On Tue, 17 May, at 10:04:34AM, Matt Fleming wrote:
>
> Now I'm wondering whether other users of FRAME_BEGIN/FRAME_END make
> this same mistake. Coccinelle might be able to detect it perhaps.
A quick bit of sed turned up the code in arch/x86/entry/entry_64.S,
which looks to suffer from the same bug,
/* rdi: arg1 ... normal C conventions. rax is saved/restored. */
.macro THUNK name, func, put_ret_addr_in_rdi=0
.globl \name
.type \name, @function
\name:
FRAME_BEGIN
/* this one pushes 9 elems, the next one would be %rIP */
pushq %rdi
pushq %rsi
pushq %rdx
pushq %rcx
pushq %rax
pushq %r8
pushq %r9
pushq %r10
pushq %r11
.if \put_ret_addr_in_rdi
/* 9*8(%rsp) is return addr on stack */
movq 9*8(%rsp), %rdi
.endif
With CONFIG_FRAME_POINTER=y 9*8(%rsp) is actually the value of %rbp on
entry, not the return address.
