[RFC PATCH 19/22] perf bpf: dump eBPF program before loading.

[Wang Nan <wangnan0@huawei.com>]

Copy print_bpf_insn() from kernel/bpf/verifier.c to bpf.c, dump the
program if called by -vv.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
 tools/perf/util/bpf-loader.c |  14 +++-
 tools/perf/util/bpf.c        | 156 +++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/bpf.h        |   1 +
 3 files changed, 170 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 0395483..6587e99 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -849,6 +849,16 @@ static __u64 ptr_to_u64(void *ptr)
 	return (__u64) (unsigned long) ptr;
 }
 
+static void
+dump_perf_prog(struct bpf_perf_prog *prog)
+{
+	if (verbose < 2)
+		return;
+	pr_info("-- BEGIN DUMP '%s' --\n", prog->name);
+	bpf_dump_prog(prog->insns, prog->insns_cnt);
+	pr_info("-- FINISH DUMP '%s' --\n", prog->name);
+}
+
 static int
 bpf_perf_prog_load(struct bpf_obj *obj, struct bpf_perf_prog *prog)
 {
@@ -857,6 +867,8 @@ bpf_perf_prog_load(struct bpf_obj *obj, struct bpf_perf_prog *prog)
 #define LOG_BUF_SIZE 65536
 	static char bpf_log_buf[LOG_BUF_SIZE];
 
+	dump_perf_prog(prog);
+
 	bzero(&attr, sizeof(attr));
 
 	attr.prog_type = BPF_PROG_TYPE_KPROBE;
@@ -902,7 +914,7 @@ int bpf__load(const char *path)
 	struct bpf_obj *obj;
 	int err;
 
-	pr_debug("bpf: loading %s\n", path);
+	pr_debug("bpf: loading %s, verbose=%d\n", path, verbose);
 
 	if (elf_version(EV_CURRENT) == EV_NONE) {
 		pr_err("bpf: failed to init libelf for %s\n", path);
diff --git a/tools/perf/util/bpf.c b/tools/perf/util/bpf.c
index f752723..eb3411b 100644
--- a/tools/perf/util/bpf.c
+++ b/tools/perf/util/bpf.c
@@ -8,12 +8,14 @@
  */
 
 #include <stdlib.h>
+#include <stdio.h>
 #include <string.h>
 #include <linux/unistd.h>
 #include <unistd.h>
 #include <linux/bpf.h>
 #include <errno.h>
 #include "perf.h"
+#include "debug.h"
 #include "bpf.h"
 
 int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, size_t size)
@@ -37,3 +39,157 @@ int bpf_create_map(struct bpf_map_def *map_def)
 
 	return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
 }
+
+/* Taken from kernel/bpf/verifier.c, s/verbose/_verbose/g*/
+static const char *const bpf_class_string[] = {
+	[BPF_LD]    = "ld",
+	[BPF_LDX]   = "ldx",
+	[BPF_ST]    = "st",
+	[BPF_STX]   = "stx",
+	[BPF_ALU]   = "alu",
+	[BPF_JMP]   = "jmp",
+	[BPF_RET]   = "BUG",
+	[BPF_ALU64] = "alu64",
+};
+
+static const char *const bpf_alu_string[] = {
+	[BPF_ADD >> 4]  = "+=",
+	[BPF_SUB >> 4]  = "-=",
+	[BPF_MUL >> 4]  = "*=",
+	[BPF_DIV >> 4]  = "/=",
+	[BPF_OR  >> 4]  = "|=",
+	[BPF_AND >> 4]  = "&=",
+	[BPF_LSH >> 4]  = "<<=",
+	[BPF_RSH >> 4]  = ">>=",
+	[BPF_NEG >> 4]  = "neg",
+	[BPF_MOD >> 4]  = "%=",
+	[BPF_XOR >> 4]  = "^=",
+	[BPF_MOV >> 4]  = "=",
+	[BPF_ARSH >> 4] = "s>>=",
+	[BPF_END >> 4]  = "endian",
+};
+
+static const char *const bpf_ldst_string[] = {
+	[BPF_W >> 3]  = "u32",
+	[BPF_H >> 3]  = "u16",
+	[BPF_B >> 3]  = "u8",
+	[BPF_DW >> 3] = "u64",
+};
+
+static const char *const bpf_jmp_string[] = {
+	[BPF_JA >> 4]   = "jmp",
+	[BPF_JEQ >> 4]  = "==",
+	[BPF_JGT >> 4]  = ">",
+	[BPF_JGE >> 4]  = ">=",
+	[BPF_JSET >> 4] = "&",
+	[BPF_JNE >> 4]  = "!=",
+	[BPF_JSGT >> 4] = "s>",
+	[BPF_JSGE >> 4] = "s>=",
+	[BPF_CALL >> 4] = "call",
+	[BPF_EXIT >> 4] = "exit",
+};
+#define _verbose pr_info
+static void print_bpf_insn(struct bpf_insn *insn)
+{
+	u8 class = BPF_CLASS(insn->code);
+
+	if (class == BPF_ALU || class == BPF_ALU64) {
+		if (BPF_SRC(insn->code) == BPF_X)
+			_verbose("(%02x) %sr%d %s %sr%d\n",
+				insn->code, class == BPF_ALU ? "(u32) " : "",
+				insn->dst_reg,
+				bpf_alu_string[BPF_OP(insn->code) >> 4],
+				class == BPF_ALU ? "(u32) " : "",
+				insn->src_reg);
+		else
+			_verbose("(%02x) %sr%d %s %s%d\n",
+				insn->code, class == BPF_ALU ? "(u32) " : "",
+				insn->dst_reg,
+				bpf_alu_string[BPF_OP(insn->code) >> 4],
+				class == BPF_ALU ? "(u32) " : "",
+				insn->imm);
+	} else if (class == BPF_STX) {
+		if (BPF_MODE(insn->code) == BPF_MEM)
+			_verbose("(%02x) *(%s *)(r%d %+d) = r%d\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg,
+				insn->off, insn->src_reg);
+		else if (BPF_MODE(insn->code) == BPF_XADD)
+			_verbose("(%02x) lock *(%s *)(r%d %+d) += r%d\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg, insn->off,
+				insn->src_reg);
+		else
+			_verbose("BUG_%02x\n", insn->code);
+	} else if (class == BPF_ST) {
+		if (BPF_MODE(insn->code) != BPF_MEM) {
+			_verbose("BUG_st_%02x\n", insn->code);
+			return;
+		}
+		_verbose("(%02x) *(%s *)(r%d %+d) = %d\n",
+			insn->code,
+			bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+			insn->dst_reg,
+			insn->off, insn->imm);
+	} else if (class == BPF_LDX) {
+		if (BPF_MODE(insn->code) != BPF_MEM) {
+			_verbose("BUG_ldx_%02x\n", insn->code);
+			return;
+		}
+		_verbose("(%02x) r%d = *(%s *)(r%d %+d)\n",
+			insn->code, insn->dst_reg,
+			bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+			insn->src_reg, insn->off);
+	} else if (class == BPF_LD) {
+		if (BPF_MODE(insn->code) == BPF_ABS) {
+			_verbose("(%02x) r0 = *(%s *)skb[%d]\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->imm);
+		} else if (BPF_MODE(insn->code) == BPF_IND) {
+			_verbose("(%02x) r0 = *(%s *)skb[r%d + %d]\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->src_reg, insn->imm);
+		} else if (BPF_MODE(insn->code) == BPF_IMM) {
+			_verbose("(%02x) r%d = 0x%x\n",
+				insn->code, insn->dst_reg, insn->imm);
+		} else {
+			_verbose("BUG_ld_%02x\n", insn->code);
+			return;
+		}
+	} else if (class == BPF_JMP) {
+		u8 opcode = BPF_OP(insn->code);
+
+		if (opcode == BPF_CALL) {
+			_verbose("(%02x) call %d\n", insn->code, insn->imm);
+		} else if (insn->code == (BPF_JMP | BPF_JA)) {
+			_verbose("(%02x) goto pc%+d\n",
+				insn->code, insn->off);
+		} else if (insn->code == (BPF_JMP | BPF_EXIT)) {
+			_verbose("(%02x) exit\n", insn->code);
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			_verbose("(%02x) if r%d %s r%d goto pc%+d\n",
+				insn->code, insn->dst_reg,
+				bpf_jmp_string[BPF_OP(insn->code) >> 4],
+				insn->src_reg, insn->off);
+		} else {
+			_verbose("(%02x) if r%d %s 0x%x goto pc%+d\n",
+				insn->code, insn->dst_reg,
+				bpf_jmp_string[BPF_OP(insn->code) >> 4],
+				insn->imm, insn->off);
+		}
+	} else {
+		_verbose("(%02x) %s\n", insn->code, bpf_class_string[class]);
+	}
+}
+
+void bpf_dump_prog(struct bpf_insn *insn, size_t nr_insn)
+{
+	unsigned int i;
+
+	for (i = 0; i < nr_insn; i++)
+		print_bpf_insn(&insn[i]);
+}
diff --git a/tools/perf/util/bpf.h b/tools/perf/util/bpf.h
index be106b0..b4a6802 100644
--- a/tools/perf/util/bpf.h
+++ b/tools/perf/util/bpf.h
@@ -19,4 +19,5 @@ struct bpf_map_def {
 int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, size_t size);
 
 int bpf_create_map(struct bpf_map_def *map_def);
+void bpf_dump_prog(struct bpf_insn *insn, size_t nr_insn);
 #endif
-- 
1.8.3.4