Re: [PATCH V4 12/23] RISC-V: cpufeature: Avoid calling riscv_of_processor_hartid()

Conor Dooley
2023-04-04T20:47:01Z

[-- Attachment #1: Type: text/plain, Size: 2151 bytes --]

On Tue, Apr 04, 2023 at 11:50:26PM +0530, Sunil V L wrote:
> riscv_fill_hwcap() finds hartid of each cpu but never really uses
> it. So, remove this unnecessary call.

"Never uses it" or "never really uses it"?
This commit message misses the point though I think - is this here to
get the hartid, or is it here to do all the property validation that
riscv_of_processor_hartid() does for a cpu node?

This was added all the way back in 4.20 in commit 732e8e4130ff ("RISC-V:
properly determine hardware caps").
As the loop is a for_each_of_cpu_node(), I don't think this change is
actually valid - there's no guarantee that the cpu we are iterating over
is actually available and the riscv_of_processor_hartid() check is used
to skip "bad" cpus AFAICT.

Perhaps I am missing something, I don't think you can do this until you
switch the loop to use something that only uses cpus that you know are
valid.

Cheers,
Conor.

> Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> ---
> arch/riscv/kernel/cpufeature.c | 5 -----
> 1 file changed, 5 deletions(-)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 59d58ee0f68d..63e56ce04162 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -91,7 +91,6 @@ void __init riscv_fill_hwcap(void)
> char print_str[NUM_ALPHA_EXTS + 1];
> int i, j, rc;
> unsigned long isa2hwcap[26] = {0};
> - unsigned long hartid;
>
> isa2hwcap['i' - 'a'] = COMPAT_HWCAP_ISA_I;
> isa2hwcap['m' - 'a'] = COMPAT_HWCAP_ISA_M;
> @@ -109,10 +108,6 @@ void __init riscv_fill_hwcap(void)
> DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
> const char *temp;
>
> - rc = riscv_of_processor_hartid(node, &hartid);
> - if (rc < 0)
> - continue;
> -
> if (of_property_read_string(node, "riscv,isa", &isa)) {
> pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
> continue;
> --
> 2.34.1
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]