From: Rob Herring <robh@kernel.org>
To: Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
Raphael Gault <raphael.gault@arm.com>
Subject: [PATCH v2] arm64: Restrict undef hook for cpufeature registers
Date: Mon, 17 May 2021 13:02:56 -0500 [thread overview]
Message-ID: <20210517180256.2881891-1-robh@kernel.org> (raw)
From: Raphael Gault <raphael.gault@arm.com>
This commit modifies the mask of the mrs_hook declared in
arch/arm64/kernel/cpufeatures.c which emulates only feature register
access. This is necessary because this hook's mask was too large and
thus masking any mrs instruction, even if not related to the emulated
registers which made the pmu emulation inefficient.
Signed-off-by: Raphael Gault <raphael.gault@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
---
I don't *think* I'm going to need this for the perf userspace counter
access, but this patch stands on its own as the PMU registers are not
emulated. So please apply it.
v2:
- Fix warning for set but unused sys_reg
---
arch/arm64/kernel/cpufeature.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index efed2830d141..c773f7c3c007 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2905,8 +2905,8 @@ static int emulate_mrs(struct pt_regs *regs, u32 insn)
}
static struct undef_hook mrs_hook = {
- .instr_mask = 0xfff00000,
- .instr_val = 0xd5300000,
+ .instr_mask = 0xffff0000,
+ .instr_val = 0xd5380000,
.pstate_mask = PSR_AA32_MODE_MASK,
.pstate_val = PSR_MODE_EL0t,
.fn = emulate_mrs,
--
2.27.0
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next reply other threads:[~2021-05-17 18:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-17 18:02 Rob Herring [this message]
2021-06-08 15:20 ` [PATCH v2] arm64: Restrict undef hook for cpufeature registers Catalin Marinas
2021-06-08 16:34 ` Will Deacon
2021-06-11 16:04 ` Rob Herring
2021-06-23 14:00 ` Will Deacon
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