xref: /openbmc/qemu/target/i386/gdbstub.c (revision a010bdbe)
1 /*
2  * x86 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 
24 #ifdef TARGET_X86_64
25 static const int gpr_map[16] = {
26     R_EAX, R_EBX, R_ECX, R_EDX, R_ESI, R_EDI, R_EBP, R_ESP,
27     8, 9, 10, 11, 12, 13, 14, 15
28 };
29 #else
30 #define gpr_map gpr_map32
31 #endif
32 static const int gpr_map32[8] = { 0, 1, 2, 3, 4, 5, 6, 7 };
33 
34 /*
35  * Keep these in sync with assignment to
36  * gdb_num_core_regs in target/i386/cpu.c
37  * and with the machine description
38  */
39 
40 /*
41  * SEG: 6 segments, plus fs_base, gs_base, kernel_gs_base
42  */
43 
44 /*
45  * general regs ----->  8 or 16
46  */
47 #define IDX_NB_IP       1
48 #define IDX_NB_FLAGS    1
49 #define IDX_NB_SEG      (6 + 3)
50 #define IDX_NB_CTL      6
51 #define IDX_NB_FP       16
52 /*
53  * fpu regs ----------> 8 or 16
54  */
55 #define IDX_NB_MXCSR    1
56 /*
57  *          total ----> 8+1+1+9+6+16+8+1=50 or 16+1+1+9+6+16+16+1=66
58  */
59 
60 #define IDX_IP_REG      CPU_NB_REGS
61 #define IDX_FLAGS_REG   (IDX_IP_REG + IDX_NB_IP)
62 #define IDX_SEG_REGS    (IDX_FLAGS_REG + IDX_NB_FLAGS)
63 #define IDX_CTL_REGS    (IDX_SEG_REGS + IDX_NB_SEG)
64 #define IDX_FP_REGS     (IDX_CTL_REGS + IDX_NB_CTL)
65 #define IDX_XMM_REGS    (IDX_FP_REGS + IDX_NB_FP)
66 #define IDX_MXCSR_REG   (IDX_XMM_REGS + CPU_NB_REGS)
67 
68 #define IDX_CTL_CR0_REG     (IDX_CTL_REGS + 0)
69 #define IDX_CTL_CR2_REG     (IDX_CTL_REGS + 1)
70 #define IDX_CTL_CR3_REG     (IDX_CTL_REGS + 2)
71 #define IDX_CTL_CR4_REG     (IDX_CTL_REGS + 3)
72 #define IDX_CTL_CR8_REG     (IDX_CTL_REGS + 4)
73 #define IDX_CTL_EFER_REG    (IDX_CTL_REGS + 5)
74 
75 #ifdef TARGET_X86_64
76 #define GDB_FORCE_64 1
77 #else
78 #define GDB_FORCE_64 0
79 #endif
80 
81 
82 int x86_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
83 {
84     X86CPU *cpu = X86_CPU(cs);
85     CPUX86State *env = &cpu->env;
86 
87     uint64_t tpr;
88 
89     /* N.B. GDB can't deal with changes in registers or sizes in the middle
90        of a session. So if we're in 32-bit mode on a 64-bit cpu, still act
91        as if we're on a 64-bit cpu. */
92 
93     if (n < CPU_NB_REGS) {
94         if (TARGET_LONG_BITS == 64) {
95             if (env->hflags & HF_CS64_MASK) {
96                 return gdb_get_reg64(mem_buf, env->regs[gpr_map[n]]);
97             } else if (n < CPU_NB_REGS32) {
98                 return gdb_get_reg64(mem_buf,
99                                      env->regs[gpr_map[n]] & 0xffffffffUL);
100             } else {
101                 return gdb_get_regl(mem_buf, 0);
102             }
103         } else {
104             return gdb_get_reg32(mem_buf, env->regs[gpr_map32[n]]);
105         }
106     } else if (n >= IDX_FP_REGS && n < IDX_FP_REGS + 8) {
107         floatx80 *fp = (floatx80 *) &env->fpregs[n - IDX_FP_REGS];
108         int len = gdb_get_reg64(mem_buf, cpu_to_le64(fp->low));
109         len += gdb_get_reg16(mem_buf + len, cpu_to_le16(fp->high));
110         return len;
111     } else if (n >= IDX_XMM_REGS && n < IDX_XMM_REGS + CPU_NB_REGS) {
112         n -= IDX_XMM_REGS;
113         if (n < CPU_NB_REGS32 || TARGET_LONG_BITS == 64) {
114             return gdb_get_reg128(mem_buf,
115                                   env->xmm_regs[n].ZMM_Q(0),
116                                   env->xmm_regs[n].ZMM_Q(1));
117         }
118     } else {
119         switch (n) {
120         case IDX_IP_REG:
121             if (TARGET_LONG_BITS == 64) {
122                 if (env->hflags & HF_CS64_MASK) {
123                     return gdb_get_reg64(mem_buf, env->eip);
124                 } else {
125                     return gdb_get_reg64(mem_buf, env->eip & 0xffffffffUL);
126                 }
127             } else {
128                 return gdb_get_reg32(mem_buf, env->eip);
129             }
130         case IDX_FLAGS_REG:
131             return gdb_get_reg32(mem_buf, env->eflags);
132 
133         case IDX_SEG_REGS:
134             return gdb_get_reg32(mem_buf, env->segs[R_CS].selector);
135         case IDX_SEG_REGS + 1:
136             return gdb_get_reg32(mem_buf, env->segs[R_SS].selector);
137         case IDX_SEG_REGS + 2:
138             return gdb_get_reg32(mem_buf, env->segs[R_DS].selector);
139         case IDX_SEG_REGS + 3:
140             return gdb_get_reg32(mem_buf, env->segs[R_ES].selector);
141         case IDX_SEG_REGS + 4:
142             return gdb_get_reg32(mem_buf, env->segs[R_FS].selector);
143         case IDX_SEG_REGS + 5:
144             return gdb_get_reg32(mem_buf, env->segs[R_GS].selector);
145 
146         case IDX_SEG_REGS + 6:
147             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
148                 return gdb_get_reg64(mem_buf, env->segs[R_FS].base);
149             }
150             return gdb_get_reg32(mem_buf, env->segs[R_FS].base);
151 
152         case IDX_SEG_REGS + 7:
153             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
154                 return gdb_get_reg64(mem_buf, env->segs[R_GS].base);
155             }
156             return gdb_get_reg32(mem_buf, env->segs[R_GS].base);
157 
158         case IDX_SEG_REGS + 8:
159 #ifdef TARGET_X86_64
160             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
161                 return gdb_get_reg64(mem_buf, env->kernelgsbase);
162             }
163             return gdb_get_reg32(mem_buf, env->kernelgsbase);
164 #else
165             return gdb_get_reg32(mem_buf, 0);
166 #endif
167 
168         case IDX_FP_REGS + 8:
169             return gdb_get_reg32(mem_buf, env->fpuc);
170         case IDX_FP_REGS + 9:
171             return gdb_get_reg32(mem_buf, (env->fpus & ~0x3800) |
172                                           (env->fpstt & 0x7) << 11);
173         case IDX_FP_REGS + 10:
174             return gdb_get_reg32(mem_buf, 0); /* ftag */
175         case IDX_FP_REGS + 11:
176             return gdb_get_reg32(mem_buf, 0); /* fiseg */
177         case IDX_FP_REGS + 12:
178             return gdb_get_reg32(mem_buf, 0); /* fioff */
179         case IDX_FP_REGS + 13:
180             return gdb_get_reg32(mem_buf, 0); /* foseg */
181         case IDX_FP_REGS + 14:
182             return gdb_get_reg32(mem_buf, 0); /* fooff */
183         case IDX_FP_REGS + 15:
184             return gdb_get_reg32(mem_buf, 0); /* fop */
185 
186         case IDX_MXCSR_REG:
187             return gdb_get_reg32(mem_buf, env->mxcsr);
188 
189         case IDX_CTL_CR0_REG:
190             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
191                 return gdb_get_reg64(mem_buf, env->cr[0]);
192             }
193             return gdb_get_reg32(mem_buf, env->cr[0]);
194 
195         case IDX_CTL_CR2_REG:
196             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
197                 return gdb_get_reg64(mem_buf, env->cr[2]);
198             }
199             return gdb_get_reg32(mem_buf, env->cr[2]);
200 
201         case IDX_CTL_CR3_REG:
202             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
203                 return gdb_get_reg64(mem_buf, env->cr[3]);
204             }
205             return gdb_get_reg32(mem_buf, env->cr[3]);
206 
207         case IDX_CTL_CR4_REG:
208             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
209                 return gdb_get_reg64(mem_buf, env->cr[4]);
210             }
211             return gdb_get_reg32(mem_buf, env->cr[4]);
212 
213         case IDX_CTL_CR8_REG:
214 #ifdef CONFIG_SOFTMMU
215             tpr = cpu_get_apic_tpr(cpu->apic_state);
216 #else
217             tpr = 0;
218 #endif
219             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
220                 return gdb_get_reg64(mem_buf, tpr);
221             }
222             return gdb_get_reg32(mem_buf, tpr);
223 
224         case IDX_CTL_EFER_REG:
225             if ((env->hflags & HF_CS64_MASK) || GDB_FORCE_64) {
226                 return gdb_get_reg64(mem_buf, env->efer);
227             }
228             return gdb_get_reg32(mem_buf, env->efer);
229         }
230     }
231     return 0;
232 }
233 
234 static int x86_cpu_gdb_load_seg(X86CPU *cpu, int sreg, uint8_t *mem_buf)
235 {
236     CPUX86State *env = &cpu->env;
237     uint16_t selector = ldl_p(mem_buf);
238 
239     if (selector != env->segs[sreg].selector) {
240 #if defined(CONFIG_USER_ONLY)
241         cpu_x86_load_seg(env, sreg, selector);
242 #else
243         unsigned int limit, flags;
244         target_ulong base;
245 
246         if (!(env->cr[0] & CR0_PE_MASK) || (env->eflags & VM_MASK)) {
247             int dpl = (env->eflags & VM_MASK) ? 3 : 0;
248             base = selector << 4;
249             limit = 0xffff;
250             flags = DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |
251                     DESC_A_MASK | (dpl << DESC_DPL_SHIFT);
252         } else {
253             if (!cpu_x86_get_descr_debug(env, selector, &base, &limit,
254                                          &flags)) {
255                 return 4;
256             }
257         }
258         cpu_x86_load_seg_cache(env, sreg, selector, base, limit, flags);
259 #endif
260     }
261     return 4;
262 }
263 
264 int x86_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
265 {
266     X86CPU *cpu = X86_CPU(cs);
267     CPUX86State *env = &cpu->env;
268     uint32_t tmp;
269 
270     /* N.B. GDB can't deal with changes in registers or sizes in the middle
271        of a session. So if we're in 32-bit mode on a 64-bit cpu, still act
272        as if we're on a 64-bit cpu. */
273 
274     if (n < CPU_NB_REGS) {
275         if (TARGET_LONG_BITS == 64) {
276             if (env->hflags & HF_CS64_MASK) {
277                 env->regs[gpr_map[n]] = ldtul_p(mem_buf);
278             } else if (n < CPU_NB_REGS32) {
279                 env->regs[gpr_map[n]] = ldtul_p(mem_buf) & 0xffffffffUL;
280             }
281             return sizeof(target_ulong);
282         } else if (n < CPU_NB_REGS32) {
283             n = gpr_map32[n];
284             env->regs[n] &= ~0xffffffffUL;
285             env->regs[n] |= (uint32_t)ldl_p(mem_buf);
286             return 4;
287         }
288     } else if (n >= IDX_FP_REGS && n < IDX_FP_REGS + 8) {
289         floatx80 *fp = (floatx80 *) &env->fpregs[n - IDX_FP_REGS];
290         fp->low = le64_to_cpu(* (uint64_t *) mem_buf);
291         fp->high = le16_to_cpu(* (uint16_t *) (mem_buf + 8));
292         return 10;
293     } else if (n >= IDX_XMM_REGS && n < IDX_XMM_REGS + CPU_NB_REGS) {
294         n -= IDX_XMM_REGS;
295         if (n < CPU_NB_REGS32 || TARGET_LONG_BITS == 64) {
296             env->xmm_regs[n].ZMM_Q(0) = ldq_p(mem_buf);
297             env->xmm_regs[n].ZMM_Q(1) = ldq_p(mem_buf + 8);
298             return 16;
299         }
300     } else {
301         switch (n) {
302         case IDX_IP_REG:
303             if (TARGET_LONG_BITS == 64) {
304                 if (env->hflags & HF_CS64_MASK) {
305                     env->eip = ldq_p(mem_buf);
306                 } else {
307                     env->eip = ldq_p(mem_buf) & 0xffffffffUL;
308                 }
309                 return 8;
310             } else {
311                 env->eip &= ~0xffffffffUL;
312                 env->eip |= (uint32_t)ldl_p(mem_buf);
313                 return 4;
314             }
315         case IDX_FLAGS_REG:
316             env->eflags = ldl_p(mem_buf);
317             return 4;
318 
319         case IDX_SEG_REGS:
320             return x86_cpu_gdb_load_seg(cpu, R_CS, mem_buf);
321         case IDX_SEG_REGS + 1:
322             return x86_cpu_gdb_load_seg(cpu, R_SS, mem_buf);
323         case IDX_SEG_REGS + 2:
324             return x86_cpu_gdb_load_seg(cpu, R_DS, mem_buf);
325         case IDX_SEG_REGS + 3:
326             return x86_cpu_gdb_load_seg(cpu, R_ES, mem_buf);
327         case IDX_SEG_REGS + 4:
328             return x86_cpu_gdb_load_seg(cpu, R_FS, mem_buf);
329         case IDX_SEG_REGS + 5:
330             return x86_cpu_gdb_load_seg(cpu, R_GS, mem_buf);
331 
332         case IDX_SEG_REGS + 6:
333             if (env->hflags & HF_CS64_MASK) {
334                 env->segs[R_FS].base = ldq_p(mem_buf);
335                 return 8;
336             }
337             env->segs[R_FS].base = ldl_p(mem_buf);
338             return 4;
339 
340         case IDX_SEG_REGS + 7:
341             if (env->hflags & HF_CS64_MASK) {
342                 env->segs[R_GS].base = ldq_p(mem_buf);
343                 return 8;
344             }
345             env->segs[R_GS].base = ldl_p(mem_buf);
346             return 4;
347 
348         case IDX_SEG_REGS + 8:
349 #ifdef TARGET_X86_64
350             if (env->hflags & HF_CS64_MASK) {
351                 env->kernelgsbase = ldq_p(mem_buf);
352                 return 8;
353             }
354             env->kernelgsbase = ldl_p(mem_buf);
355 #endif
356             return 4;
357 
358         case IDX_FP_REGS + 8:
359             cpu_set_fpuc(env, ldl_p(mem_buf));
360             return 4;
361         case IDX_FP_REGS + 9:
362             tmp = ldl_p(mem_buf);
363             env->fpstt = (tmp >> 11) & 7;
364             env->fpus = tmp & ~0x3800;
365             return 4;
366         case IDX_FP_REGS + 10: /* ftag */
367             return 4;
368         case IDX_FP_REGS + 11: /* fiseg */
369             return 4;
370         case IDX_FP_REGS + 12: /* fioff */
371             return 4;
372         case IDX_FP_REGS + 13: /* foseg */
373             return 4;
374         case IDX_FP_REGS + 14: /* fooff */
375             return 4;
376         case IDX_FP_REGS + 15: /* fop */
377             return 4;
378 
379         case IDX_MXCSR_REG:
380             cpu_set_mxcsr(env, ldl_p(mem_buf));
381             return 4;
382 
383         case IDX_CTL_CR0_REG:
384             if (env->hflags & HF_CS64_MASK) {
385                 cpu_x86_update_cr0(env, ldq_p(mem_buf));
386                 return 8;
387             }
388             cpu_x86_update_cr0(env, ldl_p(mem_buf));
389             return 4;
390 
391         case IDX_CTL_CR2_REG:
392             if (env->hflags & HF_CS64_MASK) {
393                 env->cr[2] = ldq_p(mem_buf);
394                 return 8;
395             }
396             env->cr[2] = ldl_p(mem_buf);
397             return 4;
398 
399         case IDX_CTL_CR3_REG:
400             if (env->hflags & HF_CS64_MASK) {
401                 cpu_x86_update_cr3(env, ldq_p(mem_buf));
402                 return 8;
403             }
404             cpu_x86_update_cr3(env, ldl_p(mem_buf));
405             return 4;
406 
407         case IDX_CTL_CR4_REG:
408             if (env->hflags & HF_CS64_MASK) {
409                 cpu_x86_update_cr4(env, ldq_p(mem_buf));
410                 return 8;
411             }
412             cpu_x86_update_cr4(env, ldl_p(mem_buf));
413             return 4;
414 
415         case IDX_CTL_CR8_REG:
416             if (env->hflags & HF_CS64_MASK) {
417 #ifdef CONFIG_SOFTMMU
418                 cpu_set_apic_tpr(cpu->apic_state, ldq_p(mem_buf));
419 #endif
420                 return 8;
421             }
422 #ifdef CONFIG_SOFTMMU
423             cpu_set_apic_tpr(cpu->apic_state, ldl_p(mem_buf));
424 #endif
425             return 4;
426 
427         case IDX_CTL_EFER_REG:
428             if (env->hflags & HF_CS64_MASK) {
429                 cpu_load_efer(env, ldq_p(mem_buf));
430                 return 8;
431             }
432             cpu_load_efer(env, ldl_p(mem_buf));
433             return 4;
434 
435         }
436     }
437     /* Unrecognised register.  */
438     return 0;
439 }
440