On 01/11/17 16:58, Mark Salyzyn wrote: > Cross compiling to aarch32 (for vdso32) using clang correctly > identifies that (the unused) write_sysreg inline asm directive is > illegal in that architectural context: > > arch/arm64/include/asm/arch_timer.h: error: invalid input constraint 'rZ' in > asm > write_sysreg(cntkctl, cntkctl_el1); > ^ > arch/arm64/include/asm/sysreg.h: note: expanded from macro 'write_sysreg' > : : "rZ" (__val)); > ^ > > GCC normally checks for correctness everywhere. But uniquely for > unused asm, will optimize out and suppress the error report.
It sounds more like some paths are wrong in the compat vDSO build if it's pulling in this header in the first place - nothing in this file is relevant to AArch32. Robin. > Signed-off-by: Mark Salyzyn <[email protected]> > Cc: Catalin Marinas <[email protected]> > Cc: Will Deacon <[email protected]> > Cc: Christoffer Dall <[email protected]> > Cc: Mark Rutland <[email protected]> > Cc: Marc Zyngier <[email protected]> > Cc: Suzuki K Poulose <[email protected]> > Cc: Stefan Traby <[email protected]> > Cc: Dave Martin <[email protected]> > Cc: [email protected] > Cc: [email protected] > --- > arch/arm64/include/asm/sysreg.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h > index f707fed5886f..a7b61c9327db 100644 > --- a/arch/arm64/include/asm/sysreg.h > +++ b/arch/arm64/include/asm/sysreg.h > @@ -492,11 +492,15 @@ asm( > * The "Z" constraint normally means a zero immediate, but when combined with > * the "%x0" template means XZR. > */ > +#if defined(__aarch64__) > #define write_sysreg(v, r) do { \ > u64 __val = (u64)(v); \ > asm volatile("msr " __stringify(r) ", %x0" \ > : : "rZ" (__val)); \ > } while (0) > +#else > +#define write_sysreg(v, r) BUG() > +#endif > > /* > * For registers without architectural names, or simply unsupported by >
