On Thu, Mar 9, 2023 at 10:02 AM Hari Bathini <hbathini@xxxxxxxxxxxxx> wrote:
>
> Implement bpf_arch_text_invalidate and use it to fill unused part of
> the bpf_prog_pack with trap instructions when a BPF program is freed.
>
> Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxx>
> ---
> arch/powerpc/net/bpf_jit_comp.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
> index 0a70319116d1..d1794d9f0154 100644
> --- a/arch/powerpc/net/bpf_jit_comp.c
> +++ b/arch/powerpc/net/bpf_jit_comp.c
> @@ -293,3 +293,18 @@ void *bpf_arch_text_copy(void *dst, void *src, size_t len)
>
> return ret;
> }
> +
> +int bpf_arch_text_invalidate(void *dst, size_t len)
> +{
> + u32 inst = BREAKPOINT_INSTRUCTION;
> + int ret = -EINVAL;
No need to set to -EINVAL here.
> +
> + if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
> + return ret;
Just return -EINVAL instead.
> +
> + mutex_lock(&text_mutex);
> + ret = patch_instructions(dst, &inst, true, len);
> + mutex_unlock(&text_mutex);
> +
> + return ret;
> +}
> --
> 2.39.2
>
