X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Fx86-64-assem.S;h=f687c822a23ac51d84d295f60a10d08a86f45021;hb=0285aa5ff8416027932daa001b84429be2ca559b;hp=388c3bf90d01f6bec1cc1aab2a6c57fe468b50a8;hpb=11b5ac86a98f058fe0375b0a707c6ef9e24590c9;p=sbcl.git

diff --git a/src/runtime/x86-64-assem.S b/src/runtime/x86-64-assem.S
index 388c3bf..f687c82 100644
--- 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	$3,%rcx		# (fixnumize num-args)
+	shl	$(N_FIXNUM_TAG_BITS),%rcx	# (fixnumize num-args)
 	cmp	$0,%rcx
 	je	Ldone
 	mov	0(%rbx),%rdx	# arg0
@@ -266,6 +268,7 @@ GNAME(fpu_restore):
 	.globl  GNAME(undefined_tramp)
 	TYPE(GNAME(undefined_tramp))
 GNAME(undefined_tramp):
+	pop	8(%rbp)         # Save return PC for backtrace.
 	TRAP
 	.byte	trap_Error
         .byte   2
@@ -274,6 +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
@@ -343,6 +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
@@ -451,4 +463,84 @@ Lend:
 	ret
 	SIZE(GNAME(fast_bzero))
 
+
+/* 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))
+
+	.globl GNAME(gc_safepoint_page)
+	.data
+        .align  align_page
+GNAME(gc_safepoint_page):
+        .fill 32768,1,0
+
         END()