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Message-ID: <20250317104616.GCZ9f9eF-0n0qPbWwk@fat_crate.local>
Date: Mon, 17 Mar 2025 11:46:16 +0100
From: Borislav Petkov <bp@...en8.de>
To: Uros Bizjak <ubizjak@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-tip-commits@...r.kernel.org,
Ingo Molnar <mingo@...nel.org>, Andy Lutomirski <luto@...nel.org>,
Brian Gerst <brgerst@...il.com>, "H. Peter Anvin" <hpa@...or.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Linus Torvalds <torvalds@...ux-foundation.org>, x86@...nel.org
Subject: Re: [tip: x86/fpu] x86/fpu: Use XSAVE{,OPT,C,S} and XRSTOR{,S}
mnemonics in xstate.h
On Mon, Mar 17, 2025 at 11:28:58AM +0100, Uros Bizjak wrote:
> > > @@ -114,10 +113,10 @@ static inline int update_pkru_in_sigframe(struct xregs_state __user *buf, u64 ma
> > > #define XSTATE_OP(op, st, lmask, hmask, err) \
> > > asm volatile("1:" op "\n\t" \
> > > "xor %[err], %[err]\n" \
> > > - "2:\n\t" \
> > > + "2:\n" \
> > > _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_FAULT_MCE_SAFE) \
> > > : [err] "=a" (err) \
> > > - : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
> > > + : [xa] "m" (*(st)), "a" (lmask), "d" (hmask) \
> >
> > This [xa] needs documenting in the comment above this.
> >
> > What does "xa" even mean?
>
> xsave area.
That's struct xregs_state in kernel nomenclature.
And the macro's argument is called "st".
And when it says [xa] there, one wonders where that "xa" comes from. So please
add a comment above the macro explaining that.
And you can redo the whole patch - it is the topmost one in tip:x86/fpu and
can simply be replaced.
Thx.
--
Regards/Gruss,
Boris.
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