On 1 February 2018 at 12:40, Robin Murphy <robin.murphy@xxxxxxx> wrote: > On 01/02/18 11:46, Marc Zyngier wrote: >> >> Function identifiers are a 32bit, unsigned quantity. But we never >> tell so to the compiler, resulting in the following: >> >> 4ac: b26187e0 mov x0, #0xffffffff80000001 >> >> We thus rely on the firmware narrowing it for us, which is not >> always a reasonable expectation. > > > I think technically it might be OK, since SMCCC states "A Function > Identifier is passed in register W0.", which implies that a conforming > implementation should also read w0, not x0, but it's certainly far easier to > be completely right than to justify being possibly wrong. > > Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx> > In my case, the function identifier wasn't the issue, but the argument, which, for SMCCC_ARCH_FEATURES is also defined as uint32_t, but did end up being interpreted incorrectly by the SMCCCv1.1 implementation that is now upstream in ARM-TF > >> Cc: stable@xxxxxxxxxxxxxxx >> Reported-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> >> Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> >> Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> >> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> >> --- >> include/linux/arm-smccc.h | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h >> index e1ef944ef1da..dd44d8458c04 100644 >> --- a/include/linux/arm-smccc.h >> +++ b/include/linux/arm-smccc.h >> @@ -14,14 +14,16 @@ >> #ifndef __LINUX_ARM_SMCCC_H >> #define __LINUX_ARM_SMCCC_H >> +#include <uapi/linux/const.h> >> + >> /* >> * This file provides common defines for ARM SMC Calling Convention as >> * specified in >> * http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html >> */ >> -#define ARM_SMCCC_STD_CALL 0 >> -#define ARM_SMCCC_FAST_CALL 1 >> +#define ARM_SMCCC_STD_CALL _AC(0,U) >> +#define ARM_SMCCC_FAST_CALL _AC(1,U) >> #define ARM_SMCCC_TYPE_SHIFT 31 >> #define ARM_SMCCC_SMC_32 0 >> > _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
