Fix 16-byte stack alignment requirement for x86_64 ABI
Change-Id: I43304803ac54c8688c61688bd96c7160614172d4
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
diff --git a/libc/arch-common/bionic/crtbegin.c b/libc/arch-common/bionic/crtbegin.c
index bc67bfb..fa9f3f3 100644
--- a/libc/arch-common/bionic/crtbegin.c
+++ b/libc/arch-common/bionic/crtbegin.c
@@ -50,6 +50,10 @@
array.fini_array = &__FINI_ARRAY__;
void* raw_args = (void*) ((uintptr_t) __builtin_frame_address(0) + sizeof(void*));
+#ifdef __x86_64__
+ // 16-byte stack alignment is required by x86_64 ABI
+ asm("andq $~15, %rsp");
+#endif
__libc_init(raw_args, NULL, &main, &array);
}
diff --git a/libc/arch-x86_64/bionic/clone.S b/libc/arch-x86_64/bionic/clone.S
index 2ae0e85..7511e86 100644
--- a/libc/arch-x86_64/bionic/clone.S
+++ b/libc/arch-x86_64/bionic/clone.S
@@ -59,10 +59,11 @@
# We're in the child now, so call __thread_entry
# with the arguments from the child stack moved into
- # the appropriate registers.
- popq %rdi # fn
- popq %rsi # arg
- popq %rdx # tls
+ # the appropriate registers. We avoid pop here to keep
+ # the required 16-byte stack alignment.
+ movq (%rsp), %rdi # fn
+ movq 8(%rsp), %rsi # arg
+ movq 16(%rsp), %rdx # tls
call __thread_entry
hlt
2:
