Re: [PATCH v5 3/9] riscv/kprobe: Prepare the skeleton to prepare optimized kprobe

[Björn Töpel]

Chen Guokai <chenguokai17@xxxxxxxxxxxxxxxx> writes:

> From: Liao Chang <liaochang1@xxxxxxxxxx>

>  arch/riscv/kernel/probes/opt.c | 107 ++++++++++++++++++++++++++++++++-
>
> diff --git a/arch/riscv/kernel/probes/opt.c b/arch/riscv/kernel/probes/opt.c
> index 56c8a227c857..a4271e6033ba 100644
> --- a/arch/riscv/kernel/probes/opt.c
> +++ b/arch/riscv/kernel/probes/opt.c

> @@ -24,7 +72,64 @@ int arch_check_optimized_kprobe(struct optimized_kprobe *op)
>  int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
>  				  struct kprobe *orig)
>  {
> -	return 0;
> +	long rel;
> +	int rd, ra, ret;
> +	kprobe_opcode_t *code = NULL, *slot = NULL;
> +
> +	if (!can_optimize((unsigned long)orig->addr, op))
> +		return -EILSEQ;
> +
> +	code = kzalloc(MAX_OPTINSN_SIZE, GFP_KERNEL);
> +	slot = get_optinsn_slot();
> +	if (!code || !slot) {
> +		ret = -ENOMEM;
> +		goto on_error;
> +	}
> +
> +	/*
> +	 * Verify if the address gap is within 4GB range, because this uses
> +	 * a auipc+jalr pair.

Try to be consistent. You're mixing "AUIPC/JALR" with "auipc+jalr".

> +	 */
> +	rel = (unsigned long)slot - (unsigned long)orig->addr;
> +	if (!in_auipc_jalr_range(rel)) {
> +		/*
> +		 * Different from x86, we free code buf directly instead
> of

Reword for readers that are not familiar with x86.


Björn