[PATCH v7 09/11] arm64: BTI: Reset BTYPE when skipping emulated instructions

Mark Brown
2020-02-26T15:57:58Z

Since normal execution of any non-branch instruction resets the
PSTATE BTYPE field to 0, so do the same thing when emulating a
trapped instruction.

Branches don't trap directly, so we should never need to assign a
non-zero value to BTYPE here.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/kernel/traps.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 3c07a7074145..52ed261e7739 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -335,6 +335,8 @@ void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)

if (compat_user_mode(regs))
advance_itstate(regs);
+ else
+ regs->pstate &= ~PSR_BTYPE_MASK;
}

static LIST_HEAD(undef_hook);
--
2.20.1