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RISC-V: Extract multi-letter extension names from "riscv, isa"

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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 <research_trasio@irq.a4lg.com>
[Improved commit text and comments]
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Tsukasa OI 2022-03-14 13:38:42 -07:00 committed by Palmer Dabbelt
parent 2a31c54be0
commit 40a4d0dfbc
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
1 changed files with 27 additions and 8 deletions
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35
arch/riscv/kernel/cpufeature.c
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@ -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'));
}
}
/*