From: Dominik Brodowski <linux@dominikbrodowski.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
viro@ZenIV.linux.org.uk, arnd@arndb.de,
linux-arch@vger.kernel.org, Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH 23/45] sched: add do_sched_yield() helper; remove in-kernel call to sched_yield()
Date: Thu, 22 Mar 2018 18:41:43 +0100 [thread overview]
Message-ID: <20180322174143.GA2433@light.dominikbrodowski.net> (raw)
In-Reply-To: <20180322172959.GX4043@hirez.programming.kicks-ass.net>
On Thu, Mar 22, 2018 at 06:29:59PM +0100, Peter Zijlstra wrote:
> On Thu, Mar 22, 2018 at 10:00:37AM +0100, Dominik Brodowski wrote:
> > Using the sched-internal do_sched_yield() helper allows us to get rid of
> > the sched-internal call to the sys_sched_yield() syscall.
> >
> > This patch is part of a series which tries to remove in-kernel calls to
> > syscalls. On this basis, the syscall entry path can be streamlined.
>
> But why !? Either Cc me on more of the series such that the whole makes
> sense, or better yet, write a proper Changelog.
Well, the summary is right there in the changelog: Kernel code simply should
not pretend to be userspace and call a syscall function. For a more
detailled description, see, for instance, Linus' explanation in
http://lkml.kernel.org/r/CA+55aFwo7yA1gm8AUYMEQA8ZNY-9GGF8Oup09jJFvEa4J7C+jA@mail.gmail.com :
| On x86-64, we'd like to just pass the 'struct pt_regs *' pointer, and
| have the sys_xyz() function itself just pick out the arguments it
| needs from there.
|
| That has a few reasons for it:
|
| - we can clear all registers at system call entry, which helps defeat
| some of the "pass seldom used register with user-controlled value that
| survives deep into the callchain" things that people used to leak
| information
|
| - we can streamline the low-level system call code, which needs to
| pass around 'struct pt_regs *' anyway, and the system call only picks
| up the values it actually needs
I can add such a long description to all these patches, but that seems to
be a bit... longwinded.
Thanks,
Dominik
next prev parent reply other threads:[~2018-03-22 17:41 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-22 9:00 [PATCH 00/45] remove in-kernel syscall invocations (part 3 == remainder outside arch/) Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 01/45] fs: add ksys_getdents64() helper; remove in-kernel calls to sys_getdents64() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 02/45] fs: add ksys_ioctl() helper; remove in-kernel calls to sys_ioctl() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 03/45] fs: add ksys_lseek() helper; remove in-kernel calls to sys_lseek() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 04/45] fs: add ksys_read() helper; remove in-kernel calls to sys_read() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 05/45] fs: add ksys_sync() helper; remove in-kernel calls to sys_sync() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 06/45] fs: add do_lookup_dcookie() helper; remove in-kernel call to syscall Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 07/45] fs: add do_vmsplice() " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 08/45] fs: add kern_select() helper; remove in-kernel call to sys_select() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 09/45] fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 10/45] fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscalls Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 11/45] fs: add ksys_fallocate() wrapper; remove in-kernel calls to sys_fallocate() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 12/45] fs: add do_compat_fcntl64() helper; remove in-kernel call to comapt syscall Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 13/45] fs: add do_compat_select() " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 14/45] fs: add do_compat_signalfd4() " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 15/45] fs: add do_compat_futimesat() " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 16/45] inotify: add do_inotify_init() helper; remove in-kernel call to syscall Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-26 12:25 ` Jan Kara
2018-03-26 12:25 ` Jan Kara
2018-03-22 9:00 ` [PATCH 17/45] fanotify: add do_fanotify_mark() " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-26 12:25 ` Jan Kara
2018-03-26 12:25 ` Jan Kara
2018-03-22 9:00 ` [PATCH 18/45] fs/quota: add kernel_quotactl() " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-26 12:26 ` Jan Kara
2018-03-26 12:26 ` Jan Kara
2018-03-22 9:00 ` [PATCH 19/45] fs/quota: use COMPAT_SYSCALL_DEFINE for sys32_quotactl() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-26 12:33 ` Jan Kara
2018-03-26 12:33 ` Jan Kara
2018-03-22 9:00 ` [PATCH 20/45] kernel: add do_compat_sigaltstack() helper; remove in-kernel call to compat syscall Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 21/45] kernel: add ksys_setsid() helper; remove in-kernel call to sys_setsid() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 22/45] kernel: provide ksys_*() wrappers for syscalls called by kernel/uid16.c Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 10:21 ` Any chance that kernel/uid6.c can go? [Was: [PATCH 22/45] kernel: provide ksys_*() wrappers for syscalls called by kernel/uid16.c] Dominik Brodowski
2018-03-22 10:21 ` Dominik Brodowski
2018-03-22 17:57 ` Linus Torvalds
2018-03-22 17:57 ` Linus Torvalds
2018-03-22 9:00 ` [PATCH 23/45] sched: add do_sched_yield() helper; remove in-kernel call to sched_yield() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 17:29 ` Peter Zijlstra
2018-03-22 17:29 ` Peter Zijlstra
2018-03-22 17:41 ` Dominik Brodowski [this message]
2018-03-22 17:41 ` Dominik Brodowski
2018-03-22 17:44 ` Linus Torvalds
2018-03-22 17:44 ` Linus Torvalds
2018-03-22 9:00 ` [PATCH 24/45] kexec: call do_kexec_load() in compat syscall directly Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 25/45] mm: add kernel_migrate_pages() helper, move compat syscall to mm/mempolicy.c Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 26/45] mm: add kernel_move_pages() helper, move compat syscall to mm/migrate.c Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 27/45] mm: add kernel_mbind() helper; remove in-kernel call to syscall Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 28/45] mm: add kernel_[sg]et_mempolicy() helpers; remove in-kernel calls to syscalls Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 29/45] mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 30/45] ipc: add semtimedop syscall/compat_syscall wrappers Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 31/45] ipc: add semget syscall wrapper Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 32/45] ipc: add semctl syscall/compat_syscall wrappers Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 33/45] ipc: add msgget syscall wrapper Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 34/45] ipc: add shmget " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 35/45] ipc: add shmdt " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 36/45] ipc: add shmctl syscall/compat_syscall wrappers Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 37/45] ipc: add msgctl " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 38/45] ipc: add msgrcv " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 39/45] ipc: add msgsnd " Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 40/45] x86: use _do_fork() in compat_sys_x86_clone() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:26 ` Thomas Gleixner
2018-03-22 9:26 ` Thomas Gleixner
2018-03-22 9:00 ` [PATCH 41/45] x86: remove compat_sys_x86_waitpid() Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:27 ` Thomas Gleixner
2018-03-22 9:27 ` Thomas Gleixner
2018-03-22 9:00 ` [PATCH 42/45] x86: fix sys_sigreturn() return type to be long, not unsigned long Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:27 ` Thomas Gleixner
2018-03-22 9:27 ` Thomas Gleixner
2018-03-22 9:00 ` [PATCH 43/45] x86/sigreturn: use SYSCALL_DEFINE0 Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:27 ` Thomas Gleixner
2018-03-22 9:27 ` Thomas Gleixner
2018-03-22 9:00 ` [PATCH 44/45] kernel/sys_ni: sort cond_syscall() entries Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 9:00 ` [PATCH 45/45] bpf: whitelist all syscalls for error injection Dominik Brodowski
2018-03-22 9:00 ` Dominik Brodowski
2018-03-22 20:29 ` [PATCH 00/45] remove in-kernel syscall invocations (part 3 == remainder outside arch/) Linus Torvalds
2018-03-22 20:29 ` Linus Torvalds
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