xref: /openbmc/qemu/target/arm/gdbstub.c (revision 3973e7ae)
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         if (n == 13 && arm_feature(env, ARM_FEATURE_M)) {
88             /* M profile SP low bits are always 0 */
89             tmp &= ~3;
90         }
91         env->regs[n] = tmp;
92         return 4;
93     }
94     if (n < 24) { /* 16-23 */
95         /* FPA registers (ignored).  */
96         if (gdb_has_xml) {
97             return 0;
98         }
99         return 12;
100     }
101     switch (n) {
102     case 24:
103         /* FPA status register (ignored).  */
104         if (gdb_has_xml) {
105             return 0;
106         }
107         return 4;
108     case 25:
109         /* CPSR, or XPSR for M-profile */
110         if (arm_feature(env, ARM_FEATURE_M)) {
111             /*
112              * Don't allow writing to XPSR.Exception as it can cause
113              * a transition into or out of handler mode (it's not
114              * writeable via the MSR insn so this is a reasonable
115              * restriction). Other fields are safe to update.
116              */
117             xpsr_write(env, tmp, ~XPSR_EXCP);
118         } else {
119             cpsr_write(env, tmp, 0xffffffff, CPSRWriteByGDBStub);
120         }
121         return 4;
122     }
123     /* Unknown register.  */
124     return 0;
125 }
126 
127 static void arm_gen_one_xml_sysreg_tag(GString *s, DynamicGDBXMLInfo *dyn_xml,
128                                        ARMCPRegInfo *ri, uint32_t ri_key,
129                                        int bitsize, int regnum)
130 {
131     g_string_append_printf(s, "<reg name=\"%s\"", ri->name);
132     g_string_append_printf(s, " bitsize=\"%d\"", bitsize);
133     g_string_append_printf(s, " regnum=\"%d\"", regnum);
134     g_string_append_printf(s, " group=\"cp_regs\"/>");
135     dyn_xml->data.cpregs.keys[dyn_xml->num] = ri_key;
136     dyn_xml->num++;
137 }
138 
139 static void arm_register_sysreg_for_xml(gpointer key, gpointer value,
140                                         gpointer p)
141 {
142     uint32_t ri_key = *(uint32_t *)key;
143     ARMCPRegInfo *ri = value;
144     RegisterSysregXmlParam *param = (RegisterSysregXmlParam *)p;
145     GString *s = param->s;
146     ARMCPU *cpu = ARM_CPU(param->cs);
147     CPUARMState *env = &cpu->env;
148     DynamicGDBXMLInfo *dyn_xml = &cpu->dyn_sysreg_xml;
149 
150     if (!(ri->type & (ARM_CP_NO_RAW | ARM_CP_NO_GDB))) {
151         if (arm_feature(env, ARM_FEATURE_AARCH64)) {
152             if (ri->state == ARM_CP_STATE_AA64) {
153                 arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
154                                            param->n++);
155             }
156         } else {
157             if (ri->state == ARM_CP_STATE_AA32) {
158                 if (!arm_feature(env, ARM_FEATURE_EL3) &&
159                     (ri->secure & ARM_CP_SECSTATE_S)) {
160                     return;
161                 }
162                 if (ri->type & ARM_CP_64BIT) {
163                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
164                                                param->n++);
165                 } else {
166                     arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 32,
167                                                param->n++);
168                 }
169             }
170         }
171     }
172 }
173 
174 int arm_gen_dynamic_sysreg_xml(CPUState *cs, int base_reg)
175 {
176     ARMCPU *cpu = ARM_CPU(cs);
177     GString *s = g_string_new(NULL);
178     RegisterSysregXmlParam param = {cs, s, base_reg};
179 
180     cpu->dyn_sysreg_xml.num = 0;
181     cpu->dyn_sysreg_xml.data.cpregs.keys = g_new(uint32_t, g_hash_table_size(cpu->cp_regs));
182     g_string_printf(s, "<?xml version=\"1.0\"?>");
183     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
184     g_string_append_printf(s, "<feature name=\"org.qemu.gdb.arm.sys.regs\">");
185     g_hash_table_foreach(cpu->cp_regs, arm_register_sysreg_for_xml, &param);
186     g_string_append_printf(s, "</feature>");
187     cpu->dyn_sysreg_xml.desc = g_string_free(s, false);
188     return cpu->dyn_sysreg_xml.num;
189 }
190 
191 struct TypeSize {
192     const char *gdb_type;
193     int  size;
194     const char sz, suffix;
195 };
196 
197 static const struct TypeSize vec_lanes[] = {
198     /* quads */
199     { "uint128", 128, 'q', 'u' },
200     { "int128", 128, 'q', 's' },
201     /* 64 bit */
202     { "ieee_double", 64, 'd', 'f' },
203     { "uint64", 64, 'd', 'u' },
204     { "int64", 64, 'd', 's' },
205     /* 32 bit */
206     { "ieee_single", 32, 's', 'f' },
207     { "uint32", 32, 's', 'u' },
208     { "int32", 32, 's', 's' },
209     /* 16 bit */
210     { "ieee_half", 16, 'h', 'f' },
211     { "uint16", 16, 'h', 'u' },
212     { "int16", 16, 'h', 's' },
213     /* bytes */
214     { "uint8", 8, 'b', 'u' },
215     { "int8", 8, 'b', 's' },
216 };
217 
218 
219 int arm_gen_dynamic_svereg_xml(CPUState *cs, int base_reg)
220 {
221     ARMCPU *cpu = ARM_CPU(cs);
222     GString *s = g_string_new(NULL);
223     DynamicGDBXMLInfo *info = &cpu->dyn_svereg_xml;
224     g_autoptr(GString) ts = g_string_new("");
225     int i, j, bits, reg_width = (cpu->sve_max_vq * 128);
226     info->num = 0;
227     g_string_printf(s, "<?xml version=\"1.0\"?>");
228     g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
229     g_string_append_printf(s, "<feature name=\"org.gnu.gdb.aarch64.sve\">");
230 
231     /* First define types and totals in a whole VL */
232     for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
233         int count = reg_width / vec_lanes[i].size;
234         g_string_printf(ts, "svev%c%c", vec_lanes[i].sz, vec_lanes[i].suffix);
235         g_string_append_printf(s,
236                                "<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
237                                ts->str, vec_lanes[i].gdb_type, count);
238     }
239     /*
240      * Now define a union for each size group containing unsigned and
241      * signed and potentially float versions of each size from 128 to
242      * 8 bits.
243      */
244     for (bits = 128, i = 0; bits >= 8; bits /= 2, i++) {
245         const char suf[] = { 'q', 'd', 's', 'h', 'b' };
246         g_string_append_printf(s, "<union id=\"svevn%c\">", suf[i]);
247         for (j = 0; j < ARRAY_SIZE(vec_lanes); j++) {
248             if (vec_lanes[j].size == bits) {
249                 g_string_append_printf(s, "<field name=\"%c\" type=\"svev%c%c\"/>",
250                                        vec_lanes[j].suffix,
251                                        vec_lanes[j].sz, vec_lanes[j].suffix);
252             }
253         }
254         g_string_append(s, "</union>");
255     }
256     /* And now the final union of unions */
257     g_string_append(s, "<union id=\"svev\">");
258     for (bits = 128, i = 0; bits >= 8; bits /= 2, i++) {
259         const char suf[] = { 'q', 'd', 's', 'h', 'b' };
260         g_string_append_printf(s, "<field name=\"%c\" type=\"svevn%c\"/>",
261                                suf[i], suf[i]);
262     }
263     g_string_append(s, "</union>");
264 
265     /* Finally the sve prefix type */
266     g_string_append_printf(s,
267                            "<vector id=\"svep\" type=\"uint8\" count=\"%d\"/>",
268                            reg_width / 8);
269 
270     /* Then define each register in parts for each vq */
271     for (i = 0; i < 32; i++) {
272         g_string_append_printf(s,
273                                "<reg name=\"z%d\" bitsize=\"%d\""
274                                " regnum=\"%d\" type=\"svev\"/>",
275                                i, reg_width, base_reg++);
276         info->num++;
277     }
278     /* fpscr & status registers */
279     g_string_append_printf(s, "<reg name=\"fpsr\" bitsize=\"32\""
280                            " regnum=\"%d\" group=\"float\""
281                            " type=\"int\"/>", base_reg++);
282     g_string_append_printf(s, "<reg name=\"fpcr\" bitsize=\"32\""
283                            " regnum=\"%d\" group=\"float\""
284                            " type=\"int\"/>", base_reg++);
285     info->num += 2;
286 
287     for (i = 0; i < 16; i++) {
288         g_string_append_printf(s,
289                                "<reg name=\"p%d\" bitsize=\"%d\""
290                                " regnum=\"%d\" type=\"svep\"/>",
291                                i, cpu->sve_max_vq * 16, base_reg++);
292         info->num++;
293     }
294     g_string_append_printf(s,
295                            "<reg name=\"ffr\" bitsize=\"%d\""
296                            " regnum=\"%d\" group=\"vector\""
297                            " type=\"svep\"/>",
298                            cpu->sve_max_vq * 16, base_reg++);
299     g_string_append_printf(s,
300                            "<reg name=\"vg\" bitsize=\"64\""
301                            " regnum=\"%d\" type=\"int\"/>",
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