1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_PTRACE_H 3 #define _ASM_X86_PTRACE_H 4 5 #include <asm/segment.h> 6 #include <asm/page_types.h> 7 #include <uapi/asm/ptrace.h> 8 9 #ifndef __ASSEMBLY__ 10 #ifdef __i386__ 11 12 struct pt_regs { 13 /* 14 * NB: 32-bit x86 CPUs are inconsistent as what happens in the 15 * following cases (where %seg represents a segment register): 16 * 17 * - pushl %seg: some do a 16-bit write and leave the high 18 * bits alone 19 * - movl %seg, [mem]: some do a 16-bit write despite the movl 20 * - IDT entry: some (e.g. 486) will leave the high bits of CS 21 * and (if applicable) SS undefined. 22 * 23 * Fortunately, x86-32 doesn't read the high bits on POP or IRET, 24 * so we can just treat all of the segment registers as 16-bit 25 * values. 26 */ 27 unsigned long bx; 28 unsigned long cx; 29 unsigned long dx; 30 unsigned long si; 31 unsigned long di; 32 unsigned long bp; 33 unsigned long ax; 34 unsigned short ds; 35 unsigned short __dsh; 36 unsigned short es; 37 unsigned short __esh; 38 unsigned short fs; 39 unsigned short __fsh; 40 /* 41 * On interrupt, gs and __gsh store the vector number. They never 42 * store gs any more. 43 */ 44 unsigned short gs; 45 unsigned short __gsh; 46 /* On interrupt, this is the error code. */ 47 unsigned long orig_ax; 48 unsigned long ip; 49 unsigned short cs; 50 unsigned short __csh; 51 unsigned long flags; 52 unsigned long sp; 53 unsigned short ss; 54 unsigned short __ssh; 55 }; 56 57 #else /* __i386__ */ 58 59 struct fred_cs { 60 /* CS selector */ 61 u64 cs : 16, 62 /* Stack level at event time */ 63 sl : 2, 64 /* IBT in WAIT_FOR_ENDBRANCH state */ 65 wfe : 1, 66 : 45; 67 }; 68 69 struct fred_ss { 70 /* SS selector */ 71 u64 ss : 16, 72 /* STI state */ 73 sti : 1, 74 /* Set if syscall, sysenter or INT n */ 75 swevent : 1, 76 /* Event is NMI type */ 77 nmi : 1, 78 : 13, 79 /* Event vector */ 80 vector : 8, 81 : 8, 82 /* Event type */ 83 type : 4, 84 : 4, 85 /* Event was incident to enclave execution */ 86 enclave : 1, 87 /* CPU was in long mode */ 88 lm : 1, 89 /* 90 * Nested exception during FRED delivery, not set 91 * for #DF. 92 */ 93 nested : 1, 94 : 1, 95 /* 96 * The length of the instruction causing the event. 97 * Only set for INTO, INT1, INT3, INT n, SYSCALL 98 * and SYSENTER. 0 otherwise. 99 */ 100 insnlen : 4; 101 }; 102 103 struct pt_regs { 104 /* 105 * C ABI says these regs are callee-preserved. They aren't saved on 106 * kernel entry unless syscall needs a complete, fully filled 107 * "struct pt_regs". 108 */ 109 unsigned long r15; 110 unsigned long r14; 111 unsigned long r13; 112 unsigned long r12; 113 unsigned long bp; 114 unsigned long bx; 115 116 /* These regs are callee-clobbered. Always saved on kernel entry. */ 117 unsigned long r11; 118 unsigned long r10; 119 unsigned long r9; 120 unsigned long r8; 121 unsigned long ax; 122 unsigned long cx; 123 unsigned long dx; 124 unsigned long si; 125 unsigned long di; 126 127 /* 128 * orig_ax is used on entry for: 129 * - the syscall number (syscall, sysenter, int80) 130 * - error_code stored by the CPU on traps and exceptions 131 * - the interrupt number for device interrupts 132 * 133 * A FRED stack frame starts here: 134 * 1) It _always_ includes an error code; 135 * 136 * 2) The return frame for ERET[US] starts here, but 137 * the content of orig_ax is ignored. 138 */ 139 unsigned long orig_ax; 140 141 /* The IRETQ return frame starts here */ 142 unsigned long ip; 143 144 union { 145 /* CS selector */ 146 u16 cs; 147 /* The extended 64-bit data slot containing CS */ 148 u64 csx; 149 /* The FRED CS extension */ 150 struct fred_cs fred_cs; 151 }; 152 153 unsigned long flags; 154 unsigned long sp; 155 156 union { 157 /* SS selector */ 158 u16 ss; 159 /* The extended 64-bit data slot containing SS */ 160 u64 ssx; 161 /* The FRED SS extension */ 162 struct fred_ss fred_ss; 163 }; 164 165 /* 166 * Top of stack on IDT systems, while FRED systems have extra fields 167 * defined above for storing exception related information, e.g. CR2 or 168 * DR6. 169 */ 170 }; 171 172 #endif /* !__i386__ */ 173 174 #ifdef CONFIG_PARAVIRT 175 #include <asm/paravirt_types.h> 176 #endif 177 178 #include <asm/proto.h> 179 180 struct cpuinfo_x86; 181 struct task_struct; 182 183 extern unsigned long profile_pc(struct pt_regs *regs); 184 185 extern unsigned long 186 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs); 187 extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code); 188 189 190 static inline unsigned long regs_return_value(struct pt_regs *regs) 191 { 192 return regs->ax; 193 } 194 195 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) 196 { 197 regs->ax = rc; 198 } 199 200 /* 201 * user_mode(regs) determines whether a register set came from user 202 * mode. On x86_32, this is true if V8086 mode was enabled OR if the 203 * register set was from protected mode with RPL-3 CS value. This 204 * tricky test checks that with one comparison. 205 * 206 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need 207 * the extra check. 208 */ 209 static __always_inline int user_mode(struct pt_regs *regs) 210 { 211 #ifdef CONFIG_X86_32 212 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; 213 #else 214 return !!(regs->cs & 3); 215 #endif 216 } 217 218 static __always_inline int v8086_mode(struct pt_regs *regs) 219 { 220 #ifdef CONFIG_X86_32 221 return (regs->flags & X86_VM_MASK); 222 #else 223 return 0; /* No V86 mode support in long mode */ 224 #endif 225 } 226 227 static inline bool user_64bit_mode(struct pt_regs *regs) 228 { 229 #ifdef CONFIG_X86_64 230 #ifndef CONFIG_PARAVIRT_XXL 231 /* 232 * On non-paravirt systems, this is the only long mode CPL 3 233 * selector. We do not allow long mode selectors in the LDT. 234 */ 235 return regs->cs == __USER_CS; 236 #else 237 /* Headers are too twisted for this to go in paravirt.h. */ 238 return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs; 239 #endif 240 #else /* !CONFIG_X86_64 */ 241 return false; 242 #endif 243 } 244 245 /* 246 * Determine whether the register set came from any context that is running in 247 * 64-bit mode. 248 */ 249 static inline bool any_64bit_mode(struct pt_regs *regs) 250 { 251 #ifdef CONFIG_X86_64 252 return !user_mode(regs) || user_64bit_mode(regs); 253 #else 254 return false; 255 #endif 256 } 257 258 #ifdef CONFIG_X86_64 259 #define current_user_stack_pointer() current_pt_regs()->sp 260 #define compat_user_stack_pointer() current_pt_regs()->sp 261 262 static __always_inline bool ip_within_syscall_gap(struct pt_regs *regs) 263 { 264 bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 && 265 regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack); 266 267 ret = ret || (regs->ip >= (unsigned long)entry_SYSRETQ_unsafe_stack && 268 regs->ip < (unsigned long)entry_SYSRETQ_end); 269 #ifdef CONFIG_IA32_EMULATION 270 ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat && 271 regs->ip < (unsigned long)entry_SYSCALL_compat_safe_stack); 272 ret = ret || (regs->ip >= (unsigned long)entry_SYSRETL_compat_unsafe_stack && 273 regs->ip < (unsigned long)entry_SYSRETL_compat_end); 274 #endif 275 276 return ret; 277 } 278 #endif 279 280 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) 281 { 282 return regs->sp; 283 } 284 285 static inline unsigned long instruction_pointer(struct pt_regs *regs) 286 { 287 return regs->ip; 288 } 289 290 static inline void instruction_pointer_set(struct pt_regs *regs, 291 unsigned long val) 292 { 293 regs->ip = val; 294 } 295 296 static inline unsigned long frame_pointer(struct pt_regs *regs) 297 { 298 return regs->bp; 299 } 300 301 static inline unsigned long user_stack_pointer(struct pt_regs *regs) 302 { 303 return regs->sp; 304 } 305 306 static inline void user_stack_pointer_set(struct pt_regs *regs, 307 unsigned long val) 308 { 309 regs->sp = val; 310 } 311 312 static __always_inline bool regs_irqs_disabled(struct pt_regs *regs) 313 { 314 return !(regs->flags & X86_EFLAGS_IF); 315 } 316 317 /* Query offset/name of register from its name/offset */ 318 extern int regs_query_register_offset(const char *name); 319 extern const char *regs_query_register_name(unsigned int offset); 320 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) 321 322 /** 323 * regs_get_register() - get register value from its offset 324 * @regs: pt_regs from which register value is gotten. 325 * @offset: offset number of the register. 326 * 327 * regs_get_register returns the value of a register. The @offset is the 328 * offset of the register in struct pt_regs address which specified by @regs. 329 * If @offset is bigger than MAX_REG_OFFSET, this returns 0. 330 */ 331 static inline unsigned long regs_get_register(struct pt_regs *regs, 332 unsigned int offset) 333 { 334 if (unlikely(offset > MAX_REG_OFFSET)) 335 return 0; 336 #ifdef CONFIG_X86_32 337 /* The selector fields are 16-bit. */ 338 if (offset == offsetof(struct pt_regs, cs) || 339 offset == offsetof(struct pt_regs, ss) || 340 offset == offsetof(struct pt_regs, ds) || 341 offset == offsetof(struct pt_regs, es) || 342 offset == offsetof(struct pt_regs, fs) || 343 offset == offsetof(struct pt_regs, gs)) { 344 return *(u16 *)((unsigned long)regs + offset); 345 346 } 347 #endif 348 return *(unsigned long *)((unsigned long)regs + offset); 349 } 350 351 /** 352 * regs_within_kernel_stack() - check the address in the stack 353 * @regs: pt_regs which contains kernel stack pointer. 354 * @addr: address which is checked. 355 * 356 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 357 * If @addr is within the kernel stack, it returns true. If not, returns false. 358 */ 359 static inline int regs_within_kernel_stack(struct pt_regs *regs, 360 unsigned long addr) 361 { 362 return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1))); 363 } 364 365 /** 366 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack 367 * @regs: pt_regs which contains kernel stack pointer. 368 * @n: stack entry number. 369 * 370 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the 371 * kernel stack which is specified by @regs. If the @n th entry is NOT in 372 * the kernel stack, this returns NULL. 373 */ 374 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n) 375 { 376 unsigned long *addr = (unsigned long *)regs->sp; 377 378 addr += n; 379 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 380 return addr; 381 else 382 return NULL; 383 } 384 385 /* To avoid include hell, we can't include uaccess.h */ 386 extern long copy_from_kernel_nofault(void *dst, const void *src, size_t size); 387 388 /** 389 * regs_get_kernel_stack_nth() - get Nth entry of the stack 390 * @regs: pt_regs which contains kernel stack pointer. 391 * @n: stack entry number. 392 * 393 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 394 * is specified by @regs. If the @n th entry is NOT in the kernel stack 395 * this returns 0. 396 */ 397 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, 398 unsigned int n) 399 { 400 unsigned long *addr; 401 unsigned long val; 402 long ret; 403 404 addr = regs_get_kernel_stack_nth_addr(regs, n); 405 if (addr) { 406 ret = copy_from_kernel_nofault(&val, addr, sizeof(val)); 407 if (!ret) 408 return val; 409 } 410 return 0; 411 } 412 413 /** 414 * regs_get_kernel_argument() - get Nth function argument in kernel 415 * @regs: pt_regs of that context 416 * @n: function argument number (start from 0) 417 * 418 * regs_get_argument() returns @n th argument of the function call. 419 * Note that this chooses most probably assignment, in some case 420 * it can be incorrect. 421 * This is expected to be called from kprobes or ftrace with regs 422 * where the top of stack is the return address. 423 */ 424 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, 425 unsigned int n) 426 { 427 static const unsigned int argument_offs[] = { 428 #ifdef __i386__ 429 offsetof(struct pt_regs, ax), 430 offsetof(struct pt_regs, dx), 431 offsetof(struct pt_regs, cx), 432 #define NR_REG_ARGUMENTS 3 433 #else 434 offsetof(struct pt_regs, di), 435 offsetof(struct pt_regs, si), 436 offsetof(struct pt_regs, dx), 437 offsetof(struct pt_regs, cx), 438 offsetof(struct pt_regs, r8), 439 offsetof(struct pt_regs, r9), 440 #define NR_REG_ARGUMENTS 6 441 #endif 442 }; 443 444 if (n >= NR_REG_ARGUMENTS) { 445 n -= NR_REG_ARGUMENTS - 1; 446 return regs_get_kernel_stack_nth(regs, n); 447 } else 448 return regs_get_register(regs, argument_offs[n]); 449 } 450 451 #define arch_has_single_step() (1) 452 #ifdef CONFIG_X86_DEBUGCTLMSR 453 #define arch_has_block_step() (1) 454 #else 455 #define arch_has_block_step() (boot_cpu_data.x86 >= 6) 456 #endif 457 458 #define ARCH_HAS_USER_SINGLE_STEP_REPORT 459 460 struct user_desc; 461 extern int do_get_thread_area(struct task_struct *p, int idx, 462 struct user_desc __user *info); 463 extern int do_set_thread_area(struct task_struct *p, int idx, 464 struct user_desc __user *info, int can_allocate); 465 466 #ifdef CONFIG_X86_64 467 # define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t) 468 #else 469 # define do_set_thread_area_64(p, s, t) (0) 470 #endif 471 472 #endif /* !__ASSEMBLY__ */ 473 #endif /* _ASM_X86_PTRACE_H */ 474