xref: /openbmc/qemu/target/xtensa/gdbstub.c (revision a010bdbe)
1 /*
2  * Xtensa 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 #include "qemu/log.h"
24 
25 enum {
26   xtRegisterTypeArRegfile = 1,  /* Register File ar0..arXX.  */
27   xtRegisterTypeSpecialReg,     /* CPU states, such as PS, Booleans, (rsr).  */
28   xtRegisterTypeUserReg,        /* User defined registers (rur).  */
29   xtRegisterTypeTieRegfile,     /* User define register files.  */
30   xtRegisterTypeTieState,       /* TIE States (mapped on user regs).  */
31   xtRegisterTypeMapped,         /* Mapped on Special Registers.  */
32   xtRegisterTypeUnmapped,       /* Special case of masked registers.  */
33   xtRegisterTypeWindow,         /* Live window registers (a0..a15).  */
34   xtRegisterTypeVirtual,        /* PC, FP.  */
35   xtRegisterTypeUnknown
36 };
37 
38 #define XTENSA_REGISTER_FLAGS_PRIVILEGED        0x0001
39 #define XTENSA_REGISTER_FLAGS_READABLE          0x0002
40 #define XTENSA_REGISTER_FLAGS_WRITABLE          0x0004
41 #define XTENSA_REGISTER_FLAGS_VOLATILE          0x0008
42 
43 void xtensa_count_regs(const XtensaConfig *config,
44                        unsigned *n_regs, unsigned *n_core_regs)
45 {
46     unsigned i;
47     bool count_core_regs = true;
48 
49     for (i = 0; config->gdb_regmap.reg[i].targno >= 0; ++i) {
50         if (config->gdb_regmap.reg[i].type != xtRegisterTypeTieState &&
51             config->gdb_regmap.reg[i].type != xtRegisterTypeMapped &&
52             config->gdb_regmap.reg[i].type != xtRegisterTypeUnmapped) {
53             ++*n_regs;
54             if (count_core_regs) {
55                 if ((config->gdb_regmap.reg[i].flags &
56                      XTENSA_REGISTER_FLAGS_PRIVILEGED) == 0) {
57                     ++*n_core_regs;
58                 } else {
59                     count_core_regs = false;
60                 }
61             }
62         }
63     }
64 }
65 
66 int xtensa_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
67 {
68     XtensaCPU *cpu = XTENSA_CPU(cs);
69     CPUXtensaState *env = &cpu->env;
70     const XtensaGdbReg *reg = env->config->gdb_regmap.reg + n;
71 #ifdef CONFIG_USER_ONLY
72     int num_regs = env->config->gdb_regmap.num_core_regs;
73 #else
74     int num_regs = env->config->gdb_regmap.num_regs;
75 #endif
76     unsigned i;
77 
78     if (n < 0 || n >= num_regs) {
79         return 0;
80     }
81 
82     switch (reg->type) {
83     case xtRegisterTypeVirtual: /*pc*/
84         return gdb_get_reg32(mem_buf, env->pc);
85 
86     case xtRegisterTypeArRegfile: /*ar*/
87         xtensa_sync_phys_from_window(env);
88         return gdb_get_reg32(mem_buf, env->phys_regs[(reg->targno & 0xff)
89                                                      % env->config->nareg]);
90 
91     case xtRegisterTypeSpecialReg: /*SR*/
92         return gdb_get_reg32(mem_buf, env->sregs[reg->targno & 0xff]);
93 
94     case xtRegisterTypeUserReg: /*UR*/
95         return gdb_get_reg32(mem_buf, env->uregs[reg->targno & 0xff]);
96 
97     case xtRegisterTypeTieRegfile: /*f*/
98         i = reg->targno & 0x0f;
99         switch (reg->size) {
100         case 4:
101             return gdb_get_reg32(mem_buf,
102                                  float32_val(env->fregs[i].f32[FP_F32_LOW]));
103         case 8:
104             return gdb_get_reg64(mem_buf, float64_val(env->fregs[i].f64));
105         default:
106             qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported size %d\n",
107                           __func__, n, reg->size);
108             memset(mem_buf, 0, reg->size);
109             return reg->size;
110         }
111 
112     case xtRegisterTypeWindow: /*a*/
113         return gdb_get_reg32(mem_buf, env->regs[reg->targno & 0x0f]);
114 
115     default:
116         qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported type %d\n",
117                       __func__, n, reg->type);
118         memset(mem_buf, 0, reg->size);
119         return reg->size;
120     }
121 }
122 
123 int xtensa_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
124 {
125     XtensaCPU *cpu = XTENSA_CPU(cs);
126     CPUXtensaState *env = &cpu->env;
127     uint32_t tmp;
128     const XtensaGdbReg *reg = env->config->gdb_regmap.reg + n;
129 #ifdef CONFIG_USER_ONLY
130     int num_regs = env->config->gdb_regmap.num_core_regs;
131 #else
132     int num_regs = env->config->gdb_regmap.num_regs;
133 #endif
134 
135     if (n < 0 || n >= num_regs) {
136         return 0;
137     }
138 
139     tmp = ldl_p(mem_buf);
140 
141     switch (reg->type) {
142     case xtRegisterTypeVirtual: /*pc*/
143         env->pc = tmp;
144         break;
145 
146     case xtRegisterTypeArRegfile: /*ar*/
147         env->phys_regs[(reg->targno & 0xff) % env->config->nareg] = tmp;
148         xtensa_sync_window_from_phys(env);
149         break;
150 
151     case xtRegisterTypeSpecialReg: /*SR*/
152         env->sregs[reg->targno & 0xff] = tmp;
153         break;
154 
155     case xtRegisterTypeUserReg: /*UR*/
156         env->uregs[reg->targno & 0xff] = tmp;
157         break;
158 
159     case xtRegisterTypeTieRegfile: /*f*/
160         switch (reg->size) {
161         case 4:
162             env->fregs[reg->targno & 0x0f].f32[FP_F32_LOW] = make_float32(tmp);
163             return 4;
164         case 8:
165             env->fregs[reg->targno & 0x0f].f64 = make_float64(tmp);
166             return 8;
167         default:
168             qemu_log_mask(LOG_UNIMP, "%s to reg %d of unsupported size %d\n",
169                           __func__, n, reg->size);
170             return reg->size;
171         }
172 
173     case xtRegisterTypeWindow: /*a*/
174         env->regs[reg->targno & 0x0f] = tmp;
175         break;
176 
177     default:
178         qemu_log_mask(LOG_UNIMP, "%s to reg %d of unsupported type %d\n",
179                       __func__, n, reg->type);
180         return reg->size;
181     }
182 
183     return 4;
184 }
185