From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Anvin <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] de-asmify the x86-64 system call slowpath
Date: Mon, 27 Jan 2014 11:27:59 +0100 [thread overview]
Message-ID: <20140127102759.GY11314@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <CA+55aFzNxTtvNX7zqBELHs489e5mEx1sM=i=red=aQAGviXrNw@mail.gmail.com>
On Sun, Jan 26, 2014 at 02:28:15PM -0800, Linus Torvalds wrote:
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index 1e96c3628bf2..15b5953da958 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -658,30 +658,24 @@ sysret_check:
> /* Handle reschedules */
> /* edx: work, edi: workmask */
> sysret_careful:
> TRACE_IRQS_ON
> ENABLE_INTERRUPTS(CLBR_NONE)
> + SAVE_REST
> + FIXUP_TOP_OF_STACK %r11
> + movq %rsp,%rdi
> + movl %edx,%esi
> + call syscall_exit_slowpath
> + movl $_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT,%edi
> + testl %eax,%eax
> + jne sysret_using_iret
> + addq $REST_SKIP,%rsp
> + jmp sysret_check;
Obviously I don't particularly like the SAVE_REST/FIXUP_TOP_OF_STACK
being added to the reschedule path.
Can't we do as Al suggested earlier and have 2 slowpath calls, one
without PT_REGS and one with?
That said, yes its a nice cleanup, entry.S always hurts my brain.
next prev parent reply other threads:[~2014-01-27 10:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-26 22:28 [RFC] de-asmify the x86-64 system call slowpath Linus Torvalds
2014-01-27 0:22 ` Al Viro
2014-01-27 4:32 ` Linus Torvalds
2014-01-27 4:48 ` H. Peter Anvin
2014-01-27 7:42 ` Al Viro
2014-01-27 22:06 ` Andy Lutomirski
2014-01-27 22:17 ` Linus Torvalds
2014-01-27 22:32 ` Al Viro
2014-01-27 22:43 ` Linus Torvalds
2014-01-27 22:46 ` Andy Lutomirski
2014-01-28 0:22 ` H. Peter Anvin
2014-01-28 0:44 ` Andy Lutomirski
2014-01-27 23:07 ` Al Viro
2014-01-27 10:27 ` Peter Zijlstra [this message]
2014-01-27 11:36 ` Al Viro
2014-01-27 17:39 ` Oleg Nesterov
2014-01-28 1:18 ` Al Viro
2014-01-28 16:38 ` Oleg Nesterov
2014-01-28 16:48 ` Al Viro
2014-01-28 17:19 ` Oleg Nesterov
2014-02-06 0:32 ` Linus Torvalds
2014-02-06 0:55 ` Kirill A. Shutemov
2014-02-06 2:32 ` Linus Torvalds
2014-02-06 4:33 ` Linus Torvalds
2014-02-06 21:29 ` Linus Torvalds
2014-02-06 22:24 ` Kirill A. Shutemov
2014-02-07 1:31 ` Linus Torvalds
2014-02-07 15:42 ` [RFC, PATCH] mm: map few pages around fault address if they are in page cache Kirill A. Shutemov
2014-02-07 17:32 ` Andi Kleen
2014-02-07 17:56 ` Kirill A. Shutemov
2014-02-07 18:11 ` Andi Kleen
2014-02-06 5:42 ` [RFC] de-asmify the x86-64 system call slowpath Ingo Molnar
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