1 files changed, 215 insertions, 46 deletions

diff --git a/tools/bpf/bpftool/jit_disasm.c b/tools/bpf/bpftool/jit_disasm.c
index aaf99a0168c9..7b8d9ec89ebd 100644
--- a/tools/bpf/bpftool/jit_disasm.c
+++ b/tools/bpf/bpftool/jit_disasm.c
@@ -11,35 +11,151 @@
  * Licensed under the GNU General Public License, version 2.0 (GPLv2)
  */
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdint.h>
 #include <stdlib.h>
-#include <assert.h>
 #include <unistd.h>
 #include <string.h>
-#include <bfd.h>
-#include <dis-asm.h>
 #include <sys/stat.h>
 #include <limits.h>
 #include <bpf/libbpf.h>
+
+#ifdef HAVE_LLVM_SUPPORT
+#include <llvm-c/Core.h>
+#include <llvm-c/Disassembler.h>
+#include <llvm-c/Target.h>
+#include <llvm-c/TargetMachine.h>
+#endif
+
+#ifdef HAVE_LIBBFD_SUPPORT
+#include <bfd.h>
+#include <dis-asm.h>
 #include <tools/dis-asm-compat.h>
+#endif
 
 #include "json_writer.h"
 #include "main.h"
 
-static void get_exec_path(char *tpath, size_t size)
+static int oper_count;
+
+#ifdef HAVE_LLVM_SUPPORT
+#define DISASM_SPACER
+
+typedef LLVMDisasmContextRef disasm_ctx_t;
+
+static int printf_json(char *s)
+{
+	s = strtok(s, " \t");
+	jsonw_string_field(json_wtr, "operation", s);
+
+	jsonw_name(json_wtr, "operands");
+	jsonw_start_array(json_wtr);
+	oper_count = 1;
+
+	while ((s = strtok(NULL, " \t,()")) != 0) {
+		jsonw_string(json_wtr, s);
+		oper_count++;
+	}
+	return 0;
+}
+
+/* This callback to set the ref_type is necessary to have the LLVM disassembler
+ * print PC-relative addresses instead of byte offsets for branch instruction
+ * targets.
+ */
+static const char *
+symbol_lookup_callback(__maybe_unused void *disasm_info,
+		       __maybe_unused uint64_t ref_value,
+		       uint64_t *ref_type, __maybe_unused uint64_t ref_PC,
+		       __maybe_unused const char **ref_name)
+{
+	*ref_type = LLVMDisassembler_ReferenceType_InOut_None;
+	return NULL;
+}
+
+static int
+init_context(disasm_ctx_t *ctx, const char *arch,
+	     __maybe_unused const char *disassembler_options,
+	     __maybe_unused unsigned char *image, __maybe_unused ssize_t len)
+{
+	char *triple;
+
+	if (arch)
+		triple = LLVMNormalizeTargetTriple(arch);
+	else
+		triple = LLVMGetDefaultTargetTriple();
+	if (!triple) {
+		p_err("Failed to retrieve triple");
+		return -1;
+	}
+	*ctx = LLVMCreateDisasm(triple, NULL, 0, NULL, symbol_lookup_callback);
+	LLVMDisposeMessage(triple);
+
+	if (!*ctx) {
+		p_err("Failed to create disassembler");
+		return -1;
+	}
+
+	return 0;
+}
+
+static void destroy_context(disasm_ctx_t *ctx)
+{
+	LLVMDisposeMessage(*ctx);
+}
+
+static int
+disassemble_insn(disasm_ctx_t *ctx, unsigned char *image, ssize_t len, int pc)
+{
+	char buf[256];
+	int count;
+
+	count = LLVMDisasmInstruction(*ctx, image + pc, len - pc, pc,
+				      buf, sizeof(buf));
+	if (json_output)
+		printf_json(buf);
+	else
+		printf("%s", buf);
+
+	return count;
+}
+
+int disasm_init(void)
+{
+	LLVMInitializeAllTargetInfos();
+	LLVMInitializeAllTargetMCs();
+	LLVMInitializeAllDisassemblers();
+	return 0;
+}
+#endif /* HAVE_LLVM_SUPPORT */
+
+#ifdef HAVE_LIBBFD_SUPPORT
+#define DISASM_SPACER "\t"
+
+typedef struct {
+	struct disassemble_info *info;
+	disassembler_ftype disassemble;
+	bfd *bfdf;
+} disasm_ctx_t;
+
+static int get_exec_path(char *tpath, size_t size)
 {
 	const char *path = "/proc/self/exe";
 	ssize_t len;
 
 	len = readlink(path, tpath, size - 1);
-	assert(len > 0);
+	if (len <= 0)
+		return -1;
+
 	tpath[len] = 0;
+
+	return 0;
 }
 
-static int oper_count;
 static int printf_json(void *out, const char *fmt, va_list ap)
 {
 	char *s;
@@ -97,37 +213,44 @@ static int fprintf_json_styled(void *out,
 	return r;
 }
 
-void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
-		       const char *arch, const char *disassembler_options,
-		       const struct btf *btf,
-		       const struct bpf_prog_linfo *prog_linfo,
-		       __u64 func_ksym, unsigned int func_idx,
-		       bool linum)
+static int init_context(disasm_ctx_t *ctx, const char *arch,
+			const char *disassembler_options,
+			unsigned char *image, ssize_t len)
 {
-	const struct bpf_line_info *linfo = NULL;
-	disassembler_ftype disassemble;
-	struct disassemble_info info;
-	unsigned int nr_skip = 0;
-	int count, i, pc = 0;
+	struct disassemble_info *info;
 	char tpath[PATH_MAX];
 	bfd *bfdf;
 
-	if (!len)
-		return;
-
 	memset(tpath, 0, sizeof(tpath));
-	get_exec_path(tpath, sizeof(tpath));
+	if (get_exec_path(tpath, sizeof(tpath))) {
+		p_err("failed to create disassembler (get_exec_path)");
+		return -1;
+	}
 
-	bfdf = bfd_openr(tpath, NULL);
-	assert(bfdf);
-	assert(bfd_check_format(bfdf, bfd_object));
+	ctx->bfdf = bfd_openr(tpath, NULL);
+	if (!ctx->bfdf) {
+		p_err("failed to create disassembler (bfd_openr)");
+		return -1;
+	}
+	if (!bfd_check_format(ctx->bfdf, bfd_object)) {
+		p_err("failed to create disassembler (bfd_check_format)");
+		goto err_close;
+	}
+	bfdf = ctx->bfdf;
+
+	ctx->info = malloc(sizeof(struct disassemble_info));
+	if (!ctx->info) {
+		p_err("mem alloc failed");
+		goto err_close;
+	}
+	info = ctx->info;
 
 	if (json_output)
-		init_disassemble_info_compat(&info, stdout,
+		init_disassemble_info_compat(info, stdout,
 					     (fprintf_ftype) fprintf_json,
 					     fprintf_json_styled);
 	else
-		init_disassemble_info_compat(&info, stdout,
+		init_disassemble_info_compat(info, stdout,
 					     (fprintf_ftype) fprintf,
 					     fprintf_styled);
 
@@ -139,28 +262,77 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
 			bfdf->arch_info = inf;
 		} else {
 			p_err("No libbfd support for %s", arch);
-			return;
+			goto err_free;
 		}
 	}
 
-	info.arch = bfd_get_arch(bfdf);
-	info.mach = bfd_get_mach(bfdf);
+	info->arch = bfd_get_arch(bfdf);
+	info->mach = bfd_get_mach(bfdf);
 	if (disassembler_options)
-		info.disassembler_options = disassembler_options;
-	info.buffer = image;
-	info.buffer_length = len;
+		info->disassembler_options = disassembler_options;
+	info->buffer = image;
+	info->buffer_length = len;
 
-	disassemble_init_for_target(&info);
+	disassemble_init_for_target(info);
 
 #ifdef DISASM_FOUR_ARGS_SIGNATURE
-	disassemble = disassembler(info.arch,
-				   bfd_big_endian(bfdf),
-				   info.mach,
-				   bfdf);
+	ctx->disassemble = disassembler(info->arch,
+					bfd_big_endian(bfdf),
+					info->mach,
+					bfdf);
 #else
-	disassemble = disassembler(bfdf);
+	ctx->disassemble = disassembler(bfdf);
 #endif
-	assert(disassemble);
+	if (!ctx->disassemble) {
+		p_err("failed to create disassembler");
+		goto err_free;
+	}
+	return 0;
+
+err_free:
+	free(info);
+err_close:
+	bfd_close(ctx->bfdf);
+	return -1;
+}
+
+static void destroy_context(disasm_ctx_t *ctx)
+{
+	free(ctx->info);
+	bfd_close(ctx->bfdf);
+}
+
+static int
+disassemble_insn(disasm_ctx_t *ctx, __maybe_unused unsigned char *image,
+		 __maybe_unused ssize_t len, int pc)
+{
+	return ctx->disassemble(pc, ctx->info);
+}
+
+int disasm_init(void)
+{
+	bfd_init();
+	return 0;
+}
+#endif /* HAVE_LIBBPFD_SUPPORT */
+
+int disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
+		      const char *arch, const char *disassembler_options,
+		      const struct btf *btf,
+		      const struct bpf_prog_linfo *prog_linfo,
+		      __u64 func_ksym, unsigned int func_idx,
+		      bool linum)
+{
+	const struct bpf_line_info *linfo = NULL;
+	unsigned int nr_skip = 0;
+	int count, i, pc = 0;
+	disasm_ctx_t ctx;
+
+	if (!len)
+		return -1;
+
+	if (init_context(&ctx, arch, disassembler_options, image, len))
+		return -1;
 
 	if (json_output)
 		jsonw_start_array(json_wtr);
@@ -185,10 +357,11 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
 			if (linfo)
 				btf_dump_linfo_plain(btf, linfo, "; ",
 						     linum);
-			printf("%4x:\t", pc);
+			printf("%4x:" DISASM_SPACER, pc);
 		}
 
-		count = disassemble(pc, &info);
+		count = disassemble_insn(&ctx, image, len, pc);
+
 		if (json_output) {
 			/* Operand array, was started in fprintf_json. Before
 			 * that, make sure we have a _null_ value if no operand
@@ -224,11 +397,7 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
 	if (json_output)
 		jsonw_end_array(json_wtr);
 
-	bfd_close(bfdf);
-}
+	destroy_context(&ctx);
 
-int disasm_init(void)
-{
-	bfd_init();
 	return 0;
 }