[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2 2/6] x86: reduce CET-SS related #ifdef-ary
On 28.09.2020 14:30, Jan Beulich wrote: > Commit b586a81b7a90 ("x86/CET: Fix build following c/s 43b98e7190") had > to introduce a number of #ifdef-s to make the build work with older tool > chains. Introduce an assembler macro covering for tool chains not > knowing of CET-SS, allowing some conditionals where just SETSSBSY is the > problem to be dropped again. > > No change to generated code. > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> > --- > Now that I've done this I'm no longer sure which direction is better to > follow: On one hand this introduces dead code (even if just NOPs) into > CET-SS-disabled builds. A possible compromise here might be to ... > --- a/xen/include/asm-x86/asm-defns.h > +++ b/xen/include/asm-x86/asm-defns.h > @@ -7,3 +7,9 @@ > .byte 0x0f, 0x01, 0xcb > .endm > #endif > + > +#ifndef CONFIG_HAS_AS_CET_SS > +.macro setssbsy > + .byte 0xf3, 0x0f, 0x01, 0xe8 > +.endm > +#endif ... comment out this macro's body. If we went this route, incssp and wrssp could be dealt with in similar ways, to allow dropping further #ifdef-s. Jan
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