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 pt_regs { 60 /* 61 * C ABI says these regs are callee-preserved. They aren't saved on kernel entry 62 * unless syscall needs a complete, fully filled "struct pt_regs". 63 */ 64 unsigned long r15; 65 unsigned long r14; 66 unsigned long r13; 67 unsigned long r12; 68 unsigned long bp; 69 unsigned long bx; 70 /* These regs are callee-clobbered. Always saved on kernel entry. */ 71 unsigned long r11; 72 unsigned long r10; 73 unsigned long r9; 74 unsigned long r8; 75 unsigned long ax; 76 unsigned long cx; 77 unsigned long dx; 78 unsigned long si; 79 unsigned long di; 80 /* 81 * On syscall entry, this is syscall#. On CPU exception, this is error code. 82 * On hw interrupt, it's IRQ number: 83 */ 84 unsigned long orig_ax; 85 /* Return frame for iretq */ 86 unsigned long ip; 87 unsigned long cs; 88 unsigned long flags; 89 unsigned long sp; 90 unsigned long ss; 91 /* top of stack page */ 92 }; 93 94 #endif /* !__i386__ */ 95 96 #ifdef CONFIG_PARAVIRT 97 #include <asm/paravirt_types.h> 98 #endif 99 100 #include <asm/proto.h> 101 102 struct cpuinfo_x86; 103 struct task_struct; 104 105 extern unsigned long profile_pc(struct pt_regs *regs); 106 107 extern unsigned long 108 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs); 109 extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code); 110 111 112 static inline unsigned long regs_return_value(struct pt_regs *regs) 113 { 114 return regs->ax; 115 } 116 117 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) 118 { 119 regs->ax = rc; 120 } 121 122 /* 123 * user_mode(regs) determines whether a register set came from user 124 * mode. On x86_32, this is true if V8086 mode was enabled OR if the 125 * register set was from protected mode with RPL-3 CS value. This 126 * tricky test checks that with one comparison. 127 * 128 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need 129 * the extra check. 130 */ 131 static __always_inline int user_mode(struct pt_regs *regs) 132 { 133 #ifdef CONFIG_X86_32 134 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; 135 #else 136 return !!(regs->cs & 3); 137 #endif 138 } 139 140 static inline int v8086_mode(struct pt_regs *regs) 141 { 142 #ifdef CONFIG_X86_32 143 return (regs->flags & X86_VM_MASK); 144 #else 145 return 0; /* No V86 mode support in long mode */ 146 #endif 147 } 148 149 static inline bool user_64bit_mode(struct pt_regs *regs) 150 { 151 #ifdef CONFIG_X86_64 152 #ifndef CONFIG_PARAVIRT_XXL 153 /* 154 * On non-paravirt systems, this is the only long mode CPL 3 155 * selector. We do not allow long mode selectors in the LDT. 156 */ 157 return regs->cs == __USER_CS; 158 #else 159 /* Headers are too twisted for this to go in paravirt.h. */ 160 return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs; 161 #endif 162 #else /* !CONFIG_X86_64 */ 163 return false; 164 #endif 165 } 166 167 /* 168 * Determine whether the register set came from any context that is running in 169 * 64-bit mode. 170 */ 171 static inline bool any_64bit_mode(struct pt_regs *regs) 172 { 173 #ifdef CONFIG_X86_64 174 return !user_mode(regs) || user_64bit_mode(regs); 175 #else 176 return false; 177 #endif 178 } 179 180 #ifdef CONFIG_X86_64 181 #define current_user_stack_pointer() current_pt_regs()->sp 182 #define compat_user_stack_pointer() current_pt_regs()->sp 183 184 static inline bool ip_within_syscall_gap(struct pt_regs *regs) 185 { 186 bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 && 187 regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack); 188 189 #ifdef CONFIG_IA32_EMULATION 190 ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat && 191 regs->ip < (unsigned long)entry_SYSCALL_compat_safe_stack); 192 #endif 193 194 return ret; 195 } 196 #endif 197 198 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) 199 { 200 return regs->sp; 201 } 202 203 static inline unsigned long instruction_pointer(struct pt_regs *regs) 204 { 205 return regs->ip; 206 } 207 208 static inline void instruction_pointer_set(struct pt_regs *regs, 209 unsigned long val) 210 { 211 regs->ip = val; 212 } 213 214 static inline unsigned long frame_pointer(struct pt_regs *regs) 215 { 216 return regs->bp; 217 } 218 219 static inline unsigned long user_stack_pointer(struct pt_regs *regs) 220 { 221 return regs->sp; 222 } 223 224 static inline void user_stack_pointer_set(struct pt_regs *regs, 225 unsigned long val) 226 { 227 regs->sp = val; 228 } 229 230 static __always_inline bool regs_irqs_disabled(struct pt_regs *regs) 231 { 232 return !(regs->flags & X86_EFLAGS_IF); 233 } 234 235 /* Query offset/name of register from its name/offset */ 236 extern int regs_query_register_offset(const char *name); 237 extern const char *regs_query_register_name(unsigned int offset); 238 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) 239 240 /** 241 * regs_get_register() - get register value from its offset 242 * @regs: pt_regs from which register value is gotten. 243 * @offset: offset number of the register. 244 * 245 * regs_get_register returns the value of a register. The @offset is the 246 * offset of the register in struct pt_regs address which specified by @regs. 247 * If @offset is bigger than MAX_REG_OFFSET, this returns 0. 248 */ 249 static inline unsigned long regs_get_register(struct pt_regs *regs, 250 unsigned int offset) 251 { 252 if (unlikely(offset > MAX_REG_OFFSET)) 253 return 0; 254 #ifdef CONFIG_X86_32 255 /* The selector fields are 16-bit. */ 256 if (offset == offsetof(struct pt_regs, cs) || 257 offset == offsetof(struct pt_regs, ss) || 258 offset == offsetof(struct pt_regs, ds) || 259 offset == offsetof(struct pt_regs, es) || 260 offset == offsetof(struct pt_regs, fs) || 261 offset == offsetof(struct pt_regs, gs)) { 262 return *(u16 *)((unsigned long)regs + offset); 263 264 } 265 #endif 266 return *(unsigned long *)((unsigned long)regs + offset); 267 } 268 269 /** 270 * regs_within_kernel_stack() - check the address in the stack 271 * @regs: pt_regs which contains kernel stack pointer. 272 * @addr: address which is checked. 273 * 274 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 275 * If @addr is within the kernel stack, it returns true. If not, returns false. 276 */ 277 static inline int regs_within_kernel_stack(struct pt_regs *regs, 278 unsigned long addr) 279 { 280 return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1))); 281 } 282 283 /** 284 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack 285 * @regs: pt_regs which contains kernel stack pointer. 286 * @n: stack entry number. 287 * 288 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the 289 * kernel stack which is specified by @regs. If the @n th entry is NOT in 290 * the kernel stack, this returns NULL. 291 */ 292 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n) 293 { 294 unsigned long *addr = (unsigned long *)regs->sp; 295 296 addr += n; 297 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 298 return addr; 299 else 300 return NULL; 301 } 302 303 /* To avoid include hell, we can't include uaccess.h */ 304 extern long copy_from_kernel_nofault(void *dst, const void *src, size_t size); 305 306 /** 307 * regs_get_kernel_stack_nth() - get Nth entry of the stack 308 * @regs: pt_regs which contains kernel stack pointer. 309 * @n: stack entry number. 310 * 311 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 312 * is specified by @regs. If the @n th entry is NOT in the kernel stack 313 * this returns 0. 314 */ 315 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, 316 unsigned int n) 317 { 318 unsigned long *addr; 319 unsigned long val; 320 long ret; 321 322 addr = regs_get_kernel_stack_nth_addr(regs, n); 323 if (addr) { 324 ret = copy_from_kernel_nofault(&val, addr, sizeof(val)); 325 if (!ret) 326 return val; 327 } 328 return 0; 329 } 330 331 /** 332 * regs_get_kernel_argument() - get Nth function argument in kernel 333 * @regs: pt_regs of that context 334 * @n: function argument number (start from 0) 335 * 336 * regs_get_argument() returns @n th argument of the function call. 337 * Note that this chooses most probably assignment, in some case 338 * it can be incorrect. 339 * This is expected to be called from kprobes or ftrace with regs 340 * where the top of stack is the return address. 341 */ 342 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, 343 unsigned int n) 344 { 345 static const unsigned int argument_offs[] = { 346 #ifdef __i386__ 347 offsetof(struct pt_regs, ax), 348 offsetof(struct pt_regs, dx), 349 offsetof(struct pt_regs, cx), 350 #define NR_REG_ARGUMENTS 3 351 #else 352 offsetof(struct pt_regs, di), 353 offsetof(struct pt_regs, si), 354 offsetof(struct pt_regs, dx), 355 offsetof(struct pt_regs, cx), 356 offsetof(struct pt_regs, r8), 357 offsetof(struct pt_regs, r9), 358 #define NR_REG_ARGUMENTS 6 359 #endif 360 }; 361 362 if (n >= NR_REG_ARGUMENTS) { 363 n -= NR_REG_ARGUMENTS - 1; 364 return regs_get_kernel_stack_nth(regs, n); 365 } else 366 return regs_get_register(regs, argument_offs[n]); 367 } 368 369 #define arch_has_single_step() (1) 370 #ifdef CONFIG_X86_DEBUGCTLMSR 371 #define arch_has_block_step() (1) 372 #else 373 #define arch_has_block_step() (boot_cpu_data.x86 >= 6) 374 #endif 375 376 #define ARCH_HAS_USER_SINGLE_STEP_REPORT 377 378 struct user_desc; 379 extern int do_get_thread_area(struct task_struct *p, int idx, 380 struct user_desc __user *info); 381 extern int do_set_thread_area(struct task_struct *p, int idx, 382 struct user_desc __user *info, int can_allocate); 383 384 #ifdef CONFIG_X86_64 385 # define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t) 386 #else 387 # define do_set_thread_area_64(p, s, t) (0) 388 #endif 389 390 #endif /* !__ASSEMBLY__ */ 391 #endif /* _ASM_X86_PTRACE_H */ 392