lkml.org 
[lkml]   [2020]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v9 09/13] arm64: BTI: Reset BTYPE when skipping emulated instructions
Date
From: Dave Martin <Dave.Martin@arm.com>

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
\
 
 \ /
  Last update: 2020-03-11 20:33    [W:0.142 / U:0.396 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site