Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sat, 10 Feb 2024 11:40:39 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v3 06/19] x86/startup_64: Drop global variables keeping track of LA57 state |
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On Fri, Feb 09, 2024 at 01:55:02PM +0000, Ard Biesheuvel wrote: > I was trying to get rid of global variable assignments and accesses > from the 1:1 mapping, but since we cannot get rid of those entirely, > we might just keep __pgtable_l5_enabled but use RIP_REL_REF() in the > accessors, and move the assignment to the asm startup code.
Yeah.
> asm(ALTERNATIVE_TERNARY( > "movq %%cr4, %[reg] \n\t btl %[la57], %k[reg]" CC_SET(c), > %P[feat], "stc", "clc") > : [reg] "=r" (r), CC_OUT(c) (ret) > : [feat] "i" (X86_FEATURE_LA57), > [la57] "i" (X86_CR4_LA57_BIT) > : "cc");
Creative :)
> but we'd still have two versions in that case.
Yap. RIP_REL_REF() ain't too bad ...
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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