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