xref: /openbmc/qemu/target/xtensa/gdbstub.c (revision 4921d0a7)
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 2.1 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 "gdbstub/helpers.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     CPUXtensaState *env = cpu_env(cs);
69     const XtensaGdbReg *reg = env->config->gdb_regmap.reg + n;
70 #ifdef CONFIG_USER_ONLY
71     int num_regs = env->config->gdb_regmap.num_core_regs;
72 #else
73     int num_regs = env->config->gdb_regmap.num_regs;
74 #endif
75     unsigned i;
76 
77     if (n < 0 || n >= num_regs) {
78         return 0;
79     }
80 
81     switch (reg->type) {
82     case xtRegisterTypeVirtual: /*pc*/
83         return gdb_get_reg32(mem_buf, env->pc);
84 
85     case xtRegisterTypeArRegfile: /*ar*/
86         xtensa_sync_phys_from_window(env);
87         return gdb_get_reg32(mem_buf, env->phys_regs[(reg->targno & 0xff)
88                                                      % env->config->nareg]);
89 
90     case xtRegisterTypeSpecialReg: /*SR*/
91         return gdb_get_reg32(mem_buf, env->sregs[reg->targno & 0xff]);
92 
93     case xtRegisterTypeUserReg: /*UR*/
94         return gdb_get_reg32(mem_buf, env->uregs[reg->targno & 0xff]);
95 
96     case xtRegisterTypeTieRegfile: /*f*/
97         i = reg->targno & 0x0f;
98         switch (reg->size) {
99         case 4:
100             return gdb_get_reg32(mem_buf,
101                                  float32_val(env->fregs[i].f32[FP_F32_LOW]));
102         case 8:
103             return gdb_get_reg64(mem_buf, float64_val(env->fregs[i].f64));
104         default:
105             qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported size %d\n",
106                           __func__, n, reg->size);
107             return gdb_get_zeroes(mem_buf, reg->size);
108         }
109 
110     case xtRegisterTypeWindow: /*a*/
111         return gdb_get_reg32(mem_buf, env->regs[reg->targno & 0x0f]);
112 
113     default:
114         qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported type %d\n",
115                       __func__, n, reg->type);
116         return gdb_get_zeroes(mem_buf, reg->size);
117     }
118 }
119 
120 int xtensa_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
121 {
122     CPUXtensaState *env = cpu_env(cs);
123     uint32_t tmp;
124     const XtensaGdbReg *reg = env->config->gdb_regmap.reg + n;
125 #ifdef CONFIG_USER_ONLY
126     int num_regs = env->config->gdb_regmap.num_core_regs;
127 #else
128     int num_regs = env->config->gdb_regmap.num_regs;
129 #endif
130 
131     if (n < 0 || n >= num_regs) {
132         return 0;
133     }
134 
135     tmp = ldl_p(mem_buf);
136 
137     switch (reg->type) {
138     case xtRegisterTypeVirtual: /*pc*/
139         env->pc = tmp;
140         break;
141 
142     case xtRegisterTypeArRegfile: /*ar*/
143         env->phys_regs[(reg->targno & 0xff) % env->config->nareg] = tmp;
144         xtensa_sync_window_from_phys(env);
145         break;
146 
147     case xtRegisterTypeSpecialReg: /*SR*/
148         env->sregs[reg->targno & 0xff] = tmp;
149         break;
150 
151     case xtRegisterTypeUserReg: /*UR*/
152         env->uregs[reg->targno & 0xff] = tmp;
153         break;
154 
155     case xtRegisterTypeTieRegfile: /*f*/
156         switch (reg->size) {
157         case 4:
158             env->fregs[reg->targno & 0x0f].f32[FP_F32_LOW] = make_float32(tmp);
159             return 4;
160         case 8:
161             env->fregs[reg->targno & 0x0f].f64 = make_float64(tmp);
162             return 8;
163         default:
164             qemu_log_mask(LOG_UNIMP, "%s to reg %d of unsupported size %d\n",
165                           __func__, n, reg->size);
166             return reg->size;
167         }
168 
169     case xtRegisterTypeWindow: /*a*/
170         env->regs[reg->targno & 0x0f] = tmp;
171         break;
172 
173     default:
174         qemu_log_mask(LOG_UNIMP, "%s to reg %d of unsupported type %d\n",
175                       __func__, n, reg->type);
176         return reg->size;
177     }
178 
179     return 4;
180 }
181