include/ust/processor.h

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