// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) IBM Corporation, 2009
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <stdarg.h>
#include <linux/kallsyms.h>

#include <asm/insn.h>
#include <inat.c>
#include <insn.c>

/*
 * Test of instruction analysis in general and insn_get_length() in
 * particular.  See if insn_get_length() and the disassembler agree
 * on the length of each instruction in an elf disassembly.
 *
 * Usage: objdump -d a.out | awk -f objdump_reformat.awk | ./insn_decoder_test
 */

const char *prog;
static int verbose;
static int x86_64;

static void usage(void)
{
        fprintf(stderr, "Usage: objdump -d a.out | awk -f objdump_reformat.awk"
                " | %s [-y|-n] [-v]\n", prog);
        fprintf(stderr, "\t-y   64bit mode\n");
        fprintf(stderr, "\t-n   32bit mode\n");
        fprintf(stderr, "\t-v   verbose mode\n");
        exit(1);
}

static void malformed_line(const char *line, int line_nr)
{
        fprintf(stderr, "%s: error: malformed line %d:\n%s",
                prog, line_nr, line);
        exit(3);
}

static void pr_warn(const char *fmt, ...)
{
        va_list ap;

        fprintf(stderr, "%s: warning: ", prog);
        va_start(ap, fmt);
        vfprintf(stderr, fmt, ap);
        va_end(ap);
}

static void dump_field(FILE *fp, const char *name, const char *indent,
                       struct insn_field *field)
{
        fprintf(fp, "%s.%s = {\n", indent, name);
        fprintf(fp, "%s\t.value = %d, bytes[] = {%x, %x, %x, %x},\n",
                indent, field->value, field->bytes[0], field->bytes[1],
                field->bytes[2], field->bytes[3]);
        fprintf(fp, "%s\t.got = %d, .nbytes = %d},\n", indent,
                field->got, field->nbytes);
}

static void dump_insn(FILE *fp, struct insn *insn)
{
        fprintf(fp, "Instruction = {\n");
        dump_field(fp, "prefixes", "\t",        &insn->prefixes);
        dump_field(fp, "rex_prefix", "\t",      &insn->rex_prefix);
        dump_field(fp, "vex_prefix", "\t",      &insn->vex_prefix);
        dump_field(fp, "opcode", "\t",          &insn->opcode);
        dump_field(fp, "modrm", "\t",           &insn->modrm);
        dump_field(fp, "sib", "\t",             &insn->sib);
        dump_field(fp, "displacement", "\t",    &insn->displacement);
        dump_field(fp, "immediate1", "\t",      &insn->immediate1);
        dump_field(fp, "immediate2", "\t",      &insn->immediate2);
        fprintf(fp, "\t.attr = %x, .opnd_bytes = %d, .addr_bytes = %d,\n",
                insn->attr, insn->opnd_bytes, insn->addr_bytes);
        fprintf(fp, "\t.length = %d, .x86_64 = %d, .kaddr = %p}\n",
                insn->length, insn->x86_64, insn->kaddr);
}

static void parse_args(int argc, char **argv)
{
        int c;
        prog = argv[0];
        while ((c = getopt(argc, argv, "ynv")) != -1) {
                switch (c) {
                case 'y':
                        x86_64 = 1;
                        break;
                case 'n':
                        x86_64 = 0;
                        break;
                case 'v':
                        verbose = 1;
                        break;
                default:
                        usage();
                }
        }
}

#define BUFSIZE (256 + KSYM_NAME_LEN)

int main(int argc, char **argv)
{
        char line[BUFSIZE], sym[BUFSIZE] = "<unknown>";
        unsigned char insn_buff[16];
        struct insn insn;
        int insns = 0;
        int warnings = 0;

        parse_args(argc, argv);

        while (fgets(line, BUFSIZE, stdin)) {
                char copy[BUFSIZE], *s, *tab1, *tab2;
                int nb = 0, ret;
                unsigned int b;

                if (line[0] == '<') {
                        /* Symbol line */
                        strcpy(sym, line);
                        continue;
                }

                insns++;
                memset(insn_buff, 0, 16);
                strcpy(copy, line);
                tab1 = strchr(copy, '\t');
                if (!tab1)
                        malformed_line(line, insns);
                s = tab1 + 1;
                s += strspn(s, " ");
                tab2 = strchr(s, '\t');
                if (!tab2)
                        malformed_line(line, insns);
                *tab2 = '\0';   /* Characters beyond tab2 aren't examined */
                while (s < tab2) {
                        if (sscanf(s, "%x", &b) == 1) {
                                insn_buff[nb++] = (unsigned char) b;
                                s += 3;
                        } else
                                break;
                }

                /* Decode an instruction */
                ret = insn_decode(&insn, insn_buff, sizeof(insn_buff),
                                  x86_64 ? INSN_MODE_64 : INSN_MODE_32);

                if (ret < 0 || insn.length != nb) {
                        warnings++;
                        pr_warn("Found an x86 instruction decoder bug, "
                                "please report this.\n", sym);
                        pr_warn("%s", line);
                        pr_warn("objdump says %d bytes, but insn_get_length() "
                                "says %d\n", nb, insn.length);
                        if (verbose)
                                dump_insn(stderr, &insn);
                }
        }
        if (warnings)
                pr_warn("Decoded and checked %d instructions with %d "
                        "failures\n", insns, warnings);
        else
                fprintf(stdout, "  %s: success: Decoded and checked %d"
                        " instructions\n", prog, insns);
        return 0;
}