From: Mark Brown <broonie@kernel.org>
To: Dave Martin <Dave.Martin@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Jeremy Linton <jeremy.linton@arm.com>,
"H . J . Lu" <hjl.tools@gmail.com>,
Yu-cheng Yu <yu-cheng.yu@intel.com>,
linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
libc-alpha@sourceware.org
Subject: Re: [PATCH v2 2/3] arm64: Enable BTI for main executable as well as the interpreter
Date: Thu, 10 Jun 2021 14:19:05 +0100 [thread overview]
Message-ID: <YMIRSSMnP3UMwdRy@sirena.org.uk> (raw)
In-Reply-To: <20210609151713.GL4187@arm.com>
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On Wed, Jun 09, 2021 at 04:17:13PM +0100, Dave Martin wrote:
> On Fri, Jun 04, 2021 at 12:24:49PM +0100, Mark Brown wrote:
> > - if (system_supports_bti() && has_interp == is_interp &&
> > - (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
> > - arch->flags |= ARM64_ELF_BTI;
> > + if (system_supports_bti() &&
> > + (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
> > + if (is_interp) {
> > + arch->flags |= ARM64_ELF_INTERP_BTI;
> > + } else {
> > + arch->flags |= ARM64_ELF_EXEC_BTI;
> > + }
> Nit: surplus curlies? (coding-style.rst does actually say to drop them
> when all branches of an if are single-statement one-liners -- I had
> presumed I was just being pedantic...)
I really think this hurts readability with the nested if inside
another if with a multi-line condition.
> > - if (prot & PROT_EXEC)
> > - prot |= PROT_BTI;
> > + if (state->flags & ARM64_ELF_EXEC_BTI && !is_interp)
> > + prot |= PROT_BTI;
> > + }
> Is it worth adding () around the bitwise-& expressions? I'm always a
> little uneasy about the operator precedence of binary &, although
> without looking it up I think you're correct.
Sure. I'm fairly sure the compiler would've complained about
this case if it were ambiguous, I'm vaguely surprised it didn't
already.
> Feel free to adopt if this appeals to you, otherwise I'm also fine with
> your version.)
I'll see what I think when I get back to looking at this
properly.
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next prev parent reply other threads:[~2021-06-10 13:54 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 11:24 [PATCH v2 0/3] arm64: Enable BTI for the executable as well as the interpreter Mark Brown
2021-06-04 11:24 ` [PATCH v2 1/3] elf: Allow architectures to parse properties on the main executable Mark Brown
2021-06-09 15:16 ` Dave Martin
2021-06-10 13:41 ` Mark Brown
2021-06-04 11:24 ` [PATCH v2 2/3] arm64: Enable BTI for main executable as well as the interpreter Mark Brown
2021-06-09 15:17 ` Dave Martin
2021-06-10 13:19 ` Mark Brown [this message]
2021-06-10 15:34 ` Dave Martin
2021-06-04 11:24 ` [PATCH v2 3/3] elf: Remove has_interp property from arch_adjust_elf_prot() Mark Brown
2021-06-09 15:17 ` Dave Martin
2021-06-09 16:55 ` Yu, Yu-cheng
2021-06-10 9:58 ` Dave Martin
2021-06-10 18:17 ` Yu, Yu-cheng
2021-06-10 13:34 ` Mark Brown
2021-06-10 15:40 ` Dave Martin
2021-06-10 16:28 ` [PATCH v2 0/3] arm64: Enable BTI for the executable as well as the interpreter Jeremy Linton
2021-06-14 16:00 ` Mark Brown
2021-06-15 15:22 ` Dave Martin
2021-06-15 15:33 ` Mark Brown
2021-06-15 15:41 ` Dave Martin
2021-06-16 5:12 ` Jeremy Linton
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