tools: bpftool: use 4 context mode for the NFP disasm

The nfp driver is currently always JITing the BPF for 4 context/thread
mode of the NFP flow processors.  Tell this to the disassembler,
otherwise some registers may be incorrectly decoded.

Signed-off-by: Jakub Kicinski <[email protected]>
Reviewed-by: Jiong Wang <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>

Author: Jakub Kicinski

tools/bpf/bpftool/common.c

@@ -554,7 +554,9 @@ static int read_sysfs_netdev_hex_int(char *devname, const char *entry_name)
 	return read_sysfs_hex_int(full_path);
 }
 
-const char *ifindex_to_bfd_name_ns(__u32 ifindex, __u64 ns_dev, __u64 ns_ino)
+const char *
+ifindex_to_bfd_params(__u32 ifindex, __u64 ns_dev, __u64 ns_ino,
+		      const char **opt)
 {
 	char devname[IF_NAMESIZE];
 	int vendor_id;
@@ -579,6 +581,7 @@ const char *ifindex_to_bfd_name_ns(__u32 ifindex, __u64 ns_dev, __u64 ns_ino)
 		    device_id != 0x6000 &&
 		    device_id != 0x6003)
 			p_info("Unknown NFP device ID, assuming it is NFP-6xxx arch");
+		*opt = "ctx4";
 		return "NFP-6xxx";
 	default:
 		p_err("Can't get bfd arch name for device vendor id 0x%04x",

tools/bpf/bpftool/jit_disasm.c

@@ -77,7 +77,7 @@ static int fprintf_json(void *out, const char *fmt, ...)
 }
 
 void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
-		       const char *arch)
+		       const char *arch, const char *disassembler_options)
 {
 	disassembler_ftype disassemble;
 	struct disassemble_info info;
@@ -116,6 +116,8 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
 
 	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;
 

tools/bpf/bpftool/main.h

@@ -145,13 +145,15 @@ int map_parse_fd(int *argc, char ***argv);
 int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len);
 
 void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
-		       const char *arch);
+		       const char *arch, const char *disassembler_options);
 void print_data_json(uint8_t *data, size_t len);
 void print_hex_data_json(uint8_t *data, size_t len);
 
 unsigned int get_page_size(void);
 unsigned int get_possible_cpus(void);
-const char *ifindex_to_bfd_name_ns(__u32 ifindex, __u64 ns_dev, __u64 ns_ino);
+const char *
+ifindex_to_bfd_params(__u32 ifindex, __u64 ns_dev, __u64 ns_ino,
+		      const char **opt);
 
 struct btf_dumper {
 	const struct btf *btf;

tools/bpf/bpftool/prog.c

@@ -449,6 +449,7 @@ static int do_dump(int argc, char **argv)
 	unsigned long *func_ksyms = NULL;
 	struct bpf_prog_info info = {};
 	unsigned int *func_lens = NULL;
+	const char *disasm_opt = NULL;
 	unsigned int nr_func_ksyms;
 	unsigned int nr_func_lens;
 	struct dump_data dd = {};
@@ -607,9 +608,10 @@ static int do_dump(int argc, char **argv)
 		const char *name = NULL;
 
 		if (info.ifindex) {
-			name = ifindex_to_bfd_name_ns(info.ifindex,
-						      info.netns_dev,
-						      info.netns_ino);
+			name = ifindex_to_bfd_params(info.ifindex,
+						     info.netns_dev,
+						     info.netns_ino,
+						     &disasm_opt);
 			if (!name)
 				goto err_free;
 		}
@@ -651,7 +653,8 @@ static int do_dump(int argc, char **argv)
 					printf("%s:\n", sym_name);
 				}
 
-				disasm_print_insn(img, lens[i], opcodes, name);
+				disasm_print_insn(img, lens[i], opcodes, name,
+						  disasm_opt);
 				img += lens[i];
 
 				if (json_output)
@@ -663,7 +666,8 @@ static int do_dump(int argc, char **argv)
 			if (json_output)
 				jsonw_end_array(json_wtr);
 		} else {
-			disasm_print_insn(buf, *member_len, opcodes, name);
+			disasm_print_insn(buf, *member_len, opcodes, name,
+					  disasm_opt);
 		}
 	} else if (visual) {
 		if (json_output)