From 93b988cf8e4c68b823e70a02e4c7c39eaa0053be Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 17 Apr 2025 14:30:56 +0200 Subject: [PATCH] s390/crc32: Remove have_vxrs static key Replace the have_vxrs static key with a cpu_has_vx() call. cpu_has_vx() resolves into a compile time constant (true) if the kernel is compiled for z13 or newer. Otherwise it generates an unconditional one instruction branch, which is patched based on CPU alternatives. In any case the generated code is at least as good as before and avoids static key handling. Signed-off-by: Heiko Carstens Link: https://lore.kernel.org/r/20250417125318.12521F12-hca@linux.ibm.com/ Signed-off-by: Eric Biggers --- arch/s390/lib/crc32-glue.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/arch/s390/lib/crc32-glue.c b/arch/s390/lib/crc32-glue.c index 8f20a8e595c38..649ed7e8b99c8 100644 --- a/arch/s390/lib/crc32-glue.c +++ b/arch/s390/lib/crc32-glue.c @@ -18,8 +18,6 @@ #define VX_ALIGNMENT 16L #define VX_ALIGN_MASK (VX_ALIGNMENT - 1) -static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_vxrs); - /* * DEFINE_CRC32_VX() - Define a CRC-32 function using the vector extension * @@ -34,8 +32,7 @@ static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_vxrs); unsigned long prealign, aligned, remaining; \ DECLARE_KERNEL_FPU_ONSTACK16(vxstate); \ \ - if (datalen < VX_MIN_LEN + VX_ALIGN_MASK || \ - !static_branch_likely(&have_vxrs)) \ + if (datalen < VX_MIN_LEN + VX_ALIGN_MASK || !cpu_has_vx()) \ return ___crc32_sw(crc, data, datalen); \ \ if ((unsigned long)data & VX_ALIGN_MASK) { \ @@ -66,8 +63,6 @@ DEFINE_CRC32_VX(crc32c_arch, crc32c_le_vgfm_16, crc32c_base) static int __init crc32_s390_init(void) { - if (cpu_have_feature(S390_CPU_FEATURE_VXRS)) - static_branch_enable(&have_vxrs); return 0; } arch_initcall(crc32_s390_init); @@ -79,10 +74,11 @@ module_exit(crc32_s390_exit); u32 crc32_optimizations(void) { - if (static_key_enabled(&have_vxrs)) + if (cpu_has_vx()) { return CRC32_LE_OPTIMIZATION | CRC32_BE_OPTIMIZATION | CRC32C_OPTIMIZATION; + } return 0; } EXPORT_SYMBOL(crc32_optimizations); -- 2.39.5