linux-kernel - Re: [PATCH v2] arm64: vdso32: add CONFIG_THUMB2_COMPAT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200609203502.GA21214@gaia>
Date:   Tue, 9 Jun 2020 21:35:03 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Will Deacon <will@...nel.org>, Stephen Boyd <swboyd@...gle.com>,
        Robin Murphy <robin.murphy@....com>,
        Dave Martin <Dave.Martin@....com>,
        Luis Lozano <llozano@...gle.com>,
        Manoj Gupta <manojgupta@...gle.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Nathan Chancellor <natechancellor@...il.com>,
        Naohiro Aota <naohiro.aota@....com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH v2] arm64: vdso32: add CONFIG_THUMB2_COMPAT_VDSO

On Mon, Jun 08, 2020 at 01:57:08PM -0700, Nick Desaulniers wrote:
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 7f9d38444d6d..fe9e6b231cac 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1299,6 +1299,14 @@ config COMPAT_VDSO
>  	  You must have a 32-bit build of glibc 2.22 or later for programs
>  	  to seamlessly take advantage of this.
>  
> +config THUMB2_COMPAT_VDSO
> +	bool "Compile the vDSO in THUMB2 mode"
> +	depends on COMPAT_VDSO
> +	default y
> +	help
> +	  Compile the compat vDSO with -mthumb -fomit-frame-pointer if y, otherwise
> +	  as -marm.

Now that we understood the issue (I think), do we actually need this
choice? Why not going for -mthumb -fomit-frame-pointer always for the
compat vdso?

-- 
Catalin