From: "Li, Xin3" <xin3.li@intel.com>
To: Brian Gerst <brgerst@gmail.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"bp@alien8.de" <bp@alien8.de>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"hpa@zytor.com" <hpa@zytor.com>
Subject: RE: [PATCH 6/6] x86/gsseg: use the LKGS instruction if available for load_gs_index()
Date: Mon, 10 Oct 2022 04:32:34 +0000 [thread overview]
Message-ID: <BN6PR1101MB2161FFEB80E3D3AE06035384A8209@BN6PR1101MB2161.namprd11.prod.outlook.com> (raw)
In-Reply-To: <CAMzpN2i52orTgPqRARoCkuA=c2GEyWXLscrFRgDkb0LoFV01Rw@mail.gmail.com>
> > > There are not that many call sites, so using something like this
> > > (incorporating Peter Z's suggestion for the exception handler) would
> > > be better from a code readability perspective vs. a tiny increase in code size.
> >
> > The existing approach patches the binary code thus we don't need to check it
> at runtime.
>
> static_cpu_has() uses alternatives to patch the branch, so there is no runtime
> check after early boot.
>
Sorry, didn't know it, thanks for point it out.
If we prefer static_cpu_has, are you asking to replace all alternative macros with it?
Xin
next prev parent reply other threads:[~2022-10-10 4:33 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-06 15:40 [PATCH 0/6] Enable LKGS instruction Xin Li
2022-10-06 15:40 ` [PATCH 1/6] x86/cpufeature: add cpu feature bit for LKGS Xin Li
2022-10-06 15:40 ` [PATCH 2/6] x86/opcode: add LKGS instruction to x86-opcode-map Xin Li
2022-10-06 15:40 ` [PATCH 3/6] x86/gsseg: make asm_load_gs_index() take an u16 Xin Li
2022-10-06 15:40 ` [PATCH 4/6] x86/gsseg: move local_irq_save/restore() into asm_load_gs_index() Xin Li
2022-10-07 14:50 ` Peter Zijlstra
2022-10-07 17:47 ` H. Peter Anvin
2022-10-06 15:40 ` [PATCH 5/6] x86/gsseg: move load_gs_index() to its own header file Xin Li
2022-10-07 15:40 ` Brian Gerst
2022-10-07 17:43 ` H. Peter Anvin
2022-10-07 22:41 ` Li, Xin3
2022-10-06 15:40 ` [PATCH 6/6] x86/gsseg: use the LKGS instruction if available for load_gs_index() Xin Li
2022-10-07 14:47 ` Peter Zijlstra
2022-10-07 17:45 ` H. Peter Anvin
2022-10-07 18:07 ` Li, Xin3
2022-10-07 18:49 ` H. Peter Anvin
2022-10-07 18:01 ` Li, Xin3
2022-10-07 19:24 ` Peter Zijlstra
2022-10-07 20:03 ` H. Peter Anvin
2022-10-07 20:23 ` Peter Zijlstra
2022-10-07 20:33 ` H. Peter Anvin
2022-10-08 5:32 ` Li, Xin3
2022-10-08 7:16 ` H. Peter Anvin
2022-10-10 4:21 ` Li, Xin3
2022-10-14 4:36 ` Li, Xin3
2022-10-07 14:52 ` Peter Zijlstra
2022-10-07 15:09 ` Peter Zijlstra
2022-10-08 5:31 ` Li, Xin3
2022-10-07 16:18 ` Brian Gerst
2022-10-08 5:40 ` Li, Xin3
2022-10-08 12:40 ` Brian Gerst
2022-10-10 4:32 ` Li, Xin3 [this message]
2022-10-10 4:51 ` H. Peter Anvin
2022-10-10 7:53 ` Peter Zijlstra
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