2022-12-04 18:04:54

by Jisheng Zhang

[permalink] [raw]
Subject: [PATCH v2 03/13] riscv: cpufeature: detect RISCV_ALTERNATIVES_EARLY_BOOT earlier

Now, the riscv_cpufeature_patch_func() do nothing in the stage of
RISCV_ALTERNATIVES_EARLY_BOOT. We can move the detection of "early
boot" stage earlier.

In following patch, we will make riscv_cpufeature_patch_func() scans
all ISA extensions.

Signed-off-by: Jisheng Zhang <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Reviewed-by: Heiko Stuebner <[email protected]>
---
arch/riscv/kernel/cpufeature.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 364d1fe86bea..a4d2af67e05c 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -305,6 +305,9 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
struct alt_entry *alt;
u32 tmp;

+ if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
+ return;
+
for (alt = begin; alt < end; alt++) {
if (alt->vendor_id != 0)
continue;
--
2.37.2


2022-12-05 20:36:59

by Conor Dooley

[permalink] [raw]
Subject: Re: [PATCH v2 03/13] riscv: cpufeature: detect RISCV_ALTERNATIVES_EARLY_BOOT earlier

On Mon, Dec 05, 2022 at 01:46:22AM +0800, Jisheng Zhang wrote:
> Now, the riscv_cpufeature_patch_func() do nothing in the stage of
> RISCV_ALTERNATIVES_EARLY_BOOT. We can move the detection of "early
> boot" stage earlier.
>
> In following patch, we will make riscv_cpufeature_patch_func() scans
> all ISA extensions.

I'm not 100% on the motivation here. Let me try and regurgitate the
changelog in a way that makes more sense to me and maybe you can confirm
it.

Currently riscv_cpufeature_patch_func() does nothing at the
RISCV_ALTERNATIVES_EARLY_BOOT stage.
Add a check to detect whether we are in this stage and exit early.
This will allow us to use riscv_cpufeature_patch_func() for scanning of
all ISA extensions.

Would that be a correct summary?

Thanks,
Conor.

>
> Signed-off-by: Jisheng Zhang <[email protected]>
> Reviewed-by: Andrew Jones <[email protected]>
> Reviewed-by: Heiko Stuebner <[email protected]>
> ---
> arch/riscv/kernel/cpufeature.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 364d1fe86bea..a4d2af67e05c 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -305,6 +305,9 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
> struct alt_entry *alt;
> u32 tmp;
>
> + if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
> + return;
> +
> for (alt = begin; alt < end; alt++) {
> if (alt->vendor_id != 0)
> continue;
> --
> 2.37.2
>


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