[v2,03/13] riscv: cpufeature: detect RISCV_ALTERNATIVES_EARLY_BOOT earlier

Commit Message

Jisheng Zhang Dec. 4, 2022, 5:46 p.m. UTC

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 <[e-mail]>
Reviewed-by: Andrew Jones <[e-mail]>
Reviewed-by: Heiko Stuebner <[e-mail]>
---
 arch/riscv/kernel/cpufeature.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Conor Dooley Dec. 5, 2022, 7:09 p.m. UTC | #1

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 <[e-mail]>
> Reviewed-by: Andrew Jones <[e-mail]>
> Reviewed-by: Heiko Stuebner <[e-mail]>
> ---
>  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
>

Patch

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;