From: Andi Kleen <andi@firstfloor.org>
To: Brian Gerst <brgerst@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
the arch/x86 maintainers <x86@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 4/9] x86: Enumerate kernel FSGS capability in AT_HWCAP2
Date: Mon, 21 Mar 2016 20:43:36 +0100 [thread overview]
Message-ID: <20160321194336.GC5083@two.firstfloor.org> (raw)
In-Reply-To: <CAMzpN2jJKU0nocK8O1=D7ahs5Ai62=ga7fon4Xt=O6xs=N0WiQ@mail.gmail.com>
> It would be less complicated actually, as normal userspace would just
> continue to call arch_prctl() as it does today. Glibc would implement
We already have that through the system call, no advantage of
putting it into a vsyscall.
Also the experience with getcpu and similar so far is that
vsyscalls are too slow for the users who want really fast paths.
So they're prefer to use the direct instructions anyways.
> arch_prctl() just like it does with gettimeofday() -- with an ifunc
> selector [1] that calls the VDSO function if it is available, or the
> syscall if not. No custom assembly needed.
vdso always needs custom assembler, please see how glibc implements it.
-Andi
next prev parent reply other threads:[~2016-03-21 19:43 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-21 16:16 Updated version of RD/WR FS/GS BASE patchkit Andi Kleen
2016-03-21 16:16 ` [PATCH 1/9] x86: Add intrinsics/macros for new rd/wr fs/gs base instructions Andi Kleen
2016-03-21 18:14 ` Andy Lutomirski
2016-03-21 16:16 ` [PATCH 2/9] x86: Add support for rd/wr fs/gs base Andi Kleen
2016-03-21 18:13 ` Andy Lutomirski
2016-03-21 19:05 ` Andi Kleen
2016-03-21 19:22 ` Andy Lutomirski
2016-03-21 22:05 ` Andi Kleen
2016-03-21 22:08 ` Andy Lutomirski
2016-03-21 22:15 ` Andi Kleen
2016-03-22 8:36 ` Thomas Gleixner
2016-03-22 14:40 ` Brian Gerst
2016-04-15 0:06 ` Andy Lutomirski
2016-03-21 16:16 ` [PATCH 3/9] x86: Make old K8 swapgs workaround conditional Andi Kleen
2016-03-21 16:16 ` [PATCH 4/9] x86: Enumerate kernel FSGS capability in AT_HWCAP2 Andi Kleen
2016-03-21 18:49 ` Brian Gerst
2016-03-21 18:54 ` Andi Kleen
2016-03-21 19:32 ` Brian Gerst
2016-03-21 19:43 ` Andi Kleen [this message]
2016-03-21 22:10 ` Andy Lutomirski
2016-03-21 16:16 ` [PATCH 5/9] x86: Add documentation for rd/wr fs/gs base Andi Kleen
2016-03-23 19:14 ` Valdis.Kletnieks
2016-03-21 16:16 ` [PATCH 6/9] x86: Use rd/wr fs/gs base in arch_prctl Andi Kleen
2016-03-21 18:17 ` Andy Lutomirski
2016-03-21 16:16 ` [PATCH 7/9] x86: Add self test code for fsgsbase Andi Kleen
2016-03-21 16:16 ` [PATCH 8/9] x86: Support arbitrary fs/gs base in getregs Andi Kleen
2016-03-21 16:16 ` [PATCH 9/9] x86: Save FS/GS base in core dump Andi Kleen
2016-03-21 18:39 ` Updated version of RD/WR FS/GS BASE patchkit Andy Lutomirski
2016-03-21 19:03 ` Andi Kleen
2016-03-21 19:23 ` Andy Lutomirski
2016-03-21 19:40 ` Andi Kleen
2016-03-21 22:05 ` Andy Lutomirski
2016-03-21 22:11 ` Andi Kleen
2016-03-21 22:27 ` Andy Lutomirski
2016-03-21 22:41 ` Andi Kleen
2016-03-21 22:47 ` Andy Lutomirski
2016-03-21 22:52 ` Andi Kleen
2016-03-21 22:57 ` Andy Lutomirski
2016-03-21 23:02 ` Andi Kleen
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