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 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 "qemu-common.h"
  22 #include "cpu.h"
  23 #include "exec/gdbstub.h"
  24
  25 typedef struct RegisterSysregXmlParam {
  26     CPUState *cs;
  27     GString *s;
  28 } RegisterSysregXmlParam;
  29
  30 /* Old gdb always expect FPA registers.  Newer (xml-aware) gdb only expect
  31    whatever the target description contains.  Due to a historical mishap
  32    the FPA registers appear in between core integer regs and the CPSR.
  33    We hack round this by giving the FPA regs zero size when talking to a
  34    newer gdb.  */
  35
  36 int arm_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
  37 {
  38     ARMCPU *cpu = ARM_CPU(cs);
  39     CPUARMState *env = &cpu->env;
  40
  41     if (n < 16) {
  42         /* Core integer register.  */
  43         return gdb_get_reg32(mem_buf, env->regs[n]);
  44     }
  45     if (n < 24) {
  46         /* FPA registers.  */
  47         if (gdb_has_xml) {
  48             return 0;
  49         }
  50         memset(mem_buf, 0, 12);
  51         return 12;
  52     }
  53     switch (n) {
  54     case 24:
  55         /* FPA status register.  */
  56         if (gdb_has_xml) {
  57             return 0;
  58         }
  59         return gdb_get_reg32(mem_buf, 0);
  60     case 25:
  61         /* CPSR */
  62         return gdb_get_reg32(mem_buf, cpsr_read(env));
  63     }
  64     /* Unknown register.  */
  65     return 0;
  66 }
  67
  68 int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
  69 {
  70     ARMCPU *cpu = ARM_CPU(cs);
  71     CPUARMState *env = &cpu->env;
  72     uint32_t tmp;
  73
  74     tmp = ldl_p(mem_buf);
  75
  76     /* Mask out low bit of PC to workaround gdb bugs.  This will probably
  77        cause problems if we ever implement the Jazelle DBX extensions.  */
  78     if (n == 15) {
  79         tmp &= ~1;
  80     }
  81
  82     if (n < 16) {
  83         /* Core integer register.  */
  84         env->regs[n] = tmp;
  85         return 4;
  86     }
  87     if (n < 24) { /* 16-23 */
  88         /* FPA registers (ignored).  */
  89         if (gdb_has_xml) {
  90             return 0;
  91         }
  92         return 12;
  93     }
  94     switch (n) {
  95     case 24:
  96         /* FPA status register (ignored).  */
  97         if (gdb_has_xml) {
  98             return 0;
  99         }
 100         return 4;
 101     case 25:
 102         /* CPSR */
 103         cpsr_write(env, tmp, 0xffffffff, CPSRWriteByGDBStub);
 104         return 4;
 105     }
 106     /* Unknown register.  */
 107     return 0;
 108 }
 109
 110 static void arm_gen_one_xml_reg_tag(GString *s, DynamicGDBXMLInfo *dyn_xml,
 111                                     ARMCPRegInfo *ri, uint32_t ri_key,
 112                                     int bitsize)
 113 {
 114     g_string_append_printf(s, "<reg name=\"%s\"", ri->name);
 115     g_string_append_printf(s, " bitsize=\"%d\"", bitsize);
 116     g_string_append_printf(s, " group=\"cp_regs\"/>");
 117     dyn_xml->num_cpregs++;
 118     dyn_xml->cpregs_keys[dyn_xml->num_cpregs - 1] = ri_key;
 119 }
 120
 121 static void arm_register_sysreg_for_xml(gpointer key, gpointer value,
 122                                         gpointer p)
 123 {
 124     uint32_t ri_key = *(uint32_t *)key;
 125     ARMCPRegInfo *ri = value;
 126     RegisterSysregXmlParam *param = (RegisterSysregXmlParam *)p;
 127     GString *s = param->s;
 128     ARMCPU *cpu = ARM_CPU(param->cs);
 129     CPUARMState *env = &cpu->env;
 130     DynamicGDBXMLInfo *dyn_xml = &cpu->dyn_xml;
 131
 132     if (!(ri->type & (ARM_CP_NO_RAW | ARM_CP_NO_GDB))) {
 133         if (arm_feature(env, ARM_FEATURE_AARCH64)) {
 134             if (ri->state == ARM_CP_STATE_AA64) {
 135                 arm_gen_one_xml_reg_tag(s , dyn_xml, ri, ri_key, 64);
 136             }
 137         } else {
 138             if (ri->state == ARM_CP_STATE_AA32) {
 139                 if (!arm_feature(env, ARM_FEATURE_EL3) &&
 140                     (ri->secure & ARM_CP_SECSTATE_S)) {
 141                     return;
 142                 }
 143                 if (ri->type & ARM_CP_64BIT) {
 144                     arm_gen_one_xml_reg_tag(s , dyn_xml, ri, ri_key, 64);
 145                 } else {
 146                     arm_gen_one_xml_reg_tag(s , dyn_xml, ri, ri_key, 32);
 147                 }
 148             }
 149         }
 150     }
 151 }
 152
 153 int arm_gen_dynamic_xml(CPUState *cs)
 154 {
 155     ARMCPU *cpu = ARM_CPU(cs);
 156     GString *s = g_string_new(NULL);
 157     RegisterSysregXmlParam param = {cs, s};
 158
 159     cpu->dyn_xml.num_cpregs = 0;
 160     cpu->dyn_xml.cpregs_keys = g_new(uint32_t, g_hash_table_size(cpu->cp_regs));
 161     g_string_printf(s, "<?xml version=\"1.0\"?>");
 162     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
 163     g_string_append_printf(s, "<feature name=\"org.qemu.gdb.arm.sys.regs\">");
 164     g_hash_table_foreach(cpu->cp_regs, arm_register_sysreg_for_xml, &param);
 165     g_string_append_printf(s, "</feature>");
 166     cpu->dyn_xml.desc = g_string_free(s, false);
 167     return cpu->dyn_xml.num_cpregs;
 168 }
 169
 170 const char *arm_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
 171 {
 172     ARMCPU *cpu = ARM_CPU(cs);
 173
 174     if (strcmp(xmlname, "system-registers.xml") == 0) {
 175         return cpu->dyn_xml.desc;
 176     }
 177     return NULL;
 178 }