On Wed, 12 May 2021 14:29:27 +0000 (UTC)
Christophe Leroy <christophe.le...@csgroup.eu> wrote:
> Commit 51c9c0843993 ("powerpc/kprobes: Implement Optprobes")
> implemented a powerpc specific version of optinsn in order
> to workaround the 32Mb limitation for direct branches.
>
> Instead of implementing a dedicated powerpc version, use the
> common optinsn and override the allocation and freeing functions.
>
> This also indirectly remove the CLANG warning about
> is_kprobe_ppc_optinsn_slot() not being use, and the powerpc will
> now benefit from commit 5b485629ba0d ("kprobes, extable: Identify
> kprobes trampolines as kernel text area")
>
This looks good to me.
Acked-by: Masami Hiramatsu <mhira...@kernel.org>
> Suggested-by: Masami Hiramatsu <mhira...@kernel.org>
> Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
> ---
> arch/powerpc/kernel/optprobes.c | 23 +++++------------------
> 1 file changed, 5 insertions(+), 18 deletions(-)
>
> diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
> index cdf87086fa33..a370190cd02a 100644
> --- a/arch/powerpc/kernel/optprobes.c
> +++ b/arch/powerpc/kernel/optprobes.c
> @@ -31,11 +31,9 @@
> #define TMPL_END_IDX \
> (optprobe_template_end - optprobe_template_entry)
>
> -DEFINE_INSN_CACHE_OPS(ppc_optinsn);
> -
> static bool insn_page_in_use;
>
> -static void *__ppc_alloc_insn_page(void)
> +void *alloc_optinsn_page(void)
> {
> if (insn_page_in_use)
> return NULL;
> @@ -43,20 +41,11 @@ static void *__ppc_alloc_insn_page(void)
> return &optinsn_slot;
> }
>
> -static void __ppc_free_insn_page(void *page __maybe_unused)
> +void free_optinsn_page(void *page)
> {
> insn_page_in_use = false;
> }
>
> -struct kprobe_insn_cache kprobe_ppc_optinsn_slots = {
> - .mutex = __MUTEX_INITIALIZER(kprobe_ppc_optinsn_slots.mutex),
> - .pages = LIST_HEAD_INIT(kprobe_ppc_optinsn_slots.pages),
> - /* insn_size initialized later */
> - .alloc = __ppc_alloc_insn_page,
> - .free = __ppc_free_insn_page,
> - .nr_garbage = 0,
> -};
> -
> /*
> * Check if we can optimize this probe. Returns NIP post-emulation if this
> can
> * be optimized and 0 otherwise.
> @@ -136,7 +125,7 @@ NOKPROBE_SYMBOL(optimized_callback);
> void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
> {
> if (op->optinsn.insn) {
> - free_ppc_optinsn_slot(op->optinsn.insn, 1);
> + free_optinsn_slot(op->optinsn.insn, 1);
> op->optinsn.insn = NULL;
> }
> }
> @@ -203,14 +192,12 @@ int arch_prepare_optimized_kprobe(struct
> optimized_kprobe *op, struct kprobe *p)
> unsigned long nip, size;
> int rc, i;
>
> - kprobe_ppc_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
> -
> nip = can_optimize(p);
> if (!nip)
> return -EILSEQ;
>
> /* Allocate instruction slot for detour buffer */
> - buff = get_ppc_optinsn_slot();
> + buff = get_optinsn_slot();
> if (!buff)
> return -ENOMEM;
>
> @@ -297,7 +284,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe
> *op, struct kprobe *p)
> return 0;
>
> error:
> - free_ppc_optinsn_slot(buff, 0);
> + free_optinsn_slot(buff, 0);
> return -ERANGE;
>
> }
> --
> 2.25.0
>
--
Masami Hiramatsu <mhira...@kernel.org>
