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authorBernd Schmidt <bernds_cb1@t-online.de>2008-04-24 02:51:36 +0800
committerBryan Wu <cooloney@kernel.org>2008-04-24 02:51:36 +0800
commit697a9d65aa799940da1c9145944c6b9bd0f442c5 (patch)
treec92b8e314e3bcc5ccaca4cfa26b00648230abe9e
parent5af29f595813cce3c125d01d2500be483732ef4f (diff)
[Blackfin] arch: a rather old performance improvement for the signal handling code
This is a rather old performance improvement for the signal handling code, which was originally only committed on the 2007R1 branch as a workaround for what we suspected to be a hardware bug. There's no point in constructing a sigreturn stub on the stack and flushing caches; we can just make signal handlers return to a known location in the fixed code area. Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de> Signed-off-by: Bryan Wu <cooloney@kernel.org>
-rw-r--r--arch/blackfin/kernel/signal.c20
1 files changed, 4 insertions, 16 deletions
diff --git a/arch/blackfin/kernel/signal.c b/arch/blackfin/kernel/signal.c
index 71cfcd28b39..d1fa24401dc 100644
--- a/arch/blackfin/kernel/signal.c
+++ b/arch/blackfin/kernel/signal.c
@@ -38,6 +38,7 @@
#include <asm/cacheflush.h>
#include <asm/ucontext.h>
+#include <asm/fixed_code.h>
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
@@ -50,6 +51,8 @@ struct rt_sigframe {
int sig;
struct siginfo *pinfo;
void *puc;
+ /* This is no longer needed by the kernel, but unfortunately userspace
+ * code expects it to be there. */
char retcode[8];
struct siginfo info;
struct ucontext uc;
@@ -159,11 +162,6 @@ static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *reg
return err;
}
-static inline void push_cache(unsigned long vaddr, unsigned int len)
-{
- flush_icache_range(vaddr, vaddr + len);
-}
-
static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
size_t frame_size)
{
@@ -209,19 +207,9 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
- /* Set up to return from userspace. */
- err |= __put_user(0x28, &(frame->retcode[0]));
- err |= __put_user(0xe1, &(frame->retcode[1]));
- err |= __put_user(0xad, &(frame->retcode[2]));
- err |= __put_user(0x00, &(frame->retcode[3]));
- err |= __put_user(0xa0, &(frame->retcode[4]));
- err |= __put_user(0x00, &(frame->retcode[5]));
-
if (err)
goto give_sigsegv;
- push_cache((unsigned long)&frame->retcode, sizeof(frame->retcode));
-
/* Set up registers for signal handler */
wrusp((unsigned long)frame);
if (get_personality & FDPIC_FUNCPTRS) {
@@ -231,7 +219,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
__get_user(regs->p3, &funcptr->GOT);
} else
regs->pc = (unsigned long)ka->sa.sa_handler;
- regs->rets = (unsigned long)(frame->retcode);
+ regs->rets = SIGRETURN_STUB;
regs->r0 = frame->sig;
regs->r1 = (unsigned long)(&frame->info);