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 __always_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 static __always_inline bool regs_irqs_disabled(struct pt_regs *regs) 213 { 214 return !(regs->flags & X86_EFLAGS_IF); 215 } 216 217 /* Query offset/name of register from its name/offset */ 218 extern int regs_query_register_offset(const char *name); 219 extern const char *regs_query_register_name(unsigned int offset); 220 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) 221 222 /** 223 * regs_get_register() - get register value from its offset 224 * @regs: pt_regs from which register value is gotten. 225 * @offset: offset number of the register. 226 * 227 * regs_get_register returns the value of a register. The @offset is the 228 * offset of the register in struct pt_regs address which specified by @regs. 229 * If @offset is bigger than MAX_REG_OFFSET, this returns 0. 230 */ 231 static inline unsigned long regs_get_register(struct pt_regs *regs, 232 unsigned int offset) 233 { 234 if (unlikely(offset > MAX_REG_OFFSET)) 235 return 0; 236 #ifdef CONFIG_X86_32 237 /* The selector fields are 16-bit. */ 238 if (offset == offsetof(struct pt_regs, cs) || 239 offset == offsetof(struct pt_regs, ss) || 240 offset == offsetof(struct pt_regs, ds) || 241 offset == offsetof(struct pt_regs, es) || 242 offset == offsetof(struct pt_regs, fs) || 243 offset == offsetof(struct pt_regs, gs)) { 244 return *(u16 *)((unsigned long)regs + offset); 245 246 } 247 #endif 248 return *(unsigned long *)((unsigned long)regs + offset); 249 } 250 251 /** 252 * regs_within_kernel_stack() - check the address in the stack 253 * @regs: pt_regs which contains kernel stack pointer. 254 * @addr: address which is checked. 255 * 256 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 257 * If @addr is within the kernel stack, it returns true. If not, returns false. 258 */ 259 static inline int regs_within_kernel_stack(struct pt_regs *regs, 260 unsigned long addr) 261 { 262 return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1))); 263 } 264 265 /** 266 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack 267 * @regs: pt_regs which contains kernel stack pointer. 268 * @n: stack entry number. 269 * 270 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the 271 * kernel stack which is specified by @regs. If the @n th entry is NOT in 272 * the kernel stack, this returns NULL. 273 */ 274 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n) 275 { 276 unsigned long *addr = (unsigned long *)regs->sp; 277 278 addr += n; 279 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 280 return addr; 281 else 282 return NULL; 283 } 284 285 /* To avoid include hell, we can't include uaccess.h */ 286 extern long copy_from_kernel_nofault(void *dst, const void *src, size_t size); 287 288 /** 289 * regs_get_kernel_stack_nth() - get Nth entry of the stack 290 * @regs: pt_regs which contains kernel stack pointer. 291 * @n: stack entry number. 292 * 293 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 294 * is specified by @regs. If the @n th entry is NOT in the kernel stack 295 * this returns 0. 296 */ 297 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, 298 unsigned int n) 299 { 300 unsigned long *addr; 301 unsigned long val; 302 long ret; 303 304 addr = regs_get_kernel_stack_nth_addr(regs, n); 305 if (addr) { 306 ret = copy_from_kernel_nofault(&val, addr, sizeof(val)); 307 if (!ret) 308 return val; 309 } 310 return 0; 311 } 312 313 /** 314 * regs_get_kernel_argument() - get Nth function argument in kernel 315 * @regs: pt_regs of that context 316 * @n: function argument number (start from 0) 317 * 318 * regs_get_argument() returns @n th argument of the function call. 319 * Note that this chooses most probably assignment, in some case 320 * it can be incorrect. 321 * This is expected to be called from kprobes or ftrace with regs 322 * where the top of stack is the return address. 323 */ 324 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, 325 unsigned int n) 326 { 327 static const unsigned int argument_offs[] = { 328 #ifdef __i386__ 329 offsetof(struct pt_regs, ax), 330 offsetof(struct pt_regs, cx), 331 offsetof(struct pt_regs, dx), 332 #define NR_REG_ARGUMENTS 3 333 #else 334 offsetof(struct pt_regs, di), 335 offsetof(struct pt_regs, si), 336 offsetof(struct pt_regs, dx), 337 offsetof(struct pt_regs, cx), 338 offsetof(struct pt_regs, r8), 339 offsetof(struct pt_regs, r9), 340 #define NR_REG_ARGUMENTS 6 341 #endif 342 }; 343 344 if (n >= NR_REG_ARGUMENTS) { 345 n -= NR_REG_ARGUMENTS - 1; 346 return regs_get_kernel_stack_nth(regs, n); 347 } else 348 return regs_get_register(regs, argument_offs[n]); 349 } 350 351 #define arch_has_single_step() (1) 352 #ifdef CONFIG_X86_DEBUGCTLMSR 353 #define arch_has_block_step() (1) 354 #else 355 #define arch_has_block_step() (boot_cpu_data.x86 >= 6) 356 #endif 357 358 #define ARCH_HAS_USER_SINGLE_STEP_REPORT 359 360 struct user_desc; 361 extern int do_get_thread_area(struct task_struct *p, int idx, 362 struct user_desc __user *info); 363 extern int do_set_thread_area(struct task_struct *p, int idx, 364 struct user_desc __user *info, int can_allocate); 365 366 #ifdef CONFIG_X86_64 367 # define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t) 368 #else 369 # define do_set_thread_area_64(p, s, t) (0) 370 #endif 371 372 #endif /* !__ASSEMBLY__ */ 373 #endif /* _ASM_X86_PTRACE_H */ 374