xref: /openbmc/qemu/target/arm/gdbstub.c (revision 20a4f14f)
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     int n;
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, GByteArray *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_sysreg_tag(GString *s, DynamicGDBXMLInfo *dyn_xml,
111                                        ARMCPRegInfo *ri, uint32_t ri_key,
112                                        int bitsize, int regnum)
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, " regnum=\"%d\"", regnum);
117     g_string_append_printf(s, " group=\"cp_regs\"/>");
118     dyn_xml->data.cpregs.keys[dyn_xml->num] = ri_key;
119     dyn_xml->num++;
120 }
121 
122 static void arm_register_sysreg_for_xml(gpointer key, gpointer value,
123                                         gpointer p)
124 {
125     uint32_t ri_key = *(uint32_t *)key;
126     ARMCPRegInfo *ri = value;
127     RegisterSysregXmlParam *param = (RegisterSysregXmlParam *)p;
128     GString *s = param->s;
129     ARMCPU *cpu = ARM_CPU(param->cs);
130     CPUARMState *env = &cpu->env;
131     DynamicGDBXMLInfo *dyn_xml = &cpu->dyn_sysreg_xml;
132 
133     if (!(ri->type & (ARM_CP_NO_RAW | ARM_CP_NO_GDB))) {
134         if (arm_feature(env, ARM_FEATURE_AARCH64)) {
135             if (ri->state == ARM_CP_STATE_AA64) {
136                 arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
137                                            param->n++);
138             }
139         } else {
140             if (ri->state == ARM_CP_STATE_AA32) {
141                 if (!arm_feature(env, ARM_FEATURE_EL3) &&
142                     (ri->secure & ARM_CP_SECSTATE_S)) {
143                     return;
144                 }
145                 if (ri->type & ARM_CP_64BIT) {
146                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
147                                                param->n++);
148                 } else {
149                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 32,
150                                                param->n++);
151                 }
152             }
153         }
154     }
155 }
156 
157 int arm_gen_dynamic_sysreg_xml(CPUState *cs, int base_reg)
158 {
159     ARMCPU *cpu = ARM_CPU(cs);
160     GString *s = g_string_new(NULL);
161     RegisterSysregXmlParam param = {cs, s, base_reg};
162 
163     cpu->dyn_sysreg_xml.num = 0;
164     cpu->dyn_sysreg_xml.data.cpregs.keys = g_new(uint32_t, g_hash_table_size(cpu->cp_regs));
165     g_string_printf(s, "<?xml version=\"1.0\"?>");
166     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
167     g_string_append_printf(s, "<feature name=\"org.qemu.gdb.arm.sys.regs\">");
168     g_hash_table_foreach(cpu->cp_regs, arm_register_sysreg_for_xml, &param);
169     g_string_append_printf(s, "</feature>");
170     cpu->dyn_sysreg_xml.desc = g_string_free(s, false);
171     return cpu->dyn_sysreg_xml.num;
172 }
173 
174 struct TypeSize {
175     const char *gdb_type;
176     int  size;
177     const char sz, suffix;
178 };
179 
180 static const struct TypeSize vec_lanes[] = {
181     /* quads */
182     { "uint128", 128, 'q', 'u' },
183     { "int128", 128, 'q', 's' },
184     /* 64 bit */
185     { "uint64", 64, 'd', 'u' },
186     { "int64", 64, 'd', 's' },
187     { "ieee_double", 64, 'd', 'f' },
188     /* 32 bit */
189     { "uint32", 32, 's', 'u' },
190     { "int32", 32, 's', 's' },
191     { "ieee_single", 32, 's', 'f' },
192     /* 16 bit */
193     { "uint16", 16, 'h', 'u' },
194     { "int16", 16, 'h', 's' },
195     /*
196      * TODO: currently there is no reliable way of telling
197      * if the remote gdb actually understands ieee_half so
198      * we don't expose it in the target description for now.
199      * { "ieee_half", 16, 'h', 'f' },
200      */
201     /* bytes */
202     { "uint8", 8, 'b', 'u' },
203     { "int8", 8, 'b', 's' },
204 };
205 
206 
207 int arm_gen_dynamic_svereg_xml(CPUState *cs, int base_reg)
208 {
209     ARMCPU *cpu = ARM_CPU(cs);
210     GString *s = g_string_new(NULL);
211     DynamicGDBXMLInfo *info = &cpu->dyn_svereg_xml;
212     g_autoptr(GString) ts = g_string_new("");
213     int i, bits, reg_width = (cpu->sve_max_vq * 128);
214     info->num = 0;
215     g_string_printf(s, "<?xml version=\"1.0\"?>");
216     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
217     g_string_append_printf(s, "<feature name=\"org.qemu.gdb.aarch64.sve\">");
218 
219     /* First define types and totals in a whole VL */
220     for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
221         int count = reg_width / vec_lanes[i].size;
222         g_string_printf(ts, "vq%d%c%c", count,
223                         vec_lanes[i].sz, vec_lanes[i].suffix);
224         g_string_append_printf(s,
225                                "<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
226                                ts->str, vec_lanes[i].gdb_type, count);
227     }
228     /*
229      * Now define a union for each size group containing unsigned and
230      * signed and potentially float versions of each size from 128 to
231      * 8 bits.
232      */
233     for (bits = 128; bits >= 8; bits /= 2) {
234         int count = reg_width / bits;
235         g_string_append_printf(s, "<union id=\"vq%dn\">", count);
236         for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
237             if (vec_lanes[i].size == bits) {
238                 g_string_append_printf(s, "<field name=\"%c\" type=\"vq%d%c%c\"/>",
239                                        vec_lanes[i].suffix,
240                                        count,
241                                        vec_lanes[i].sz, vec_lanes[i].suffix);
242             }
243         }
244         g_string_append(s, "</union>");
245     }
246     /* And now the final union of unions */
247     g_string_append(s, "<union id=\"vq\">");
248     for (bits = 128; bits >= 8; bits /= 2) {
249         int count = reg_width / bits;
250         for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
251             if (vec_lanes[i].size == bits) {
252                 g_string_append_printf(s, "<field name=\"%c\" type=\"vq%dn\"/>",
253                                        vec_lanes[i].sz, count);
254                 break;
255             }
256         }
257     }
258     g_string_append(s, "</union>");
259 
260     /* Then define each register in parts for each vq */
261     for (i = 0; i < 32; i++) {
262         g_string_append_printf(s,
263                                "<reg name=\"z%d\" bitsize=\"%d\""
264                                " regnum=\"%d\" group=\"vector\""
265                                " type=\"vq\"/>",
266                                i, reg_width, base_reg++);
267         info->num++;
268     }
269     /* fpscr & status registers */
270     g_string_append_printf(s, "<reg name=\"fpsr\" bitsize=\"32\""
271                            " regnum=\"%d\" group=\"float\""
272                            " type=\"int\"/>", base_reg++);
273     g_string_append_printf(s, "<reg name=\"fpcr\" bitsize=\"32\""
274                            " regnum=\"%d\" group=\"float\""
275                            " type=\"int\"/>", base_reg++);
276     info->num += 2;
277     /*
278      * Predicate registers aren't so big they are worth splitting up
279      * but we do need to define a type to hold the array of quad
280      * references.
281      */
282     g_string_append_printf(s,
283                            "<vector id=\"vqp\" type=\"uint16\" count=\"%d\"/>",
284                            cpu->sve_max_vq);
285     for (i = 0; i < 16; i++) {
286         g_string_append_printf(s,
287                                "<reg name=\"p%d\" bitsize=\"%d\""
288                                " regnum=\"%d\" group=\"vector\""
289                                " type=\"vqp\"/>",
290                                i, cpu->sve_max_vq * 16, base_reg++);
291         info->num++;
292     }
293     g_string_append_printf(s,
294                            "<reg name=\"ffr\" bitsize=\"%d\""
295                            " regnum=\"%d\" group=\"vector\""
296                            " type=\"vqp\"/>",
297                            cpu->sve_max_vq * 16, base_reg++);
298     g_string_append_printf(s,
299                            "<reg name=\"vg\" bitsize=\"64\""
300                            " regnum=\"%d\" group=\"vector\""
301                            " type=\"uint32\"/>",
302                            base_reg++);
303     info->num += 2;
304     g_string_append_printf(s, "</feature>");
305     cpu->dyn_svereg_xml.desc = g_string_free(s, false);
306 
307     return cpu->dyn_svereg_xml.num;
308 }
309 
310 
311 const char *arm_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
312 {
313     ARMCPU *cpu = ARM_CPU(cs);
314 
315     if (strcmp(xmlname, "system-registers.xml") == 0) {
316         return cpu->dyn_sysreg_xml.desc;
317     } else if (strcmp(xmlname, "sve-registers.xml") == 0) {
318         return cpu->dyn_svereg_xml.desc;
319     }
320     return NULL;
321 }
322