From: Atish Patra <atishp@rivosinc.com>
To: linux-kernel@vger.kernel.org
Cc: Tsukasa OI <research_trasio@irq.a4lg.com>,
Atish Patra <atishp@rivosinc.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Atish Patra <atishp@atishpatra.org>,
Anup Patel <anup@brainfault.org>,
Damien Le Moal <damien.lemoal@wdc.com>,
devicetree@vger.kernel.org, Jisheng Zhang <jszhang@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
linux-riscv@lists.infradead.org,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Rob Herring <robh+dt@kernel.org>
Subject: [PATCH v2 3/6] RISC-V: Extract multi-letter extension names from "riscv,isa"
Date: Thu, 10 Feb 2022 13:40:15 -0800 [thread overview]
Message-ID: <20220210214018.55739-4-atishp@rivosinc.com> (raw)
In-Reply-To: <20220210214018.55739-1-atishp@rivosinc.com>
From: Tsukasa OI <research_trasio@irq.a4lg.com>
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.
Signed-off-by: Tsukasa OI <research_trasio@irq.a4lg.com>
[Improved commit text and comments]
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
arch/riscv/kernel/cpufeature.c | 41 +++++++++++++++++++++++++---------
1 file changed, 31 insertions(+), 10 deletions(-)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index e19ae4391a9b..e9e3b0693d16 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -102,6 +102,7 @@ void __init riscv_fill_hwcap(void)
#endif
for (; *isa; ++isa) {
const char *ext = isa++;
+ const char *ext_end = isa;
bool ext_long, ext_err = false;
switch (*ext) {
@@ -119,19 +120,39 @@ 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;
- /* ... but must be ignored. */
+ /* 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:
ext_long = false;
- if (!islower(*ext)) {
+ if (unlikely(!islower(*ext))) {
ext_err = true;
break;
}
/* Find next extension */
if (!isdigit(*isa))
break;
+ /* Skip the minor version */
while (isdigit(*++isa))
;
if (*isa != 'p')
@@ -140,20 +161,20 @@ void __init riscv_fill_hwcap(void)
--isa;
break;
}
+ /* Skip the major version */
while (isdigit(*++isa))
;
break;
}
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
next prev parent reply other threads:[~2022-02-10 21:40 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-10 21:40 [PATCH v2 0/6] Provide a fraemework for RISC-V ISA extensions Atish Patra
2022-02-10 21:40 ` [PATCH v2 1/6] RISC-V: Correctly print supported extensions Atish Patra
2022-02-10 21:40 ` [PATCH v2 2/6] RISC-V: Minimal parser for "riscv, isa" strings Atish Patra
2022-02-10 21:40 ` Atish Patra [this message]
2022-02-10 21:40 ` [PATCH v2 4/6] RISC-V: Implement multi-letter ISA extension probing framework Atish Patra
2022-02-14 20:05 ` Heiko Stübner
2022-02-14 20:14 ` Atish Patra
2022-02-14 20:24 ` Heiko Stübner
2022-02-14 20:42 ` Atish Patra
2022-02-14 22:22 ` Heiko Stübner
2022-02-14 23:22 ` Atish Kumar Patra
2022-02-15 9:12 ` Atish Kumar Patra
2022-02-15 9:48 ` Heiko Stübner
2022-02-15 9:50 ` Heiko Stübner
2022-02-16 0:47 ` Atish Kumar Patra
2022-02-10 21:40 ` [PATCH v2 5/6] RISC-V: Do no continue isa string parsing without correct XLEN Atish Patra
2022-02-10 21:58 ` Andreas Schwab
2022-02-11 12:52 ` Geert Uytterhoeven
2022-02-14 20:15 ` Atish Patra
2022-02-14 20:06 ` Heiko Stübner
2022-02-10 21:40 ` [PATCH v2 6/6] RISC-V: Improve /proc/cpuinfo output for ISA extensions Atish Patra
2022-02-14 20:07 ` Heiko Stübner
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