From 726855549cf8d5c6b05795cf74a9c23584f45544 Mon Sep 17 00:00:00 2001 From: Andrew Jones Date: Tue, 29 Nov 2022 15:34:45 +0100 Subject: [PATCH] RISC-V: Improve use of isa2hwcap[] Improve isa2hwcap[] by removing it from static storage, as riscv_fill_hwcap() is only called once, and by reducing its size from 256 bytes to 26. The latter improvement is possible because isa2hwcap[] will never be indexed with capital letters and we can precompute the offsets from 'a'. No functional change intended. Signed-off-by: Andrew Jones Reviewed-by: Conor Dooley Reviewed-by: Heiko Stuebner Link: https://lore.kernel.org/r/20221129143447.49714-2-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpufeature.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 694267d..4677320 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -74,15 +74,15 @@ void __init riscv_fill_hwcap(void) const char *isa; char print_str[NUM_ALPHA_EXTS + 1]; int i, j, rc; - static unsigned long isa2hwcap[256] = {0}; + unsigned long isa2hwcap[26] = {0}; unsigned long hartid; - isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I; - isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M; - isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A; - isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F; - isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D; - isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C; + isa2hwcap['i' - 'a'] = COMPAT_HWCAP_ISA_I; + isa2hwcap['m' - 'a'] = COMPAT_HWCAP_ISA_M; + isa2hwcap['a' - 'a'] = COMPAT_HWCAP_ISA_A; + isa2hwcap['f' - 'a'] = COMPAT_HWCAP_ISA_F; + isa2hwcap['d' - 'a'] = COMPAT_HWCAP_ISA_D; + isa2hwcap['c' - 'a'] = COMPAT_HWCAP_ISA_C; elf_hwcap = 0; @@ -196,8 +196,10 @@ void __init riscv_fill_hwcap(void) if (unlikely(ext_err)) continue; if (!ext_long) { - this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; - set_bit(*ext - 'a', this_isa); + int nr = *ext - 'a'; + + this_hwcap |= isa2hwcap[nr]; + set_bit(nr, this_isa); } else { SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF); SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT); -- 2.7.4