diff options
Diffstat (limited to 'src/arch')
| -rw-r--r-- | src/arch/x86/lib/c_start.S | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/src/arch/x86/lib/c_start.S b/src/arch/x86/lib/c_start.S index fd9dce78c5..9c1fdb106f 100644 --- a/src/arch/x86/lib/c_start.S +++ b/src/arch/x86/lib/c_start.S @@ -16,17 +16,21 @@ _start: post_code(POST_ENTRY_C_START) /* post 13 */ - /** clear stack */ + /** poison the stack. Code should not count on the + * stack being full of zeros. This stack poisoning + * recently uncovered a bug in the broadcast SIPI + * code. + */ cld leal _stack, %edi movl $_estack, %ecx subl %edi, %ecx shrl $2, %ecx /* it is 32 bit aligned, right? */ - xorl %eax, %eax + movl $0xDEADBEEF, %eax rep stosl - /** clear bss */ + /** clear bss, which unlike the stack is zero by definition */ leal _bss, %edi movl $_ebss, %ecx subl %edi, %ecx |