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arm64: kprobes: WARN if attempting to step with PSTATE.D=1

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Stepping with PSTATE.D=1 is bad news. The step won't generate a debug
exception and we'll likely walk off into random data structures. This
should never happen, but when it does, it's a PITA to debug. Add a
WARN_ON to shout if we realise this is about to take place.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Will Deacon 2016-07-19 15:07:39 +01:00 committed by Catalin Marinas
parent af78cede8b
commit 44bd887ce1
1 changed files with 2 additions and 0 deletions
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arch/arm64/kernel/probes/kprobes.c
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@ -254,6 +254,8 @@ static void __kprobes setup_singlestep(struct kprobe *p,
if (kcb->kprobe_status == KPROBE_REENTER)
spsr_set_debug_flag(regs, 0);
else
WARN_ON(regs->pstate & PSR_D_BIT);
/* IRQs and single stepping do not mix well. */
kprobes_save_local_irqflag(kcb, regs);