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 < 64; ++i) {
 103         note.vfp.vregs[i] = cpu_to_dump64(s, float64_val(env->vfp.regs[i]));
 104     }
 105
 106     if (s->dump_info.d_endian == ELFDATA2MSB) {
 107         /* For AArch64 we must always swap the vfp.regs's 2n and 2n+1
 108          * entries when generating BE notes, because even big endian
 109          * hosts use 2n+1 for the high half.
 110          */
 111         for (i = 0; i < 32; ++i) {
 112             uint64_t tmp = note.vfp.vregs[2*i];
 113             note.vfp.vregs[2*i] = note.vfp.vregs[2*i+1];
 114             note.vfp.vregs[2*i+1] = tmp;
 115         }
 116     }
 117
 118     note.vfp.fpsr = cpu_to_dump32(s, vfp_get_fpsr(env));
 119     note.vfp.fpcr = cpu_to_dump32(s, vfp_get_fpcr(env));
 120
 121     ret = f(&note, AARCH64_PRFPREG_NOTE_SIZE, s);
 122     if (ret < 0) {
 123         return -1;
 124     }
 125
 126     return 0;
 127 }
 128
 129 int arm_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs,
 130                              int cpuid, void *opaque)
 131 {
 132     struct aarch64_note note;
 133     CPUARMState *env = &ARM_CPU(cs)->env;
 134     DumpState *s = opaque;
 135     uint64_t pstate, sp;
 136     int ret, i;
 137
 138     aarch64_note_init(&note, s, "CORE", 5, NT_PRSTATUS, sizeof(note.prstatus));
 139
 140     note.prstatus.pr_pid = cpu_to_dump32(s, cpuid);
 141     note.prstatus.pr_fpvalid = cpu_to_dump32(s, 1);
 142
 143     if (!is_a64(env)) {
 144         aarch64_sync_32_to_64(env);
 145         pstate = cpsr_read(env);
 146         sp = 0;
 147     } else {
 148         pstate = pstate_read(env);
 149         sp = env->xregs[31];
 150     }
 151
 152     for (i = 0; i < 31; ++i) {
 153         note.prstatus.pr_reg.regs[i] = cpu_to_dump64(s, env->xregs[i]);
 154     }
 155     note.prstatus.pr_reg.sp = cpu_to_dump64(s, sp);
 156     note.prstatus.pr_reg.pc = cpu_to_dump64(s, env->pc);
 157     note.prstatus.pr_reg.pstate = cpu_to_dump64(s, pstate);
 158
 159     ret = f(&note, AARCH64_PRSTATUS_NOTE_SIZE, s);
 160     if (ret < 0) {
 161         return -1;
 162     }
 163
 164     return aarch64_write_elf64_prfpreg(f, env, cpuid, s);
 165 }
 166
 167 /* struct pt_regs from arch/arm/include/asm/ptrace.h */
 168 struct arm_user_regs {
 169     uint32_t regs[17];
 170     char pad[4];
 171 } QEMU_PACKED;
 172
 173 QEMU_BUILD_BUG_ON(sizeof(struct arm_user_regs) != 72);
 174
 175 /* struct elf_prstatus from include/uapi/linux/elfcore.h */
 176 struct arm_elf_prstatus {
 177     char pad1[24]; /* 24 == offsetof(struct elf_prstatus, pr_pid) */
 178     uint32_t pr_pid;
 179     char pad2[44]; /* 44 == offsetof(struct elf_prstatus, pr_reg) -
 180                             offsetof(struct elf_prstatus, pr_ppid) */
 181     struct arm_user_regs pr_reg;
 182     uint32_t pr_fpvalid;
 183 } QEMU_PACKED arm_elf_prstatus;
 184
 185 QEMU_BUILD_BUG_ON(sizeof(struct arm_elf_prstatus) != 148);
 186
 187 /* struct user_vfp from arch/arm/include/asm/user.h */
 188 struct arm_user_vfp_state {
 189     uint64_t vregs[32];
 190     uint32_t fpscr;
 191 } QEMU_PACKED;
 192
 193 QEMU_BUILD_BUG_ON(sizeof(struct arm_user_vfp_state) != 260);
 194
 195 struct arm_note {
 196     Elf32_Nhdr hdr;
 197     char name[8]; /* align_up(sizeof("LINUX"), 4) */
 198     union {
 199         struct arm_elf_prstatus prstatus;
 200         struct arm_user_vfp_state vfp;
 201     };
 202 } QEMU_PACKED;
 203
 204 #define ARM_NOTE_HEADER_SIZE offsetof(struct arm_note, prstatus)
 205 #define ARM_PRSTATUS_NOTE_SIZE \
 206             (ARM_NOTE_HEADER_SIZE + sizeof(struct arm_elf_prstatus))
 207 #define ARM_VFP_NOTE_SIZE \
 208             (ARM_NOTE_HEADER_SIZE + sizeof(struct arm_user_vfp_state))
 209
 210 static void arm_note_init(struct arm_note *note, DumpState *s,
 211                           const char *name, Elf32_Word namesz,
 212                           Elf32_Word type, Elf32_Word descsz)
 213 {
 214     memset(note, 0, sizeof(*note));
 215
 216     note->hdr.n_namesz = cpu_to_dump32(s, namesz);
 217     note->hdr.n_descsz = cpu_to_dump32(s, descsz);
 218     note->hdr.n_type = cpu_to_dump32(s, type);
 219
 220     memcpy(note->name, name, namesz);
 221 }
 222
 223 static int arm_write_elf32_vfp(WriteCoreDumpFunction f, CPUARMState *env,
 224                                int cpuid, DumpState *s)
 225 {
 226     struct arm_note note;
 227     int ret, i;
 228
 229     arm_note_init(&note, s, "LINUX", 6, NT_ARM_VFP, sizeof(note.vfp));
 230
 231     for (i = 0; i < 32; ++i) {
 232         note.vfp.vregs[i] = cpu_to_dump64(s, float64_val(env->vfp.regs[i]));
 233     }
 234
 235     note.vfp.fpscr = cpu_to_dump32(s, vfp_get_fpscr(env));
 236
 237     ret = f(&note, ARM_VFP_NOTE_SIZE, s);
 238     if (ret < 0) {
 239         return -1;
 240     }
 241
 242     return 0;
 243 }
 244
 245 int arm_cpu_write_elf32_note(WriteCoreDumpFunction f, CPUState *cs,
 246                              int cpuid, void *opaque)
 247 {
 248     struct arm_note note;
 249     CPUARMState *env = &ARM_CPU(cs)->env;
 250     DumpState *s = opaque;
 251     int ret, i, fpvalid = !!arm_feature(env, ARM_FEATURE_VFP);
 252
 253     arm_note_init(&note, s, "CORE", 5, NT_PRSTATUS, sizeof(note.prstatus));
 254
 255     note.prstatus.pr_pid = cpu_to_dump32(s, cpuid);
 256     note.prstatus.pr_fpvalid = cpu_to_dump32(s, fpvalid);
 257
 258     for (i = 0; i < 16; ++i) {
 259         note.prstatus.pr_reg.regs[i] = cpu_to_dump32(s, env->regs[i]);
 260     }
 261     note.prstatus.pr_reg.regs[16] = cpu_to_dump32(s, cpsr_read(env));
 262
 263     ret = f(&note, ARM_PRSTATUS_NOTE_SIZE, s);
 264     if (ret < 0) {
 265         return -1;
 266     } else if (fpvalid) {
 267         return arm_write_elf32_vfp(f, env, cpuid, s);
 268     }
 269
 270     return 0;
 271 }
 272
 273 int cpu_get_dump_info(ArchDumpInfo *info,
 274                       const GuestPhysBlockList *guest_phys_blocks)
 275 {
 276     ARMCPU *cpu = ARM_CPU(first_cpu);
 277     CPUARMState *env = &cpu->env;
 278     GuestPhysBlock *block;
 279     hwaddr lowest_addr = ULLONG_MAX;
 280
 281     /* Take a best guess at the phys_base. If we get it wrong then crash
 282      * will need '--machdep phys_offset=<phys-offset>' added to its command
 283      * line, which isn't any worse than assuming we can use zero, but being
 284      * wrong. This is the same algorithm the crash utility uses when
 285      * attempting to guess as it loads non-dumpfile formatted files.
 286      */
 287     QTAILQ_FOREACH(block, &guest_phys_blocks->head, next) {
 288         if (block->target_start < lowest_addr) {
 289             lowest_addr = block->target_start;
 290         }
 291     }
 292
 293     if (arm_feature(env, ARM_FEATURE_AARCH64)) {
 294         info->d_machine = EM_AARCH64;
 295         info->d_class = ELFCLASS64;
 296         info->page_size = (1 << 16); /* aarch64 max pagesize */
 297         if (lowest_addr != ULLONG_MAX) {
 298             info->phys_base = lowest_addr;
 299         }
 300     } else {
 301         info->d_machine = EM_ARM;
 302         info->d_class = ELFCLASS32;
 303         info->page_size = (1 << 12);
 304         if (lowest_addr < UINT_MAX) {
 305             info->phys_base = lowest_addr;
 306         }
 307     }
 308
 309     /* We assume the relevant endianness is that of EL1; this is right
 310      * for kernels, but might give the wrong answer if you're trying to
 311      * dump a hypervisor that happens to be running an opposite-endian
 312      * kernel.
 313      */
 314     info->d_endian = (env->cp15.sctlr_el[1] & SCTLR_EE) != 0
 315                      ? ELFDATA2MSB : ELFDATA2LSB;
 316
 317     return 0;
 318 }
 319
 320 ssize_t cpu_get_note_size(int class, int machine, int nr_cpus)
 321 {
 322     ARMCPU *cpu = ARM_CPU(first_cpu);
 323     CPUARMState *env = &cpu->env;
 324     size_t note_size;
 325
 326     if (class == ELFCLASS64) {
 327         note_size = AARCH64_PRSTATUS_NOTE_SIZE;
 328         note_size += AARCH64_PRFPREG_NOTE_SIZE;
 329     } else {
 330         note_size = ARM_PRSTATUS_NOTE_SIZE;
 331         if (arm_feature(env, ARM_FEATURE_VFP)) {
 332             note_size += ARM_VFP_NOTE_SIZE;
 333         }
 334     }
 335
 336     return note_size * nr_cpus;
 337 }