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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-03-07 05:48:45 (GMT) |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-03-08 23:55:08 (GMT) |
commit | a546498f3bf9aac311c66f965186373aee2ca0b0 (patch) | |
tree | 86fb9a778aba26df3810acd8e52a921a2d84489b /arch/powerpc/mm | |
parent | 1b70117924a4f254840ed70fbe3020d4519a1a9a (diff) | |
download | linux-fsl-qoriq-a546498f3bf9aac311c66f965186373aee2ca0b0.tar.xz |
powerpc: Call do_page_fault() with interrupts off
We currently turn interrupts back to their previous state before
calling do_page_fault(). This can be annoying when debugging as
a bad fault will potentially have lost some processor state before
getting into the debugger.
We also end up calling some generic code with interrupts enabled
such as notify_page_fault() with interrupts enabled, which could
be unexpected.
This changes our code to behave more like other architectures,
and make the assembly entry code call into do_page_faults() with
interrupts disabled. They are conditionally re-enabled from
within do_page_fault() in the same spot x86 does it.
While there, add the might_sleep() test in the case of a successful
trylock of the mmap semaphore, again like x86.
Also fix a bug in the existing assembly where r12 (_MSR) could get
clobbered by C calls (the DTL accounting in the exception common
macro and DISABLE_INTS) in some cases.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
v2. Add the r12 clobber fix
Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r-- | arch/powerpc/mm/fault.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 2f0d1b0..7e89006 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -179,6 +179,10 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, } #endif + /* We restore the interrupt state now */ + if (!arch_irq_disabled_regs(regs)) + local_irq_enable(); + if (in_atomic() || mm == NULL) { if (!user_mode(regs)) return SIGSEGV; @@ -213,6 +217,13 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, goto bad_area_nosemaphore; down_read(&mm->mmap_sem); + } else { + /* + * The above down_read_trylock() might have succeeded in + * which case we'll have missed the might_sleep() from + * down_read(): + */ + might_sleep(); } vma = find_vma(mm, address); |