From: "Li, Xin3" <xin3.li@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
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: Sat, 8 Oct 2022 05:31:20 +0000 [thread overview]
Message-ID: <BN6PR1101MB21619BD3724574B79211F1FCA85E9@BN6PR1101MB2161.namprd11.prod.outlook.com> (raw)
In-Reply-To: <Y0BBLhHrgxYZahfi@hirez.programming.kicks-ass.net>
> Something like so perhaps?
>
> asm_inline volatile("1:\n"
> ALTERNATIVE("call asm_load_gs_index\n",
> LKGS_DI,
> X86_FEATURE_LKGS)
> _ASM_EXTABLE_TYPE_REG(1b, 1b,
> EX_TYPE_ZERO_REG, %k[sel])
> : ASM_CALL_CONSTRAINT
> : [sel] "D" (sel)
> : "memory", _ASM_AX);
>
>
> (completely untested, not even seen a compiler upclose)
It compiles (after adding "0x3e" to make it 5 bytes to match the size of "call asm_load_gs_index") and passes my fixup test, thanks!
next prev parent reply other threads:[~2022-10-08 5:31 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 [this message]
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
2022-10-10 4:51 ` H. Peter Anvin
2022-10-10 7:53 ` Peter Zijlstra
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