From: Andy Lutomirski <luto@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <maz@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
kvm list <kvm@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>
Subject: Re: [RFC patch 01/15] entry: Provide generic syscall entry functionality
Date: Fri, 20 Sep 2019 16:38:28 -0700 [thread overview]
Message-ID: <CALCETrXB92rZqHMyhSULWVY3Q5=t9q4N9aZFCTn4k0DMNPJfMQ@mail.gmail.com> (raw)
In-Reply-To: <20190919150808.521907403@linutronix.de>
On Thu, Sep 19, 2019 at 8:09 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On syscall entry certain work needs to be done conditionally like tracing,
> seccomp etc. This code is duplicated in all architectures.
>
> Provide a generic version.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/Kconfig | 3 +
> include/linux/entry-common.h | 122 +++++++++++++++++++++++++++++++++++++++++++
> kernel/Makefile | 1
> kernel/entry/Makefile | 3 +
> kernel/entry/common.c | 33 +++++++++++
> 5 files changed, 162 insertions(+)
>
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -27,6 +27,9 @@ config HAVE_IMA_KEXEC
> config HOTPLUG_SMT
> bool
>
> +config GENERIC_ENTRY
> + bool
> +
> config OPROFILE
> tristate "OProfile system profiling"
> depends on PROFILING
> --- /dev/null
> +++ b/include/linux/entry-common.h
> @@ -0,0 +1,122 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __LINUX_ENTRYCOMMON_H
> +#define __LINUX_ENTRYCOMMON_H
> +
> +#include <linux/tracehook.h>
> +#include <linux/syscalls.h>
> +#include <linux/seccomp.h>
> +#include <linux/sched.h>
> +#include <linux/audit.h>
> +
> +#include <asm/entry-common.h>
> +
> +/*
> + * Define dummy _TIF work flags if not defined by the architecture or for
> + * disabled functionality.
> + */
> +#ifndef _TIF_SYSCALL_TRACE
> +# define _TIF_SYSCALL_TRACE (0)
> +#endif
> +
> +#ifndef _TIF_SYSCALL_EMU
> +# define _TIF_SYSCALL_EMU (0)
> +#endif
> +
> +#ifndef _TIF_SYSCALL_TRACEPOINT
> +# define _TIF_SYSCALL_TRACEPOINT (0)
> +#endif
> +
> +#ifndef _TIF_SECCOMP
> +# define _TIF_SECCOMP (0)
> +#endif
> +
> +#ifndef _TIF_AUDIT
> +# define _TIF_AUDIT (0)
> +#endif
I'm wondering if these should be __TIF (double-underscore) or
MAYBE_TIF_ or something to avoid errors where people do flags |=
TIF_WHATEVER and get surprised.
> +/**
> + * syscall_enter_from_usermode - Check and handle work before invoking
> + * a syscall
> + * @regs: Pointer to currents pt_regs
> + * @syscall: The syscall number
> + *
> + * Invoked from architecture specific syscall entry code with interrupts
> + * enabled.
> + *
> + * Returns: The original or a modified syscall number
> + */
Maybe document that it can return -1 to skip the syscall and that, if
this happens, it may use syscall_set_error() or
syscall_set_return_value() first. If neither of those is called and
-1 is returned, then the syscall will fail with ENOSYS.
next prev parent reply other threads:[~2019-09-20 23:38 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 15:03 [RFC patch 00/15] entry: Provide generic implementation for host and guest entry/exit work Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 01/15] entry: Provide generic syscall entry functionality Thomas Gleixner
2019-09-20 23:38 ` Andy Lutomirski [this message]
2019-10-20 11:49 ` Thomas Gleixner
2019-09-23 9:05 ` Mike Rapoport
2019-09-19 15:03 ` [RFC patch 02/15] x86/entry: Remove _TIF_NOHZ from _TIF_WORK_SYSCALL_ENTRY Thomas Gleixner
2019-09-20 23:39 ` Andy Lutomirski
2019-09-23 20:43 ` Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 03/15] x86/entry: Use generic syscall entry function Thomas Gleixner
2019-09-20 23:41 ` Andy Lutomirski
2019-09-23 8:31 ` Peter Zijlstra
2019-09-23 8:40 ` Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 04/15] arm64/entry: " Thomas Gleixner
2019-09-20 12:21 ` Catalin Marinas
2019-09-19 15:03 ` [RFC patch 05/15] entry: Provide generic syscall exit function Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 06/15] x86/entry: Use generic syscall exit functionality Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 07/15] arm64/syscall: Remove obscure flag check Thomas Gleixner
2019-09-20 14:29 ` Catalin Marinas
2019-09-19 15:03 ` [RFC patch 08/15] arm64/syscall: Use generic syscall exit functionality Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 09/15] entry: Provide generic exit to usermode functionality Thomas Gleixner
2019-09-23 8:30 ` Peter Zijlstra
2019-09-19 15:03 ` [RFC patch 10/15] x86/entry: Move irq tracing to C code Thomas Gleixner
2019-09-23 8:47 ` Peter Zijlstra
2019-09-23 10:27 ` Thomas Gleixner
2019-09-23 11:49 ` Peter Zijlstra
2019-09-23 11:55 ` Peter Zijlstra
2019-09-23 12:10 ` Peter Zijlstra
2019-09-23 17:24 ` Andy Lutomirski
2019-09-26 2:59 ` Josh Poimboeuf
2019-09-19 15:03 ` [RFC patch 11/15] x86/entry: Use generic exit to usermode Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 12/15] arm64/entry: " Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 13/15] arm64/entry: Move FPU restore out of exit_to_usermode() loop Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 14/15] workpending: Provide infrastructure for work before entering a guest Thomas Gleixner
2019-09-19 15:40 ` Paolo Bonzini
2019-09-20 11:48 ` Thomas Gleixner
2019-09-23 18:17 ` Andy Lutomirski
2019-09-26 11:35 ` Miroslav Benes
2019-09-19 15:03 ` [RFC patch 15/15] x86/kvm: Use GENERIC_EXIT_WORKPENDING Thomas Gleixner
2019-09-19 15:40 ` Paolo Bonzini
2019-09-20 15:12 ` [RFC patch 00/15] entry: Provide generic implementation for host and guest entry/exit work Mark Rutland
2019-09-23 20:50 ` Thomas Gleixner
2019-09-23 18:18 ` Andy Lutomirski
2019-09-24 6:50 ` Christian Borntraeger
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