linux-kernel - Re: [PATCH v2 3/4] arm64: arch_timer: Disable the compat vdso for cores affected by ARM64_WORKAROUND

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: <20200706165712.GB61340@C02TD0UTHF1T.local>
Date:   Mon, 6 Jul 2020 17:57:12 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     Marc Zyngier <maz@...nel.org>
Cc:     Will Deacon <will@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel-team@...roid.com, stable@...r.kernel.org
Subject: Re: [PATCH v2 3/4] arm64: arch_timer: Disable the compat vdso for
 cores affected by ARM64_WORKAROUND_1418040

On Mon, Jul 06, 2020 at 05:38:01PM +0100, Marc Zyngier wrote:
> ARM64_WORKAROUND_1418040 requires that AArch32 EL0 accesses to
> the virtual counter register are trapped and emulated by the kernel.
> This makes the vdso pretty pointless, and in some cases livelock
> prone.
> 
> Provide a workaround entry that limits the vdso to 64bit tasks.
> 
> Cc: stable@...r.kernel.org
> Signed-off-by: Marc Zyngier <maz@...nel.org>

Acked-by: Mark Rutland <mark.rutland@....com>

Mark.

> ---
>  drivers/clocksource/arm_arch_timer.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index a8e4fb429f52..6c3e84180146 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -480,6 +480,14 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = {
>  		.set_next_event_virt = erratum_set_next_event_tval_virt,
>  	},
>  #endif
> +#ifdef CONFIG_ARM64_ERRATUM_1418040
> +	{
> +		.match_type = ate_match_local_cap_id,
> +		.id = (void *)ARM64_WORKAROUND_1418040,
> +		.desc = "ARM erratum 1418040",
> +		.disable_compat_vdso = true,
> +	},
> +#endif
>  };
>  
>  typedef bool (*ate_match_fn_t)(const struct arch_timer_erratum_workaround *,
> -- 
> 2.27.0
>