Messages in this thread | | | Date | Fri, 07 Oct 2022 13:03:12 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 6/6] x86/gsseg: use the LKGS in struction if available for load gs index() |
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On October 7, 2022 12:24:13 PM PDT, Peter Zijlstra <peterz@infradead.org> wrote: >On Fri, Oct 07, 2022 at 06:01:06PM +0000, Li, Xin3 wrote: >> > > + alternative_io("1: call asm_load_gs_index\n" >> > > + ".pushsection \".fixup\",\"ax\"\n" >> > > + "2: xorl %k[sel], %k[sel]\n" >> > > + " jmp 1b\n" >> > > + ".popsection\n" >> > > + _ASM_EXTABLE(1b, 2b), >> > > + _ASM_BYTES(0x3e) LKGS_DI, >> > > + X86_FEATURE_LKGS, >> > > + ASM_OUTPUT2([sel] "+D" (sel), ASM_CALL_CONSTRAINT), >> > > + ASM_NO_INPUT_CLOBBER(_ASM_AX)); >> > > } >> > >> > I'm very sure none of this was tested... the .fixup section hasn't existed for >> > almost a year now. >> >> Weird, did you ever check a kernel dump? > >$ readelf -WS defconfig-build/vmlinux | grep fixup >[ 5] .pci_fixup PROGBITS ffffffff826a5350 18a5350 003570 00 A 0 0 16 >[ 6] .rela.pci_fixup RELA 0000000000000000 360c388 005028 18 I 60 5 8 > >In fact, when I add one I get: > >ld: warning: orphan section `.fixup' from `arch/x86/kernel/traps.o' being placed in section `.fixup'
Perhaps the two of you need to compare confugurations?
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