diff mbox series

[v3,1/6] RISC-V: Correctly print supported extensions

Message ID 20220215090211.911366-2-atishp@rivosinc.com (mailing list archive)
State New, archived
Headers show
Series Provide a fraemework for RISC-V ISA extensions | expand

Commit Message

Atish Kumar Patra Feb. 15, 2022, 9:02 a.m. UTC
From: Tsukasa OI <research_trasio@irq.a4lg.com>

This commit replaces BITS_PER_LONG with number of alphabet letters.

Current ISA pretty-printing code expects extension 'a' (bit 0) through
'z' (bit 25).  Although bit 26 and higher is not currently used (thus never
cause an issue in practice), it will be an annoying problem if we start to
use those in the future.

This commit disables printing high bits for now.

Signed-off-by: Tsukasa OI <research_trasio@irq.a4lg.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
---
 arch/riscv/kernel/cpufeature.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Comments

Anup Patel Feb. 15, 2022, 9:41 a.m. UTC | #1
On Tue, Feb 15, 2022 at 2:32 PM Atish Patra <atishp@rivosinc.com> wrote:
>
> From: Tsukasa OI <research_trasio@irq.a4lg.com>
>
> This commit replaces BITS_PER_LONG with number of alphabet letters.
>
> Current ISA pretty-printing code expects extension 'a' (bit 0) through
> 'z' (bit 25).  Although bit 26 and higher is not currently used (thus never
> cause an issue in practice), it will be an annoying problem if we start to
> use those in the future.
>
> This commit disables printing high bits for now.
>
> Signed-off-by: Tsukasa OI <research_trasio@irq.a4lg.com>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> Tested-by: Heiko Stuebner <heiko@sntech.de>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/kernel/cpufeature.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index d959d207a40d..dd3d57eb4eea 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -13,6 +13,8 @@
>  #include <asm/smp.h>
>  #include <asm/switch_to.h>
>
> +#define NUM_ALPHA_EXTS ('z' - 'a' + 1)
> +
>  unsigned long elf_hwcap __read_mostly;
>
>  /* Host ISA bitmap */
> @@ -63,7 +65,7 @@ void __init riscv_fill_hwcap(void)
>  {
>         struct device_node *node;
>         const char *isa;
> -       char print_str[BITS_PER_LONG + 1];
> +       char print_str[NUM_ALPHA_EXTS + 1];
>         size_t i, j, isa_len;
>         static unsigned long isa2hwcap[256] = {0};
>
> @@ -133,13 +135,13 @@ void __init riscv_fill_hwcap(void)
>         }
>
>         memset(print_str, 0, sizeof(print_str));
> -       for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> +       for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
>                 if (riscv_isa[0] & BIT_MASK(i))
>                         print_str[j++] = (char)('a' + i);
>         pr_info("riscv: ISA extensions %s\n", print_str);
>
>         memset(print_str, 0, sizeof(print_str));
> -       for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> +       for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
>                 if (elf_hwcap & BIT_MASK(i))
>                         print_str[j++] = (char)('a' + i);
>         pr_info("riscv: ELF capabilities %s\n", print_str);
> --
> 2.30.2
>
diff mbox series

Patch

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index d959d207a40d..dd3d57eb4eea 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -13,6 +13,8 @@ 
 #include <asm/smp.h>
 #include <asm/switch_to.h>
 
+#define NUM_ALPHA_EXTS ('z' - 'a' + 1)
+
 unsigned long elf_hwcap __read_mostly;
 
 /* Host ISA bitmap */
@@ -63,7 +65,7 @@  void __init riscv_fill_hwcap(void)
 {
 	struct device_node *node;
 	const char *isa;
-	char print_str[BITS_PER_LONG + 1];
+	char print_str[NUM_ALPHA_EXTS + 1];
 	size_t i, j, isa_len;
 	static unsigned long isa2hwcap[256] = {0};
 
@@ -133,13 +135,13 @@  void __init riscv_fill_hwcap(void)
 	}
 
 	memset(print_str, 0, sizeof(print_str));
-	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
+	for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
 		if (riscv_isa[0] & BIT_MASK(i))
 			print_str[j++] = (char)('a' + i);
 	pr_info("riscv: ISA extensions %s\n", print_str);
 
 	memset(print_str, 0, sizeof(print_str));
-	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
+	for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
 		if (elf_hwcap & BIT_MASK(i))
 			print_str[j++] = (char)('a' + i);
 	pr_info("riscv: ELF capabilities %s\n", print_str);