2008-10-24 00:15:38

by Hiroshi Shimamoto

Subject: [PATCH] x86: signal_64.c: get_stack() doesn't need entire regs

From: Hiroshi Shimamoto <[email protected]>

get_stack() uses sp only, entire regs is not needed.

Signed-off-by: Hiroshi Shimamoto <[email protected]>
---
arch/x86/kernel/signal_64.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 9c469da..3d0deb3 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -199,12 +199,10 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
*/

static void __user *
-get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
+get_stack(struct k_sigaction *ka, unsigned long sp, unsigned long size)
{
- unsigned long sp;
-
/* Default to using normal stack - redzone*/
- sp = regs->sp - 128;
+ sp -= 128;

/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
@@ -224,14 +222,14 @@ static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
struct task_struct *me = current;

if (used_math()) {
- fp = get_stack(ka, regs, sig_xstate_size);
+ fp = get_stack(ka, regs->sp, sig_xstate_size);
frame = (void __user *)round_down(
(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;

if (save_i387_xstate(fp) < 0)
return -EFAULT;
} else
- frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
+ frame = get_stack(ka, regs->sp, sizeof(struct rt_sigframe)) - 8;

if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return -EFAULT;
--
1.5.6

2008-10-27 13:13:18

by Ingo Molnar

Subject: Re: [PATCH] x86: signal_64.c: get_stack() doesn't need entire regs

* Hiroshi Shimamoto <[email protected]> wrote:

> From: Hiroshi Shimamoto <[email protected]>
>
> get_stack() uses sp only, entire regs is not needed.
>
> Signed-off-by: Hiroshi Shimamoto <[email protected]>
> ---
> arch/x86/kernel/signal_64.c | 10 ++++------
> 1 files changed, 4 insertions(+), 6 deletions(-)

applied to tip/x86/signal, thanks!

Ingo