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 /* On interrupt, gs and __gsh store the vector number. */ 41 unsigned short gs; 42 unsigned short __gsh; 43 /* On interrupt, this is the error code. */ 44 unsigned long orig_ax; 45 unsigned long ip; 46 unsigned short cs; 47 unsigned short __csh; 48 unsigned long flags; 49 unsigned long sp; 50 unsigned short ss; 51 unsigned short __ssh; 52 }; 53 54 #else /* __i386__ */ 55 56 struct pt_regs { 57 /* 58 * C ABI says these regs are callee-preserved. They aren't saved on kernel entry 59 * unless syscall needs a complete, fully filled "struct pt_regs". 60 */ 61 unsigned long r15; 62 unsigned long r14; 63 unsigned long r13; 64 unsigned long r12; 65 unsigned long bp; 66 unsigned long bx; 67 /* These regs are callee-clobbered. Always saved on kernel entry. */ 68 unsigned long r11; 69 unsigned long r10; 70 unsigned long r9; 71 unsigned long r8; 72 unsigned long ax; 73 unsigned long cx; 74 unsigned long dx; 75 unsigned long si; 76 unsigned long di; 77 /* 78 * On syscall entry, this is syscall#. On CPU exception, this is error code. 79 * On hw interrupt, it's IRQ number: 80 */ 81 unsigned long orig_ax; 82 /* Return frame for iretq */ 83 unsigned long ip; 84 unsigned long cs; 85 unsigned long flags; 86 unsigned long sp; 87 unsigned long ss; 88 /* top of stack page */ 89 }; 90 91 #endif /* !__i386__ */ 92 93 #ifdef CONFIG_PARAVIRT 94 #include <asm/paravirt_types.h> 95 #endif 96 97 struct cpuinfo_x86; 98 struct task_struct; 99 100 extern unsigned long profile_pc(struct pt_regs *regs); 101 102 extern unsigned long 103 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs); 104 extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code); 105 106 107 static inline unsigned long regs_return_value(struct pt_regs *regs) 108 { 109 return regs->ax; 110 } 111 112 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) 113 { 114 regs->ax = rc; 115 } 116 117 /* 118 * user_mode(regs) determines whether a register set came from user 119 * mode. On x86_32, this is true if V8086 mode was enabled OR if the 120 * register set was from protected mode with RPL-3 CS value. This 121 * tricky test checks that with one comparison. 122 * 123 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need 124 * the extra check. 125 */ 126 static inline int user_mode(struct pt_regs *regs) 127 { 128 #ifdef CONFIG_X86_32 129 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; 130 #else 131 return !!(regs->cs & 3); 132 #endif 133 } 134 135 static inline int v8086_mode(struct pt_regs *regs) 136 { 137 #ifdef CONFIG_X86_32 138 return (regs->flags & X86_VM_MASK); 139 #else 140 return 0; /* No V86 mode support in long mode */ 141 #endif 142 } 143 144 static inline bool user_64bit_mode(struct pt_regs *regs) 145 { 146 #ifdef CONFIG_X86_64 147 #ifndef CONFIG_PARAVIRT_XXL 148 /* 149 * On non-paravirt systems, this is the only long mode CPL 3 150 * selector. We do not allow long mode selectors in the LDT. 151 */ 152 return regs->cs == __USER_CS; 153 #else 154 /* Headers are too twisted for this to go in paravirt.h. */ 155 return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs; 156 #endif 157 #else /* !CONFIG_X86_64 */ 158 return false; 159 #endif 160 } 161 162 /* 163 * Determine whether the register set came from any context that is running in 164 * 64-bit mode. 165 */ 166 static inline bool any_64bit_mode(struct pt_regs *regs) 167 { 168 #ifdef CONFIG_X86_64 169 return !user_mode(regs) || user_64bit_mode(regs); 170 #else 171 return false; 172 #endif 173 } 174 175 #ifdef CONFIG_X86_64 176 #define current_user_stack_pointer() current_pt_regs()->sp 177 #define compat_user_stack_pointer() current_pt_regs()->sp 178 #endif 179 180 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) 181 { 182 return regs->sp; 183 } 184 185 static inline unsigned long instruction_pointer(struct pt_regs *regs) 186 { 187 return regs->ip; 188 } 189 190 static inline void instruction_pointer_set(struct pt_regs *regs, 191 unsigned long val) 192 { 193 regs->ip = val; 194 } 195 196 static inline unsigned long frame_pointer(struct pt_regs *regs) 197 { 198 return regs->bp; 199 } 200 201 static inline unsigned long user_stack_pointer(struct pt_regs *regs) 202 { 203 return regs->sp; 204 } 205 206 static inline void user_stack_pointer_set(struct pt_regs *regs, 207 unsigned long val) 208 { 209 regs->sp = val; 210 } 211 212 /* Query offset/name of register from its name/offset */ 213 extern int regs_query_register_offset(const char *name); 214 extern const char *regs_query_register_name(unsigned int offset); 215 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) 216 217 /** 218 * regs_get_register() - get register value from its offset 219 * @regs: pt_regs from which register value is gotten. 220 * @offset: offset number of the register. 221 * 222 * regs_get_register returns the value of a register. The @offset is the 223 * offset of the register in struct pt_regs address which specified by @regs. 224 * If @offset is bigger than MAX_REG_OFFSET, this returns 0. 225 */ 226 static inline unsigned long regs_get_register(struct pt_regs *regs, 227 unsigned int offset) 228 { 229 if (unlikely(offset > MAX_REG_OFFSET)) 230 return 0; 231 #ifdef CONFIG_X86_32 232 /* The selector fields are 16-bit. */ 233 if (offset == offsetof(struct pt_regs, cs) || 234 offset == offsetof(struct pt_regs, ss) || 235 offset == offsetof(struct pt_regs, ds) || 236 offset == offsetof(struct pt_regs, es) || 237 offset == offsetof(struct pt_regs, fs) || 238 offset == offsetof(struct pt_regs, gs)) { 239 return *(u16 *)((unsigned long)regs + offset); 240 241 } 242 #endif 243 return *(unsigned long *)((unsigned long)regs + offset); 244 } 245 246 /** 247 * regs_within_kernel_stack() - check the address in the stack 248 * @regs: pt_regs which contains kernel stack pointer. 249 * @addr: address which is checked. 250 * 251 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 252 * If @addr is within the kernel stack, it returns true. If not, returns false. 253 */ 254 static inline int regs_within_kernel_stack(struct pt_regs *regs, 255 unsigned long addr) 256 { 257 return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1))); 258 } 259 260 /** 261 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack 262 * @regs: pt_regs which contains kernel stack pointer. 263 * @n: stack entry number. 264 * 265 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the 266 * kernel stack which is specified by @regs. If the @n th entry is NOT in 267 * the kernel stack, this returns NULL. 268 */ 269 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n) 270 { 271 unsigned long *addr = (unsigned long *)regs->sp; 272 273 addr += n; 274 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 275 return addr; 276 else 277 return NULL; 278 } 279 280 /* To avoid include hell, we can't include uaccess.h */ 281 extern long probe_kernel_read(void *dst, const void *src, size_t size); 282 283 /** 284 * regs_get_kernel_stack_nth() - get Nth entry of the stack 285 * @regs: pt_regs which contains kernel stack pointer. 286 * @n: stack entry number. 287 * 288 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 289 * is specified by @regs. If the @n th entry is NOT in the kernel stack 290 * this returns 0. 291 */ 292 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, 293 unsigned int n) 294 { 295 unsigned long *addr; 296 unsigned long val; 297 long ret; 298 299 addr = regs_get_kernel_stack_nth_addr(regs, n); 300 if (addr) { 301 ret = probe_kernel_read(&val, addr, sizeof(val)); 302 if (!ret) 303 return val; 304 } 305 return 0; 306 } 307 308 /** 309 * regs_get_kernel_argument() - get Nth function argument in kernel 310 * @regs: pt_regs of that context 311 * @n: function argument number (start from 0) 312 * 313 * regs_get_argument() returns @n th argument of the function call. 314 * Note that this chooses most probably assignment, in some case 315 * it can be incorrect. 316 * This is expected to be called from kprobes or ftrace with regs 317 * where the top of stack is the return address. 318 */ 319 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, 320 unsigned int n) 321 { 322 static const unsigned int argument_offs[] = { 323 #ifdef __i386__ 324 offsetof(struct pt_regs, ax), 325 offsetof(struct pt_regs, cx), 326 offsetof(struct pt_regs, dx), 327 #define NR_REG_ARGUMENTS 3 328 #else 329 offsetof(struct pt_regs, di), 330 offsetof(struct pt_regs, si), 331 offsetof(struct pt_regs, dx), 332 offsetof(struct pt_regs, cx), 333 offsetof(struct pt_regs, r8), 334 offsetof(struct pt_regs, r9), 335 #define NR_REG_ARGUMENTS 6 336 #endif 337 }; 338 339 if (n >= NR_REG_ARGUMENTS) { 340 n -= NR_REG_ARGUMENTS - 1; 341 return regs_get_kernel_stack_nth(regs, n); 342 } else 343 return regs_get_register(regs, argument_offs[n]); 344 } 345 346 #define arch_has_single_step() (1) 347 #ifdef CONFIG_X86_DEBUGCTLMSR 348 #define arch_has_block_step() (1) 349 #else 350 #define arch_has_block_step() (boot_cpu_data.x86 >= 6) 351 #endif 352 353 #define ARCH_HAS_USER_SINGLE_STEP_REPORT 354 355 struct user_desc; 356 extern int do_get_thread_area(struct task_struct *p, int idx, 357 struct user_desc __user *info); 358 extern int do_set_thread_area(struct task_struct *p, int idx, 359 struct user_desc __user *info, int can_allocate); 360 361 #ifdef CONFIG_X86_64 362 # define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t) 363 #else 364 # define do_set_thread_area_64(p, s, t) (0) 365 #endif 366 367 #endif /* !__ASSEMBLY__ */ 368 #endif /* _ASM_X86_PTRACE_H */ 369