From a546498f3bf9aac311c66f965186373aee2ca0b0 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 7 Mar 2012 16:48:45 +1100 Subject: 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 --- v2. Add the r12 clobber fix --- arch/powerpc/kernel/head_32.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/head_32.S') diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index 0654dba2c1f1..dc0488b6f6e1 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -395,7 +395,7 @@ DataAccess: bl hash_page 1: lwz r5,_DSISR(r11) /* get DSISR value */ mfspr r4,SPRN_DAR - EXC_XFER_EE_LITE(0x300, handle_page_fault) + EXC_XFER_LITE(0x300, handle_page_fault) /* Instruction access exception. */ @@ -410,7 +410,7 @@ InstructionAccess: bl hash_page 1: mr r4,r12 mr r5,r9 - EXC_XFER_EE_LITE(0x400, handle_page_fault) + EXC_XFER_LITE(0x400, handle_page_fault) /* External interrupt */ EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE) -- cgit v1.2.3