From aaba098fe6ce594ae6f963dc041be6307e499f19 Mon Sep 17 00:00:00 2001 From: Andrew Murray Date: Tue, 9 Apr 2019 10:52:40 +0100 Subject: arm64: HWCAP: add support for AT_HWCAP2 As we will exhaust the first 32 bits of AT_HWCAP let's start exposing AT_HWCAP2 to userspace to give us up to 64 caps. Whilst it's possible to use the remaining 32 bits of AT_HWCAP, we prefer to expand into AT_HWCAP2 in order to provide a consistent view to userspace between ILP32 and LP64. However internal to the kernel we prefer to continue to use the full space of elf_hwcap. To reduce complexity and allow for future expansion, we now represent hwcaps in the kernel as ordinals and use a KERNEL_HWCAP_ prefix. This allows us to support automatic feature based module loading for all our hwcaps. We introduce cpu_set_feature to set hwcaps which complements the existing cpu_have_feature helper. These helpers allow us to clean up existing direct uses of elf_hwcap and reduce any future effort required to move beyond 64 caps. For convenience we also introduce cpu_{have,set}_named_feature which makes use of the cpu_feature macro to allow providing a hwcap name without a {KERNEL_}HWCAP_ prefix. Signed-off-by: Andrew Murray [will: use const_ilog2() and tweak documentation] Signed-off-by: Will Deacon --- arch/arm64/kernel/fpsimd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm64/kernel/fpsimd.c') diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 5ebe73b69961..735cf1f8b109 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1258,14 +1258,14 @@ static inline void fpsimd_hotplug_init(void) { } */ static int __init fpsimd_init(void) { - if (elf_hwcap & HWCAP_FP) { + if (cpu_have_named_feature(FP)) { fpsimd_pm_init(); fpsimd_hotplug_init(); } else { pr_notice("Floating-point is not implemented\n"); } - if (!(elf_hwcap & HWCAP_ASIMD)) + if (!cpu_have_named_feature(ASIMD)) pr_notice("Advanced SIMD is not implemented\n"); return sve_sysctl_init(); -- cgit