From: Amit Daniel Kachhap <amit.kachhap@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Brown <broonie@kernel.org>,
James Morse <james.morse@arm.com>,
Amit Daniel Kachhap <amit.kachhap@arm.com>,
Vincenzo Frascino <Vincenzo.Frascino@arm.com>,
Will Deacon <will@kernel.org>, Dave Martin <Dave.Martin@arm.com>
Subject: [PATCH v8 6/6] arm64: kprobe: clarify the comment of steppable hint instructions
Date: Mon, 14 Sep 2020 14:06:56 +0530 [thread overview]
Message-ID: <20200914083656.21428-7-amit.kachhap@arm.com> (raw)
In-Reply-To: <20200914083656.21428-1-amit.kachhap@arm.com>
The existing comment about steppable hint instruction is not complete
and only describes NOP instructions as steppable. As the function
aarch64_insn_is_steppable_hint allows all white-listed instruction
to be probed so the comment is updated to reflect this.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
---
arch/arm64/kernel/probes/decode-insn.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c
index c541fb48886e..104101f633b1 100644
--- a/arch/arm64/kernel/probes/decode-insn.c
+++ b/arch/arm64/kernel/probes/decode-insn.c
@@ -43,8 +43,10 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn)
!= AARCH64_INSN_SPCLREG_DAIF;
/*
- * The HINT instruction is is problematic when single-stepping,
- * except for the NOP case.
+ * The HINT instruction is steppable only if it is in whitelist
+ * and the rest of other such instructions are blocked for
+ * single stepping as they may cause exception or other
+ * unintended behaviour.
*/
if (aarch64_insn_is_hint(insn))
return aarch64_insn_is_steppable_hint(insn);
--
2.17.1
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next prev parent reply other threads:[~2020-09-14 8:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-14 8:36 [PATCH v8 0/6] arm64: add Armv8.3 pointer authentication enhancements Amit Daniel Kachhap
2020-09-14 8:36 ` [PATCH v8 1/6] arm64: kprobe: add checks for ARMv8.3-PAuth combined instructions Amit Daniel Kachhap
2020-09-14 8:36 ` [PATCH v8 2/6] arm64: traps: Allow force_signal_inject to pass esr error code Amit Daniel Kachhap
2020-09-14 8:36 ` [PATCH v8 3/6] arm64: ptrauth: Introduce Armv8.3 pointer authentication enhancements Amit Daniel Kachhap
2020-09-14 8:36 ` [PATCH v8 4/6] arm64: cpufeature: Modify address authentication cpufeature to exact Amit Daniel Kachhap
2020-09-14 10:22 ` Catalin Marinas
2020-09-14 8:36 ` [PATCH v8 5/6] arm64: kprobe: disable probe of fault prone ptrauth instruction Amit Daniel Kachhap
2020-09-14 8:36 ` Amit Daniel Kachhap [this message]
2020-09-14 12:16 ` [PATCH v8 0/6] arm64: add Armv8.3 pointer authentication enhancements Will Deacon
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