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x86: do_page_fault small unification

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Copy the prefetch of map_sem from X86_64 and move the check
notify_page_fault (soon to be kprobe_handle_fault) out of
the unlikely if() statement.

This makes the X86_32|64 pagefault handlers closer to each
other.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Harvey Harrison 2008-01-30 13:33:12 +01:00 committed by Ingo Molnar
parent f2857ce920
commit 608566b4ed
2 changed files with 9 additions and 14 deletions
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16
arch/x86/mm/fault_32.c
View File

@ -295,13 +295,18 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
*/
trace_hardirqs_fixup();
tsk = current;
mm = tsk->mm;
prefetchw(&mm->mmap_sem);
/* get the address */
address = read_cr2();
tsk = current;
si_code = SEGV_MAPERR;
if (notify_page_fault(regs))
return;
/*
* We fault-in kernel-space virtual memory on-demand. The
* 'reference' page table is init_mm.pgd.
@ -319,8 +324,6 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
vmalloc_fault(address) >= 0)
return;
if (notify_page_fault(regs))
return;
/*
* Don't take the mm semaphore here. If we fixup a prefetch
* fault we could otherwise deadlock.
@ -328,16 +331,11 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
goto bad_area_nosemaphore;
}
if (notify_page_fault(regs))
return;
/* It's safe to allow irq's after cr2 has been saved and the vmalloc
fault has been handled. */
if (regs->flags & (X86_EFLAGS_IF|VM_MASK))
local_irq_enable();
mm = tsk->mm;
/*
* If we're in an interrupt, have no user context or are running in an
* atomic region then we must not take the fault.

7
arch/x86/mm/fault_64.c
View File

@ -355,6 +355,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
si_code = SEGV_MAPERR;
if (notify_page_fault(regs))
return;
/*
* We fault-in kernel-space virtual memory on-demand. The
@ -380,8 +382,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
if (vmalloc_fault(address) >= 0)
return;
}
if (notify_page_fault(regs))
return;
/*
* Don't take the mm semaphore here. If we fixup a prefetch
* fault we could otherwise deadlock.
@ -389,9 +389,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
goto bad_area_nosemaphore;
}
if (notify_page_fault(regs))
return;
if (likely(regs->flags & X86_EFLAGS_IF))
local_irq_enable();