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| author | Ingo Molnar <mingo@elte.hu> | 2005-09-03 15:56:26 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@evo.osdl.org> | 2005-09-05 00:06:09 -0700 |
| commit | 869f96a00e8f53c7db8470ca9cf72e2e3fa40119 (patch) | |
| tree | e28e526eb0e9d304d79dab3a20c944959a6ee38e | |
| parent | 7e06066b87ffd2c7a7f4c3f1c612293307270976 (diff) | |
| download | talos-op-linux-869f96a00e8f53c7db8470ca9cf72e2e3fa40119.tar.gz talos-op-linux-869f96a00e8f53c7db8470ca9cf72e2e3fa40119.zip | |
[PATCH] x86: compress the stack layout of do_page_fault()
This patch pushes the creation of a rare signal frame (SIGBUS or SIGSEGV)
into a separate function, thus saving stackspace in the main
do_page_fault() stackframe. The effect is 132 bytes less of stack used by
the typical do_page_fault() invocation - resulting in a denser
cache-layout.
(Another minor effect is that in case of kernel crashes that come from a
pagefault, we add less space to the already existing frame, giving the
crash functions a slightly higher chance to do their stuff without
overflowing the stack.)
(The changes also result in slightly cleaner code.)
argument bugfix from "Guillaume C." <guichaz@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | arch/i386/mm/fault.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index 8e90339d6eaa..61d9e34af5a6 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -199,6 +199,18 @@ static inline int is_prefetch(struct pt_regs *regs, unsigned long addr, return 0; } +static noinline void force_sig_info_fault(int si_signo, int si_code, + unsigned long address, struct task_struct *tsk) +{ + siginfo_t info; + + info.si_signo = si_signo; + info.si_errno = 0; + info.si_code = si_code; + info.si_addr = (void __user *)address; + force_sig_info(si_signo, &info, tsk); +} + fastcall void do_invalid_op(struct pt_regs *, unsigned long); /* @@ -218,8 +230,7 @@ fastcall void do_page_fault(struct pt_regs *regs, unsigned long error_code) struct vm_area_struct * vma; unsigned long address; unsigned long page; - int write; - siginfo_t info; + int write, si_code; /* get the address */ __asm__("movl %%cr2,%0":"=r" (address)); @@ -233,7 +244,7 @@ fastcall void do_page_fault(struct pt_regs *regs, unsigned long error_code) tsk = current; - info.si_code = SEGV_MAPERR; + si_code = SEGV_MAPERR; /* * We fault-in kernel-space virtual memory on-demand. The @@ -313,7 +324,7 @@ fastcall void do_page_fault(struct pt_regs *regs, unsigned long error_code) * we can handle it.. */ good_area: - info.si_code = SEGV_ACCERR; + si_code = SEGV_ACCERR; write = 0; switch (error_code & 3) { default: /* 3: write, present */ @@ -387,11 +398,7 @@ bad_area_nosemaphore: /* Kernel addresses are always protection faults */ tsk->thread.error_code = error_code | (address >= TASK_SIZE); tsk->thread.trap_no = 14; - info.si_signo = SIGSEGV; - info.si_errno = 0; - /* info.si_code has been set above */ - info.si_addr = (void __user *)address; - force_sig_info(SIGSEGV, &info, tsk); + force_sig_info_fault(SIGSEGV, si_code, address, tsk); return; } @@ -500,11 +507,7 @@ do_sigbus: tsk->thread.cr2 = address; tsk->thread.error_code = error_code; tsk->thread.trap_no = 14; - info.si_signo = SIGBUS; - info.si_errno = 0; - info.si_code = BUS_ADRERR; - info.si_addr = (void __user *)address; - force_sig_info(SIGBUS, &info, tsk); + force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk); return; vmalloc_fault: |
