xref: /openbmc/qemu/target/arm/gdbstub.c (revision 37677d7d)
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 }
178