Commit 90772291 authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
Browse files

arm64: Use build-time assertions for cpucap ordering 



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: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent bc9bbb78

arch/arm64/kernel/fpsimd.c

+6 −8
Original line number Diff line number Diff line
@@ -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);