target/arm/arch_dump.c

   1 /* Support for writing ELF notes for ARM architectures
   2  *
   3  * Copyright (C) 2015 Red Hat Inc.
   4  *
   5  * Author: Andrew Jones <drjones@redhat.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "cpu.h"
  23 #include "elf.h"
  24 #include "sysemu/dump.h"
  25
  26 /* struct user_pt_regs from arch/arm64/include/uapi/asm/ptrace.h */
  27 struct aarch64_user_regs {
  28     uint64_t regs[31];
  29     uint64_t sp;
  30     uint64_t pc;
  31     uint64_t pstate;
  32 } QEMU_PACKED;
  33
  34 QEMU_BUILD_BUG_ON(sizeof(struct aarch64_user_regs) != 272);
  35
  36 /* struct elf_prstatus from include/uapi/linux/elfcore.h */
  37 struct aarch64_elf_prstatus {
  38     char pad1[32]; /* 32 == offsetof(struct elf_prstatus, pr_pid) */
  39     uint32_t pr_pid;
  40     char pad2[76]; /* 76 == offsetof(struct elf_prstatus, pr_reg) -
  41                             offsetof(struct elf_prstatus, pr_ppid) */
  42     struct aarch64_user_regs pr_reg;
  43     uint32_t pr_fpvalid;
  44     char pad3[4];
  45 } QEMU_PACKED;
  46
  47 QEMU_BUILD_BUG_ON(sizeof(struct aarch64_elf_prstatus) != 392);
  48
  49 /* struct user_fpsimd_state from arch/arm64/include/uapi/asm/ptrace.h
  50  *
  51  * While the vregs member of user_fpsimd_state is of type __uint128_t,
  52  * QEMU uses an array of uint64_t, where the high half of the 128-bit
  53  * value is always in the 2n+1'th index. Thus we also break the 128-
  54  * bit values into two halves in this reproduction of user_fpsimd_state.
  55  */
  56 struct aarch64_user_vfp_state {
  57     uint64_t vregs[64];
  58     uint32_t fpsr;
  59     uint32_t fpcr;
  60     char pad[8];
  61 } QEMU_PACKED;
  62
  63 QEMU_BUILD_BUG_ON(sizeof(struct aarch64_user_vfp_state) != 528);
  64
  65 struct aarch64_note {
  66     Elf64_Nhdr hdr;
  67     char name[8]; /* align_up(sizeof("CORE"), 4) */
  68     union {
  69         struct aarch64_elf_prstatus prstatus;
  70         struct aarch64_user_vfp_state vfp;
  71     };
  72 } QEMU_PACKED;
  73
  74 #define AARCH64_NOTE_HEADER_SIZE offsetof(struct aarch64_note, prstatus)
  75 #define AARCH64_PRSTATUS_NOTE_SIZE \
  76             (AARCH64_NOTE_HEADER_SIZE + sizeof(struct aarch64_elf_prstatus))
  77 #define AARCH64_PRFPREG_NOTE_SIZE \
  78             (AARCH64_NOTE_HEADER_SIZE + sizeof(struct aarch64_user_vfp_state))
  79
  80 static void aarch64_note_init(struct aarch64_note *note, DumpState *s,
  81                               const char *name, Elf64_Word namesz,
  82                               Elf64_Word type, Elf64_Word descsz)
  83 {
  84     memset(note, 0, sizeof(*note));
  85
  86     note->hdr.n_namesz = cpu_to_dump32(s, namesz);
  87     note->hdr.n_descsz = cpu_to_dump32(s, descsz);
  88     note->hdr.n_type = cpu_to_dump32(s, type);
  89
  90     memcpy(note->name, name, namesz);
  91 }
  92
  93 static int aarch64_write_elf64_prfpreg(WriteCoreDumpFunction f,
  94                                        CPUARMState *env, int cpuid,
  95                                        DumpState *s)
  96 {
  97     struct aarch64_note note;
  98     int ret, i;
  99
 100     aarch64_note_init(&note, s, "CORE", 5, NT_PRFPREG, sizeof(note.vfp));
 101
 102     for (i = 0; i < 32; ++i) {
 103         uint64_t *q = aa64_vfp_qreg(env, i);
 104         note.vfp.vregs[2*i + 0] = cpu_to_dump64(s, q[0]);
 105         note.vfp.vregs[2*i + 1] = cpu_to_dump64(s, q[1]);
 106     }
 107
 108     if (s->dump_info.d_endian == ELFDATA2MSB) {
 109         /* For AArch64 we must always swap the vfp.regs's 2n and 2n+1
 110          * entries when generating BE notes, because even big endian
 111          * hosts use 2n+1 for the high half.
 112          */
 113         for (i = 0; i < 32; ++i) {
 114             uint64_t tmp = note.vfp.vregs[2*i];
 115             note.vfp.vregs[2*i] = note.vfp.vregs[2*i+1];
 116             note.vfp.vregs[2*i+1] = tmp;
 117         }
 118     }
 119
 120     note.vfp.fpsr = cpu_to_dump32(s, vfp_get_fpsr(env));
 121     note.vfp.fpcr = cpu_to_dump32(s, vfp_get_fpcr(env));
 122
 123     ret = f(&note, AARCH64_PRFPREG_NOTE_SIZE, s);
 124     if (ret < 0) {
 125         return -1;
 126     }
 127
 128     return 0;
 129 }
 130
 131 int arm_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs,
 132                              int cpuid, void *opaque)
 133 {
 134     struct aarch64_note note;
 135     CPUARMState *env = &ARM_CPU(cs)->env;
 136     DumpState *s = opaque;
 137     uint64_t pstate, sp;
 138     int ret, i;
 139
 140     aarch64_note_init(&note, s, "CORE", 5, NT_PRSTATUS, sizeof(note.prstatus));
 141
 142     note.prstatus.pr_pid = cpu_to_dump32(s, cpuid);
 143     note.prstatus.pr_fpvalid = cpu_to_dump32(s, 1);
 144
 145     if (!is_a64(env)) {
 146         aarch64_sync_32_to_64(env);
 147         pstate = cpsr_read(env);
 148         sp = 0;
 149     } else {
 150         pstate = pstate_read(env);
 151         sp = env->xregs[31];
 152     }
 153
 154     for (i = 0; i < 31; ++i) {
 155         note.prstatus.pr_reg.regs[i] = cpu_to_dump64(s, env->xregs[i]);
 156     }
 157     note.prstatus.pr_reg.sp = cpu_to_dump64(s, sp);
 158     note.prstatus.pr_reg.pc = cpu_to_dump64(s, env->pc);
 159     note.prstatus.pr_reg.pstate = cpu_to_dump64(s, pstate);
 160
 161     ret = f(&note, AARCH64_PRSTATUS_NOTE_SIZE, s);
 162     if (ret < 0) {
 163         return -1;
 164     }
 165
 166     return aarch64_write_elf64_prfpreg(f, env, cpuid, s);
 167 }
 168
 169 /* struct pt_regs from arch/arm/include/asm/ptrace.h */
 170 struct arm_user_regs {
 171     uint32_t regs[17];
 172     char pad[4];
 173 } QEMU_PACKED;
 174
 175 QEMU_BUILD_BUG_ON(sizeof(struct arm_user_regs) != 72);
 176
 177 /* struct elf_prstatus from include/uapi/linux/elfcore.h */
 178 struct arm_elf_prstatus {
 179     char pad1[24]; /* 24 == offsetof(struct elf_prstatus, pr_pid) */
 180     uint32_t pr_pid;
 181     char pad2[44]; /* 44 == offsetof(struct elf_prstatus, pr_reg) -
 182                             offsetof(struct elf_prstatus, pr_ppid) */
 183     struct arm_user_regs pr_reg;
 184     uint32_t pr_fpvalid;
 185 } QEMU_PACKED arm_elf_prstatus;
 186
 187 QEMU_BUILD_BUG_ON(sizeof(struct arm_elf_prstatus) != 148);
 188
 189 /* struct user_vfp from arch/arm/include/asm/user.h */
 190 struct arm_user_vfp_state {
 191     uint64_t vregs[32];
 192     uint32_t fpscr;
 193 } QEMU_PACKED;
 194
 195 QEMU_BUILD_BUG_ON(sizeof(struct arm_user_vfp_state) != 260);
 196
 197 struct arm_note {
 198     Elf32_Nhdr hdr;
 199     char name[8]; /* align_up(sizeof("LINUX"), 4) */
 200     union {
 201         struct arm_elf_prstatus prstatus;
 202         struct arm_user_vfp_state vfp;
 203     };
 204 } QEMU_PACKED;
 205
 206 #define ARM_NOTE_HEADER_SIZE offsetof(struct arm_note, prstatus)
 207 #define ARM_PRSTATUS_NOTE_SIZE \
 208             (ARM_NOTE_HEADER_SIZE + sizeof(struct arm_elf_prstatus))
 209 #define ARM_VFP_NOTE_SIZE \
 210             (ARM_NOTE_HEADER_SIZE + sizeof(struct arm_user_vfp_state))
 211
 212 static void arm_note_init(struct arm_note *note, DumpState *s,
 213                           const char *name, Elf32_Word namesz,
 214                           Elf32_Word type, Elf32_Word descsz)
 215 {
 216     memset(note, 0, sizeof(*note));
 217
 218     note->hdr.n_namesz = cpu_to_dump32(s, namesz);
 219     note->hdr.n_descsz = cpu_to_dump32(s, descsz);
 220     note->hdr.n_type = cpu_to_dump32(s, type);
 221
 222     memcpy(note->name, name, namesz);
 223 }
 224
 225 static int arm_write_elf32_vfp(WriteCoreDumpFunction f, CPUARMState *env,
 226                                int cpuid, DumpState *s)
 227 {
 228     struct arm_note note;
 229     int ret, i;
 230
 231     arm_note_init(&note, s, "LINUX", 6, NT_ARM_VFP, sizeof(note.vfp));
 232
 233     for (i = 0; i < 32; ++i) {
 234         note.vfp.vregs[i] = cpu_to_dump64(s, *aa32_vfp_dreg(env, i));
 235     }
 236
 237     note.vfp.fpscr = cpu_to_dump32(s, vfp_get_fpscr(env));
 238
 239     ret = f(&note, ARM_VFP_NOTE_SIZE, s);
 240     if (ret < 0) {
 241         return -1;
 242     }
 243
 244     return 0;
 245 }
 246
 247 int arm_cpu_write_elf32_note(WriteCoreDumpFunction f, CPUState *cs,
 248                              int cpuid, void *opaque)
 249 {
 250     struct arm_note note;
 251     CPUARMState *env = &ARM_CPU(cs)->env;
 252     DumpState *s = opaque;
 253     int ret, i, fpvalid = !!arm_feature(env, ARM_FEATURE_VFP);
 254
 255     arm_note_init(&note, s, "CORE", 5, NT_PRSTATUS, sizeof(note.prstatus));
 256
 257     note.prstatus.pr_pid = cpu_to_dump32(s, cpuid);
 258     note.prstatus.pr_fpvalid = cpu_to_dump32(s, fpvalid);
 259
 260     for (i = 0; i < 16; ++i) {
 261         note.prstatus.pr_reg.regs[i] = cpu_to_dump32(s, env->regs[i]);
 262     }
 263     note.prstatus.pr_reg.regs[16] = cpu_to_dump32(s, cpsr_read(env));
 264
 265     ret = f(&note, ARM_PRSTATUS_NOTE_SIZE, s);
 266     if (ret < 0) {
 267         return -1;
 268     } else if (fpvalid) {
 269         return arm_write_elf32_vfp(f, env, cpuid, s);
 270     }
 271
 272     return 0;
 273 }
 274
 275 int cpu_get_dump_info(ArchDumpInfo *info,
 276                       const GuestPhysBlockList *guest_phys_blocks)
 277 {
 278     ARMCPU *cpu;
 279     CPUARMState *env;
 280     GuestPhysBlock *block;
 281     hwaddr lowest_addr = ULLONG_MAX;
 282
 283     if (first_cpu == NULL) {
 284         return -1;
 285     }
 286
 287     cpu = ARM_CPU(first_cpu);
 288     env = &cpu->env;
 289
 290     /* Take a best guess at the phys_base. If we get it wrong then crash
 291      * will need '--machdep phys_offset=<phys-offset>' added to its command
 292      * line, which isn't any worse than assuming we can use zero, but being
 293      * wrong. This is the same algorithm the crash utility uses when
 294      * attempting to guess as it loads non-dumpfile formatted files.
 295      */
 296     QTAILQ_FOREACH(block, &guest_phys_blocks->head, next) {
 297         if (block->target_start < lowest_addr) {
 298             lowest_addr = block->target_start;
 299         }
 300     }
 301
 302     if (arm_feature(env, ARM_FEATURE_AARCH64)) {
 303         info->d_machine = EM_AARCH64;
 304         info->d_class = ELFCLASS64;
 305         info->page_size = (1 << 16); /* aarch64 max pagesize */
 306         if (lowest_addr != ULLONG_MAX) {
 307             info->phys_base = lowest_addr;
 308         }
 309     } else {
 310         info->d_machine = EM_ARM;
 311         info->d_class = ELFCLASS32;
 312         info->page_size = (1 << 12);
 313         if (lowest_addr < UINT_MAX) {
 314             info->phys_base = lowest_addr;
 315         }
 316     }
 317
 318     /* We assume the relevant endianness is that of EL1; this is right
 319      * for kernels, but might give the wrong answer if you're trying to
 320      * dump a hypervisor that happens to be running an opposite-endian
 321      * kernel.
 322      */
 323     info->d_endian = (env->cp15.sctlr_el[1] & SCTLR_EE) != 0
 324                      ? ELFDATA2MSB : ELFDATA2LSB;
 325
 326     return 0;
 327 }
 328
 329 ssize_t cpu_get_note_size(int class, int machine, int nr_cpus)
 330 {
 331     ARMCPU *cpu = ARM_CPU(first_cpu);
 332     CPUARMState *env = &cpu->env;
 333     size_t note_size;
 334
 335     if (class == ELFCLASS64) {
 336         note_size = AARCH64_PRSTATUS_NOTE_SIZE;
 337         note_size += AARCH64_PRFPREG_NOTE_SIZE;
 338     } else {
 339         note_size = ARM_PRSTATUS_NOTE_SIZE;
 340         if (arm_feature(env, ARM_FEATURE_VFP)) {
 341             note_size += ARM_VFP_NOTE_SIZE;
 342         }
 343     }
 344
 345     return note_size * nr_cpus;
 346 }