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| author | Dave Martin <Dave.Martin@arm.com> | 2018-09-28 14:39:21 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2019-03-29 14:41:54 +0000 |
| commit | ead9e430c0fba1a7aa6d948a626c48ef9c4aa069 (patch) | |
| tree | f4c9958e218eee29e80cd3e7de44699cf2e0d44f /arch/arm64/include | |
| parent | 8e3c54c8b6a9286b1571c4a4ba1d4afbd217f297 (diff) | |
| download | linux-ead9e430c0fba1a7aa6d948a626c48ef9c4aa069.tar.bz2 | |
arm64/sve: In-kernel vector length availability query interface
KVM will need to interrogate the set of SVE vector lengths
available on the system.
This patch exposes the relevant bits to the kernel, along with a
sve_vq_available() helper to check whether a particular vector
length is supported.
__vq_to_bit() and __bit_to_vq() are not intended for use outside
these functions: now that these are exposed outside fpsimd.c, they
are prefixed with __ in order to provide an extra hint that they
are not intended for general-purpose use.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: zhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/fpsimd.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index df7a14305222..ad6d2e41eb37 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -24,10 +24,13 @@ #ifndef __ASSEMBLY__ +#include <linux/bitmap.h> #include <linux/build_bug.h> +#include <linux/bug.h> #include <linux/cache.h> #include <linux/init.h> #include <linux/stddef.h> +#include <linux/types.h> #if defined(__KERNEL__) && defined(CONFIG_COMPAT) /* Masks for extracting the FPSR and FPCR from the FPSCR */ @@ -89,6 +92,32 @@ extern u64 read_zcr_features(void); extern int __ro_after_init sve_max_vl; extern int __ro_after_init sve_max_virtualisable_vl; +/* Set of available vector lengths, as vq_to_bit(vq): */ +extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); + +/* + * Helpers to translate bit indices in sve_vq_map to VQ values (and + * vice versa). This allows find_next_bit() to be used to find the + * _maximum_ VQ not exceeding a certain value. + */ +static inline unsigned int __vq_to_bit(unsigned int vq) +{ + return SVE_VQ_MAX - vq; +} + +static inline unsigned int __bit_to_vq(unsigned int bit) +{ + if (WARN_ON(bit >= SVE_VQ_MAX)) + bit = SVE_VQ_MAX - 1; + + return SVE_VQ_MAX - bit; +} + +/* Ensure vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX before calling this function */ +static inline bool sve_vq_available(unsigned int vq) +{ + return test_bit(__vq_to_bit(vq), sve_vq_map); +} #ifdef CONFIG_ARM64_SVE |