main.c

   1 /*  Bare metal PPC KVM app, for libre-soc simulator comparison purposes
   2     Copyright (C) 2021 Lauri Kasanen
   3
   4     This program is free software: you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation, version 3 of the License.
   7
   8     This program is distributed in the hope that it will be useful,
   9     but WITHOUT ANY WARRANTY; without even the implied warranty of
  10     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11     GNU General Public License for more details.
  12
  13     You should have received a copy of the GNU General Public License
  14     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 #define _GNU_SOURCE
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <getopt.h>
  22 #include <linux/kvm.h>
  23 #include <limits.h>
  24 #include <stdio.h>
  25 #include <stdint.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/ioctl.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31 #include <sys/types.h>
  32 #include <unistd.h>
  33
  34 #define MAXDUMPS 10
  35 #define RAMSIZE (64 * 1024 * 1024)
  36 #define PROGSTART 0x20000000
  37
  38 #define MSR_64  (1UL<<63)
  39 #define MSR_LE  (1UL<<0)
  40
  41 enum {
  42         SPR_LR,
  43 };
  44
  45 static void nukenewline(char buf[]) {
  46         unsigned i;
  47         for (i = 0; buf[i]; i++) {
  48                 if (buf[i] == '\n') {
  49                         buf[i] = '\0';
  50                         break;
  51                 }
  52         }
  53 }
  54
  55 static void help(const char argv0[]) {
  56
  57         printf("Usage: %s [args] -i file.bin\n\n"
  58
  59                 "-i --binary file       Raw, bare metal executable\n"
  60                 "-g --intregs file      Text file setting up GPRs\n"
  61                 "-f --fpregs file       Text file setting up FPRs\n"
  62                 "-s --spregs file       Text file setting up SPRs (unnecessary if only LR is needed)\n"
  63                 "-l --load file:addr    Load this binary to RAM\n"
  64                 "-d --dump file:addr:len        Save this RAM area after running\n"
  65                 "-t --trace file                Save a full trace to this file\n"
  66                 "-h --help              This help\n\n"
  67
  68                 "Load and dump may be given multiple times. GPR/FPR are numbered,\n"
  69                 "SPRs are named.\n", argv0);
  70
  71         exit(0);
  72 }
  73
  74 static void parseregs(const char name[], const uint8_t gpr, struct kvm_regs *regs,
  75                         struct kvm_fpu *fpregs) {
  76
  77         FILE *f = fopen(name, "r");
  78         if (!f) {
  79                 printf("Can't open %s\n", name);
  80                 exit(1);
  81         }
  82
  83         char buf[256];
  84
  85         while (fgets(buf, 256, f)) {
  86                 if (buf[0] == '#')
  87                         continue;
  88                 nukenewline(buf);
  89
  90                 const uint8_t reg = strtol(buf, NULL, 0);
  91                 const char *ptr = strchr(buf + 1, ' ');
  92                 if (!ptr) {
  93                         printf("Invalid line '%s'\n", buf);
  94                         continue;
  95                 }
  96
  97                 const uint64_t val = strtol(ptr, NULL, 0);
  98
  99                 // apply reg
 100                 if (gpr) {
 101                         regs->gpr[reg] = val;
 102                 } else {
 103                         fpregs->fpr[reg] = val;
 104                 }
 105         }
 106
 107         fclose(f);
 108 }
 109
 110 static void parsesprs(const char name[], struct kvm_regs *regs) {
 111
 112         FILE *f = fopen(name, "r");
 113         if (!f) {
 114                 printf("Can't open %s\n", name);
 115                 exit(1);
 116         }
 117
 118         char buf[256];
 119
 120         while (fgets(buf, 256, f)) {
 121                 if (buf[0] == '#')
 122                         continue;
 123                 nukenewline(buf);
 124
 125                 uint8_t reg = 0xff;
 126
 127                 #define check(a) if (!strncasecmp(buf, a, sizeof(a) - 1))
 128
 129                 check("LR:") {
 130                         reg = SPR_LR;
 131                 }
 132
 133                 #undef check
 134
 135                 if (reg == 0xff) {
 136                         printf("Unknown (unimplemented?) SPR register '%s'\n",
 137                                 buf);
 138                         continue;
 139                 }
 140
 141                 const char *ptr = strchr(buf + 1, ' ');
 142                 if (!ptr) {
 143                         printf("Invalid line '%s'\n", buf);
 144                         continue;
 145                 }
 146
 147                 const uint64_t val = strtol(ptr, NULL, 0);
 148
 149                 // apply reg
 150                 switch (reg) {
 151                         case SPR_LR:
 152                                 regs->lr = val;
 153                         break;
 154                 }
 155         }
 156
 157         fclose(f);
 158 }
 159
 160 static void load(const char arg[], uint8_t *ram) {
 161
 162         char name[PATH_MAX];
 163         const char *ptr = strchr(arg, ':');
 164         if (!ptr) {
 165                 printf("Invalid load\n");
 166                 exit(1);
 167         }
 168
 169         const unsigned namelen = ptr - arg;
 170
 171         strncpy(name, arg, namelen);
 172         name[namelen] = '\0';
 173
 174         const uint64_t addr = strtol(ptr + 1, NULL, 0);
 175
 176         FILE *f = fopen(name, "r");
 177         if (!f) {
 178                 printf("Can't open %s\n", name);
 179                 exit(1);
 180         }
 181
 182         fseek(f, 0, SEEK_END);
 183         const unsigned len = ftell(f);
 184         rewind(f);
 185
 186         if (addr + len >= RAMSIZE) {
 187                 printf("Tried to use too much RAM\n");
 188                 exit(1);
 189         }
 190
 191         printf("Loading %s to 0x%lx, %u bytes\n", name, addr, len);
 192
 193         if (fread(&ram[addr], len, 1, f) != 1)
 194                 abort();
 195
 196         fclose(f);
 197 }
 198
 199 int main(int argc, char **argv) {
 200
 201         const struct option longopts[] = {
 202                 { "binary", 1, NULL, 'i' },
 203                 { "intregs", 1, NULL, 'g' },
 204                 { "fpregs", 1, NULL, 'f' },
 205                 { "spregs", 1, NULL, 's' },
 206                 { "load", 1, NULL, 'l' },
 207                 { "dump", 1, NULL, 'd' },
 208                 { "trace", 1, NULL, 't' },
 209                 { "help", 0, NULL, 'h' },
 210                 { NULL, 0, NULL, 0 }
 211         };
 212         const char opts[] = "i:g:f:s:l:d:t:h";
 213
 214         struct kvm_run *run;
 215         struct kvm_regs regs;
 216         struct kvm_sregs sregs;
 217         struct kvm_fpu fpregs;
 218         int kvm, vmfd, vcpu;
 219         FILE *binary = NULL, *trace = NULL;
 220         char dumps[MAXDUMPS][PATH_MAX];
 221         unsigned num_dumps = 0;
 222         uint8_t *ram, *progmem;
 223         const char *binpath;
 224
 225         // Yes, we're frugal
 226         if (posix_memalign((void **) &ram, 64 * 1024, RAMSIZE))
 227                 abort();
 228         memset(ram, 0, RAMSIZE);
 229
 230         memset(&regs, 0, sizeof(struct kvm_regs));
 231         memset(&fpregs, 0, sizeof(struct kvm_fpu));
 232
 233         regs.lr = -1;
 234         regs.pc = PROGSTART;
 235         regs.msr = MSR_64 | MSR_LE;
 236
 237         while (1) {
 238                 const int c = getopt_long(argc, argv, opts, longopts, NULL);
 239                 if (c == -1)
 240                         break;
 241
 242                 switch (c) {
 243                         case 'i':
 244                                 if (binary) {
 245                                         printf("Only one binary allowed\n");
 246                                         return 1;
 247                                 }
 248
 249                                 binary = fopen(optarg, "r");
 250                                 if (!binary) {
 251                                         printf("Failed to open %s\n", optarg);
 252                                         return 1;
 253                                 }
 254
 255                                 binpath = strdup(optarg);
 256                         break;
 257                         case 'g':
 258                                 parseregs(optarg, 1, &regs, &fpregs);
 259                         break;
 260                         case 'f':
 261                                 parseregs(optarg, 0, &regs, &fpregs);
 262                         break;
 263                         case 's':
 264                                 parsesprs(optarg, &regs);
 265                         break;
 266                         case 'l':
 267                                 load(optarg, ram);
 268                         break;
 269                         case 'd':
 270                                 if (num_dumps >= MAXDUMPS) {
 271                                         printf("Too many dumps\n");
 272                                         return 1;
 273                                 }
 274
 275                                 strncpy(dumps[num_dumps], optarg, PATH_MAX);
 276                                 dumps[num_dumps][PATH_MAX - 1] = '\0';
 277                                 num_dumps++;
 278                         break;
 279                         case 't':
 280                                 if (trace) {
 281                                         printf("Only one trace allowed\n");
 282                                         return 1;
 283                                 }
 284
 285                                 trace = fopen(optarg, "w");
 286                                 if (!trace) {
 287                                         printf("Failed to open %s\n", optarg);
 288                                         return 1;
 289                                 }
 290                         break;
 291                         case 'h':
 292                         default:
 293                                 help(argv[0]);
 294                         break;
 295                 }
 296         }
 297
 298         if (!binary) {
 299                 help(argv[0]);
 300         }
 301
 302         fseek(binary, 0, SEEK_END);
 303         const unsigned binlen = ftell(binary);
 304         rewind(binary);
 305
 306         printf("Loading binary %u bytes\n", binlen);
 307
 308         if (posix_memalign((void **) &progmem, 64 * 1024, binlen))
 309                 abort();
 310
 311         if (fread(progmem, binlen, 1, binary) != 1)
 312                 abort();
 313         fclose(binary);
 314
 315         kvm = open("/dev/kvm", O_RDWR | O_CLOEXEC);
 316         if (kvm < 0) {
 317                 printf("Failed to open kvm, perhaps you lack permissions?\n");
 318                 return 1;
 319         }
 320
 321         int ret;
 322         ret = ioctl(kvm, KVM_GET_API_VERSION, NULL);
 323         if (ret == -1 || ret != 12) abort();
 324
 325         ret = ioctl(kvm, KVM_CHECK_EXTENSION, KVM_CAP_PPC_GUEST_DEBUG_SSTEP);
 326         if (ret == -1 || !ret) {
 327                 printf("This system lacks single-stepping!\n");
 328                 return 1;
 329         }
 330
 331         vmfd = ioctl(kvm, KVM_CREATE_VM, (unsigned long)0);
 332
 333         struct kvm_userspace_memory_region region = {
 334                 .slot = 0,
 335                 .guest_phys_addr = 0,
 336                 .memory_size = RAMSIZE,
 337                 .userspace_addr = (uint64_t) ram,
 338                 .flags = 0
 339         };
 340         ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &region);
 341
 342         region.slot = 1;
 343         region.guest_phys_addr = PROGSTART;
 344         region.memory_size = binlen;
 345         region.userspace_addr = (uint64_t) progmem;
 346         region.flags = KVM_MEM_READONLY;
 347         ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &region);
 348
 349         vcpu = ioctl(vmfd, KVM_CREATE_VCPU, (unsigned long)0);
 350         const unsigned vcpulen = ioctl(kvm, KVM_GET_VCPU_MMAP_SIZE, NULL);
 351
 352         run = mmap(NULL, vcpulen, PROT_READ | PROT_WRITE, MAP_SHARED, vcpu, 0);
 353
 354         if (ioctl(vcpu, KVM_GET_SREGS, &sregs) == -1)
 355                 abort();
 356         if (ioctl(vcpu, KVM_SET_SREGS, &sregs) == -1)
 357                 abort();
 358
 359         if (ioctl(vcpu, KVM_SET_REGS, &regs) == -1)
 360                 abort();
 361         if (ioctl(vcpu, KVM_SET_FPU, &fpregs) == -1)
 362                 abort();
 363
 364         const struct kvm_guest_debug dbg = {
 365                 .control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP
 366         };
 367         if (ioctl(vcpu, KVM_SET_GUEST_DEBUG, &dbg) == -1)
 368                 abort();
 369
 370         // Runtime
 371         while (1) {
 372                 if (ioctl(vcpu, KVM_RUN, NULL) == -1)
 373                         abort();
 374                 printf("Exited because %u\n", run->exit_reason);
 375         }
 376
 377         close(kvm);
 378         free(progmem);
 379         free(ram);
 380         free((char *) binpath);
 381         return 0;
 382 }