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
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index fc921bf..0e41753 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -359,7 +359,7 @@
mfspr r5,SPRN_ESR; /* Grab the ESR and save it */ \
stw r5,_ESR(r11); \
mfspr r4,SPRN_DEAR; /* Grab the DEAR */ \
- EXC_XFER_EE_LITE(0x0300, handle_page_fault)
+ EXC_XFER_LITE(0x0300, handle_page_fault)
#define INSTRUCTION_STORAGE_EXCEPTION \
START_EXCEPTION(InstructionStorage) \
@@ -368,7 +368,7 @@
stw r5,_ESR(r11); \
mr r4,r12; /* Pass SRR0 as arg2 */ \
li r5,0; /* Pass zero as arg3 */ \
- EXC_XFER_EE_LITE(0x0400, handle_page_fault)
+ EXC_XFER_LITE(0x0400, handle_page_fault)
#define ALIGNMENT_EXCEPTION \
START_EXCEPTION(Alignment) \