From: Will Deacon <will@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 3/3] arm64: insn: Report PAC and BTI instructions as NOPs
Date: Thu, 30 Apr 2020 17:09:29 +0100 [thread overview]
Message-ID: <20200430160928.GD25258@willie-the-truck> (raw)
In-Reply-To: <20200428172433.48830-4-broonie@kernel.org>
On Tue, Apr 28, 2020 at 06:24:33PM +0100, Mark Brown wrote:
> In order to allow probing of PAC and BTI instructions without more
> specialized support recognize them as NOPs.
>
> Signed-off-by: Mark Brown <broonie@kernel.org>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> ---
> arch/arm64/kernel/insn.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
> index fd77cdd87c47..82afc582d29a 100644
> --- a/arch/arm64/kernel/insn.c
> +++ b/arch/arm64/kernel/insn.c
> @@ -57,7 +57,27 @@ bool __kprobes aarch64_insn_is_nop(u32 insn)
> if (!aarch64_insn_is_hint(insn))
> return false;
>
> + /*
> + * The PAC and BTI instructons are not strictly NOPs but until
> + * better support is added we can treat them as such.
> + */
> switch (insn & 0xFE0) {
Are you deliberately omitting XPACLRI? If so, maybe add a comment to say
why, since it looks a bit weird without it.
Will
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next prev parent reply other threads:[~2020-04-30 16:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 17:24 [PATCH v2 0/3] arm64: Make NOP handling a whitelist Mark Brown
2020-04-28 17:24 ` [PATCH v2 1/3] arm64: insn: Don't assume unrecognized HINTs are NOPs Mark Brown
2020-04-30 16:08 ` Will Deacon
2020-04-28 17:24 ` [PATCH v2 2/3] arm64: insn: Add constants for PAC and BTI instruction decode Mark Brown
2020-04-30 16:07 ` Will Deacon
2020-04-30 16:45 ` Mark Brown
2020-04-28 17:24 ` [PATCH v2 3/3] arm64: insn: Report PAC and BTI instructions as NOPs Mark Brown
2020-04-30 16:09 ` Will Deacon [this message]
2020-04-30 17:16 ` Mark Brown
2020-04-30 17:20 ` Will Deacon
2020-04-30 17:36 ` Mark Brown
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