linux-kernel - [PATCH bpf-next 2/2] bpf: Add BPF_CALL

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Message-Id: <20240920153706.919154-1-chen.dylane@gmail.com>
Date: Fri, 20 Sep 2024 23:37:06 +0800
From: Tao Chen <chen.dylane@...il.com>
To: Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	John Fastabend <john.fastabend@...il.com>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	Jiri Olsa <jolsa@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org,
	"H . Peter Anvin" <hpa@...or.com>
Cc: bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	sparclinux@...r.kernel.org,
	Tao Chen <chen.dylane@...il.com>
Subject: [PATCH bpf-next 2/2] bpf: Add BPF_CALL_FUNC* to simplify code

No logic changed, like macro BPF_CALL_IMM, add BPF_CALL_FUNC/_FUNC_ARGS
to simplify code.

Signed-off-by: Tao Chen <chen.dylane@...il.com>
---
 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           | 4 ++++
 kernel/bpf/core.c                | 6 +++---
 5 files changed, 11 insertions(+), 8 deletions(-)

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..d06526decc6d 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -461,6 +461,10 @@ 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)
+
+#define BPF_CALL_FUNC_ARGS(x)	((x) + (u8 *)__bpf_call_base_args)
+
 #define BPF_EMIT_CALL(FUNC)					\
 	((struct bpf_insn) {					\
 		.code  = BPF_JMP | BPF_CALL,			\
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 4e07cc057d6f..f965f0d586f3 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1278,7 +1278,7 @@ int bpf_jit_get_func_addr(const struct bpf_prog *prog,
 		 * and the helper with imm relative to it are both in core
 		 * kernel.
 		 */
-		addr = (u8 *)__bpf_call_base + imm;
+		addr = BPF_CALL_FUNC(imm);
 	}
 
 	*func_addr = (unsigned long)addr;
@@ -2007,12 +2007,12 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
 		 * preserves BPF_R6-BPF_R9, and stores return value
 		 * into BPF_R0.
 		 */
-		BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
+		BPF_R0 = BPF_CALL_FUNC(insn->imm)(BPF_R1, BPF_R2, BPF_R3,
 						       BPF_R4, BPF_R5);
 		CONT;
 
 	JMP_CALL_ARGS:
-		BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
+		BPF_R0 = BPF_CALL_FUNC_ARGS(insn->imm)(BPF_R1, BPF_R2,
 							    BPF_R3, BPF_R4,
 							    BPF_R5,
 							    insn + insn->off + 1);
-- 
2.43.0