powerpc/kprobes: Do not disable External interrupts during single step (85f395c5) · Commits · 戴 / test

External/Decrement exceptions have lower priority than the Debug Exception. So, we don't have to disable the External interrupts before a single step. However, on BookE, Critical Input Exception(CE) has higher priority than a Debug Exception. Hence we mask them. Signed-off-by:

Suzuki K. Poulose <suzuki@in.ibm.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Ananth N Mavinakaynahalli <ananth@in.ibm.com> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: linuxppc-dev@ozlabs.org Signed-off-by:

Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/kprobes.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -104,13 +104,13 @@ void __kprobes arch_remove_kprobe(struct kprobe *p)

		static void __kprobes prepare_singlestep(struct kprobe p, struct pt_regs regs)
		{
		/* We turn off async exceptions to ensure that the single step will
		* be for the instruction we have the kprobe on, if we dont its
		* possible we'd get the single step reported for an exception handler
		* like Decrementer or External Interrupt */
		regs->msr &= ~MSR_EE;
		regs->msr \|= MSR_SINGLESTEP;
		#ifdef CONFIG_PPC_ADV_DEBUG_REGS
		/*
		* We turn off Critical Input Exception(CE) to ensure that the single
		* step will be for the instruction we have the probe on; if we don't,
		* it is possible we'd get the single step reported for CE.
		*/
		regs->msr &= ~MSR_CE;
		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) \| DBCR0_IC \| DBCR0_IDM);
		#ifdef CONFIG_PPC_47x

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