[PATCH RFC v2 riscv/for-next 5/5] riscv: align arch_static_branch function

[Jessica Clarke]

On 13 Sept 2022, at 10:42, Andy Chiu <andy.chiu at sifive.com> wrote:
> 
> runtime code patching must be done at a naturally aligned address, or we
> may execute on a partial instruction.
> 
> Signed-off-by: Andy Chiu <andy.chiu at sifive.com>
> Reviewed-by: Greentime Hu <greentime.hu at sifive.com>
> ---
> arch/riscv/include/asm/jump_label.h | 2 ++
> 1 file changed, 2 insertions(+)
> 
> diff --git a/arch/riscv/include/asm/jump_label.h b/arch/riscv/include/asm/jump_label.h
> index 38af2ec7b9bf..729991e8f782 100644
> --- a/arch/riscv/include/asm/jump_label.h
> +++ b/arch/riscv/include/asm/jump_label.h
> @@ -18,6 +18,7 @@ static __always_inline bool arch_static_branch(struct static_key *key,
> 					       bool branch)
> {
> 	asm_volatile_goto(
> +		"	.align		2			\n\t"

.align is a horrible directive whose meaning changes between
architectures and requires careful thought, especially when the
argument is a power of 2. Better to use .balign 4, or .p2align 2 if you
really want to for some reason.

Jess

> 		"	.option push				\n\t"
> 		"	.option norelax				\n\t"
> 		"	.option norvc				\n\t"
> @@ -39,6 +40,7 @@ static __always_inline bool arch_static_branch_jump(struct static_key *key,
> 						    bool branch)
> {
> 	asm_volatile_goto(
> +		"	.align		2			\n\t"
> 		"	.option push				\n\t"
> 		"	.option norelax				\n\t"
> 		"	.option norvc				\n\t"
> -- 
> 2.36.0
> 
> 
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