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/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index bb712c9..531ba00 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -79,6 +79,11 @@
get_paca()->hard_enabled = 0; \
} while(0)
+static inline bool arch_irq_disabled_regs(struct pt_regs *regs)
+{
+ return !regs->softe;
+}
+
#else /* CONFIG_PPC64 */
#define SET_MSR_EE(x) mtmsr(x)
@@ -139,6 +144,11 @@
#define hard_irq_disable() arch_local_irq_disable()
+static inline bool arch_irq_disabled_regs(struct pt_regs *regs)
+{
+ return !(regs->msr & MSR_EE);
+}
+
#endif /* CONFIG_PPC64 */
#define ARCH_IRQ_INIT_FLAGS IRQ_NOREQUEST