Windows console I/O overhaul

[sbcl.git] / src / runtime / x86-64-assem.S

diff --git a/src/runtime/x86-64-assem.S b/src/runtime/x86-64-assem.S
index e2bc331..f687c82 100644 (file)
--- a/src/runtime/x86-64-assem.S
+++ b/src/runtime/x86-64-assem.S
@@ -38,10 +38,12 @@
 #define align_8byte    8
 #define align_16byte   16
 #define align_32byte   32
+#define align_page     32768
 #else
 #define        align_4byte     2
 #define        align_8byte     3
 #define        align_16byte    4       
+#define        align_page      15
 #endif                 
 
 /*
@@ -194,7 +196,7 @@ Lstack:
        xor     %rdx,%rdx       # clear any descriptor registers 
        xor     %rdi,%rdi       # that we can't be sure we'll 
        xor     %rsi,%rsi       # initialise properly.  XX do r8-r15 too?
-       shl     $N_FIXNUM_TAG_BITS,%rcx # (fixnumize num-args)
+       shl     $(N_FIXNUM_TAG_BITS),%rcx       # (fixnumize num-args)
        cmp     $0,%rcx
        je      Ldone
        mov     0(%rbx),%rdx    # arg0
@@ -275,6 +277,9 @@ GNAME(undefined_tramp):
        ret
        SIZE(GNAME(undefined_tramp))
 
+/* KLUDGE: FIND-ESCAPED-FRAME (SYS:SRC;CODE;DEBUG-INT.LISP) needs
+ * to know the name of the function immediately following the
+ * undefined-function trampoline. */
 
        .text
        .align  align_16byte,0x90
@@ -344,6 +349,12 @@ GNAME(closure_tramp):
 /*
  * fun-end breakpoint magic
  */
+
+/*
+ * For an explanation of the magic involved in function-end
+ * breakpoints, see the implementation in ppc-assem.S.
+ */
+
        .text
        .globl  GNAME(fun_end_breakpoint_guts)
        .align  align_16byte
@@ -452,4 +463,84 @@ Lend:
        ret
        SIZE(GNAME(fast_bzero))
 
+\f
+/* When LISP_FEATURE_C_STACK_IS_CONTROL_STACK, we cannot safely scrub
+ * the control stack from C, largely due to not knowing where the
+ * active stack frame ends.  On such platforms, we reimplement the
+ * core scrubbing logic in assembly, in this case here:
+ */
+       .text
+       .align  align_16byte,0x90
+       .globl GNAME(arch_scrub_control_stack)
+       TYPE(GNAME(arch_scrub_control_stack))
+GNAME(arch_scrub_control_stack):
+       /* We are passed three parameters:
+        * A (struct thread *) in RDI,
+        * the address of the guard page in RSI, and
+        * the address of the hard guard page in RDX.
+        * We may trash RAX, RCX, and R8-R11 with impunity.
+        * [RSP] is our return address, [RSP-8] is the first
+        * stack slot to scrub. */
+
+       /* We start by setting up our scrub pointer in RAX, our
+        * guard page upper bound in R8, and our hard guard
+        * page upper bound in R9. */
+       lea     -8(%rsp), %rax
+#ifdef LISP_FEATURE_DARWIN
+       mov     GSYM(GNAME(os_vm_page_size)),%r9
+#else
+       mov     os_vm_page_size,%r9
+#endif
+       lea     (%rsi,%r9), %r8
+       lea     (%rdx,%r9), %r9
+
+       /* Now we begin our main scrub loop. */
+ascs_outer_loop:
+
+       /* If we're about to scrub the hard guard page, exit. */
+       cmp     %r9, %rax
+       jae     ascs_check_guard_page
+       cmp     %rax, %rdx
+       jbe     ascs_finished
+
+ascs_check_guard_page:
+       /* If we're about to scrub the guard page, and the guard
+        * page is protected, exit. */
+       cmp     %r8, %rax
+       jae     ascs_clear_loop
+       cmp     %rax, %rsi
+       ja      ascs_clear_loop
+       cmpq    $(NIL), THREAD_CONTROL_STACK_GUARD_PAGE_PROTECTED_OFFSET(%rdi)
+       jne     ascs_finished
+
+       /* Clear memory backwards to the start of the (4KiB) page */
+ascs_clear_loop:
+       movq    $0, (%rax)
+       test    $0xfff, %rax
+       lea     -8(%rax), %rax
+       jnz     ascs_clear_loop
+
+       /* If we're about to hit the hard guard page, exit. */
+       cmp     %r9, %rax
+       jae     ascs_finished
+
+       /* If the next (previous?) 4KiB page contains a non-zero
+        * word, continue scrubbing. */
+ascs_check_loop:
+       testq   $-1, (%rax)
+       jnz     ascs_outer_loop
+       test    $0xfff, %rax
+       lea     -8(%rax), %rax
+       jnz     ascs_check_loop
+
+ascs_finished:
+       ret
+       SIZE(GNAME(arch_scrub_control_stack))
+\f
+       .globl GNAME(gc_safepoint_page)
+       .data
+        .align  align_page
+GNAME(gc_safepoint_page):
+        .fill 32768,1,0
+\f
         END()