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From: Kees Cook <keescook@chromium.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, linux-arch@vger.kernel.org,
	Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Mark Rutland <mark.rutland@arm.com>,
	Keno Fischer <keno@juliacomputing.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	kvm@vger.kernel.org
Subject: Re: [patch V3 02/13] entry: Provide generic syscall exit function
Date: Thu, 16 Jul 2020 13:55:11 -0700	[thread overview]
Message-ID: <202007161354.62030182F@keescook> (raw)
In-Reply-To: <20200716185424.116500611@linutronix.de>

On Thu, Jul 16, 2020 at 08:22:10PM +0200, Thomas Gleixner wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
> 
> Like syscall entry all architectures have similar and pointlessly different
> code to handle pending work before returning from a syscall to user space.
> 
>   1) One-time syscall exit work:
>       - rseq syscall exit
>       - audit
>       - syscall tracing
>       - tracehook (single stepping)
> 
>   2) Preparatory work
>       - Exit to user mode loop (common TIF handling).
>       - Architecture specific one time work arch_exit_to_user_mode_prepare()
>       - Address limit and lockdep checks
>      
>   3) Final transition (lockdep, tracing, context tracking, RCU). Invokes
>      arch_exit_to_user_mode() to handle e.g. speculation mitigations
> 
> Provide a generic version based on the x86 code which has all the RCU and
> instrumentation protections right.
> 
> Provide a variant for interrupt return to user mode as well which shares
> the above #2 and #3 work items.
> 
> After syscall_exit_to_user_mode() and irqentry_exit_to_user_mode() the
> architecture code just has to return to user space. The code after
> returning from these functions must not be instrumented.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

This looks correct to me. Did you happen to run the seccomp selftests
under this series?

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

  reply	other threads:[~2020-07-16 20:55 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16 18:22 [patch V3 00/13] entry, x86, kvm: Generic entry/exit functionality for host and guest Thomas Gleixner
2020-07-16 18:22 ` [patch V3 01/13] entry: Provide generic syscall entry functionality Thomas Gleixner
2020-07-16 20:52   ` Kees Cook
2020-07-16 21:55     ` Thomas Gleixner
2020-07-17 17:49       ` Kees Cook
2020-07-17 19:29         ` Thomas Gleixner
2020-07-17 21:56           ` Andy Lutomirski
2020-07-18 14:16             ` Thomas Gleixner
2020-07-18 14:41               ` Andy Lutomirski
2020-07-19 10:17                 ` Thomas Gleixner
2020-07-19 10:17                   ` Thomas Gleixner
2020-07-19 10:17                   ` Thomas Gleixner
2020-07-19 15:25                   ` Andy Lutomirski
2020-07-20  6:50                     ` Thomas Gleixner
2020-07-27 22:28   ` Andy Lutomirski
2020-07-16 18:22 ` [patch V3 02/13] entry: Provide generic syscall exit function Thomas Gleixner
2020-07-16 20:55   ` Kees Cook [this message]
2020-07-16 21:28     ` Thomas Gleixner
2020-07-16 18:22 ` [patch V3 03/13] entry: Provide generic interrupt entry/exit code Thomas Gleixner
2020-07-16 18:22 ` [patch V3 04/13] entry: Provide infrastructure for work before exiting to guest mode Thomas Gleixner
2020-07-16 18:22 ` [patch V3 05/13] x86/entry: Consolidate check_user_regs() Thomas Gleixner
2020-07-16 20:56   ` Kees Cook
2020-07-16 18:22 ` [patch V3 06/13] x86/entry: Consolidate 32/64 bit syscall entry Thomas Gleixner
2020-07-16 18:22 ` [patch V3 07/13] x86/ptrace: Provide pt_regs helpers for entry/exit Thomas Gleixner
2020-07-16 20:57   ` Kees Cook
2020-07-16 18:22 ` [patch V3 08/13] x86/entry: Use generic syscall entry function Thomas Gleixner
2020-07-16 21:13   ` Kees Cook
2020-07-16 21:33     ` Thomas Gleixner
2020-07-16 18:22 ` [patch V3 09/13] x86/entry: Use generic syscall exit functionality Thomas Gleixner
2020-07-16 18:22 ` [patch V3 10/13] x86/entry: Cleanup idtentry_entry/exit_user Thomas Gleixner
2020-07-16 18:22 ` [patch V3 11/13] x86/entry: Use generic interrupt entry/exit code Thomas Gleixner
2020-07-16 18:22 ` [patch V3 12/13] x86/entry: Cleanup idtentry_enter/exit Thomas Gleixner
2020-07-16 18:22 ` [patch V3 13/13] x86/kvm: Use generic exit to guest work function Thomas Gleixner

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