target/arm/gdbstub.c

   1 /*
   2  * ARM gdb server stub
   3  *
   4  * Copyright (c) 2003-2005 Fabrice Bellard
   5  * Copyright (c) 2013 SUSE LINUX Products GmbH
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library 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 GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20 #include "qemu/osdep.h"
  21 #include "cpu.h"
  22 #include "exec/gdbstub.h"
  23 #include "internals.h"
  24 #include "cpregs.h"
  25
  26 typedef struct RegisterSysregXmlParam {
  27     CPUState *cs;
  28     GString *s;
  29     int n;
  30 } RegisterSysregXmlParam;
  31
  32 /* Old gdb always expect FPA registers.  Newer (xml-aware) gdb only expect
  33    whatever the target description contains.  Due to a historical mishap
  34    the FPA registers appear in between core integer regs and the CPSR.
  35    We hack round this by giving the FPA regs zero size when talking to a
  36    newer gdb.  */
  37
  38 int arm_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
  39 {
  40     ARMCPU *cpu = ARM_CPU(cs);
  41     CPUARMState *env = &cpu->env;
  42
  43     if (n < 16) {
  44         /* Core integer register.  */
  45         return gdb_get_reg32(mem_buf, env->regs[n]);
  46     }
  47     if (n < 24) {
  48         /* FPA registers.  */
  49         if (gdb_has_xml) {
  50             return 0;
  51         }
  52         return gdb_get_zeroes(mem_buf, 12);
  53     }
  54     switch (n) {
  55     case 24:
  56         /* FPA status register.  */
  57         if (gdb_has_xml) {
  58             return 0;
  59         }
  60         return gdb_get_reg32(mem_buf, 0);
  61     case 25:
  62         /* CPSR, or XPSR for M-profile */
  63         if (arm_feature(env, ARM_FEATURE_M)) {
  64             return gdb_get_reg32(mem_buf, xpsr_read(env));
  65         } else {
  66             return gdb_get_reg32(mem_buf, cpsr_read(env));
  67         }
  68     }
  69     /* Unknown register.  */
  70     return 0;
  71 }
  72
  73 int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
  74 {
  75     ARMCPU *cpu = ARM_CPU(cs);
  76     CPUARMState *env = &cpu->env;
  77     uint32_t tmp;
  78
  79     tmp = ldl_p(mem_buf);
  80
  81     /*
  82      * Mask out low bits of PC to workaround gdb bugs.
  83      * This avoids an assert in thumb_tr_translate_insn, because it is
  84      * architecturally impossible to misalign the pc.
  85      * This will probably cause problems if we ever implement the
  86      * Jazelle DBX extensions.
  87      */
  88     if (n == 15) {
  89         tmp &= ~1;
  90     }
  91
  92     if (n < 16) {
  93         /* Core integer register.  */
  94         if (n == 13 && arm_feature(env, ARM_FEATURE_M)) {
  95             /* M profile SP low bits are always 0 */
  96             tmp &= ~3;
  97         }
  98         env->regs[n] = tmp;
  99         return 4;
 100     }
 101     if (n < 24) { /* 16-23 */
 102         /* FPA registers (ignored).  */
 103         if (gdb_has_xml) {
 104             return 0;
 105         }
 106         return 12;
 107     }
 108     switch (n) {
 109     case 24:
 110         /* FPA status register (ignored).  */
 111         if (gdb_has_xml) {
 112             return 0;
 113         }
 114         return 4;
 115     case 25:
 116         /* CPSR, or XPSR for M-profile */
 117         if (arm_feature(env, ARM_FEATURE_M)) {
 118             /*
 119              * Don't allow writing to XPSR.Exception as it can cause
 120              * a transition into or out of handler mode (it's not
 121              * writable via the MSR insn so this is a reasonable
 122              * restriction). Other fields are safe to update.
 123              */
 124             xpsr_write(env, tmp, ~XPSR_EXCP);
 125         } else {
 126             cpsr_write(env, tmp, 0xffffffff, CPSRWriteByGDBStub);
 127         }
 128         return 4;
 129     }
 130     /* Unknown register.  */
 131     return 0;
 132 }
 133
 134 static int vfp_gdb_get_reg(CPUARMState *env, GByteArray *buf, int reg)
 135 {
 136     ARMCPU *cpu = env_archcpu(env);
 137     int nregs = cpu_isar_feature(aa32_simd_r32, cpu) ? 32 : 16;
 138
 139     /* VFP data registers are always little-endian.  */
 140     if (reg < nregs) {
 141         return gdb_get_reg64(buf, *aa32_vfp_dreg(env, reg));
 142     }
 143     if (arm_feature(env, ARM_FEATURE_NEON)) {
 144         /* Aliases for Q regs.  */
 145         nregs += 16;
 146         if (reg < nregs) {
 147             uint64_t *q = aa32_vfp_qreg(env, reg - 32);
 148             return gdb_get_reg128(buf, q[0], q[1]);
 149         }
 150     }
 151     switch (reg - nregs) {
 152     case 0:
 153         return gdb_get_reg32(buf, vfp_get_fpscr(env));
 154     }
 155     return 0;
 156 }
 157
 158 static int vfp_gdb_set_reg(CPUARMState *env, uint8_t *buf, int reg)
 159 {
 160     ARMCPU *cpu = env_archcpu(env);
 161     int nregs = cpu_isar_feature(aa32_simd_r32, cpu) ? 32 : 16;
 162
 163     if (reg < nregs) {
 164         *aa32_vfp_dreg(env, reg) = ldq_le_p(buf);
 165         return 8;
 166     }
 167     if (arm_feature(env, ARM_FEATURE_NEON)) {
 168         nregs += 16;
 169         if (reg < nregs) {
 170             uint64_t *q = aa32_vfp_qreg(env, reg - 32);
 171             q[0] = ldq_le_p(buf);
 172             q[1] = ldq_le_p(buf + 8);
 173             return 16;
 174         }
 175     }
 176     switch (reg - nregs) {
 177     case 0:
 178         vfp_set_fpscr(env, ldl_p(buf));
 179         return 4;
 180     }
 181     return 0;
 182 }
 183
 184 static int vfp_gdb_get_sysreg(CPUARMState *env, GByteArray *buf, int reg)
 185 {
 186     switch (reg) {
 187     case 0:
 188         return gdb_get_reg32(buf, env->vfp.xregs[ARM_VFP_FPSID]);
 189     case 1:
 190         return gdb_get_reg32(buf, env->vfp.xregs[ARM_VFP_FPEXC]);
 191     }
 192     return 0;
 193 }
 194
 195 static int vfp_gdb_set_sysreg(CPUARMState *env, uint8_t *buf, int reg)
 196 {
 197     switch (reg) {
 198     case 0:
 199         env->vfp.xregs[ARM_VFP_FPSID] = ldl_p(buf);
 200         return 4;
 201     case 1:
 202         env->vfp.xregs[ARM_VFP_FPEXC] = ldl_p(buf) & (1 << 30);
 203         return 4;
 204     }
 205     return 0;
 206 }
 207
 208 static int mve_gdb_get_reg(CPUARMState *env, GByteArray *buf, int reg)
 209 {
 210     switch (reg) {
 211     case 0:
 212         return gdb_get_reg32(buf, env->v7m.vpr);
 213     default:
 214         return 0;
 215     }
 216 }
 217
 218 static int mve_gdb_set_reg(CPUARMState *env, uint8_t *buf, int reg)
 219 {
 220     switch (reg) {
 221     case 0:
 222         env->v7m.vpr = ldl_p(buf);
 223         return 4;
 224     default:
 225         return 0;
 226     }
 227 }
 228
 229 /**
 230  * arm_get/set_gdb_*: get/set a gdb register
 231  * @env: the CPU state
 232  * @buf: a buffer to copy to/from
 233  * @reg: register number (offset from start of group)
 234  *
 235  * We return the number of bytes copied
 236  */
 237
 238 static int arm_gdb_get_sysreg(CPUARMState *env, GByteArray *buf, int reg)
 239 {
 240     ARMCPU *cpu = env_archcpu(env);
 241     const ARMCPRegInfo *ri;
 242     uint32_t key;
 243
 244     key = cpu->dyn_sysreg_xml.data.cpregs.keys[reg];
 245     ri = get_arm_cp_reginfo(cpu->cp_regs, key);
 246     if (ri) {
 247         if (cpreg_field_is_64bit(ri)) {
 248             return gdb_get_reg64(buf, (uint64_t)read_raw_cp_reg(env, ri));
 249         } else {
 250             return gdb_get_reg32(buf, (uint32_t)read_raw_cp_reg(env, ri));
 251         }
 252     }
 253     return 0;
 254 }
 255
 256 static int arm_gdb_set_sysreg(CPUARMState *env, uint8_t *buf, int reg)
 257 {
 258     return 0;
 259 }
 260
 261 static void arm_gen_one_xml_sysreg_tag(GString *s, DynamicGDBXMLInfo *dyn_xml,
 262                                        ARMCPRegInfo *ri, uint32_t ri_key,
 263                                        int bitsize, int regnum)
 264 {
 265     g_string_append_printf(s, "<reg name=\"%s\"", ri->name);
 266     g_string_append_printf(s, " bitsize=\"%d\"", bitsize);
 267     g_string_append_printf(s, " regnum=\"%d\"", regnum);
 268     g_string_append_printf(s, " group=\"cp_regs\"/>");
 269     dyn_xml->data.cpregs.keys[dyn_xml->num] = ri_key;
 270     dyn_xml->num++;
 271 }
 272
 273 static void arm_register_sysreg_for_xml(gpointer key, gpointer value,
 274                                         gpointer p)
 275 {
 276     uint32_t ri_key = (uintptr_t)key;
 277     ARMCPRegInfo *ri = value;
 278     RegisterSysregXmlParam *param = (RegisterSysregXmlParam *)p;
 279     GString *s = param->s;
 280     ARMCPU *cpu = ARM_CPU(param->cs);
 281     CPUARMState *env = &cpu->env;
 282     DynamicGDBXMLInfo *dyn_xml = &cpu->dyn_sysreg_xml;
 283
 284     if (!(ri->type & (ARM_CP_NO_RAW | ARM_CP_NO_GDB))) {
 285         if (arm_feature(env, ARM_FEATURE_AARCH64)) {
 286             if (ri->state == ARM_CP_STATE_AA64) {
 287                 arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
 288                                            param->n++);
 289             }
 290         } else {
 291             if (ri->state == ARM_CP_STATE_AA32) {
 292                 if (!arm_feature(env, ARM_FEATURE_EL3) &&
 293                     (ri->secure & ARM_CP_SECSTATE_S)) {
 294                     return;
 295                 }
 296                 if (ri->type & ARM_CP_64BIT) {
 297                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
 298                                                param->n++);
 299                 } else {
 300                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 32,
 301                                                param->n++);
 302                 }
 303             }
 304         }
 305     }
 306 }
 307
 308 static int arm_gen_dynamic_sysreg_xml(CPUState *cs, int base_reg)
 309 {
 310     ARMCPU *cpu = ARM_CPU(cs);
 311     GString *s = g_string_new(NULL);
 312     RegisterSysregXmlParam param = {cs, s, base_reg};
 313
 314     cpu->dyn_sysreg_xml.num = 0;
 315     cpu->dyn_sysreg_xml.data.cpregs.keys = g_new(uint32_t, g_hash_table_size(cpu->cp_regs));
 316     g_string_printf(s, "<?xml version=\"1.0\"?>");
 317     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
 318     g_string_append_printf(s, "<feature name=\"org.qemu.gdb.arm.sys.regs\">");
 319     g_hash_table_foreach(cpu->cp_regs, arm_register_sysreg_for_xml, &param);
 320     g_string_append_printf(s, "</feature>");
 321     cpu->dyn_sysreg_xml.desc = g_string_free(s, false);
 322     return cpu->dyn_sysreg_xml.num;
 323 }
 324
 325 const char *arm_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
 326 {
 327     ARMCPU *cpu = ARM_CPU(cs);
 328
 329     if (strcmp(xmlname, "system-registers.xml") == 0) {
 330         return cpu->dyn_sysreg_xml.desc;
 331     } else if (strcmp(xmlname, "sve-registers.xml") == 0) {
 332         return cpu->dyn_svereg_xml.desc;
 333     }
 334     return NULL;
 335 }
 336
 337 void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu)
 338 {
 339     CPUState *cs = CPU(cpu);
 340     CPUARMState *env = &cpu->env;
 341
 342     if (arm_feature(env, ARM_FEATURE_AARCH64)) {
 343         /*
 344          * The lower part of each SVE register aliases to the FPU
 345          * registers so we don't need to include both.
 346          */
 347 #ifdef TARGET_AARCH64
 348         if (isar_feature_aa64_sve(&cpu->isar)) {
 349             int nreg = arm_gen_dynamic_svereg_xml(cs, cs->gdb_num_regs);
 350             gdb_register_coprocessor(cs, aarch64_gdb_get_sve_reg,
 351                                      aarch64_gdb_set_sve_reg, nreg,
 352                                      "sve-registers.xml", 0);
 353         } else {
 354             gdb_register_coprocessor(cs, aarch64_gdb_get_fpu_reg,
 355                                      aarch64_gdb_set_fpu_reg,
 356                                      34, "aarch64-fpu.xml", 0);
 357         }
 358 #endif
 359     } else {
 360         if (arm_feature(env, ARM_FEATURE_NEON)) {
 361             gdb_register_coprocessor(cs, vfp_gdb_get_reg, vfp_gdb_set_reg,
 362                                      49, "arm-neon.xml", 0);
 363         } else if (cpu_isar_feature(aa32_simd_r32, cpu)) {
 364             gdb_register_coprocessor(cs, vfp_gdb_get_reg, vfp_gdb_set_reg,
 365                                      33, "arm-vfp3.xml", 0);
 366         } else if (cpu_isar_feature(aa32_vfp_simd, cpu)) {
 367             gdb_register_coprocessor(cs, vfp_gdb_get_reg, vfp_gdb_set_reg,
 368                                      17, "arm-vfp.xml", 0);
 369         }
 370         if (!arm_feature(env, ARM_FEATURE_M)) {
 371             /*
 372              * A and R profile have FP sysregs FPEXC and FPSID that we
 373              * expose to gdb.
 374              */
 375             gdb_register_coprocessor(cs, vfp_gdb_get_sysreg, vfp_gdb_set_sysreg,
 376                                      2, "arm-vfp-sysregs.xml", 0);
 377         }
 378     }
 379     if (cpu_isar_feature(aa32_mve, cpu)) {
 380         gdb_register_coprocessor(cs, mve_gdb_get_reg, mve_gdb_set_reg,
 381                                  1, "arm-m-profile-mve.xml", 0);
 382     }
 383     gdb_register_coprocessor(cs, arm_gdb_get_sysreg, arm_gdb_set_sysreg,
 384                              arm_gen_dynamic_sysreg_xml(cs, cs->gdb_num_regs),
 385                              "system-registers.xml", 0);
 386
 387 }