2024-04-12 06:49:35

by Andy Chiu

[permalink] [raw]

Subject: [PATCH v4 1/9] riscv: vector: add a comment when calling riscv_setup_vsize()

---

The function would fail when it detects the calling hart's vlen doesn't
match the first one's. The boot hart is the first hart calling this
function during riscv_fill_hwcap, so it is impossible to fail here. Add
a comment about this behavior.

Signed-off-by: Andy Chiu <[email protected]>
---
Changelog v2:
- update the comment (Conor)
---
arch/riscv/kernel/cpufeature.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 3ed2359eae35..d22b12072579 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -683,6 +683,10 @@ void __init riscv_fill_hwcap(void)
}

if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+ /*
+ * This callsite can't fail here. It cannot fail when called on
+ * the boot hart.
+ */
riscv_v_setup_vsize();
/*
* ISA string in device tree might have 'v' flag, but

--
2.44.0.rc2

2024-04-18 09:55:24

by Conor Dooley

[permalink] [raw]

Subject: Re: [PATCH v4 1/9] riscv: vector: add a comment when calling riscv_setup_vsize()

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On Fri, Apr 12, 2024 at 02:48:57PM +0800, Andy Chiu wrote:
> The function would fail when it detects the calling hart's vlen doesn't
> match the first one's. The boot hart is the first hart calling this
> function during riscv_fill_hwcap, so it is impossible to fail here. Add
> a comment about this behavior.
>
> Signed-off-by: Andy Chiu <[email protected]>
> ---
> Changelog v2:
> - update the comment (Conor)
> ---
> arch/riscv/kernel/cpufeature.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 3ed2359eae35..d22b12072579 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -683,6 +683,10 @@ void __init riscv_fill_hwcap(void)
> }
>
> if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
> + /*
> + * This callsite can't fail here. It cannot fail when called on
> + * the boot hart.

I am loathe to comment on this again, so
Reviewed-by: Conor Dooley <[email protected]>
but you could just write this as "This cannot fail when called on the
boot hart."

Cheers,
Conor.

> + */
> riscv_v_setup_vsize();
> /*
> * ISA string in device tree might have 'v' flag, but
>
> --
> 2.44.0.rc2
>

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