[PATCH v2 11/38] arm64: use build-time assertions for cpucap ordering
Mark Rutland
mark.rutland at arm.com
Thu Oct 5 02:49:57 PDT 2023
Both sme2_kernel_enable() and fa64_kernel_enable() need to run after
sme_kernel_enable(). This happens to be true today as ARM64_SME has a
lower index than either ARM64_SME2 or ARM64_SME_FA64, and both functions
have a comment to this effect.
It would be nicer to have a build-time assertion like we for for
can_use_gic_priorities() and has_gic_prio_relaxed_sync(), as that way
it will be harder to miss any potential breakage.
This patch replaces the comments with build-time assertions.
Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Mark Brown <broonie at kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose at arm.com>
Cc: Will Deacon <will at kernel.org>
---
arch/arm64/kernel/fpsimd.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 601b973f90ad2..48338cf8f90bd 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1310,23 +1310,21 @@ void sme_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
isb();
}
-/*
- * This must be called after sme_kernel_enable(), we rely on the
- * feature table being sorted to ensure this.
- */
void sme2_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
{
+ /* This must be enabled after SME */
+ BUILD_BUG_ON(ARM64_SME2 <= ARM64_SME);
+
/* Allow use of ZT0 */
write_sysreg_s(read_sysreg_s(SYS_SMCR_EL1) | SMCR_ELx_EZT0_MASK,
SYS_SMCR_EL1);
}
-/*
- * This must be called after sme_kernel_enable(), we rely on the
- * feature table being sorted to ensure this.
- */
void fa64_kernel_enable(const struct arm64_cpu_capabilities *__always_unused p)
{
+ /* This must be enabled after SME */
+ BUILD_BUG_ON(ARM64_SME_FA64 <= ARM64_SME);
+
/* Allow use of FA64 */
write_sysreg_s(read_sysreg_s(SYS_SMCR_EL1) | SMCR_ELx_FA64_MASK,
SYS_SMCR_EL1);
--
2.30.2
More information about the linux-arm-kernel
mailing list