On 2026-01-05 01:02, Uros Bizjak wrote: > Use MOVL when reading segment registers to avoid 0x66 operand-size > override insn prefix. The segment value is always 16-bit and gets > zero-extended to the full 32-bit size. > > Signed-off-by: Uros Bizjak <[email protected]> > Tested-by: Michael Kelley <[email protected]> > Cc: Thomas Gleixner <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: Dave Hansen <[email protected]> > Cc: "H. Peter Anvin" <[email protected]> > --- > arch/x86/include/asm/segment.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h > index f59ae7186940..9f5be2bbd291 100644 > --- a/arch/x86/include/asm/segment.h > +++ b/arch/x86/include/asm/segment.h > @@ -348,7 +348,7 @@ static inline void __loadsegment_fs(unsigned short value) > * Save a segment register away: > */ > #define savesegment(seg, value) \ > - asm("mov %%" #seg ",%0":"=r" (value) : : "memory") > + asm("movl %%" #seg ",%k0" : "=r" (value) : : "memory") > > #endif /* !__ASSEMBLER__ */ > #endif /* __KERNEL__ */
Looks good to me. Reviewed-by: H. Peter Anvin (Intel) <[email protected]>
