xref: /openbmc/qemu/target/arm/gdbstub.c (revision 831734cc)
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 
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         return gdb_get_zeroes(mem_buf, 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, or XPSR for M-profile */
61         if (arm_feature(env, ARM_FEATURE_M)) {
62             return gdb_get_reg32(mem_buf, xpsr_read(env));
63         } else {
64             return gdb_get_reg32(mem_buf, cpsr_read(env));
65         }
66     }
67     /* Unknown register.  */
68     return 0;
69 }
70 
71 int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
72 {
73     ARMCPU *cpu = ARM_CPU(cs);
74     CPUARMState *env = &cpu->env;
75     uint32_t tmp;
76 
77     tmp = ldl_p(mem_buf);
78 
79     /* Mask out low bit of PC to workaround gdb bugs.  This will probably
80        cause problems if we ever implement the Jazelle DBX extensions.  */
81     if (n == 15) {
82         tmp &= ~1;
83     }
84 
85     if (n < 16) {
86         /* Core integer register.  */
87         env->regs[n] = tmp;
88         return 4;
89     }
90     if (n < 24) { /* 16-23 */
91         /* FPA registers (ignored).  */
92         if (gdb_has_xml) {
93             return 0;
94         }
95         return 12;
96     }
97     switch (n) {
98     case 24:
99         /* FPA status register (ignored).  */
100         if (gdb_has_xml) {
101             return 0;
102         }
103         return 4;
104     case 25:
105         /* CPSR, or XPSR for M-profile */
106         if (arm_feature(env, ARM_FEATURE_M)) {
107             /*
108              * Don't allow writing to XPSR.Exception as it can cause
109              * a transition into or out of handler mode (it's not
110              * writeable via the MSR insn so this is a reasonable
111              * restriction). Other fields are safe to update.
112              */
113             xpsr_write(env, tmp, ~XPSR_EXCP);
114         } else {
115             cpsr_write(env, tmp, 0xffffffff, CPSRWriteByGDBStub);
116         }
117         return 4;
118     }
119     /* Unknown register.  */
120     return 0;
121 }
122 
123 static void arm_gen_one_xml_sysreg_tag(GString *s, DynamicGDBXMLInfo *dyn_xml,
124                                        ARMCPRegInfo *ri, uint32_t ri_key,
125                                        int bitsize, int regnum)
126 {
127     g_string_append_printf(s, "<reg name=\"%s\"", ri->name);
128     g_string_append_printf(s, " bitsize=\"%d\"", bitsize);
129     g_string_append_printf(s, " regnum=\"%d\"", regnum);
130     g_string_append_printf(s, " group=\"cp_regs\"/>");
131     dyn_xml->data.cpregs.keys[dyn_xml->num] = ri_key;
132     dyn_xml->num++;
133 }
134 
135 static void arm_register_sysreg_for_xml(gpointer key, gpointer value,
136                                         gpointer p)
137 {
138     uint32_t ri_key = *(uint32_t *)key;
139     ARMCPRegInfo *ri = value;
140     RegisterSysregXmlParam *param = (RegisterSysregXmlParam *)p;
141     GString *s = param->s;
142     ARMCPU *cpu = ARM_CPU(param->cs);
143     CPUARMState *env = &cpu->env;
144     DynamicGDBXMLInfo *dyn_xml = &cpu->dyn_sysreg_xml;
145 
146     if (!(ri->type & (ARM_CP_NO_RAW | ARM_CP_NO_GDB))) {
147         if (arm_feature(env, ARM_FEATURE_AARCH64)) {
148             if (ri->state == ARM_CP_STATE_AA64) {
149                 arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
150                                            param->n++);
151             }
152         } else {
153             if (ri->state == ARM_CP_STATE_AA32) {
154                 if (!arm_feature(env, ARM_FEATURE_EL3) &&
155                     (ri->secure & ARM_CP_SECSTATE_S)) {
156                     return;
157                 }
158                 if (ri->type & ARM_CP_64BIT) {
159                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
160                                                param->n++);
161                 } else {
162                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 32,
163                                                param->n++);
164                 }
165             }
166         }
167     }
168 }
169 
170 int arm_gen_dynamic_sysreg_xml(CPUState *cs, int base_reg)
171 {
172     ARMCPU *cpu = ARM_CPU(cs);
173     GString *s = g_string_new(NULL);
174     RegisterSysregXmlParam param = {cs, s, base_reg};
175 
176     cpu->dyn_sysreg_xml.num = 0;
177     cpu->dyn_sysreg_xml.data.cpregs.keys = g_new(uint32_t, g_hash_table_size(cpu->cp_regs));
178     g_string_printf(s, "<?xml version=\"1.0\"?>");
179     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
180     g_string_append_printf(s, "<feature name=\"org.qemu.gdb.arm.sys.regs\">");
181     g_hash_table_foreach(cpu->cp_regs, arm_register_sysreg_for_xml, &param);
182     g_string_append_printf(s, "</feature>");
183     cpu->dyn_sysreg_xml.desc = g_string_free(s, false);
184     return cpu->dyn_sysreg_xml.num;
185 }
186 
187 struct TypeSize {
188     const char *gdb_type;
189     int  size;
190     const char sz, suffix;
191 };
192 
193 static const struct TypeSize vec_lanes[] = {
194     /* quads */
195     { "uint128", 128, 'q', 'u' },
196     { "int128", 128, 'q', 's' },
197     /* 64 bit */
198     { "ieee_double", 64, 'd', 'f' },
199     { "uint64", 64, 'd', 'u' },
200     { "int64", 64, 'd', 's' },
201     /* 32 bit */
202     { "ieee_single", 32, 's', 'f' },
203     { "uint32", 32, 's', 'u' },
204     { "int32", 32, 's', 's' },
205     /* 16 bit */
206     { "ieee_half", 16, 'h', 'f' },
207     { "uint16", 16, 'h', 'u' },
208     { "int16", 16, 'h', 's' },
209     /* bytes */
210     { "uint8", 8, 'b', 'u' },
211     { "int8", 8, 'b', 's' },
212 };
213 
214 
215 int arm_gen_dynamic_svereg_xml(CPUState *cs, int base_reg)
216 {
217     ARMCPU *cpu = ARM_CPU(cs);
218     GString *s = g_string_new(NULL);
219     DynamicGDBXMLInfo *info = &cpu->dyn_svereg_xml;
220     g_autoptr(GString) ts = g_string_new("");
221     int i, j, bits, reg_width = (cpu->sve_max_vq * 128);
222     info->num = 0;
223     g_string_printf(s, "<?xml version=\"1.0\"?>");
224     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
225     g_string_append_printf(s, "<feature name=\"org.gnu.gdb.aarch64.sve\">");
226 
227     /* First define types and totals in a whole VL */
228     for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
229         int count = reg_width / vec_lanes[i].size;
230         g_string_printf(ts, "svev%c%c", vec_lanes[i].sz, vec_lanes[i].suffix);
231         g_string_append_printf(s,
232                                "<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
233                                ts->str, vec_lanes[i].gdb_type, count);
234     }
235     /*
236      * Now define a union for each size group containing unsigned and
237      * signed and potentially float versions of each size from 128 to
238      * 8 bits.
239      */
240     for (bits = 128, i = 0; bits >= 8; bits /= 2, i++) {
241         const char suf[] = { 'q', 'd', 's', 'h', 'b' };
242         g_string_append_printf(s, "<union id=\"svevn%c\">", suf[i]);
243         for (j = 0; j < ARRAY_SIZE(vec_lanes); j++) {
244             if (vec_lanes[j].size == bits) {
245                 g_string_append_printf(s, "<field name=\"%c\" type=\"svev%c%c\"/>",
246                                        vec_lanes[j].suffix,
247                                        vec_lanes[j].sz, vec_lanes[j].suffix);
248             }
249         }
250         g_string_append(s, "</union>");
251     }
252     /* And now the final union of unions */
253     g_string_append(s, "<union id=\"svev\">");
254     for (bits = 128, i = 0; bits >= 8; bits /= 2, i++) {
255         const char suf[] = { 'q', 'd', 's', 'h', 'b' };
256         g_string_append_printf(s, "<field name=\"%c\" type=\"svevn%c\"/>",
257                                suf[i], suf[i]);
258     }
259     g_string_append(s, "</union>");
260 
261     /* Finally the sve prefix type */
262     g_string_append_printf(s,
263                            "<vector id=\"svep\" type=\"uint8\" count=\"%d\"/>",
264                            reg_width / 8);
265 
266     /* Then define each register in parts for each vq */
267     for (i = 0; i < 32; i++) {
268         g_string_append_printf(s,
269                                "<reg name=\"z%d\" bitsize=\"%d\""
270                                " regnum=\"%d\" type=\"svev\"/>",
271                                i, reg_width, base_reg++);
272         info->num++;
273     }
274     /* fpscr & status registers */
275     g_string_append_printf(s, "<reg name=\"fpsr\" bitsize=\"32\""
276                            " regnum=\"%d\" group=\"float\""
277                            " type=\"int\"/>", base_reg++);
278     g_string_append_printf(s, "<reg name=\"fpcr\" bitsize=\"32\""
279                            " regnum=\"%d\" group=\"float\""
280                            " type=\"int\"/>", base_reg++);
281     info->num += 2;
282 
283     for (i = 0; i < 16; i++) {
284         g_string_append_printf(s,
285                                "<reg name=\"p%d\" bitsize=\"%d\""
286                                " regnum=\"%d\" type=\"svep\"/>",
287                                i, cpu->sve_max_vq * 16, base_reg++);
288         info->num++;
289     }
290     g_string_append_printf(s,
291                            "<reg name=\"ffr\" bitsize=\"%d\""
292                            " regnum=\"%d\" group=\"vector\""
293                            " type=\"svep\"/>",
294                            cpu->sve_max_vq * 16, base_reg++);
295     g_string_append_printf(s,
296                            "<reg name=\"vg\" bitsize=\"64\""
297                            " regnum=\"%d\" type=\"int\"/>",
298                            base_reg++);
299     info->num += 2;
300     g_string_append_printf(s, "</feature>");
301     cpu->dyn_svereg_xml.desc = g_string_free(s, false);
302 
303     return cpu->dyn_svereg_xml.num;
304 }
305 
306 
307 const char *arm_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
308 {
309     ARMCPU *cpu = ARM_CPU(cs);
310 
311     if (strcmp(xmlname, "system-registers.xml") == 0) {
312         return cpu->dyn_sysreg_xml.desc;
313     } else if (strcmp(xmlname, "sve-registers.xml") == 0) {
314         return cpu->dyn_svereg_xml.desc;
315     }
316     return NULL;
317 }
318