#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
/*
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
/*
* 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
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()