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Date:   Fri, 07 Oct 2022 11:49:54 -0700
From:   "H. Peter Anvin" <hpa@zytor.com>
To:     "Li, Xin3" <xin3.li@intel.com>,
        Peter Zijlstra <peterz@infradead.org>
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        "x86@kernel.org" <x86@kernel.org>,
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        "mingo@redhat.com" <mingo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Subject: =?US-ASCII?Q?RE=3A_=5BPATCH_6/6=5D_x86/gsseg=3A_use_the_LKGS_in?= =?US-ASCII?Q?struction_if_available_for_load=5Fgs=5Findex=28=29?=
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On October 7, 2022 11:07:34 AM PDT, "Li, Xin3" <xin3=2Eli@intel=2Ecom> wrot=
e:
>> >> +	alternative_io("1: call asm_load_gs_index\n"
>> >> +		       "=2Epushsection \"=2Efixup\",\"ax\"\n"
>> >> +		       "2:	xorl %k[sel], %k[sel]\n"
>> >> +		       "	jmp 1b\n"
>> >> +		       "=2Epopsection\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=2E=2E=2E the =2Efixup section ha=
sn't
>> >existed for almost a year now=2E
>> >
>> >  e5eefda5aa51 ("x86: Remove =2Efixup section")
>>=20
>> Xin, what did you use as the forward-porting baseline?
>
>6=2E0 release, and my kernel dump shows me a fixup section is there, and =
a fixup section is created anyway if we do "pushsection "\=2Efixup\""=2E
>
>
>

Yeah=2E =2Efixup is really Just Another Text Section =E2=84=A2, so it is p=
robably not surprising if it has crept back in=2E