[PATCH v5 3/6] RISC-V: Extract multi-letter extension names from "riscv, isa"
From: Atish Patra <hidden>
Date: 2022-02-22 20:48:36
Also in:
linux-riscv, lkml
Subsystem:
risc-v architecture, the rest · Maintainers:
Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds
From: Tsukasa OI <redacted> Currently, there is no usage for version numbers in extensions as any ratified non base ISA extension will always at v1.0. Extract the extension names in place for future parsing. Tested-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Tsukasa OI <redacted> [Improved commit text and comments] Signed-off-by: Atish Patra <redacted> --- arch/riscv/kernel/cpufeature.c | 35 ++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 72c5f6ef56b5..b0df7eff47f7 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c@@ -124,8 +124,28 @@ void __init riscv_fill_hwcap(void) ext_long = true; /* Multi-letter extension must be delimited */ for (; *isa && *isa != '_'; ++isa) - if (!islower(*isa) && !isdigit(*isa)) + if (unlikely(!islower(*isa) + && !isdigit(*isa))) ext_err = true; + /* Parse backwards */ + ext_end = isa; + if (unlikely(ext_err)) + break; + if (!isdigit(ext_end[-1])) + break; + /* Skip the minor version */ + while (isdigit(*--ext_end)) + ; + if (ext_end[0] != 'p' + || !isdigit(ext_end[-1])) { + /* Advance it to offset the pre-decrement */ + ++ext_end; + break; + } + /* Skip the major version */ + while (isdigit(*--ext_end)) + ; + ++ext_end; break; default: if (unlikely(!islower(*ext))) {
@@ -151,14 +171,13 @@ void __init riscv_fill_hwcap(void) } if (*isa != '_') --isa; - /* - * TODO: Full version-aware handling including - * multi-letter extensions will be added in-future. - */ - if (ext_err || ext_long) + + if (unlikely(ext_err)) continue; - this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; - this_isa |= (1UL << (*ext - 'a')); + if (!ext_long) { + this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; + this_isa |= (1UL << (*ext - 'a')); + } } /*
--
2.30.2