From: Will Deacon <will@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>,
linux-arm-kernel@lists.infradead.org, keescook@chromium.org,
dave.martin@arm.com
Subject: Re: [PATCH v4 2/2] arm64: Introduce HWCAPS2_EXECONLY
Date: Mon, 29 Mar 2021 09:53:10 +0100 [thread overview]
Message-ID: <20210329085309.GB2965@willie-the-truck> (raw)
In-Reply-To: <20210326093553.GA5126@arm.com>
On Fri, Mar 26, 2021 at 09:35:53AM +0000, Catalin Marinas wrote:
> On Thu, Mar 25, 2021 at 07:00:00PM +0000, Will Deacon wrote:
> > On Fri, Mar 12, 2021 at 05:38:11PM +0000, Vladimir Murzin wrote:
> > > With EPAN supported it might be handy to user know that PROT_EXEC
> > > gives execute-only permission, so advertise it via HWCAPS2_EXECONLY
> > >
> > > Cc: Kees Cook <keescook@chromium.org>
> > > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > > Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
> > > ---
> > > arch/arm64/include/asm/hwcap.h | 1 +
> > > arch/arm64/include/asm/sysreg.h | 1 +
> > > arch/arm64/include/uapi/asm/hwcap.h | 1 +
> > > arch/arm64/kernel/cpufeature.c | 3 +++
> > > arch/arm64/kernel/cpuinfo.c | 1 +
> > > 5 files changed, 7 insertions(+)
> >
> > I still don't see the need for this patch. Can we avoid merging it until
> > somebody has a use for it, please?
>
> It's more about telling user-space that the feature is present though we
> didn't do this last time we had exec-only permissions either. I was
> hoping we can do better this time. OTOH, probably no-one will check for
> this HWCAP anyway, so let's wait until someone asks for it.
Yes, that's what I mean by "somebody has a use for it" -- I don't understand
what userspace would do with this and it's certainly not using it now.
Will
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next prev parent reply other threads:[~2021-03-29 21:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-12 17:38 [PATCH v4 0/2] arm64: Support Enhanced PAN Vladimir Murzin
2021-03-12 17:38 ` [PATCH v4 1/2] arm64: Support execute-only permissions with " Vladimir Murzin
2021-03-25 19:06 ` Will Deacon
2021-03-26 11:04 ` Catalin Marinas
2021-03-30 8:47 ` Geert Uytterhoeven
2021-03-30 9:30 ` Catalin Marinas
2021-03-30 9:34 ` Geert Uytterhoeven
2021-03-12 17:38 ` [PATCH v4 2/2] arm64: Introduce HWCAPS2_EXECONLY Vladimir Murzin
2021-03-25 19:00 ` Will Deacon
2021-03-26 9:35 ` Catalin Marinas
2021-03-29 8:53 ` Will Deacon [this message]
2021-03-26 11:05 ` (subset) [PATCH v4 0/2] arm64: Support Enhanced PAN Catalin Marinas
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