Messages in this thread | | | Date | Wed, 6 Jul 2022 12:24:12 +0300 | From | Alexey Dobriyan <> | Subject | Re: [PATCH -final] x86/clear_user: Make it faster |
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On Tue, Jul 05, 2022 at 07:01:06PM +0200, Borislav Petkov wrote:
> + asm volatile( > + "1:\n\t" > + ALTERNATIVE_3("rep stosb", > + "call clear_user_erms", ALT_NOT(X86_FEATURE_FSRM), > + "call clear_user_rep_good", ALT_NOT(X86_FEATURE_ERMS), > + "call clear_user_original", ALT_NOT(X86_FEATURE_REP_GOOD)) > + "2:\n" > + _ASM_EXTABLE_UA(1b, 2b) > + : "+&c" (size), "+&D" (addr), ASM_CALL_CONSTRAINT > + : "a" (0) > + /* rep_good clobbers %rdx */ > + : "rdx");
"+c" and "+D" should be enough for 1 instruction assembly?
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