Re: [PATCH v2 1/2] riscv: allow case-insensitive ISA string parsing

Andrew Jones
2023-04-29T10:11:19Z

On Fri, Apr 28, 2023 at 10:16:00PM +0800, Yangyu Chen wrote:
> According to RISC-V Hart Capabilities Table (RHCT) description in UEFI
> Forum ECR, the format of the ISA string is defined in the RISC-V
> unprivileged specification which is case-insensitive. However, the
> current ISA string parser in the kernel does not support ISA strings
> with uppercase letters.
>
> This patch modifies the ISA string parser in the kernel to support
> case-insensitive ISA string parsing.
>
> Signed-off-by: Yangyu Chen <cyy@cyyself.name>
> ---
> arch/riscv/kernel/cpu.c | 3 ++-
> arch/riscv/kernel/cpufeature.c | 25 ++++++++++++-------------
> 2 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
> index 8400f0cc9704..52b92a267121 100644
> --- a/arch/riscv/kernel/cpu.c
> +++ b/arch/riscv/kernel/cpu.c
> @@ -4,6 +4,7 @@
> */
>
> #include <linux/cpu.h>
> +#include <linux/ctype.h>
> #include <linux/init.h>
> #include <linux/seq_file.h>
> #include <linux/of.h>
> @@ -41,7 +42,7 @@ int riscv_of_processor_hartid(struct device_node *node, unsigned long *hart)
> pr_warn("CPU with hartid=%lu has no \"riscv,isa\" property\n", *hart);
> return -ENODEV;
> }
> - if (isa[0] != 'r' || isa[1] != 'v') {
> + if (tolower(isa[0]) != 'r' || tolower(isa[1]) != 'v') {
> pr_warn("CPU with hartid=%lu has an invalid ISA of \"%s\"\n", *hart, isa);
> return -ENODEV;
> }
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 59d58ee0f68d..d1991c12e546 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -119,13 +119,10 @@ void __init riscv_fill_hwcap(void)
> }
>
> temp = isa;
> -#if IS_ENABLED(CONFIG_32BIT)
> - if (!strncmp(isa, "rv32", 4))
> + if (IS_ENABLED(CONFIG_32BIT) && !strncasecmp(isa, "rv32", 4))
> isa += 4;
> -#elif IS_ENABLED(CONFIG_64BIT)
> - if (!strncmp(isa, "rv64", 4))
> + else if (IS_ENABLED(CONFIG_64BIT) && !strncasecmp(isa, "rv64", 4))
> isa += 4;
> -#endif
> /* The riscv,isa DT property must start with rv64 or rv32 */
> if (temp == isa)
> continue;
> @@ -136,6 +133,7 @@ void __init riscv_fill_hwcap(void)
> bool ext_long = false, ext_err = false;
>
> switch (*ext) {
> + case 'S':
> case 's':
> /**
> * Workaround for invalid single-letter 's' & 'u'(QEMU).
> @@ -143,19 +141,20 @@ void __init riscv_fill_hwcap(void)
> * not valid ISA extensions. It works until multi-letter
> * extension starting with "Su" appears.
> */
> - if (ext[-1] != '_' && ext[1] == 'u') {
> + if (ext[-1] != '_' && tolower(ext[1]) == 'u') {
> ++isa;
> ext_err = true;
> break;
> }
> fallthrough;
> + case 'X':
> case 'x':
> + case 'Z':
> case 'z':
> ext_long = true;
> /* Multi-letter extension must be delimited */
> for (; *isa && *isa != '_'; ++isa)
> - if (unlikely(!islower(*isa)
> - && !isdigit(*isa)))
> + if (unlikely(!isalnum(*isa)))
> ext_err = true;
> /* Parse backwards */
> ext_end = isa;
> @@ -166,7 +165,7 @@ void __init riscv_fill_hwcap(void)
> /* Skip the minor version */
> while (isdigit(*--ext_end))
> ;
> - if (ext_end[0] != 'p'
> + if (tolower(ext_end[0]) != 'p'
> || !isdigit(ext_end[-1])) {
> /* Advance it to offset the pre-decrement */
> ++ext_end;
> @@ -178,7 +177,7 @@ void __init riscv_fill_hwcap(void)
> ++ext_end;
> break;
> default:
> - if (unlikely(!islower(*ext))) {
> + if (unlikely(!isalpha(*ext))) {
> ext_err = true;
> break;
> }
> @@ -188,7 +187,7 @@ void __init riscv_fill_hwcap(void)
> /* Skip the minor version */
> while (isdigit(*++isa))
> ;
> - if (*isa != 'p')
> + if (tolower(*isa) != 'p')
> break;
> if (!isdigit(*++isa)) {
> --isa;
> @@ -205,7 +204,7 @@ void __init riscv_fill_hwcap(void)
> #define SET_ISA_EXT_MAP(name, bit) \
> do { \
> if ((ext_end - ext == sizeof(name) - 1) && \
> - !memcmp(ext, name, sizeof(name) - 1) && \
> + !strncasecmp(ext, name, sizeof(name) - 1) && \
> riscv_isa_extension_check(bit)) \
> set_bit(bit, this_isa); \
> } while (false) \
> @@ -213,7 +212,7 @@ void __init riscv_fill_hwcap(void)
> if (unlikely(ext_err))
> continue;
> if (!ext_long) {
> - int nr = *ext - 'a';
> + int nr = tolower(*ext) - 'a';
>
> if (riscv_isa_extension_check(nr)) {
> this_hwcap |= isa2hwcap[nr];
> --
> 2.40.0
>

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Thanks,
drew