Re: [PATCH 2/2] x86: ia32_signal: remove unnecessary padding

From: Ingo Molnar
Date: Wed Nov 12 2008 - 06:30:07 EST



* Hiroshi Shimamoto <h-shimamoto@xxxxxxxxxxxxx> wrote:

> From: Hiroshi Shimamoto <h-shimamoto@xxxxxxxxxxxxx>
>
> Impact: cleanup
>
> Remove unnecessary paddings, this saves 4 bytes.
>
> Signed-off-by: Hiroshi Shimamoto <h-shimamoto@xxxxxxxxxxxxx>
> ---
> arch/x86/ia32/ia32_signal.c | 5 +----
> 1 files changed, 1 insertions(+), 4 deletions(-)

applied your patches to tip/x86/signal:

9cc3c49: x86: ia32_signal: remove unnecessary padding
4a61204: x86: signal_32: introduce retcode and rt_retcode

thanks!

A question - this change:

> @@ -427,12 +427,10 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
> u16 poplmovl;
> u32 val;
> u16 int80;
> - u16 pad;
> } __attribute__((packed)) code = {
> 0xb858, /* popl %eax ; movl $...,%eax */
> __NR_ia32_sigreturn,
> 0x80cd, /* int $0x80 */
> - 0,
> };
>
> frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
> @@ -508,8 +506,7 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
> u8 movl;
> u32 val;
> u16 int80;
> - u16 pad;
> - u8 pad2;
> + u8 pad;
> } __attribute__((packed)) code = {
> 0xb8,
> __NR_ia32_rt_sigreturn,

does not impact any ABI, because it's only about the signal trampoline
the kernel pushes to the user-space stack - not about any
userspace-visible signal frame detail, right?

Ingo
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