linux-kernel - [PATCH 11/16] ARM: Advance the IT state on successful emulation of an UNDEF

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Date:   Fri, 21 Jul 2017 18:15:37 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 11/16] ARM: Advance the IT state on successful emulation of an UNDEF

When trapping a conditional Thumb instruction, we need to
advance the IT state accordingly, or we'll end-up corrupting
the execution of a subsequent instruction.

Let's add calls to arm_advance_itstate() in the relevant
spots.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 arch/arm/kernel/traps.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index ca51e80a60b6..b697e9234a07 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -472,11 +472,14 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 		else
 			regs->ARM_pc +=4;
 
+		arm_advance_itstate(regs);
 		return;
 	}
 
-	if (call_undef_hook(regs, instr) == 0)
+	if (call_undef_hook(regs, instr) == 0) {
+		arm_advance_itstate(regs);
 		return;
+	}
 
 die_sig:
 #ifdef CONFIG_DEBUG_USER
-- 
2.11.0