free_pages_lock);
+    gc_assert(ret == 0);
 
     if (unboxed) {
         first_page =
@@ -936,30 +1048,70 @@ gc_alloc_large(long nbytes, int unboxed, struct alloc_region *alloc_region)
     /* Bump up last_free_page */
     if (last_page+1 > last_free_page) {
         last_free_page = last_page+1;
-        SetSymbolValue(ALLOCATION_POINTER,
-                       (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
+        set_alloc_pointer((lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES));
     }
-    release_spinlock(&free_pages_lock);
+    ret = thread_mutex_unlock(&free_pages_lock);
+    gc_assert(ret == 0);
+
+#ifdef READ_PROTECT_FREE_PAGES
+    os_protect(page_address(first_page),
+               PAGE_BYTES*(1+last_page-first_page),
+               OS_VM_PROT_ALL);
+#endif
 
-    return((void *)(page_address(first_page)+orig_first_page_bytes_used));
+    zero_dirty_pages(first_page, last_page);
+
+    return page_address(first_page);
 }
 
-long
-gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed)
+static page_index_t gencgc_alloc_start_page = -1;
+
+void
+gc_heap_exhausted_error_or_lose (long available, long requested)
+{
+    /* Write basic information before doing anything else: if we don't
+     * call to lisp this is a must, and even if we do there is always the
+     * danger that we bounce back here before the error has been handled,
+     * or indeed even printed.
+     */
+    fprintf(stderr, "Heap exhausted during %s: %ld bytes available, %ld requested.\n",
+            gc_active_p ? "garbage collection" : "allocation", available, requested);
+    if (gc_active_p || (available == 0)) {
+        /* If we are in GC, or totally out of memory there is no way
+         * to sanely transfer control to the lisp-side of things.
+         */
+        print_generation_stats(1);
+        lose("Heap exhausted, game over.");
+    }
+    else {
+        /* FIXME: assert free_pages_lock held */
+        thread_mutex_unlock(&free_pages_lock);
+        funcall2(SymbolFunction(HEAP_EXHAUSTED_ERROR),
+                 make_fixnum(available), make_fixnum(requested));
+        lose("HEAP-EXHAUSTED-ERROR fell through");
+    }
+}
+
+page_index_t
+gc_find_freeish_pages(page_index_t *restart_page_ptr, long nbytes, int unboxed)
 {
-    long first_page;
-    long last_page;
+    page_index_t first_page;
+    page_index_t last_page;
     long region_size;
-    long restart_page=*restart_page_ptr;
+    page_index_t restart_page=*restart_page_ptr;
     long bytes_found;
     long num_pages;
-    long large_p=(nbytes>=large_object_size);
-    gc_assert(free_pages_lock);
+    int large_p=(nbytes>=large_object_size);
+    /* FIXME: assert(free_pages_lock is held); */
 
     /* Search for a contiguous free space of at least nbytes. If it's
      * a large object then align it on a page boundary by searching
      * for a free page. */
 
+    if (gencgc_alloc_start_page != -1) {
+        restart_page = gencgc_alloc_start_page;
+    }
+
     do {
         first_page = restart_page;
         if (large_p)
@@ -982,13 +1134,8 @@ gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed)
                 first_page++;
             }
 
-        if (first_page >= NUM_PAGES) {
-            fprintf(stderr,
-                    "Argh! gc_find_free_space failed (first_page), nbytes=%ld.\n",
-                    nbytes);
-            print_generation_stats(1);
-            lose(NULL);
-        }
+        if (first_page >= NUM_PAGES)
+            gc_heap_exhausted_error_or_lose(0, nbytes);
 
         gc_assert(page_table[first_page].write_protected == 0);
 
@@ -1013,14 +1160,11 @@ gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed)
     } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
 
     /* Check for a failure */
-    if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
-        fprintf(stderr,
-                "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%ld.\n",
-                nbytes);
-        print_generation_stats(1);
-        lose(NULL);
-    }
+    if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes))
+        gc_heap_exhausted_error_or_lose(bytes_found, nbytes);
+
     *restart_page_ptr=first_page;
+
     return last_page;
 }
 
@@ -1129,7 +1273,7 @@ copy_large_object(lispobj object, long nwords)
 {
     int tag;
     lispobj *new;
-    long first_page;
+    page_index_t first_page;
 
     gc_assert(is_lisp_pointer(object));
     gc_assert(from_space_p(object));
@@ -1145,7 +1289,7 @@ copy_large_object(lispobj object, long nwords)
         /* Promote the object. */
 
         long remaining_bytes;
-        long next_page;
+        page_index_t next_page;
         long bytes_freed;
         long old_bytes_used;
 
@@ -1277,7 +1421,7 @@ copy_large_unboxed_object(lispobj object, long nwords)
 {
     int tag;
     lispobj *new;
-    long first_page;
+    page_index_t first_page;
 
     gc_assert(is_lisp_pointer(object));
     gc_assert(from_space_p(object));
@@ -1295,7 +1439,7 @@ copy_large_unboxed_object(lispobj object, long nwords)
          * allocated to a BOXED region so it may be necessary to
          * change the region to UNBOXED. */
         long remaining_bytes;
-        long next_page;
+        page_index_t next_page;
         long bytes_freed;
         long old_bytes_used;
 
@@ -1403,11 +1547,12 @@ static lispobj trans_boxed(lispobj object);
  * Currently only absolute fixups to the constant vector, or to the
  * code area are checked. */
 void
-sniff_code_object(struct code *code, unsigned displacement)
+sniff_code_object(struct code *code, unsigned long displacement)
 {
+#ifdef LISP_FEATURE_X86
     long nheader_words, ncode_words, nwords;
     void *p;
-    void *constants_start_addr, *constants_end_addr;
+    void *constants_start_addr = NULL, *constants_end_addr;
     void *code_start_addr, *code_end_addr;
     int fixup_found = 0;
 
@@ -1570,16 +1715,19 @@ sniff_code_object(struct code *code, unsigned displacement)
                "/code start = %x, end = %x\n",
                code_start_addr, code_end_addr));
     }
+#endif
 }
 
 void
 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
 {
+/* x86-64 uses pc-relative addressing instead of this kludge */
+#ifndef LISP_FEATURE_X86_64
     long nheader_words, ncode_words, nwords;
     void *constants_start_addr, *constants_end_addr;
     void *code_start_addr, *code_end_addr;
     lispobj fixups = NIL;
-    unsigned displacement = (unsigned)new_code - (unsigned)old_code;
+    unsigned long displacement = (unsigned long)new_code - (unsigned long)old_code;
     struct vector *fixups_vector;
 
     ncode_words = fixnum_value(new_code->code_size);
@@ -1638,23 +1786,23 @@ gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
         long length = fixnum_value(fixups_vector->length);
         long i;
         for (i = 0; i < length; i++) {
-            unsigned offset = fixups_vector->data[i];
+            unsigned long offset = fixups_vector->data[i];
             /* Now check the current value of offset. */
-            unsigned old_value =
-                *(unsigned *)((unsigned)code_start_addr + offset);
+            unsigned long old_value =
+                *(unsigned long *)((unsigned long)code_start_addr + offset);
 
             /* If it's within the old_code object then it must be an
              * absolute fixup (relative ones are not saved) */
-            if ((old_value >= (unsigned)old_code)
-                && (old_value < ((unsigned)old_code + nwords*N_WORD_BYTES)))
+            if ((old_value >= (unsigned long)old_code)
+                && (old_value < ((unsigned long)old_code + nwords*N_WORD_BYTES)))
                 /* So add the dispacement. */
-                *(unsigned *)((unsigned)code_start_addr + offset) =
+                *(unsigned long *)((unsigned long)code_start_addr + offset) =
                     old_value + displacement;
             else
                 /* It is outside the old code object so it must be a
                  * relative fixup (absolute fixups are not saved). So
                  * subtract the displacement. */
-                *(unsigned *)((unsigned)code_start_addr + offset) =
+                *(unsigned long *)((unsigned long)code_start_addr + offset) =
                     old_value - displacement;
         }
     } else {
@@ -1665,6 +1813,7 @@ gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
     if (check_code_fixups) {
         sniff_code_object(new_code,displacement);
     }
+#endif
 }
 
 
@@ -1691,7 +1840,6 @@ trans_unboxed_large(lispobj object)
     lispobj header;
     unsigned long length;
 
-
     gc_assert(is_lisp_pointer(object));
 
     header = *((lispobj *) native_pointer(object));
@@ -1704,219 +1852,176 @@ trans_unboxed_large(lispobj object)
 
 \f
 /*
- * vector-like objects
+ * Lutexes. Using the normal finalization machinery for finalizing
+ * lutexes is tricky, since the finalization depends on working lutexes.
+ * So we track the lutexes in the GC and finalize them manually.
  */
 
+#if defined(LUTEX_WIDETAG)
 
-/* FIXME: What does this mean? */
-int gencgc_hash = 1;
+/*
+ * Start tracking LUTEX in the GC, by adding it to the linked list of
+ * lutexes in the nursery generation. The caller is responsible for
+ * locking, and GCs must be inhibited until the registration is
+ * complete.
+ */
+void
+gencgc_register_lutex (struct lutex *lutex) {
+    int index = find_page_index(lutex);
+    generation_index_t gen;
+    struct lutex *head;
 
-static long
-scav_vector(lispobj *where, lispobj object)
-{
-    unsigned long kv_length;
-    lispobj *kv_vector;
-    unsigned long length = 0; /* (0 = dummy to stop GCC warning) */
-    struct hash_table *hash_table;
-    lispobj empty_symbol;
-    unsigned long *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
-    unsigned long *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
-    unsigned long *hash_vector = NULL; /* (NULL = dummy to stop GCC warning) */
-    lispobj weak_p_obj;
-    unsigned next_vector_length = 0;
-
-    /* FIXME: A comment explaining this would be nice. It looks as
-     * though SB-VM:VECTOR-VALID-HASHING-SUBTYPE is set for EQ-based
-     * hash tables in the Lisp HASH-TABLE code, and nowhere else. */
-    if (HeaderValue(object) != subtype_VectorValidHashing)
-        return 1;
+    /* This lutex is in static space, so we don't need to worry about
+     * finalizing it.
+     */
+    if (index == -1)
+        return;
 
-    if (!gencgc_hash) {
-        /* This is set for backward compatibility. FIXME: Do we need
-         * this any more? */
-        *where =
-            (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
-        return 1;
-    }
+    gen = page_table[index].gen;
 
-    kv_length = fixnum_value(where[1]);
-    kv_vector = where + 2;  /* Skip the header and length. */
-    /*FSHOW((stderr,"/kv_length = %d\n", kv_length));*/
+    gc_assert(gen >= 0);
+    gc_assert(gen < NUM_GENERATIONS);
 
-    /* Scavenge element 0, which may be a hash-table structure. */
-    scavenge(where+2, 1);
-    if (!is_lisp_pointer(where[2])) {
-        lose("no pointer at %x in hash table", where[2]);
-    }
-    hash_table = (struct hash_table *)native_pointer(where[2]);
-    /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
-    if (widetag_of(hash_table->header) != INSTANCE_HEADER_WIDETAG) {
-        lose("hash table not instance (%x at %x)",
-             hash_table->header,
-             hash_table);
-    }
+    head = generations[gen].lutexes;
 
-    /* Scavenge element 1, which should be some internal symbol that
-     * the hash table code reserves for marking empty slots. */
-    scavenge(where+3, 1);
-    if (!is_lisp_pointer(where[3])) {
-        lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
-    }
-    empty_symbol = where[3];
-    /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
-    if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
-        SYMBOL_HEADER_WIDETAG) {
-        lose("not a symbol where empty-hash-table-slot symbol expected: %x",
-             *(lispobj *)native_pointer(empty_symbol));
-    }
+    lutex->gen = gen;
+    lutex->next = head;
+    lutex->prev = NULL;
+    if (head)
+        head->prev = lutex;
+    generations[gen].lutexes = lutex;
+}
 
-    /* Scavenge hash table, which will fix the positions of the other
-     * needed objects. */
-    scavenge((lispobj *)hash_table,
-             sizeof(struct hash_table) / sizeof(lispobj));
+/*
+ * Stop tracking LUTEX in the GC by removing it from the appropriate
+ * linked lists. This will only be called during GC, so no locking is
+ * needed.
+ */
+void
+gencgc_unregister_lutex (struct lutex *lutex) {
+    if (lutex->prev) {
+        lutex->prev->next = lutex->next;
+    } else {
+        generations[lutex->gen].lutexes = lutex->next;
+    }
 
-    /* Cross-check the kv_vector. */
-    if (where != (lispobj *)native_pointer(hash_table->table)) {
-        lose("hash_table table!=this table %x", hash_table->table);
+    if (lutex->next) {
+        lutex->next->prev = lutex->prev;
     }
 
-    /* WEAK-P */
-    weak_p_obj = hash_table->weak_p;
+    lutex->next = NULL;
+    lutex->prev = NULL;
+    lutex->gen = -1;
+}
 
-    /* index vector */
-    {
-        lispobj index_vector_obj = hash_table->index_vector;
-
-        if (is_lisp_pointer(index_vector_obj) &&
-            (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
-                 SIMPLE_ARRAY_WORD_WIDETAG)) {
-            index_vector =
-                ((unsigned long *)native_pointer(index_vector_obj)) + 2;
-            /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
-            length = fixnum_value(((lispobj *)native_pointer(index_vector_obj))[1]);
-            /*FSHOW((stderr, "/length = %d\n", length));*/
-        } else {
-            lose("invalid index_vector %x", index_vector_obj);
-        }
+/*
+ * Mark all lutexes in generation GEN as not live.
+ */
+static void
+unmark_lutexes (generation_index_t gen) {
+    struct lutex *lutex = generations[gen].lutexes;
+
+    while (lutex) {
+        lutex->live = 0;
+        lutex = lutex->next;
     }
+}
 
-    /* next vector */
-    {
-        lispobj next_vector_obj = hash_table->next_vector;
-
-        if (is_lisp_pointer(next_vector_obj) &&
-            (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
-             SIMPLE_ARRAY_WORD_WIDETAG)) {
-            next_vector = ((unsigned long *)native_pointer(next_vector_obj)) + 2;
-            /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
-            next_vector_length = fixnum_value(((lispobj *)native_pointer(next_vector_obj))[1]);
-            /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
-        } else {
-            lose("invalid next_vector %x", next_vector_obj);
+/*
+ * Finalize all lutexes in generation GEN that have not been marked live.
+ */
+static void
+reap_lutexes (generation_index_t gen) {
+    struct lutex *lutex = generations[gen].lutexes;
+
+    while (lutex) {
+        struct lutex *next = lutex->next;
+        if (!lutex->live) {
+            lutex_destroy(lutex);
+            gencgc_unregister_lutex(lutex);
         }
+        lutex = next;
     }
+}
 
-    /* maybe hash vector */
-    {
-        lispobj hash_vector_obj = hash_table->hash_vector;
-
-        if (is_lisp_pointer(hash_vector_obj) &&
-            (widetag_of(*(lispobj *)native_pointer(hash_vector_obj)) ==
-             SIMPLE_ARRAY_WORD_WIDETAG)){
-            hash_vector =
-                ((unsigned long *)native_pointer(hash_vector_obj)) + 2;
-            /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
-            gc_assert(fixnum_value(((lispobj *)native_pointer(hash_vector_obj))[1])
-                      == next_vector_length);
-        } else {
-            hash_vector = NULL;
-            /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
-        }
+/*
+ * Mark LUTEX as live.
+ */
+static void
+mark_lutex (lispobj tagged_lutex) {
+    struct lutex *lutex = (struct lutex*) native_pointer(tagged_lutex);
+
+    lutex->live = 1;
+}
+
+/*
+ * Move all lutexes in generation FROM to generation TO.
+ */
+static void
+move_lutexes (generation_index_t from, generation_index_t to) {
+    struct lutex *tail = generations[from].lutexes;
+
+    /* Nothing to move */
+    if (!tail)
+        return;
+
+    /* Change the generation of the lutexes in FROM. */
+    while (tail->next) {
+        tail->gen = to;
+        tail = tail->next;
     }
+    tail->gen = to;
 
-    /* These lengths could be different as the index_vector can be a
-     * different length from the others, a larger index_vector could help
-     * reduce collisions. */
-    gc_assert(next_vector_length*2 == kv_length);
+    /* Link the last lutex in the FROM list to the start of the TO list */
+    tail->next = generations[to].lutexes;
 
-    /* now all set up.. */
+    /* And vice versa */
+    if (generations[to].lutexes) {
+        generations[to].lutexes->prev = tail;
+    }
 
-    /* Work through the KV vector. */
-    {
-        long i;
-        for (i = 1; i < next_vector_length; i++) {
-            lispobj old_key = kv_vector[2*i];
+    /* And update the generations structures to match this */
+    generations[to].lutexes = generations[from].lutexes;
+    generations[from].lutexes = NULL;
+}
 
-#if N_WORD_BITS == 32
-            unsigned long old_index = (old_key & 0x1fffffff)%length;
-#elif N_WORD_BITS == 64
-            unsigned long old_index = (old_key & 0x1fffffffffffffff)%length;
-#endif
+static long
+scav_lutex(lispobj *where, lispobj object)
+{
+    mark_lutex((lispobj) where);
 
-            /* Scavenge the key and value. */
-            scavenge(&kv_vector[2*i],2);
+    return CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
+}
 
-            /* Check whether the key has moved and is EQ based. */
-            {
-                lispobj new_key = kv_vector[2*i];
-#if N_WORD_BITS == 32
-                unsigned long new_index = (new_key & 0x1fffffff)%length;
-#elif N_WORD_BITS == 64
-                unsigned long new_index = (new_key & 0x1fffffffffffffff)%length;
-#endif
+static lispobj
+trans_lutex(lispobj object)
+{
+    struct lutex *lutex = native_pointer(object);
+    lispobj copied;
+    size_t words = CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
+    gc_assert(is_lisp_pointer(object));
+    copied = copy_object(object, words);
 
-                if ((old_index != new_index) &&
-                    ((!hash_vector) ||
-                     (hash_vector[i] == MAGIC_HASH_VECTOR_VALUE)) &&
-                    ((new_key != empty_symbol) ||
-                     (kv_vector[2*i] != empty_symbol))) {
-
-                     /*FSHOW((stderr,
-                            "* EQ key %d moved from %x to %x; index %d to %d\n",
-                            i, old_key, new_key, old_index, new_index));*/
-
-                    if (index_vector[old_index] != 0) {
-                         /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
-
-                        /* Unlink the key from the old_index chain. */
-                        if (index_vector[old_index] == i) {
-                            /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
-                            index_vector[old_index] = next_vector[i];
-                            /* Link it into the needing rehash chain. */
-                            next_vector[i] = fixnum_value(hash_table->needing_rehash);
-                            hash_table->needing_rehash = make_fixnum(i);
-                            /*SHOW("P2");*/
-                        } else {
-                            unsigned prior = index_vector[old_index];
-                            unsigned next = next_vector[prior];
-
-                            /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
-
-                            while (next != 0) {
-                                 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
-                                if (next == i) {
-                                    /* Unlink it. */
-                                    next_vector[prior] = next_vector[next];
-                                    /* Link it into the needing rehash
-                                     * chain. */
-                                    next_vector[next] =
-                                        fixnum_value(hash_table->needing_rehash);
-                                    hash_table->needing_rehash = make_fixnum(next);
-                                    /*SHOW("/P3");*/
-                                    break;
-                                }
-                                prior = next;
-                                next = next_vector[next];
-                            }
-                        }
-                    }
-                }
-            }
-        }
+    /* Update the links, since the lutex moved in memory. */
+    if (lutex->next) {
+        lutex->next->prev = native_pointer(copied);
     }
-    return (CEILING(kv_length + 2, 2));
+
+    if (lutex->prev) {
+        lutex->prev->next = native_pointer(copied);
+    } else {
+        generations[lutex->gen].lutexes = native_pointer(copied);
+    }
+
+    return copied;
 }
 
+static long
+size_lutex(lispobj *where)
+{
+    return CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
+}
+#endif /* LUTEX_WIDETAG */
 
 \f
 /*
@@ -1995,7 +2100,7 @@ search_static_space(void *pointer)
 lispobj *
 search_dynamic_space(void *pointer)
 {
-    long page_index = find_page_index(pointer);
+    page_index_t page_index = find_page_index(pointer);
     lispobj *start;
 
     /* The address may be invalid, so do some checks. */
@@ -2050,8 +2155,8 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
             break;
         case CLOSURE_HEADER_WIDETAG:
         case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
-            if ((unsigned)pointer !=
-                ((unsigned)start_addr+FUN_POINTER_LOWTAG)) {
+            if ((unsigned long)pointer !=
+                ((unsigned long)start_addr+FUN_POINTER_LOWTAG)) {
                 if (gencgc_verbose)
                     FSHOW((stderr,
                            "/Wf2: %x %x %x\n",
@@ -2068,8 +2173,8 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
         }
         break;
     case LIST_POINTER_LOWTAG:
-        if ((unsigned)pointer !=
-            ((unsigned)start_addr+LIST_POINTER_LOWTAG)) {
+        if ((unsigned long)pointer !=
+            ((unsigned long)start_addr+LIST_POINTER_LOWTAG)) {
             if (gencgc_verbose)
                 FSHOW((stderr,
                        "/Wl1: %x %x %x\n",
@@ -2100,8 +2205,8 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
             return 0;
         }
     case INSTANCE_POINTER_LOWTAG:
-        if ((unsigned)pointer !=
-            ((unsigned)start_addr+INSTANCE_POINTER_LOWTAG)) {
+        if ((unsigned long)pointer !=
+            ((unsigned long)start_addr+INSTANCE_POINTER_LOWTAG)) {
             if (gencgc_verbose)
                 FSHOW((stderr,
                        "/Wi1: %x %x %x\n",
@@ -2117,8 +2222,8 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
         }
         break;
     case OTHER_POINTER_LOWTAG:
-        if ((unsigned)pointer !=
-            ((int)start_addr+OTHER_POINTER_LOWTAG)) {
+        if ((unsigned long)pointer !=
+            ((unsigned long)start_addr+OTHER_POINTER_LOWTAG)) {
             if (gencgc_verbose)
                 FSHOW((stderr,
                        "/Wo1: %x %x %x\n",
@@ -2135,6 +2240,7 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
         }
         switch (widetag_of(start_addr[0])) {
         case UNBOUND_MARKER_WIDETAG:
+        case NO_TLS_VALUE_MARKER_WIDETAG:
         case CHARACTER_WIDETAG:
 #if N_WORD_BITS == 64
         case SINGLE_FLOAT_WIDETAG:
@@ -2255,6 +2361,9 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
 #endif
         case SAP_WIDETAG:
         case WEAK_POINTER_WIDETAG:
+#ifdef LUTEX_WIDETAG
+        case LUTEX_WIDETAG:
+#endif
             break;
 
         default:
@@ -2277,6 +2386,8 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
     return 1;
 }
 
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+
 /* Adjust large bignum and vector objects. This will adjust the
  * allocated region if the size has shrunk, and move unboxed objects
  * into unboxed pages. The pages are not promoted here, and the
@@ -2287,11 +2398,11 @@ possibly_valid_dynamic_space_pointer(lispobj *pointer)
 static void
 maybe_adjust_large_object(lispobj *where)
 {
-    long first_page;
+    page_index_t first_page;
+    page_index_t next_page;
     long nwords;
 
     long remaining_bytes;
-    long next_page;
     long bytes_freed;
     long old_bytes_used;
 
@@ -2451,6 +2562,8 @@ maybe_adjust_large_object(lispobj *where)
     return;
 }
 
+#endif
+
 /* Take a possible pointer to a Lisp object and mark its page in the
  * page_table so that it will not be relocated during a GC.
  *
@@ -2463,13 +2576,16 @@ maybe_adjust_large_object(lispobj *where)
  *
  * It is also assumed that the current gc_alloc() region has been
  * flushed and the tables updated. */
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+
 static void
 preserve_pointer(void *addr)
 {
-    long addr_page_index = find_page_index(addr);
-    long first_page;
-    long i;
-    unsigned region_allocation;
+    page_index_t addr_page_index = find_page_index(addr);
+    page_index_t first_page;
+    page_index_t i;
+    unsigned int region_allocation;
 
     /* quick check 1: Address is quite likely to have been invalid. */
     if ((addr_page_index == -1)
@@ -2487,7 +2603,7 @@ preserve_pointer(void *addr)
     /* quick check 2: Check the offset within the page.
      *
      */
-    if (((unsigned)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
+    if (((unsigned long)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
         return;
 
     /* Filter out anything which can't be a pointer to a Lisp object
@@ -2532,7 +2648,7 @@ preserve_pointer(void *addr)
         if ((page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
             || (page_table[addr_page_index].bytes_used == 0)
             /* Check the offset within the page. */
-            || (((unsigned)addr & (PAGE_BYTES - 1))
+            || (((unsigned long)addr & (PAGE_BYTES - 1))
                 > page_table[addr_page_index].bytes_used)) {
             FSHOW((stderr,
                    "weird? ignore ptr 0x%x to freed area of large object\n",
@@ -2578,6 +2694,9 @@ preserve_pointer(void *addr)
     /* Check that the page is now static. */
     gc_assert(page_table[addr_page_index].dont_move != 0);
 }
+
+#endif
+
 \f
 /* If the given page is not write-protected, then scan it for pointers
  * to younger generations or the top temp. generation, if no
@@ -2593,9 +2712,9 @@ preserve_pointer(void *addr)
  *
  * We return 1 if the page was write-protected, else 0. */
 static int
-update_page_write_prot(long page)
+update_page_write_prot(page_index_t page)
 {
-    int gen = page_table[page].gen;
+    generation_index_t gen = page_table[page].gen;
     long j;
     int wp_it = 1;
     void **page_addr = (void **)page_address(page);
@@ -2607,6 +2726,7 @@ update_page_write_prot(long page)
 
     /* Skip if it's already write-protected, pinned, or unboxed */
     if (page_table[page].write_protected
+        /* FIXME: What's the reason for not write-protecting pinned pages? */
         || page_table[page].dont_move
         || (page_table[page].allocated & UNBOXED_PAGE_FLAG))
         return (0);
@@ -2616,7 +2736,7 @@ update_page_write_prot(long page)
 
     for (j = 0; j < num_words; j++) {
         void *ptr = *(page_addr+j);
-        long index = find_page_index(ptr);
+        page_index_t index = find_page_index(ptr);
 
         /* Check that it's in the dynamic space */
         if (index != -1)
@@ -2624,7 +2744,7 @@ update_page_write_prot(long page)
                 ((page_table[index].allocated != FREE_PAGE_FLAG)
                  && (page_table[index].bytes_used != 0)
                  && ((page_table[index].gen < gen)
-                     || (page_table[index].gen == NUM_GENERATIONS)))
+                     || (page_table[index].gen == SCRATCH_GENERATION)))
 
                 /* Or does it point within a current gc_alloc() region? */
                 || ((boxed_region.start_addr <= ptr)
@@ -2651,11 +2771,9 @@ update_page_write_prot(long page)
     return (wp_it);
 }
 
-/* Scavenge a generation.
- *
- * This will not resolve all pointers when generation is the new
- * space, as new objects may be added which are not checked here - use
- * scavenge_newspace generation.
+/* Scavenge all generations from FROM to TO, inclusive, except for
+ * new_space which needs special handling, as new objects may be
+ * added which are not checked here - use scavenge_newspace generation.
  *
  * Write-protected pages should not have any pointers to the
  * from_space so do need scavenging; thus write-protected pages are
@@ -2683,9 +2801,9 @@ update_page_write_prot(long page)
  * pointers as the objects contain a link to the next and are written
  * if a weak pointer is scavenged. Still it's a useful check. */
 static void
-scavenge_generation(int generation)
+scavenge_generations(generation_index_t from, generation_index_t to)
 {
-    long i;
+    page_index_t i;
     int num_wp = 0;
 
 #define SC_GEN_CK 0
@@ -2696,10 +2814,13 @@ scavenge_generation(int generation)
 #endif
 
     for (i = 0; i < last_free_page; i++) {
+        generation_index_t generation = page_table[i].gen;
         if ((page_table[i].allocated & BOXED_PAGE_FLAG)
             && (page_table[i].bytes_used != 0)
-            && (page_table[i].gen == generation)) {
-            long last_page,j;
+            && (generation != new_space)
+            && (generation >= from)
+            && (generation <= to)) {
+            page_index_t last_page,j;
             int write_protected=1;
 
             /* This should be the start of a region */
@@ -2729,15 +2850,15 @@ scavenge_generation(int generation)
                         num_wp += update_page_write_prot(j);
                     }
                 }
+                if ((gencgc_verbose > 1) && (num_wp != 0)) {
+                    FSHOW((stderr,
+                           "/write protected %d pages within generation %d\n",
+                           num_wp, generation));
+                }
             }
             i = last_page;
         }
     }
-    if ((gencgc_verbose > 1) && (num_wp != 0)) {
-        FSHOW((stderr,
-               "/write protected %d pages within generation %d\n",
-               num_wp, generation));
-    }
 
 #if SC_GEN_CK
     /* Check that none of the write_protected pages in this generation
@@ -2753,7 +2874,7 @@ scavenge_generation(int generation)
                     page_table[i].bytes_used,
                     page_table[i].first_object_offset,
                     page_table[i].dont_move));
-            lose("write to protected page %d in scavenge_generation()", i);
+            lose("write to protected page %d in scavenge_generation()\n", i);
         }
     }
 #endif
@@ -2788,9 +2909,9 @@ static struct new_area new_areas_2[NUM_NEW_AREAS];
  * complete the job as new objects may be added to the generation in
  * the process which are not scavenged. */
 static void
-scavenge_newspace_generation_one_scan(int generation)
+scavenge_newspace_generation_one_scan(generation_index_t generation)
 {
-    long i;
+    page_index_t i;
 
     FSHOW((stderr,
            "/starting one full scan of newspace generation %d\n",
@@ -2804,7 +2925,7 @@ scavenge_newspace_generation_one_scan(int generation)
                 /* (This may be redundant as write_protected is now
                  * cleared before promotion.) */
                 || (page_table[i].dont_move == 1))) {
-            long last_page;
+            page_index_t last_page;
             int all_wp=1;
 
             /* The scavenge will start at the first_object_offset of page i.
@@ -2856,7 +2977,7 @@ scavenge_newspace_generation_one_scan(int generation)
 
 /* Do a complete scavenge of the newspace generation. */
 static void
-scavenge_newspace_generation(int generation)
+scavenge_newspace_generation(generation_index_t generation)
 {
     long i;
 
@@ -2885,6 +3006,13 @@ scavenge_newspace_generation(int generation)
     /* Record all new areas now. */
     record_new_objects = 2;
 
+    /* Give a chance to weak hash tables to make other objects live.
+     * FIXME: The algorithm implemented here for weak hash table gcing
+     * is O(W^2+N) as Bruno Haible warns in
+     * http://www.haible.de/bruno/papers/cs/weak/WeakDatastructures-writeup.html
+     * see "Implementation 2". */
+    scav_weak_hash_tables();
+
     /* Flush the current regions updating the tables. */
     gc_alloc_update_all_page_tables();
 
@@ -2923,8 +3051,8 @@ scavenge_newspace_generation(int generation)
             if (gencgc_verbose)
                 SHOW("new_areas overflow, doing full scavenge");
 
-            /* Don't need to record new areas that get scavenge anyway
-             * during scavenge_newspace_generation_one_scan. */
+            /* Don't need to record new areas that get scavenged
+             * anyway during scavenge_newspace_generation_one_scan. */
             record_new_objects = 1;
 
             scavenge_newspace_generation_one_scan(generation);
@@ -2932,6 +3060,8 @@ scavenge_newspace_generation(int generation)
             /* Record all new areas now. */
             record_new_objects = 2;
 
+            scav_weak_hash_tables();
+
             /* Flush the current regions updating the tables. */
             gc_alloc_update_all_page_tables();
 
@@ -2946,6 +3076,8 @@ scavenge_newspace_generation(int generation)
                 scavenge(page_address(page)+offset, size);
             }
 
+            scav_weak_hash_tables();
+
             /* Flush the current regions updating the tables. */
             gc_alloc_update_all_page_tables();
         }
@@ -2969,7 +3101,7 @@ scavenge_newspace_generation(int generation)
             && (page_table[i].gen == generation)
             && (page_table[i].write_protected_cleared != 0)
             && (page_table[i].dont_move == 0)) {
-            lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
+            lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d\n",
                  i, generation, page_table[i].dont_move);
         }
     }
@@ -2984,7 +3116,7 @@ scavenge_newspace_generation(int generation)
 static void
 unprotect_oldspace(void)
 {
-    long i;
+    page_index_t i;
 
     for (i = 0; i < last_free_page; i++) {
         if ((page_table[i].allocated != FREE_PAGE_FLAG)
@@ -3012,7 +3144,7 @@ static long
 free_oldspace(void)
 {
     long bytes_freed = 0;
-    long first_page, last_page;
+    page_index_t first_page, last_page;
 
     first_page = 0;
 
@@ -3055,31 +3187,12 @@ free_oldspace(void)
                && (page_table[last_page].bytes_used != 0)
                && (page_table[last_page].gen == from_space));
 
-        /* Zero pages from first_page to (last_page-1).
-         *
-         * FIXME: Why not use os_zero(..) function instead of
-         * hand-coding this again? (Check other gencgc_unmap_zero
-         * stuff too. */
-        if (gencgc_unmap_zero) {
-            void *page_start, *addr;
-
-            page_start = (void *)page_address(first_page);
-
-            os_invalidate(page_start, PAGE_BYTES*(last_page-first_page));
-            addr = os_validate(page_start, PAGE_BYTES*(last_page-first_page));
-            if (addr == NULL || addr != page_start) {
-                lose("free_oldspace: page moved, 0x%08x ==> 0x%08x",page_start,
-                     addr);
-            }
-        } else {
-            long *page_start;
-
-            page_start = (long *)page_address(first_page);
-            memset(page_start, 0,PAGE_BYTES*(last_page-first_page));
-        }
-
+#ifdef READ_PROTECT_FREE_PAGES
+        os_protect(page_address(first_page),
+                   PAGE_BYTES*(last_page-first_page),
+                   OS_VM_PROT_NONE);
+#endif
         first_page = last_page;
-
     } while (first_page < last_free_page);
 
     bytes_allocated -= bytes_freed;
@@ -3092,7 +3205,7 @@ static void
 print_ptr(lispobj *addr)
 {
     /* If addr is in the dynamic space then out the page information. */
-    long pi1 = find_page_index((void*)addr);
+    page_index_t pi1 = find_page_index((void*)addr);
 
     if (pi1 != -1)
         fprintf(stderr,"  %x: page %d  alloc %d  gen %d  bytes_used %d  offset %d  dont_move %d\n",
@@ -3116,22 +3229,20 @@ print_ptr(lispobj *addr)
 }
 #endif
 
-extern long undefined_tramp;
-
 static void
 verify_space(lispobj *start, size_t words)
 {
     int is_in_dynamic_space = (find_page_index((void*)start) != -1);
     int is_in_readonly_space =
-        (READ_ONLY_SPACE_START <= (unsigned)start &&
-         (unsigned)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
+        (READ_ONLY_SPACE_START <= (unsigned long)start &&
+         (unsigned long)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
 
     while (words > 0) {
         size_t count = 1;
         lispobj thing = *(lispobj*)start;
 
         if (is_lisp_pointer(thing)) {
-            long page_index = find_page_index((void*)thing);
+            page_index_t page_index = find_page_index((void*)thing);
             long to_readonly_space =
                 (READ_ONLY_SPACE_START <= thing &&
                  thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
@@ -3145,15 +3256,15 @@ verify_space(lispobj *start, size_t words)
                  * page. XX Could check the offset too. */
                 if ((page_table[page_index].allocated != FREE_PAGE_FLAG)
                     && (page_table[page_index].bytes_used == 0))
-                    lose ("Ptr %x @ %x sees free page.", thing, start);
+                    lose ("Ptr %x @ %x sees free page.\n", thing, start);
                 /* Check that it doesn't point to a forwarding pointer! */
                 if (*((lispobj *)native_pointer(thing)) == 0x01) {
-                    lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
+                    lose("Ptr %x @ %x sees forwarding ptr.\n", thing, start);
                 }
                 /* Check that its not in the RO space as it would then be a
                  * pointer from the RO to the dynamic space. */
                 if (is_in_readonly_space) {
-                    lose("ptr to dynamic space %x from RO space %x",
+                    lose("ptr to dynamic space %x from RO space %x\n",
                          thing, start);
                 }
                 /* Does it point to a plausible object? This check slows
@@ -3167,14 +3278,13 @@ verify_space(lispobj *start, size_t words)
                  * dynamically. */
                 /*
                 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
-                    lose("ptr %x to invalid object %x", thing, start);
+                    lose("ptr %x to invalid object %x\n", thing, start);
                 }
                 */
             } else {
                 /* Verify that it points to another valid space. */
-                if (!to_readonly_space && !to_static_space
-                    && (thing != (unsigned)&undefined_tramp)) {
-                    lose("Ptr %x @ %x sees junk.", thing, start);
+                if (!to_readonly_space && !to_static_space) {
+                    lose("Ptr %x @ %x sees junk.\n", thing, start);
                 }
             }
         } else {
@@ -3204,11 +3314,24 @@ verify_space(lispobj *start, size_t words)
                 case SINGLE_FLOAT_WIDETAG:
 #endif
                 case UNBOUND_MARKER_WIDETAG:
-                case INSTANCE_HEADER_WIDETAG:
                 case FDEFN_WIDETAG:
                     count = 1;
                     break;
 
+                case INSTANCE_HEADER_WIDETAG:
+                    {
+                        lispobj nuntagged;
+                        long ntotal = HeaderValue(thing);
+                        lispobj layout = ((struct instance *)start)->slots[0];
+                        if (!layout) {
+                            count = 1;
+                            break;
+                        }
+                        nuntagged = ((struct layout *)native_pointer(layout))->n_untagged_slots;
+                        verify_space(start + 1, ntotal - fixnum_value(nuntagged));
+                        count = ntotal + 1;
+                        break;
+                    }
                 case CODE_HEADER_WIDETAG:
                     {
                         lispobj object = *start;
@@ -3341,10 +3464,17 @@ verify_space(lispobj *start, size_t words)
 #endif
                 case SAP_WIDETAG:
                 case WEAK_POINTER_WIDETAG:
+#ifdef LUTEX_WIDETAG
+                case LUTEX_WIDETAG:
+#endif
                     count = (sizetab[widetag_of(*start)])(start);
                     break;
 
                 default:
+                    FSHOW((stderr,
+                           "/Unhandled widetag 0x%x at 0x%x\n",
+                           widetag_of(*start), start));
+                    fflush(stderr);
                     gc_abort();
                 }
             }
@@ -3372,7 +3502,7 @@ verify_gc(void)
     struct thread *th;
     for_each_thread(th) {
     long binding_stack_size =
-            (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
+        (lispobj*)get_binding_stack_pointer(th)
             - (lispobj*)th->binding_stack_start;
         verify_space(th->binding_stack_start, binding_stack_size);
     }
@@ -3381,15 +3511,15 @@ verify_gc(void)
 }
 
 static void
-verify_generation(int  generation)
+verify_generation(generation_index_t generation)
 {
-    int i;
+    page_index_t i;
 
     for (i = 0; i < last_free_page; i++) {
         if ((page_table[i].allocated != FREE_PAGE_FLAG)
             && (page_table[i].bytes_used != 0)
             && (page_table[i].gen == generation)) {
-            long last_page;
+            page_index_t last_page;
             int region_allocation = page_table[i].allocated;
 
             /* This should be the start of a contiguous block */
@@ -3422,7 +3552,7 @@ verify_generation(int  generation)
 static void
 verify_zero_fill(void)
 {
-    long page;
+    page_index_t page;
 
     for (page = 0; page < last_free_page; page++) {
         if (page_table[page].allocated == FREE_PAGE_FLAG) {
@@ -3432,19 +3562,19 @@ verify_zero_fill(void)
             long i;
             for (i = 0; i < size; i++) {
                 if (start_addr[i] != 0) {
-                    lose("free page not zero at %x", start_addr + i);
+                    lose("free page not zero at %x\n", start_addr + i);
                 }
             }
         } else {
             long free_bytes = PAGE_BYTES - page_table[page].bytes_used;
             if (free_bytes > 0) {
-                long *start_addr = (long *)((unsigned)page_address(page)
+                long *start_addr = (long *)((unsigned long)page_address(page)
                                           + page_table[page].bytes_used);
                 long size = free_bytes / N_WORD_BYTES;
                 long i;
                 for (i = 0; i < size; i++) {
                     if (start_addr[i] != 0) {
-                        lose("free region not zero at %x", start_addr + i);
+                        lose("free region not zero at %x\n", start_addr + i);
                     }
                 }
             }
@@ -3465,9 +3595,9 @@ gencgc_verify_zero_fill(void)
 static void
 verify_dynamic_space(void)
 {
-    long i;
+    generation_index_t i;
 
-    for (i = 0; i < NUM_GENERATIONS; i++)
+    for (i = 0; i <= HIGHEST_NORMAL_GENERATION; i++)
         verify_generation(i);
 
     if (gencgc_enable_verify_zero_fill)
@@ -3476,28 +3606,41 @@ verify_dynamic_space(void)
 \f
 /* Write-protect all the dynamic boxed pages in the given generation. */
 static void
-write_protect_generation_pages(int generation)
+write_protect_generation_pages(generation_index_t generation)
 {
-    long i;
+    page_index_t start;
 
-    gc_assert(generation < NUM_GENERATIONS);
+    gc_assert(generation < SCRATCH_GENERATION);
 
-    for (i = 0; i < last_free_page; i++)
-        if ((page_table[i].allocated == BOXED_PAGE_FLAG)
-            && (page_table[i].bytes_used != 0)
-            && !page_table[i].dont_move
-            && (page_table[i].gen == generation))  {
+    for (start = 0; start < last_free_page; start++) {
+        if ((page_table[start].allocated == BOXED_PAGE_FLAG)
+            && (page_table[start].bytes_used != 0)
+            && !page_table[start].dont_move
+            && (page_table[start].gen == generation))  {
             void *page_start;
+            page_index_t last;
 
-            page_start = (void *)page_address(i);
+            /* Note the page as protected in the page tables. */
+            page_table[start].write_protected = 1;
+
+            for (last = start + 1; last < last_free_page; last++) {
+                if ((page_table[last].allocated != BOXED_PAGE_FLAG)
+                    || (page_table[last].bytes_used == 0)
+                    || page_table[last].dont_move
+                    || (page_table[last].gen != generation))
+                  break;
+                page_table[last].write_protected = 1;
+            }
+
+            page_start = (void *)page_address(start);
 
             os_protect(page_start,
-                       PAGE_BYTES,
+                       PAGE_BYTES * (last - start),
                        OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
 
-            /* Note the page as protected in the page tables. */
-            page_table[i].write_protected = 1;
+            start = last;
         }
+    }
 
     if (gencgc_verbose > 1) {
         FSHOW((stderr,
@@ -3508,29 +3651,216 @@ write_protect_generation_pages(int generation)
     }
 }
 
+#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
+
+static void
+scavenge_control_stack()
+{
+    unsigned long control_stack_size;
+
+    /* This is going to be a big problem when we try to port threads
+     * to PPC... CLH */
+    struct thread *th = arch_os_get_current_thread();
+    lispobj *control_stack =
+        (lispobj *)(th->control_stack_start);
+
+    control_stack_size = current_control_stack_pointer - control_stack;
+    scavenge(control_stack, control_stack_size);
+}
+
+/* Scavenging Interrupt Contexts */
+
+static int boxed_registers[] = BOXED_REGISTERS;
+
+static void
+scavenge_interrupt_context(os_context_t * context)
+{
+    int i;
+
+#ifdef reg_LIP
+    unsigned long lip;
+    unsigned long lip_offset;
+    int lip_register_pair;
+#endif
+    unsigned long pc_code_offset;
+
+#ifdef ARCH_HAS_LINK_REGISTER
+    unsigned long lr_code_offset;
+#endif
+#ifdef ARCH_HAS_NPC_REGISTER
+    unsigned long npc_code_offset;
+#endif
+
+#ifdef reg_LIP
+    /* Find the LIP's register pair and calculate it's offset */
+    /* before we scavenge the context. */
+
+    /*
+     * I (RLT) think this is trying to find the boxed register that is
+     * closest to the LIP address, without going past it.  Usually, it's
+     * reg_CODE or reg_LRA.  But sometimes, nothing can be found.
+     */
+    lip = *os_context_register_addr(context, reg_LIP);
+    lip_offset = 0x7FFFFFFF;
+    lip_register_pair = -1;
+    for (i = 0; i < (sizeof(boxed_registers) / sizeof(int)); i++) {
+        unsigned long reg;
+        long offset;
+        int index;
+
+        index = boxed_registers[i];
+        reg = *os_context_register_addr(context, index);
+        if ((reg & ~((1L<<N_LOWTAG_BITS)-1)) <= lip) {
+            offset = lip - reg;
+            if (offset < lip_offset) {
+                lip_offset = offset;
+                lip_register_pair = index;
+            }
+        }
+    }
+#endif /* reg_LIP */
+
+    /* Compute the PC's offset from the start of the CODE */
+    /* register. */
+    pc_code_offset = *os_context_pc_addr(context) - *os_context_register_addr(context, reg_CODE);
+#ifdef ARCH_HAS_NPC_REGISTER
+    npc_code_offset = *os_context_npc_addr(context) - *os_context_register_addr(context, reg_CODE);
+#endif /* ARCH_HAS_NPC_REGISTER */
+
+#ifdef ARCH_HAS_LINK_REGISTER
+    lr_code_offset =
+        *os_context_lr_addr(context) -
+        *os_context_register_addr(context, reg_CODE);
+#endif
+
+    /* Scanvenge all boxed registers in the context. */
+    for (i = 0; i < (sizeof(boxed_registers) / sizeof(int)); i++) {
+        int index;
+        lispobj foo;
+
+        index = boxed_registers[i];
+        foo = *os_context_register_addr(context, index);
+        scavenge(&foo, 1);
+        *os_context_register_addr(context, index) = foo;
+
+        scavenge((lispobj*) &(*os_context_register_addr(context, index)), 1);
+    }
+
+#ifdef reg_LIP
+    /* Fix the LIP */
+
+    /*
+     * But what happens if lip_register_pair is -1?  *os_context_register_addr on Solaris
+     * (see solaris_register_address in solaris-os.c) will return
+     * &context->uc_mcontext.gregs[2].  But gregs[2] is REG_nPC.  Is
+     * that what we really want?  My guess is that that is not what we
+     * want, so if lip_register_pair is -1, we don't touch reg_LIP at
+     * all.  But maybe it doesn't really matter if LIP is trashed?
+     */
+    if (lip_register_pair >= 0) {
+        *os_context_register_addr(context, reg_LIP) =
+            *os_context_register_addr(context, lip_register_pair) + lip_offset;
+    }
+#endif /* reg_LIP */
+
+    /* Fix the PC if it was in from space */
+    if (from_space_p(*os_context_pc_addr(context)))
+        *os_context_pc_addr(context) = *os_context_register_addr(context, reg_CODE) + pc_code_offset;
+
+#ifdef ARCH_HAS_LINK_REGISTER
+    /* Fix the LR ditto; important if we're being called from
+     * an assembly routine that expects to return using blr, otherwise
+     * harmless */
+    if (from_space_p(*os_context_lr_addr(context)))
+        *os_context_lr_addr(context) =
+            *os_context_register_addr(context, reg_CODE) + lr_code_offset;
+#endif
+
+#ifdef ARCH_HAS_NPC_REGISTER
+    if (from_space_p(*os_context_npc_addr(context)))
+        *os_context_npc_addr(context) = *os_context_register_addr(context, reg_CODE) + npc_code_offset;
+#endif /* ARCH_HAS_NPC_REGISTER */
+}
+
+void
+scavenge_interrupt_contexts(void)
+{
+    int i, index;
+    os_context_t *context;
+
+    struct thread *th=arch_os_get_current_thread();
+
+    index = fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,0));
+
+#if defined(DEBUG_PRINT_CONTEXT_INDEX)
+    printf("Number of active contexts: %d\n", index);
+#endif
+
+    for (i = 0; i < index; i++) {
+        context = th->interrupt_contexts[i];
+        scavenge_interrupt_context(context);
+    }
+}
+
+#endif
+
+#if defined(LISP_FEATURE_SB_THREAD)
+static void
+preserve_context_registers (os_context_t *c)
+{
+    void **ptr;
+    /* On Darwin the signal context isn't a contiguous block of memory,
+     * so just preserve_pointering its contents won't be sufficient.
+     */
+#if defined(LISP_FEATURE_DARWIN)
+#if defined LISP_FEATURE_X86
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EAX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_ECX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EDX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EBX));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_ESI));
+    preserve_pointer((void*)*os_context_register_addr(c,reg_EDI));
+    preserve_pointer((void*)*os_context_pc_addr(c));
+#else
+    #error "preserve_context_registers needs to be tweaked for non-x86 Darwin"
+#endif
+#endif
+    for(ptr = ((void **)(c+1))-1; ptr>=(void **)c; ptr--) {
+        preserve_pointer(*ptr);
+    }
+}
+#endif
+
 /* Garbage collect a generation. If raise is 0 then the remains of the
  * generation are not raised to the next generation. */
 static void
-garbage_collect_generation(int generation, int raise)
+garbage_collect_generation(generation_index_t generation, int raise)
 {
     unsigned long bytes_freed;
-    unsigned long i;
+    page_index_t i;
     unsigned long static_space_size;
     struct thread *th;
-    gc_assert(generation <= (NUM_GENERATIONS-1));
+    gc_assert(generation <= HIGHEST_NORMAL_GENERATION);
 
     /* The oldest generation can't be raised. */
-    gc_assert((generation != (NUM_GENERATIONS-1)) || (raise == 0));
+    gc_assert((generation != HIGHEST_NORMAL_GENERATION) || (raise == 0));
+
+    /* Check if weak hash tables were processed in the previous GC. */
+    gc_assert(weak_hash_tables == NULL);
 
     /* Initialize the weak pointer list. */
     weak_pointers = NULL;
 
+#ifdef LUTEX_WIDETAG
+    unmark_lutexes(generation);
+#endif
+
     /* When a generation is not being raised it is transported to a
      * temporary generation (NUM_GENERATIONS), and lowered when
      * done. Set up this new generation. There should be no pages
      * allocated to it yet. */
     if (!raise) {
-         gc_assert(generations[NUM_GENERATIONS].bytes_allocated == 0);
+         gc_assert(generations[SCRATCH_GENERATION].bytes_allocated == 0);
     }
 
     /* Set the global src and dest. generations */
@@ -3538,7 +3868,7 @@ garbage_collect_generation(int generation, int raise)
     if (raise)
         new_space = generation+1;
     else
-        new_space = NUM_GENERATIONS;
+        new_space = SCRATCH_GENERATION;
 
     /* Change to a new space for allocation, resetting the alloc_start_page */
     gc_alloc_generation = new_space;
@@ -3575,37 +3905,41 @@ garbage_collect_generation(int generation, int raise)
     /* we assume that none of the preceding applies to the thread that
      * initiates GC.  If you ever call GC from inside an altstack
      * handler, you will lose. */
-    for_each_thread(th) {
-        void **ptr;
-        void **esp=(void **)-1;
+
+#if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
+    /* And if we're saving a core, there's no point in being conservative. */
+    if (conservative_stack) {
+        for_each_thread(th) {
+            void **ptr;
+            void **esp=(void **)-1;
 #ifdef LISP_FEATURE_SB_THREAD
-        long i,free;
-        if(th==arch_os_get_current_thread()) {
-            /* Somebody is going to burn in hell for this, but casting
-             * it in two steps shuts gcc up about strict aliasing. */
-            esp = (void **)((void *)&raise);
-        } else {
-            void **esp1;
-            free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
-            for(i=free-1;i>=0;i--) {
-                os_context_t *c=th->interrupt_contexts[i];
-                esp1 = (void **) *os_context_register_addr(c,reg_SP);
-                if (esp1>=(void **)th->control_stack_start &&
-                    esp1<(void **)th->control_stack_end) {
-                    if(esp1<esp) esp=esp1;
-                    for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
-                        preserve_pointer(*ptr);
+            long i,free;
+            if(th==arch_os_get_current_thread()) {
+                /* Somebody is going to burn in hell for this, but casting
+                 * it in two steps shuts gcc up about strict aliasing. */
+                esp = (void **)((void *)&raise);
+            } else {
+                void **esp1;
+                free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
+                for(i=free-1;i>=0;i--) {
+                    os_context_t *c=th->interrupt_contexts[i];
+                    esp1 = (void **) *os_context_register_addr(c,reg_SP);
+                    if (esp1>=(void **)th->control_stack_start &&
+                        esp1<(void **)th->control_stack_end) {
+                        if(esp1<esp) esp=esp1;
+                        preserve_context_registers(c);
                     }
                 }
             }
-        }
 #else
-        esp = (void **)((void *)&raise);
+            esp = (void **)((void *)&raise);
 #endif
-        for (ptr = (void **)th->control_stack_end; ptr > esp;  ptr--) {
-            preserve_pointer(*ptr);
+            for (ptr = ((void **)th->control_stack_end)-1; ptr > esp;  ptr--) {
+                preserve_pointer(*ptr);
+            }
         }
     }
+#endif
 
 #ifdef QSHOW
     if (gencgc_verbose > 1) {
@@ -3619,27 +3953,29 @@ garbage_collect_generation(int generation, int raise)
 
     /* Scavenge all the rest of the roots. */
 
+#if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
+    /*
+     * If not x86, we need to scavenge the interrupt context(s) and the
+     * control stack.
+     */
+    scavenge_interrupt_contexts();
+    scavenge_control_stack();
+#endif
+
     /* Scavenge the Lisp functions of the interrupt handlers, taking
      * care to avoid SIG_DFL and SIG_IGN. */
-    for_each_thread(th) {
-        struct interrupt_data *data=th->interrupt_data;
-        for (i = 0; i < NSIG; i++) {
-            union interrupt_handler handler = data->interrupt_handlers[i];
-            if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
-                !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
-                scavenge((lispobj *)(data->interrupt_handlers + i), 1);
-            }
+    for (i = 0; i < NSIG; i++) {
+        union interrupt_handler handler = interrupt_handlers[i];
+        if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
+            !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
+            scavenge((lispobj *)(interrupt_handlers + i), 1);
         }
     }
-    /* Scavenge the function list for INTERRUPT-THREAD. */
-    for_each_thread(th) {
-        scavenge(&th->interrupt_fun,1);
-    }
     /* Scavenge the binding stacks. */
     {
         struct thread *th;
         for_each_thread(th) {
-            long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
+            long len= (lispobj *)get_binding_stack_pointer(th) -
                 th->binding_stack_start;
             scavenge((lispobj *) th->binding_stack_start,len);
 #ifdef LISP_FEATURE_SB_THREAD
@@ -3684,11 +4020,7 @@ garbage_collect_generation(int generation, int raise)
     /* All generations but the generation being GCed need to be
      * scavenged. The new_space generation needs special handling as
      * objects may be moved in - it is handled separately below. */
-    for (i = 0; i < NUM_GENERATIONS; i++) {
-        if ((i != generation) && (i != new_space)) {
-            scavenge_generation(i);
-        }
-    }
+    scavenge_generations(generation+1, PSEUDO_STATIC_GENERATION);
 
     /* Finally scavenge the new_space generation. Keep going until no
      * more objects are moved into the new generation */
@@ -3717,12 +4049,13 @@ garbage_collect_generation(int generation, int raise)
         bytes_allocated = bytes_allocated - old_bytes_allocated;
 
         if (bytes_allocated != 0) {
-            lose("Rescan of new_space allocated %d more bytes.",
+            lose("Rescan of new_space allocated %d more bytes.\n",
                  bytes_allocated);
         }
     }
 #endif
 
+    scan_weak_hash_tables();
     scan_weak_pointers();
 
     /* Flush the current regions, updating the tables. */
@@ -3736,12 +4069,12 @@ garbage_collect_generation(int generation, int raise)
     if (!raise) {
         for (i = 0; i < last_free_page; i++)
             if ((page_table[i].bytes_used != 0)
-                && (page_table[i].gen == NUM_GENERATIONS))
+                && (page_table[i].gen == SCRATCH_GENERATION))
                 page_table[i].gen = generation;
         gc_assert(generations[generation].bytes_allocated == 0);
         generations[generation].bytes_allocated =
-            generations[NUM_GENERATIONS].bytes_allocated;
-        generations[NUM_GENERATIONS].bytes_allocated = 0;
+            generations[SCRATCH_GENERATION].bytes_allocated;
+        generations[SCRATCH_GENERATION].bytes_allocated = 0;
     }
 
     /* Reset the alloc_start_page for generation. */
@@ -3766,14 +4099,19 @@ garbage_collect_generation(int generation, int raise)
         generations[generation].num_gc = 0;
     else
         ++generations[generation].num_gc;
+
+#ifdef LUTEX_WIDETAG
+    reap_lutexes(generation);
+    if (raise)
+        move_lutexes(generation, generation+1);
+#endif
 }
 
 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
 long
-update_x86_dynamic_space_free_pointer(void)
+update_dynamic_space_free_pointer(void)
 {
-    long last_page = -1;
-    long i;
+    page_index_t last_page = -1, i;
 
     for (i = 0; i < last_free_page; i++)
         if ((page_table[i].allocated != FREE_PAGE_FLAG)
@@ -3782,11 +4120,44 @@ update_x86_dynamic_space_free_pointer(void)
 
     last_free_page = last_page+1;
 
-    SetSymbolValue(ALLOCATION_POINTER,
-                   (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
+    set_alloc_pointer((lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES));
     return 0; /* dummy value: return something ... */
 }
 
+static void
+remap_free_pages (page_index_t from, page_index_t to)
+{
+    page_index_t first_page, last_page;
+
+    for (first_page = from; first_page <= to; first_page++) {
+        if (page_table[first_page].allocated != FREE_PAGE_FLAG ||
+            page_table[first_page].need_to_zero == 0) {
+            continue;
+        }
+
+        last_page = first_page + 1;
+        while (page_table[last_page].allocated == FREE_PAGE_FLAG &&
+               last_page < to &&
+               page_table[last_page].need_to_zero == 1) {
+            last_page++;
+        }
+
+        /* There's a mysterious Solaris/x86 problem with using mmap
+         * tricks for memory zeroing. See sbcl-devel thread
+         * "Re: patch: standalone executable redux".
+         */
+#if defined(LISP_FEATURE_SUNOS)
+        zero_pages(first_page, last_page-1);
+#else
+        zero_pages_with_mmap(first_page, last_page-1);
+#endif
+
+        first_page = last_page;
+    }
+}
+
+generation_index_t small_generation_limit = 1;
+
 /* GC all generations newer than last_gen, raising the objects in each
  * to the next older generation - we finish when all generations below
  * last_gen are empty.  Then if last_gen is due for a GC, or if
@@ -3795,18 +4166,21 @@ update_x86_dynamic_space_free_pointer(void)
  *
  * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
  * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
-
 void
-collect_garbage(unsigned last_gen)
+collect_garbage(generation_index_t last_gen)
 {
-    int gen = 0;
+    generation_index_t gen = 0, i;
     int raise;
     int gen_to_wp;
-    long i;
+    /* The largest value of last_free_page seen since the time
+     * remap_free_pages was called. */
+    static page_index_t high_water_mark = 0;
 
     FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
 
-    if (last_gen > NUM_GENERATIONS) {
+    gc_active_p = 1;
+
+    if (last_gen > HIGHEST_NORMAL_GENERATION+1) {
         FSHOW((stderr,
                "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
                last_gen));
@@ -3893,7 +4267,7 @@ collect_garbage(unsigned last_gen)
         /* Check that they are all empty. */
         for (i = 0; i < gen_to_wp; i++) {
             if (generations[i].bytes_allocated)
-                lose("trying to write-protect gen. %d when gen. %d nonempty",
+                lose("trying to write-protect gen. %d when gen. %d nonempty\n",
                      gen_to_wp, i);
         }
         write_protect_generation_pages(gen_to_wp);
@@ -3904,11 +4278,29 @@ collect_garbage(unsigned last_gen)
     gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
     gc_alloc_generation = 0;
 
-    update_x86_dynamic_space_free_pointer();
+    /* Save the high-water mark before updating last_free_page */
+    if (last_free_page > high_water_mark)
+        high_water_mark = last_free_page;
+
+    update_dynamic_space_free_pointer();
+
     auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
     if(gencgc_verbose)
         fprintf(stderr,"Next gc when %ld bytes have been consed\n",
                 auto_gc_trigger);
+
+    /* If we did a big GC (arbitrarily defined as gen > 1), release memory
+     * back to the OS.
+     */
+    if (gen > small_generation_limit) {
+        if (last_free_page > high_water_mark)
+            high_water_mark = last_free_page;
+        remap_free_pages(0, high_water_mark);
+        high_water_mark = 0;
+    }
+
+    gc_active_p = 0;
+
     SHOW("returning from collect_garbage");
 }
 
@@ -3920,7 +4312,7 @@ collect_garbage(unsigned last_gen)
 void
 gc_free_heap(void)
 {
-    long page;
+    page_index_t page;
 
     if (gencgc_verbose > 1)
         SHOW("entering gc_free_heap");
@@ -3938,6 +4330,7 @@ gc_free_heap(void)
             page_table[page].allocated = FREE_PAGE_FLAG;
             page_table[page].bytes_used = 0;
 
+#ifndef LISP_FEATURE_WIN32 /* Pages already zeroed on win32? Not sure about this change. */
             /* Zero the page. */
             page_start = (void *)page_address(page);
 
@@ -3948,19 +4341,23 @@ gc_free_heap(void)
             os_invalidate(page_start,PAGE_BYTES);
             addr = os_validate(page_start,PAGE_BYTES);
             if (addr == NULL || addr != page_start) {
-                lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
+                lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x\n",
                      page_start,
                      addr);
             }
+#else
+            page_table[page].write_protected = 0;
+#endif
         } else if (gencgc_zero_check_during_free_heap) {
             /* Double-check that the page is zero filled. */
-            long *page_start, i;
+            long *page_start;
+            page_index_t i;
             gc_assert(page_table[page].allocated == FREE_PAGE_FLAG);
             gc_assert(page_table[page].bytes_used == 0);
             page_start = (long *)page_address(page);
             for (i=0; i<1024; i++) {
                 if (page_start[i] != 0) {
-                    lose("free region not zero at %x", page_start + i);
+                    lose("free region not zero at %x\n", page_start + i);
                 }
             }
         }
@@ -3978,6 +4375,7 @@ gc_free_heap(void)
         generations[page].gc_trigger = 2000000;
         generations[page].num_gc = 0;
         generations[page].cum_sum_bytes_allocated = 0;
+        generations[page].lutexes = NULL;
     }
 
     if (gencgc_verbose > 1)
@@ -3990,7 +4388,7 @@ gc_free_heap(void)
     gc_set_region_empty(&unboxed_region);
 
     last_free_page = 0;
-    SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
+    set_alloc_pointer((lispobj)((char *)heap_base));
 
     if (verify_after_free_heap) {
         /* Check whether purify has left any bad pointers. */
@@ -4003,13 +4401,18 @@ gc_free_heap(void)
 void
 gc_init(void)
 {
-    long i;
+    page_index_t i;
 
     gc_init_tables();
-    scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
     scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
     transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
 
+#ifdef LUTEX_WIDETAG
+    scavtab[LUTEX_WIDETAG] = scav_lutex;
+    transother[LUTEX_WIDETAG] = trans_lutex;
+    sizetab[LUTEX_WIDETAG] = size_lutex;
+#endif
+
     heap_base = (void*)DYNAMIC_SPACE_START;
 
     /* Initialize each page structure. */
@@ -4040,6 +4443,7 @@ gc_init(void)
         generations[i].bytes_consed_between_gc = 2000000;
         generations[i].trigger_age = 1;
         generations[i].min_av_mem_age = 0.75;
+        generations[i].lutexes = NULL;
     }
 
     /* Initialize gc_alloc. */
@@ -4048,7 +4452,6 @@ gc_init(void)
     gc_set_region_empty(&unboxed_region);
 
     last_free_page = 0;
-
 }
 
 /*  Pick up the dynamic space from after a core load.
@@ -4059,30 +4462,47 @@ gc_init(void)
 static void
 gencgc_pickup_dynamic(void)
 {
-    long page = 0;
-    long alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
+    page_index_t page = 0;
+    long alloc_ptr = get_alloc_pointer();
     lispobj *prev=(lispobj *)page_address(page);
+    generation_index_t gen = PSEUDO_STATIC_GENERATION;
 
     do {
         lispobj *first,*ptr= (lispobj *)page_address(page);
         page_table[page].allocated = BOXED_PAGE_FLAG;
-        page_table[page].gen = 0;
+        page_table[page].gen = gen;
         page_table[page].bytes_used = PAGE_BYTES;
         page_table[page].large_object = 0;
-
-        first=gc_search_space(prev,(ptr+2)-prev,ptr);
-        if(ptr == first)  prev=ptr;
-        page_table[page].first_object_offset =
-            (void *)prev - page_address(page);
+        page_table[page].write_protected = 0;
+        page_table[page].write_protected_cleared = 0;
+        page_table[page].dont_move = 0;
+        page_table[page].need_to_zero = 1;
+
+        if (!gencgc_partial_pickup) {
+            first=gc_search_space(prev,(ptr+2)-prev,ptr);
+            if(ptr == first)  prev=ptr;
+            page_table[page].first_object_offset =
+                (void *)prev - page_address(page);
+        }
         page++;
     } while ((long)page_address(page) < alloc_ptr);
 
-    generations[0].bytes_allocated = PAGE_BYTES*page;
+#ifdef LUTEX_WIDETAG
+    /* Lutexes have been registered in generation 0 by coreparse, and
+     * need to be moved to the right one manually.
+     */
+    move_lutexes(0, PSEUDO_STATIC_GENERATION);
+#endif
+
+    last_free_page = page;
+
+    generations[gen].bytes_allocated = PAGE_BYTES*page;
     bytes_allocated = PAGE_BYTES*page;
 
+    gc_alloc_update_all_page_tables();
+    write_protect_generation_pages(gen);
 }
 
-
 void
 gc_initialize_pointers(void)
 {
@@ -4117,16 +4537,18 @@ alloc(long nbytes)
     void *new_obj;
     void *new_free_pointer;
     gc_assert(nbytes>0);
+
     /* Check for alignment allocation problems. */
-    gc_assert((((unsigned)region->free_pointer & LOWTAG_MASK) == 0)
+    gc_assert((((unsigned long)region->free_pointer & LOWTAG_MASK) == 0)
               && ((nbytes & LOWTAG_MASK) == 0));
+
 #if 0
     if(all_threads)
         /* there are a few places in the C code that allocate data in the
          * heap before Lisp starts.  This is before interrupts are enabled,
          * so we don't need to check for pseudo-atomic */
 #ifdef LISP_FEATURE_SB_THREAD
-        if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
+        if(!get_psuedo_atomic_atomic(th)) {
             register u32 fs;
             fprintf(stderr, "fatal error in thread 0x%x, tid=%ld\n",
                     th,th->os_thread);
@@ -4136,7 +4558,7 @@ alloc(long nbytes)
             lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
         }
 #else
-    gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
+    gc_assert(get_pseudo_atomic_atomic(th));
 #endif
 #endif
 
@@ -4152,7 +4574,7 @@ alloc(long nbytes)
      * we should GC in the near future
      */
     if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
-        gc_assert(fixnum_value(SymbolValue(PSEUDO_ATOMIC_ATOMIC,thread)));
+        gc_assert(get_pseudo_atomic_atomic(thread));
         /* Don't flood the system with interrupts if the need to gc is
          * already noted. This can happen for example when SUB-GC
          * allocates or after a gc triggered in a WITHOUT-GCING. */
@@ -4161,7 +4583,7 @@ alloc(long nbytes)
              * section */
             SetSymbolValue(GC_PENDING,T,thread);
             if (SymbolValue(GC_INHIBIT,thread) == NIL)
-                arch_set_pseudo_atomic_interrupted(0);
+              set_pseudo_atomic_interrupted(thread);
         }
     }
     new_obj = gc_alloc_with_region(nbytes,0,region,0);
@@ -4188,7 +4610,7 @@ void unhandled_sigmemoryfault(void);
 int
 gencgc_handle_wp_violation(void* fault_addr)
 {
-    long  page_index = find_page_index(fault_addr);
+    page_index_t page_index = find_page_index(fault_addr);
 
 #ifdef QSHOW_SIGNALS
     FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
@@ -4219,7 +4641,8 @@ gencgc_handle_wp_violation(void* fault_addr)
              * does this test after the first one has already set wp=0
              */
             if(page_table[page_index].write_protected_cleared != 1)
-                lose("fault in heap page not marked as write-protected");
+                lose("fault in heap page %d not marked as write-protected\nboxed_region.first_page: %d, boxed_region.last_page %d\n",
+                     page_index, boxed_region.first_page, boxed_region.last_page);
         }
         /* Don't worry, we can handle it. */
         return 1;
@@ -4242,6 +4665,7 @@ void gc_alloc_update_all_page_tables(void)
     gc_alloc_update_page_tables(1, &unboxed_region);
     gc_alloc_update_page_tables(0, &boxed_region);
 }
+
 void
 gc_set_region_empty(struct alloc_region *region)
 {
@@ -4251,3 +4675,92 @@ gc_set_region_empty(struct alloc_region *region)
     region->free_pointer = page_address(0);
     region->end_addr = page_address(0);
 }
+
+static void
+zero_all_free_pages()
+{
+    page_index_t i;
+
+    for (i = 0; i < last_free_page; i++) {
+        if (page_table[i].allocated == FREE_PAGE_FLAG) {
+#ifdef READ_PROTECT_FREE_PAGES
+            os_protect(page_address(i),
+                       PAGE_BYTES,
+                       OS_VM_PROT_ALL);
+#endif
+            zero_pages(i, i);
+        }
+    }
+}
+
+/* Things to do before doing a final GC before saving a core (without
+ * purify).
+ *
+ * + Pages in large_object pages aren't moved by the GC, so we need to
+ *   unset that flag from all pages.
+ * + The pseudo-static generation isn't normally collected, but it seems
+ *   reasonable to collect it at least when saving a core. So move the
+ *   pages to a normal generation.
+ */
+static void
+prepare_for_final_gc ()
+{
+    page_index_t i;
+    for (i = 0; i < last_free_page; i++) {
+        page_table[i].large_object = 0;
+        if (page_table[i].gen == PSEUDO_STATIC_GENERATION) {
+            int used = page_table[i].bytes_used;
+            page_table[i].gen = HIGHEST_NORMAL_GENERATION;
+            generations[PSEUDO_STATIC_GENERATION].bytes_allocated -= used;
+            generations[HIGHEST_NORMAL_GENERATION].bytes_allocated += used;
+        }
+    }
+}
+
+
+/* Do a non-conservative GC, and then save a core with the initial
+ * function being set to the value of the static symbol
+ * SB!VM:RESTART-LISP-FUNCTION */
+void
+gc_and_save(char *filename, int prepend_runtime)
+{
+    FILE *file;
+    void *runtime_bytes = NULL;
+    size_t runtime_size;
+
+    file = prepare_to_save(filename, prepend_runtime, &runtime_bytes,
+                           &runtime_size);
+    if (file == NULL)
+       return;
+
+    conservative_stack = 0;
+
+    /* The filename might come from Lisp, and be moved by the now
+     * non-conservative GC. */
+    filename = strdup(filename);
+
+    /* Collect twice: once into relatively high memory, and then back
+     * into low memory. This compacts the retained data into the lower
+     * pages, minimizing the size of the core file.
+     */
+    prepare_for_final_gc();
+    gencgc_alloc_start_page = last_free_page;
+    collect_garbage(HIGHEST_NORMAL_GENERATION+1);
+
+    prepare_for_final_gc();
+    gencgc_alloc_start_page = -1;
+    collect_garbage(HIGHEST_NORMAL_GENERATION+1);
+
+    if (prepend_runtime)
+        save_runtime_to_filehandle(file, runtime_bytes, runtime_size);
+
+    /* The dumper doesn't know that pages need to be zeroed before use. */
+    zero_all_free_pages();
+    save_to_filehandle(file, filename, SymbolValue(RESTART_LISP_FUNCTION,0),
+                       prepend_runtime);
+    /* Oops. Save still managed to fail. Since we've mangled the stack
+     * beyond hope, there's not much we can do.
+     * (beyond FUNCALLing RESTART_LISP_FUNCTION, but I suspect that's
+     * going to be rather unsatisfactory too... */
+    lose("Attempt to save core after non-conservative GC failed.\n");
+}