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Commit | Line | Data |
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c566080c AB |
1 | /* |
2 | * GDB Syscall Handling | |
3 | * | |
4 | * GDB can execute syscalls on the guests behalf, currently used by | |
2d3d2517 | 5 | * the various semihosting extensions. |
c566080c AB |
6 | * |
7 | * Copyright (c) 2003-2005 Fabrice Bellard | |
8 | * Copyright (c) 2023 Linaro Ltd | |
9 | * | |
10 | * SPDX-License-Identifier: LGPL-2.0+ | |
11 | */ | |
12 | ||
13 | #include "qemu/osdep.h" | |
14 | #include "qemu/error-report.h" | |
c566080c AB |
15 | #include "semihosting/semihost.h" |
16 | #include "sysemu/runstate.h" | |
17 | #include "gdbstub/user.h" | |
18 | #include "gdbstub/syscalls.h" | |
19 | #include "trace.h" | |
20 | #include "internals.h" | |
21 | ||
22 | /* Syscall specific state */ | |
23 | typedef struct { | |
24 | char syscall_buf[256]; | |
25 | gdb_syscall_complete_cb current_syscall_cb; | |
26 | } GDBSyscallState; | |
27 | ||
28 | static GDBSyscallState gdbserver_syscall_state; | |
29 | ||
30 | /* | |
31 | * Return true if there is a GDB currently connected to the stub | |
32 | * and attached to a CPU | |
33 | */ | |
34 | static bool gdb_attached(void) | |
35 | { | |
36 | return gdbserver_state.init && gdbserver_state.c_cpu; | |
37 | } | |
38 | ||
39 | static enum { | |
40 | GDB_SYS_UNKNOWN, | |
41 | GDB_SYS_ENABLED, | |
42 | GDB_SYS_DISABLED, | |
43 | } gdb_syscall_mode; | |
44 | ||
45 | /* Decide if either remote gdb syscalls or native file IO should be used. */ | |
46 | int use_gdb_syscalls(void) | |
47 | { | |
48 | SemihostingTarget target = semihosting_get_target(); | |
49 | if (target == SEMIHOSTING_TARGET_NATIVE) { | |
50 | /* -semihosting-config target=native */ | |
51 | return false; | |
52 | } else if (target == SEMIHOSTING_TARGET_GDB) { | |
53 | /* -semihosting-config target=gdb */ | |
54 | return true; | |
55 | } | |
56 | ||
57 | /* -semihosting-config target=auto */ | |
58 | /* On the first call check if gdb is connected and remember. */ | |
59 | if (gdb_syscall_mode == GDB_SYS_UNKNOWN) { | |
60 | gdb_syscall_mode = gdb_attached() ? GDB_SYS_ENABLED : GDB_SYS_DISABLED; | |
61 | } | |
62 | return gdb_syscall_mode == GDB_SYS_ENABLED; | |
63 | } | |
64 | ||
65 | /* called when the stub detaches */ | |
66 | void gdb_disable_syscalls(void) | |
67 | { | |
68 | gdb_syscall_mode = GDB_SYS_DISABLED; | |
69 | } | |
70 | ||
71 | void gdb_syscall_reset(void) | |
72 | { | |
73 | gdbserver_syscall_state.current_syscall_cb = NULL; | |
74 | } | |
75 | ||
76 | bool gdb_handled_syscall(void) | |
77 | { | |
78 | if (gdbserver_syscall_state.current_syscall_cb) { | |
79 | gdb_put_packet(gdbserver_syscall_state.syscall_buf); | |
80 | return true; | |
81 | } | |
82 | ||
83 | return false; | |
84 | } | |
85 | ||
86 | /* | |
87 | * Send a gdb syscall request. | |
88 | * This accepts limited printf-style format specifiers, specifically: | |
89 | * %x - target_ulong argument printed in hex. | |
90 | * %lx - 64-bit argument printed in hex. | |
91 | * %s - string pointer (target_ulong) and length (int) pair. | |
92 | */ | |
2f70f2d7 | 93 | void gdb_do_syscall(gdb_syscall_complete_cb cb, const char *fmt, ...) |
c566080c | 94 | { |
2f70f2d7 RH |
95 | char *p, *p_end; |
96 | va_list va; | |
c566080c AB |
97 | |
98 | if (!gdb_attached()) { | |
99 | return; | |
100 | } | |
101 | ||
102 | gdbserver_syscall_state.current_syscall_cb = cb; | |
2f70f2d7 | 103 | va_start(va, fmt); |
131f387d | 104 | |
2f70f2d7 RH |
105 | p = gdbserver_syscall_state.syscall_buf; |
106 | p_end = p + sizeof(gdbserver_syscall_state.syscall_buf); | |
c566080c AB |
107 | *(p++) = 'F'; |
108 | while (*fmt) { | |
109 | if (*fmt == '%') { | |
2f70f2d7 | 110 | uint64_t i64; |
0820a075 | 111 | uint32_t i32; |
2f70f2d7 | 112 | |
c566080c AB |
113 | fmt++; |
114 | switch (*fmt++) { | |
115 | case 'x': | |
0820a075 RH |
116 | i32 = va_arg(va, uint32_t); |
117 | p += snprintf(p, p_end - p, "%" PRIx32, i32); | |
c566080c AB |
118 | break; |
119 | case 'l': | |
120 | if (*(fmt++) != 'x') { | |
121 | goto bad_format; | |
122 | } | |
123 | i64 = va_arg(va, uint64_t); | |
124 | p += snprintf(p, p_end - p, "%" PRIx64, i64); | |
125 | break; | |
126 | case 's': | |
0820a075 RH |
127 | i64 = va_arg(va, uint64_t); |
128 | i32 = va_arg(va, uint32_t); | |
129 | p += snprintf(p, p_end - p, "%" PRIx64 "/%x" PRIx32, i64, i32); | |
c566080c AB |
130 | break; |
131 | default: | |
132 | bad_format: | |
133 | error_report("gdbstub: Bad syscall format string '%s'", | |
134 | fmt - 1); | |
135 | break; | |
136 | } | |
137 | } else { | |
138 | *(p++) = *(fmt++); | |
139 | } | |
140 | } | |
141 | *p = 0; | |
131f387d | 142 | |
c566080c | 143 | va_end(va); |
2f70f2d7 | 144 | gdb_syscall_handling(gdbserver_syscall_state.syscall_buf); |
c566080c AB |
145 | } |
146 | ||
147 | /* | |
148 | * GDB Command Handlers | |
149 | */ | |
150 | ||
151 | void gdb_handle_file_io(GArray *params, void *user_ctx) | |
152 | { | |
153 | if (params->len >= 1 && gdbserver_syscall_state.current_syscall_cb) { | |
154 | uint64_t ret; | |
155 | int err; | |
156 | ||
157 | ret = get_param(params, 0)->val_ull; | |
158 | if (params->len >= 2) { | |
159 | err = get_param(params, 1)->val_ull; | |
160 | } else { | |
161 | err = 0; | |
162 | } | |
163 | ||
164 | /* Convert GDB error numbers back to host error numbers. */ | |
165 | #define E(X) case GDB_E##X: err = E##X; break | |
166 | switch (err) { | |
167 | case 0: | |
168 | break; | |
169 | E(PERM); | |
170 | E(NOENT); | |
171 | E(INTR); | |
172 | E(BADF); | |
173 | E(ACCES); | |
174 | E(FAULT); | |
175 | E(BUSY); | |
176 | E(EXIST); | |
177 | E(NODEV); | |
178 | E(NOTDIR); | |
179 | E(ISDIR); | |
180 | E(INVAL); | |
181 | E(NFILE); | |
182 | E(MFILE); | |
183 | E(FBIG); | |
184 | E(NOSPC); | |
185 | E(SPIPE); | |
186 | E(ROFS); | |
187 | E(NAMETOOLONG); | |
188 | default: | |
189 | err = EINVAL; | |
190 | break; | |
191 | } | |
192 | #undef E | |
193 | ||
194 | gdbserver_syscall_state.current_syscall_cb(gdbserver_state.c_cpu, | |
195 | ret, err); | |
196 | gdbserver_syscall_state.current_syscall_cb = NULL; | |
197 | } | |
198 | ||
199 | if (params->len >= 3 && get_param(params, 2)->opcode == (uint8_t)'C') { | |
200 | gdb_put_packet("T02"); | |
201 | return; | |
202 | } | |
203 | ||
204 | gdb_continue(); | |
205 | } |