include/ust/processor.h

   1 /* Copyright (C) 2009  Pierre-Marc Fournier
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  16  */
  17
  18 #ifndef UST_PROCESSOR_H
  19 #define UST_PROCESSOR_H
  20
  21 #include <stddef.h>
  22 #include <string.h>
  23
  24 extern __thread long ust_reg_stack[500];
  25 extern volatile __thread long *ust_reg_stack_ptr;
  26
  27 #ifndef __x86_64
  28
  29 struct registers {
  30         short ss;
  31         short cs;
  32         long esi;
  33         long ebp;
  34         long edx;
  35         long edi;
  36         long ecx;
  37         long ebx;
  38         long eax;
  39         long eflags;
  40         long esp;
  41 };
  42
  43 #ifdef CONFIG_UST_GDB_INTEGRATION
  44
  45 /* save_registers - saves most of the processor's registers so
  46  * they are available to the probe. gdb uses this to give the
  47  * value of local variables.
  48  *
  49  * Saving all registers without losing any of their values is
  50  * tricky.
  51  *
  52  * We cannot pass to the asm stub the address of a registers structure
  53  * on the stack, because it will use a register and override its value.
  54  *
  55  * We don't want to use a stub to push the regs on the stack and then
  56  * another stub to copy them to a structure because changing %sp in asm
  57  * and then returning to C (even briefly) can have unexpected results.
  58  * Also, gcc might modify %sp between the stubs in reaction to the
  59  * register needs of the second stub that needs to know where to copy
  60  * the register values.
  61  *
  62  * So the chosen approach is to use another stack, declared in thread-
  63  * local storage, to push the registers. They are subsequently copied
  64  * to the stack, by C code.
  65  */
  66
  67 #define save_registers(regsptr) \
  68         asm volatile ( \
  69              /* save original esp */ \
  70              "pushl %%esp\n\t" \
  71              /* push original eflags */ \
  72              "pushfl\n\t" \
  73               /* eax will hold the ptr to the private stack bottom */ \
  74              "pushl %%eax\n\t" \
  75              /* ebx is used for TLS access */ \
  76              "pushl %%ebx\n\t" \
  77              /* ecx will be used to temporarily hold the stack bottom addr */\
  78              "pushl %%ecx\n\t"                                               \
  79              /* rdi is the input to __tls_get_addr, and also a temp var */   \
  80              "pushl %%edi\n\t"                                               \
  81              /* For TLS access, we have to do function calls. However,       \
  82               * we must not lose the original value of:                      \
  83               *   esp, eflags, eax, ebx, ecx, edx, esi, edi, ebp, cs, ss     \
  84               *                                                              \
  85               * Some registers' original values have already been saved:     \
  86               *   esp, eflags, eax, ebx, ecx, edi                            \
  87               *                                                              \
  88               * In addition, the i386 ABI says the following registers belong\
  89               * to the caller function:                                      \
  90               *   esp, ebp, esi, edi, ebx                                    \
  91               *                                                              \
  92               * The following registers should not be changed by the callee: \
  93               *   cs, ss                                                     \
  94               *                                                              \
  95               * Therefore, the following registers must be explicitly        \
  96               * preserved:                                                   \
  97               *   edx                                                        \
  98               */ \
  99              "pushl %%edx\n\t" \
 100              /* Get GOT address */ \
 101              "call __i686.get_pc_thunk.bx\n\t" \
 102              "addl $_GLOBAL_OFFSET_TABLE_, %%ebx\n\t" \
 103              /* Start TLS access of private reg stack pointer */ \
 104              "leal ust_reg_stack_ptr@tlsgd(,%%ebx,1),%%eax\n\t" \
 105              "call ___tls_get_addr@plt\n\t" \
 106              /* --- End TLS access */ \
 107              /* check if ust_reg_stack_ptr has been initialized */ \
 108              "movl (%%eax),%%ecx\n\t" \
 109              "testl %%ecx,%%ecx\n\t" \
 110              "jne 1f\n\t" \
 111              "movl %%eax,%%ecx\n\t" \
 112              /* Save ecx because we are using it. */ \
 113              "pushl %%ecx\n\t" \
 114              /* Start TLS access of private reg stack */ \
 115              "leal ust_reg_stack@tlsgd(,%%ebx,1),%%eax\n\t" \
 116              "call ___tls_get_addr@plt\n\t" \
 117              /* --- End TLS access */ \
 118              "popl %%ecx\n\t" \
 119              "addl $500,%%eax\n\t" \
 120              "movl %%eax,(%%ecx)\n\t" \
 121              "movl %%ecx,%%eax\n\t" \
 122              /* now the pointer to the private stack is in eax. \
 123                 must add stack size so the ptr points to the stack bottom. */ \
 124         "1:\n\t" \
 125              /* edx was pushed for function calls */ \
 126              "popl %%edx\n\t" \
 127              /* Manually push esp to private stack */ \
 128              "addl $-4,(%%eax)\n\t" \
 129              "movl 20(%%esp), %%edi\n\t" \
 130              "movl (%%eax), %%ebx\n\t" \
 131              "movl %%edi, (%%ebx)\n\t" \
 132              /* Manually push eflags to private stack */ \
 133              "addl $-4,(%%eax)\n\t" \
 134              "movl 16(%%esp), %%edi\n\t" \
 135              "movl (%%eax), %%ebx\n\t" \
 136              "movl %%edi, (%%ebx)\n\t" \
 137              /* Manually push eax to private stack */ \
 138              "addl $-4,(%%eax)\n\t" \
 139              "movl 12(%%esp), %%edi\n\t" \
 140              "movl (%%eax), %%ebx\n\t" \
 141              "movl %%edi, (%%ebx)\n\t" \
 142              /* Manually push ebx to private stack */ \
 143              "addl $-4,(%%eax)\n\t" \
 144              "movl 8(%%esp), %%edi\n\t" \
 145              "movl (%%eax), %%ebx\n\t" \
 146              "movl %%edi, (%%ebx)\n\t" \
 147              /* Manually push ecx to private stack */ \
 148              "addl $-4,(%%eax)\n\t" \
 149              "movl 4(%%esp), %%edi\n\t" \
 150              "movl (%%eax), %%ebx\n\t" \
 151              "movl %%edi, (%%ebx)\n\t" \
 152              /* Manually push edi to private stack */ \
 153              "addl $-4,(%%eax)\n\t" \
 154              "movl 0(%%esp), %%edi\n\t" \
 155              "movl (%%eax), %%ebx\n\t" \
 156              "movl %%edi, (%%ebx)\n\t" \
 157              /* now push regs to tls */ \
 158              /* -- esp already pushed -- */ \
 159              /* -- eax already pushed -- */ \
 160              /* -- ebx already pushed -- */ \
 161              /* -- ecx already pushed -- */ \
 162              /* -- edi already pushed -- */ \
 163              "addl $-4,(%%eax)\n\t" \
 164              "movl (%%eax), %%ebx\n\t" \
 165              "movl %%edx,(%%ebx)\n\t" \
 166              "addl $-4,(%%eax)\n\t" \
 167              "movl (%%eax), %%ebx\n\t" \
 168              "movl %%ebp,(%%ebx)\n\t" \
 169              "addl $-4,(%%eax)\n\t" \
 170              "movl (%%eax), %%ebx\n\t" \
 171              "movl %%esi,(%%ebx)\n\t" \
 172              /* push cs */ \
 173              "addl $-2,(%%eax)\n\t" \
 174              "movl (%%eax), %%ebx\n\t" \
 175              "movw %%cs, (%%ebx)\n\t" \
 176              /* push ss */ \
 177              "addl $-2,(%%eax)\n\t" \
 178              "movl (%%eax), %%ebx\n\t" \
 179              "movw %%ss, (%%ebx)\n\t" \
 180              /* restore original values of regs that were used internally */ \
 181              "popl %%edi\n\t" \
 182              "popl %%ecx\n\t" \
 183              "popl %%ebx\n\t" \
 184              "popl %%eax\n\t" \
 185              /* cancel push of rsp */ \
 186              "addl $4,%%esp\n\t" \
 187              /* cancel push of eflags */ \
 188              "addl $4,%%esp\n\t" \
 189              ::: "memory"); \
 190         memcpy(regsptr, (void *)ust_reg_stack_ptr, sizeof(struct registers)); \
 191         ust_reg_stack_ptr = (void *)(((long)ust_reg_stack_ptr) + sizeof(struct registers));
 192
 193 #else /* CONFIG_UST_GDB_INTEGRATION */
 194
 195 #define save_registers(a)
 196
 197 #endif /* CONFIG_UST_GDB_INTEGRATION */
 198
 199 #define RELATIVE_ADDRESS(__rel_label__) __rel_label__
 200
 201 #define ARCH_COPY_ADDR(src, dst) "lea " src "," dst
 202
 203 #define _ASM_PTR ".long "
 204
 205 #else /* below is code for x86-64 */
 206
 207 struct registers {
 208         int padding; /* 4 bytes */
 209         short ss;
 210         short cs;
 211         unsigned long r15;
 212         unsigned long r14;
 213         unsigned long r13;
 214         unsigned long r12;
 215         unsigned long r11;
 216         unsigned long r10;
 217         unsigned long r9;
 218         unsigned long r8;
 219         unsigned long rsi;
 220         unsigned long rbp;
 221         unsigned long rdx;
 222         unsigned long rcx;
 223         unsigned long rdi;
 224         unsigned long rbx;
 225         unsigned long rax;
 226         unsigned long rflags;
 227         unsigned long rsp;
 228 };
 229
 230 #ifdef CONFIG_UST_GDB_INTEGRATION
 231
 232 #define save_registers(regsptr) \
 233         asm volatile ( \
 234              /* save original rsp */ \
 235              "pushq %%rsp\n\t" \
 236              /* push original rflags */ \
 237              "pushfq\n\t" \
 238               /* rax will hold the ptr to the private stack bottom */ \
 239              "pushq %%rax\n\t" \
 240              /* rbx will be used to temporarily hold the stack bottom addr */ \
 241              "pushq %%rbx\n\t" \
 242              /* rdi is the input to __tls_get_addr, and also a temp var */ \
 243              "pushq %%rdi\n\t" \
 244              /* For TLS access, we have to do function calls. However,       \
 245               * we must not lose the original value of:                      \
 246               *   rsp, rflags, rax, rbx, rcx, rdx, rsi, rdi, rbp, r8, r9     \
 247               *   r10, r11, r12, r13, r14, r15, cs, ss                       \
 248               *                                                              \
 249               * Some registers' original values have already been saved:     \
 250               *   rsp, rflags, rax, rbx, rdi                                 \
 251               *                                                              \
 252               * In addition, the x86-64 ABI says the following registers     \
 253               * belong to the caller function:                               \
 254               *   rbp, rbx, r12, r13, r14, r15                               \
 255               *                                                              \
 256               * The following registers should not be changed by the callee: \
 257               *   cs, ss                                                     \
 258               *                                                              \
 259               * Therefore, the following registers must be explicitly        \
 260               * preserved:                                                   \
 261               *   rcx, rdx, rsi, r8, r9, r10, r11                            \
 262               */ \
 263              "pushq %%rcx\n\t" \
 264              "pushq %%rdx\n\t" \
 265              "pushq %%rsi\n\t" \
 266              "pushq %%r8\n\t" \
 267              "pushq %%r9\n\t" \
 268              "pushq %%r10\n\t" \
 269              "pushq %%r11\n\t" \
 270              /* Start TLS access of private reg stack pointer */ \
 271              ".byte 0x66\n\t" \
 272              "leaq ust_reg_stack_ptr@tlsgd(%%rip), %%rdi\n\t" \
 273              ".word 0x6666\n\t" \
 274              "rex64\n\t" \
 275              "call __tls_get_addr@plt\n\t" \
 276              /* --- End TLS access */ \
 277              /* check if ust_reg_stack_ptr has been initialized */ \
 278              "movq (%%rax),%%rbx\n\t" \
 279              "testq %%rbx,%%rbx\n\t" \
 280              "jne 1f\n\t" \
 281              "movq %%rax,%%rbx\n\t" \
 282              /* Start TLS access of private reg stack */ \
 283              ".byte 0x66\n\t" \
 284              "leaq ust_reg_stack@tlsgd(%%rip), %%rdi\n\t" \
 285              ".word 0x6666\n\t" \
 286              "rex64\n\t" \
 287              "call __tls_get_addr@plt\n\t" \
 288              /* --- End TLS access */ \
 289              "addq $500,%%rax\n\t" \
 290              "movq %%rax,(%%rbx)\n\t" \
 291              "movq %%rbx,%%rax\n\t" \
 292              /* now the pointer to the private stack is in rax.
 293                 must add stack size so the ptr points to the stack bottom. */ \
 294         "1:\n\t" \
 295              /* Pop regs that were pushed for function calls */ \
 296              "popq %%r11\n\t" \
 297              "popq %%r10\n\t" \
 298              "popq %%r9\n\t" \
 299              "popq %%r8\n\t" \
 300              "popq %%rsi\n\t" \
 301              "popq %%rdx\n\t" \
 302              "popq %%rcx\n\t" \
 303              /* Manually push rsp to private stack */ \
 304              "addq $-8,(%%rax)\n\t" \
 305              "movq 32(%%rsp), %%rdi\n\t" \
 306              "movq (%%rax), %%rbx\n\t" \
 307              "movq %%rdi, (%%rbx)\n\t" \
 308              /* Manually push eflags to private stack */ \
 309              "addq $-8,(%%rax)\n\t" \
 310              "movq 24(%%rsp), %%rdi\n\t" \
 311              "movq (%%rax), %%rbx\n\t" \
 312              "movq %%rdi, (%%rbx)\n\t" \
 313              /* Manually push rax to private stack */ \
 314              "addq $-8,(%%rax)\n\t" \
 315              "movq 16(%%rsp), %%rdi\n\t" \
 316              "movq (%%rax), %%rbx\n\t" \
 317              "movq %%rdi, (%%rbx)\n\t" \
 318              /* Manually push rbx to private stack */ \
 319              "addq $-8,(%%rax)\n\t" \
 320              "movq 8(%%rsp), %%rdi\n\t" \
 321              "movq (%%rax), %%rbx\n\t" \
 322              "movq %%rdi, (%%rbx)\n\t" \
 323              /* Manually push rdi to private stack */ \
 324              "addq $-8,(%%rax)\n\t" \
 325              "movq 0(%%rsp), %%rdi\n\t" \
 326              "movq (%%rax), %%rbx\n\t" \
 327              "movq %%rdi, (%%rbx)\n\t" \
 328              /* now push regs to tls */ \
 329              /* -- rsp already pushed -- */ \
 330              /* -- rax already pushed -- */ \
 331              /* -- rbx already pushed -- */ \
 332              /* -- rdi already pushed -- */ \
 333              "addq $-8,(%%rax)\n\t" \
 334              "movq (%%rax), %%rbx\n\t" \
 335              "movq %%rcx,(%%rbx)\n\t" \
 336              "addq $-8,(%%rax)\n\t" \
 337              "movq (%%rax), %%rbx\n\t" \
 338              "movq %%rdx,(%%rbx)\n\t" \
 339              "addq $-8,(%%rax)\n\t" \
 340              "movq (%%rax), %%rbx\n\t" \
 341              "movq %%rbp,(%%rbx)\n\t" \
 342              "addq $-8,(%%rax)\n\t" \
 343              "movq (%%rax), %%rbx\n\t" \
 344              "movq %%rsi,(%%rbx)\n\t" \
 345              "addq $-8,(%%rax)\n\t" \
 346              "movq (%%rax), %%rbx\n\t" \
 347              "movq %%r8,(%%rbx)\n\t" \
 348              "addq $-8,(%%rax)\n\t" \
 349              "movq (%%rax), %%rbx\n\t" \
 350              "movq %%r9,(%%rbx)\n\t" \
 351              "addq $-8,(%%rax)\n\t" \
 352              "movq (%%rax), %%rbx\n\t" \
 353              "movq %%r10,(%%rbx)\n\t" \
 354              "addq $-8,(%%rax)\n\t" \
 355              "movq (%%rax), %%rbx\n\t" \
 356              "movq %%r11,(%%rbx)\n\t" \
 357              "addq $-8,(%%rax)\n\t" \
 358              "movq (%%rax), %%rbx\n\t" \
 359              "movq %%r12,(%%rbx)\n\t" \
 360              "addq $-8,(%%rax)\n\t" \
 361              "movq (%%rax), %%rbx\n\t" \
 362              "movq %%r13,(%%rbx)\n\t" \
 363              "addq $-8,(%%rax)\n\t" \
 364              "movq (%%rax), %%rbx\n\t" \
 365              "movq %%r14,(%%rbx)\n\t" \
 366              "addq $-8,(%%rax)\n\t" \
 367              "movq (%%rax), %%rbx\n\t" \
 368              "movq %%r15,(%%rbx)\n\t" \
 369              /* push cs */ \
 370              "addq $-2,(%%rax)\n\t" \
 371              "movq (%%rax), %%rbx\n\t" \
 372              "movw %%cs, (%%rbx)\n\t" \
 373              /* push ss */ \
 374              "addq $-2,(%%rax)\n\t" \
 375              "movq (%%rax), %%rbx\n\t" \
 376              "movw %%ss, (%%rbx)\n\t" \
 377              /* add padding for struct registers */ \
 378              "addq $-4,(%%rax)\n\t" \
 379              /* restore original values of regs that were used internally */ \
 380              "popq %%rdi\n\t" \
 381              "popq %%rbx\n\t" \
 382              "popq %%rax\n\t" \
 383              /* cancel push of rsp */ \
 384              "addq $8,%%rsp\n\t" \
 385              /* cancel push of rflags */ \
 386              "addq $8,%%rsp\n\t" \
 387              ::); \
 388         memcpy(regsptr, (void *)ust_reg_stack_ptr, sizeof(struct registers)); \
 389         ust_reg_stack_ptr = (void *)(((long)ust_reg_stack_ptr) + sizeof(struct registers));
 390
 391 #else /* CONFIG_UST_GDB_INTEGRATION */
 392
 393 #define save_registers(a)
 394
 395 #endif /* CONFIG_UST_GDB_INTEGRATION */
 396
 397 /* Macro to insert the address of a relative jump in an assembly stub,
 398  * in a relocatable way. On x86-64, this uses a special (%rip) notation. */
 399 #define RELATIVE_ADDRESS(__rel_label__) __rel_label__(%%rip)
 400
 401 #define ARCH_COPY_ADDR(src, dst) "lea " src "(%%rip)," dst
 402
 403 #define _ASM_PTR ".quad "
 404
 405 #endif
 406
 407 #endif /* UST_PROCESSOR_H */