On Thu, Dec 01, 2016 at 09:59:03AM +0100, Andrew Jones wrote:
>
> Should this be From: Andre?
>
> On Wed, Nov 30, 2016 at 11:16:39PM -0600, Wei Huang wrote:
> > This patch defines four macros to assist creating system register
> > accessors under both ARMv7 and AArch64:
> > * DEFINE_GET_SYSREG32(name, ...)
> > * DEFINE_SET_SYSREG32(name, ...)
> > * DEFINE_GET_SYSREG64(name, ...)
> > * DEFINE_SET_SYSREG64(name, ...)
> > These macros are translated to inline functions with consistent naming,
> > get_##name() and set_##name(), which can be used by C code directly.
> >
> > Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> > Signed-off-by: Wei Huang <wei@xxxxxxxxxx>
> > ---
> > lib/arm/asm/processor.h | 37 ++++++++++++++++++++++++++++++++-----
> > lib/arm64/asm/processor.h | 35 ++++++++++++++++++++++++++++-------
> > 2 files changed, 60 insertions(+), 12 deletions(-)
> >
> > diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h
> > index f25e7ee..3ca6b42 100644
> > --- a/lib/arm/asm/processor.h
> > +++ b/lib/arm/asm/processor.h
> > @@ -33,13 +33,40 @@ static inline unsigned long current_cpsr(void)
> >
> > #define current_mode() (current_cpsr() & MODE_MASK)
> >
> > -static inline unsigned int get_mpidr(void)
> > -{
> > - unsigned int mpidr;
> > - asm volatile("mrc p15, 0, %0, c0, c0, 5" : "=r" (mpidr));
> > - return mpidr;
> > +#define DEFINE_GET_SYSREG32(name, opc1, crn, crm, opc2) \
> > +static inline uint32_t get_##name(void) \
> > +{ \
> > + uint32_t reg; \
> > + asm volatile("mrc p15, " #opc1 ", %0, " #crn ", " #crm ", " \
> > + #opc2 : "=r" (reg)); \
> > + return reg; \
> > +}
> > +
> > +#define DEFINE_SET_SYSREG32(name, opc1, crn, crm, opc2) \
> > +static inline void set_##name(uint32_t value) \
> > +{ \
> > + asm volatile("mcr p15, " #opc1 ", %0, " #crn ", " #crm ", " \
> > + #opc2 :: "r" (value)); \
> ^ nit: no space here, checkpatch would complain
> > +}
> > +
> > +#define DEFINE_GET_SYSREG64(name, opc, crm) \
> > +static inline uint64_t get_##name(void) \
> > +{ \
> > + uint32_t lo, hi; \
> > + asm volatile("mrrc p15, " #opc ", %0, %1, " #crm \
> > + : "=r" (lo), "=r" (hi)); \
> > + return (uint64_t)hi << 32 | lo; \
> > +}
> > +
> > +#define DEFINE_SET_SYSREG64(name, opc, crm) \
> > +static inline void set_##name(uint64_t value) \
> > +{ \
> > + asm volatile("mcrr p15, " #opc ", %0, %1, " #crm \
> > + :: "r" (value & 0xffffffff), "r" (value >> 32)); \
> > }
> >
> > +DEFINE_GET_SYSREG32(mpidr, 0, c0, c0, 5)
> > +
> > /* Only support Aff0 for now, up to 4 cpus */
> > #define mpidr_to_cpu(mpidr) ((int)((mpidr) & 0xff))
> >
> > diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h
> > index 84d5c7c..dfa75eb 100644
> > --- a/lib/arm64/asm/processor.h
> > +++ b/lib/arm64/asm/processor.h
> > @@ -66,14 +66,35 @@ static inline unsigned long current_level(void)
> > return el & 0xc;
> > }
> >
> > -#define DEFINE_GET_SYSREG32(reg) \
> > -static inline unsigned int get_##reg(void) \
> > -{ \
> > - unsigned int reg; \
> > - asm volatile("mrs %0, " #reg "_el1" : "=r" (reg)); \
> > - return reg; \
> > +#define DEFINE_GET_SYSREG32(reg, el) \
> > +static inline uint32_t get_##reg(void) \
> > +{ \
> > + uint32_t reg; \
> > + asm volatile("mrs %0, " #reg "_" #el : "=r" (reg)); \
> > + return reg; \
> > }
> > -DEFINE_GET_SYSREG32(mpidr)
> > +
> > +#define DEFINE_SET_SYSREG32(reg, el) \
> > +static inline void set_##reg(uint32_t value) \
> > +{ \
> > + asm volatile("msr " #reg "_" #el ", %0" :: "r" (value)); \
> > +}
Another comment for arm64's SYSREG32 accessors. Technically there's no
32-bit register in AArch64, so the asm should always use an unsigned long
and explicit casts. That's what I did in [1].
> > +
> > +#define DEFINE_GET_SYSREG64(reg, el) \
> > +static inline uint64_t get_##reg(void) \
> > +{ \
> > + uint64_t reg; \
> > + asm volatile("mrs %0, " #reg "_" #el : "=r" (reg)); \
> > + return reg; \
> > +}
> > +
> > +#define DEFINE_SET_SYSREG64(reg, el) \
> > +static inline void set_##reg(uint64_t value) \
> > +{ \
> > + asm volatile("msr " #reg "_" #el ", %0" :: "r" (value)); \
> > +}
> > +
> > +DEFINE_GET_SYSREG32(mpidr, el1)
>
> 32-bit mpidr for arm64 isn't right, and it's changed by [1] in the
> gic series. However changing it to 64-bit with this patch would result
> in a get_mpidr() call that returns uint64_t on arm64 and uint32_t on
> arm32, which won't be nice for common code. Andre brought up during the
> review of [1] that we should be using the architectural types for register
> accessors. That means, that while internally all the above functions can
> know what's 32-bit and what's 64-bit, using uint32/64_t appropriately,
> the external interfaces should be 'unsigned long', 'unsigned int',
> 'unsigned long long'.
>
> [1] https://github.com/rhdrjones/kvm-unit-tests/commit/57e48b8e6dc2ddf4b2e4eb1ceb5a5f87f2dd074b
>
> Thanks,
> drew
>
> >
> > /* Only support Aff0 for now, gicv2 only */
> > #define mpidr_to_cpu(mpidr) ((int)((mpidr) & 0xff))
> > --
> > 1.8.3.1
> >
> >
>
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
