Re: [PATCH bpf-next 2/2 v2] bpf: Add BPF_CALL_FUNC to simplify code
From: Alexei Starovoitov
Date: Wed Oct 02 2024 - 11:38:07 EST
On Wed, Oct 2, 2024 at 8:23 AM Tao Chen <chen.dylane@xxxxxxxxx> wrote:
>
> No logic changed, like macro BPF_CALL_IMM, add BPF_CALL_FUNC
> to simplify code.
>
> Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
> ---
> arch/sparc/net/bpf_jit_comp_64.c | 2 +-
> arch/x86/net/bpf_jit_comp.c | 2 +-
> arch/x86/net/bpf_jit_comp32.c | 5 ++---
> include/linux/filter.h | 2 ++
> kernel/bpf/core.c | 2 +-
> 5 files changed, 7 insertions(+), 6 deletions(-)
>
> Change list:
> - v2 -> v1:
> - fix compile error reported by kernel test robot
>
> diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c
> index 73bf0aea8baf..076b1f216360 100644
> --- a/arch/sparc/net/bpf_jit_comp_64.c
> +++ b/arch/sparc/net/bpf_jit_comp_64.c
> @@ -1213,7 +1213,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
> /* function call */
> case BPF_JMP | BPF_CALL:
> {
> - u8 *func = ((u8 *)__bpf_call_base) + imm;
> + u8 *func = BPF_CALL_FUNC(imm);
>
> ctx->saw_call = true;
>
> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index 06b080b61aa5..052e5cc65fc0 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -2126,7 +2126,7 @@ st: if (is_imm8(insn->off))
> case BPF_JMP | BPF_CALL: {
> u8 *ip = image + addrs[i - 1];
>
> - func = (u8 *) __bpf_call_base + imm32;
> + func = BPF_CALL_FUNC(imm32);
> if (tail_call_reachable) {
> LOAD_TAIL_CALL_CNT_PTR(bpf_prog->aux->stack_depth);
> ip += 7;
> diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
> index de0f9e5f9f73..f7277639bd2c 100644
> --- a/arch/x86/net/bpf_jit_comp32.c
> +++ b/arch/x86/net/bpf_jit_comp32.c
> @@ -1627,8 +1627,7 @@ static int emit_kfunc_call(const struct bpf_prog *bpf_prog, u8 *end_addr,
> /* mov dword ptr [ebp+off],eax */
> if (fm->ret_size)
> end_addr -= 3;
> -
> - jmp_offset = (u8 *)__bpf_call_base + insn->imm - end_addr;
> + jmp_offset = BPF_CALL_FUNC(insn->imm) - end_addr;
> if (!is_simm32(jmp_offset)) {
> pr_err("unsupported BPF kernel function jmp_offset:%lld\n",
> jmp_offset);
> @@ -2103,7 +2102,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
> break;
> }
>
> - func = (u8 *) __bpf_call_base + imm32;
> + func = BPF_CALL_FUNC(imm32);
> jmp_offset = func - (image + addrs[i]);
>
> if (!imm32 || !is_simm32(jmp_offset)) {
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index 99b6fc83825b..9924b581aa71 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -461,6 +461,8 @@ static inline bool insn_is_cast_user(const struct bpf_insn *insn)
>
> #define BPF_CALL_IMM(x) ((void *)(x) - (void *)__bpf_call_base)
>
> +#define BPF_CALL_FUNC(x) ((x) + (u8 *)__bpf_call_base)
> +
I don't like to hide code behind macros.
The code is cleaner as-is.
pw-bot: cr