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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 5/6] arm64: kprobe: disable probe of fault prone ptrauth instruction
Date: Mon, 14 Sep 2020 14:06:55 +0530	[thread overview]
Message-ID: <20200914083656.21428-6-amit.kachhap@arm.com> (raw)
In-Reply-To: <20200914083656.21428-1-amit.kachhap@arm.com>

With the addition of ARMv8.3-FPAC feature, the probe of authenticate
ptrauth instructions (AUT*) may cause ptrauth fault exception in case of
authenticate failure so they cannot be safely single stepped.

Hence the probe of authenticate instructions is disallowed but the
corresponding pac ptrauth instruction (PAC*) is not affected and they can
still be probed. Also AUTH* instructions do not make sense at function
entry points so most realistic probes would be unaffected by this change.

Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
---
 arch/arm64/kernel/insn.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index ccc8c9e22b25..6c0de2f60ea9 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -60,16 +60,10 @@ bool __kprobes aarch64_insn_is_steppable_hint(u32 insn)
 	case AARCH64_INSN_HINT_XPACLRI:
 	case AARCH64_INSN_HINT_PACIA_1716:
 	case AARCH64_INSN_HINT_PACIB_1716:
-	case AARCH64_INSN_HINT_AUTIA_1716:
-	case AARCH64_INSN_HINT_AUTIB_1716:
 	case AARCH64_INSN_HINT_PACIAZ:
 	case AARCH64_INSN_HINT_PACIASP:
 	case AARCH64_INSN_HINT_PACIBZ:
 	case AARCH64_INSN_HINT_PACIBSP:
-	case AARCH64_INSN_HINT_AUTIAZ:
-	case AARCH64_INSN_HINT_AUTIASP:
-	case AARCH64_INSN_HINT_AUTIBZ:
-	case AARCH64_INSN_HINT_AUTIBSP:
 	case AARCH64_INSN_HINT_BTI:
 	case AARCH64_INSN_HINT_BTIC:
 	case AARCH64_INSN_HINT_BTIJ:
-- 
2.17.1


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  parent reply	other threads:[~2020-09-14  8:38 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 ` Amit Daniel Kachhap [this message]
2020-09-14  8:36 ` [PATCH v8 6/6] arm64: kprobe: clarify the comment of steppable hint instructions Amit Daniel Kachhap
2020-09-14 12:16 ` [PATCH v8 0/6] arm64: add Armv8.3 pointer authentication enhancements Will Deacon

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