From: Catalin Marinas <catalin.marinas@arm.com>
To: D Scott Phillips <scott@os.amperecomputing.com>
Cc: linux-arm-kernel@lists.infradead.org,
Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
Darren Hart <darren@os.amperecomputing.com>,
patches@amperecomputing.com
Subject: Re: [PATCH v2] arm64: errata: Fix exec handling in erratum 1418040 workaround
Date: Fri, 17 Dec 2021 14:41:44 +0000 [thread overview]
Message-ID: <YbyhqB7XP9tHMfmE@arm.com> (raw)
In-Reply-To: <20211216191618.972956-1-scott@os.amperecomputing.com>
On Thu, Dec 16, 2021 at 11:16:18AM -0800, D Scott Phillips wrote:
> diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
> index 97932fbf973d..24036b914226 100644
> --- a/arch/arm64/include/asm/elf.h
> +++ b/arch/arm64/include/asm/elf.h
> @@ -160,8 +160,16 @@ typedef struct user_fpsimd_state elf_fpregset_t;
>
> #define SET_PERSONALITY(ex) \
> ({ \
> + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040)) \
> + preempt_disable(); \
> clear_thread_flag(TIF_32BIT); \
> current->personality &= ~READ_IMPLIES_EXEC; \
> + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040)) { \
> + if (this_cpu_has_cap(ARM64_WORKAROUND_1418040)) \
> + sysreg_clear_set(cntkctl_el1, 0, \
> + ARCH_TIMER_USR_VCT_ACCESS_EN); \
> + preempt_enable(); \
> + } \
> })
>
> /* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
> @@ -223,7 +231,16 @@ int compat_elf_check_arch(const struct elf32_hdr *);
> */
> #define COMPAT_SET_PERSONALITY(ex) \
> ({ \
> + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040)) \
> + preempt_disable(); \
> set_thread_flag(TIF_32BIT); \
> + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040)) { \
> + if (this_cpu_has_cap(ARM64_WORKAROUND_1418040)) \
> + sysreg_clear_set(cntkctl_el1, \
> + ARCH_TIMER_USR_VCT_ACCESS_EN, \
> + 0); \
> + preempt_enable(); \
> + } \
I don't particularly like adding more to these macros. There's
arch_setup_new_exec() that gets called after SET_PERSONALITY, so you can
check whether the task is compat or not.
Thanks.
--
Catalin
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next prev parent reply other threads:[~2021-12-17 14:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-16 19:16 [PATCH v2] arm64: errata: Fix exec handling in erratum 1418040 workaround D Scott Phillips
2021-12-16 19:52 ` Marc Zyngier
2021-12-17 14:41 ` Catalin Marinas [this message]
2021-12-17 16:42 ` D Scott Phillips
2021-12-17 18:38 ` Catalin Marinas
2021-12-17 19:29 ` D Scott Phillips
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