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 #ifdef CONFIG_X86_64 163 #define current_user_stack_pointer() current_pt_regs()->sp 164 #define compat_user_stack_pointer() current_pt_regs()->sp 165 #endif 166 167 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) 168 { 169 return regs->sp; 170 } 171 172 static inline unsigned long instruction_pointer(struct pt_regs *regs) 173 { 174 return regs->ip; 175 } 176 177 static inline void instruction_pointer_set(struct pt_regs *regs, 178 unsigned long val) 179 { 180 regs->ip = val; 181 } 182 183 static inline unsigned long frame_pointer(struct pt_regs *regs) 184 { 185 return regs->bp; 186 } 187 188 static inline unsigned long user_stack_pointer(struct pt_regs *regs) 189 { 190 return regs->sp; 191 } 192 193 static inline void user_stack_pointer_set(struct pt_regs *regs, 194 unsigned long val) 195 { 196 regs->sp = val; 197 } 198 199 /* Query offset/name of register from its name/offset */ 200 extern int regs_query_register_offset(const char *name); 201 extern const char *regs_query_register_name(unsigned int offset); 202 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) 203 204 /** 205 * regs_get_register() - get register value from its offset 206 * @regs: pt_regs from which register value is gotten. 207 * @offset: offset number of the register. 208 * 209 * regs_get_register returns the value of a register. The @offset is the 210 * offset of the register in struct pt_regs address which specified by @regs. 211 * If @offset is bigger than MAX_REG_OFFSET, this returns 0. 212 */ 213 static inline unsigned long regs_get_register(struct pt_regs *regs, 214 unsigned int offset) 215 { 216 if (unlikely(offset > MAX_REG_OFFSET)) 217 return 0; 218 #ifdef CONFIG_X86_32 219 /* The selector fields are 16-bit. */ 220 if (offset == offsetof(struct pt_regs, cs) || 221 offset == offsetof(struct pt_regs, ss) || 222 offset == offsetof(struct pt_regs, ds) || 223 offset == offsetof(struct pt_regs, es) || 224 offset == offsetof(struct pt_regs, fs) || 225 offset == offsetof(struct pt_regs, gs)) { 226 return *(u16 *)((unsigned long)regs + offset); 227 228 } 229 #endif 230 return *(unsigned long *)((unsigned long)regs + offset); 231 } 232 233 /** 234 * regs_within_kernel_stack() - check the address in the stack 235 * @regs: pt_regs which contains kernel stack pointer. 236 * @addr: address which is checked. 237 * 238 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 239 * If @addr is within the kernel stack, it returns true. If not, returns false. 240 */ 241 static inline int regs_within_kernel_stack(struct pt_regs *regs, 242 unsigned long addr) 243 { 244 return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1))); 245 } 246 247 /** 248 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack 249 * @regs: pt_regs which contains kernel stack pointer. 250 * @n: stack entry number. 251 * 252 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the 253 * kernel stack which is specified by @regs. If the @n th entry is NOT in 254 * the kernel stack, this returns NULL. 255 */ 256 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n) 257 { 258 unsigned long *addr = (unsigned long *)regs->sp; 259 260 addr += n; 261 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 262 return addr; 263 else 264 return NULL; 265 } 266 267 /* To avoid include hell, we can't include uaccess.h */ 268 extern long probe_kernel_read(void *dst, const void *src, size_t size); 269 270 /** 271 * regs_get_kernel_stack_nth() - get Nth entry of the stack 272 * @regs: pt_regs which contains kernel stack pointer. 273 * @n: stack entry number. 274 * 275 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 276 * is specified by @regs. If the @n th entry is NOT in the kernel stack 277 * this returns 0. 278 */ 279 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, 280 unsigned int n) 281 { 282 unsigned long *addr; 283 unsigned long val; 284 long ret; 285 286 addr = regs_get_kernel_stack_nth_addr(regs, n); 287 if (addr) { 288 ret = probe_kernel_read(&val, addr, sizeof(val)); 289 if (!ret) 290 return val; 291 } 292 return 0; 293 } 294 295 /** 296 * regs_get_kernel_argument() - get Nth function argument in kernel 297 * @regs: pt_regs of that context 298 * @n: function argument number (start from 0) 299 * 300 * regs_get_argument() returns @n th argument of the function call. 301 * Note that this chooses most probably assignment, in some case 302 * it can be incorrect. 303 * This is expected to be called from kprobes or ftrace with regs 304 * where the top of stack is the return address. 305 */ 306 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, 307 unsigned int n) 308 { 309 static const unsigned int argument_offs[] = { 310 #ifdef __i386__ 311 offsetof(struct pt_regs, ax), 312 offsetof(struct pt_regs, cx), 313 offsetof(struct pt_regs, dx), 314 #define NR_REG_ARGUMENTS 3 315 #else 316 offsetof(struct pt_regs, di), 317 offsetof(struct pt_regs, si), 318 offsetof(struct pt_regs, dx), 319 offsetof(struct pt_regs, cx), 320 offsetof(struct pt_regs, r8), 321 offsetof(struct pt_regs, r9), 322 #define NR_REG_ARGUMENTS 6 323 #endif 324 }; 325 326 if (n >= NR_REG_ARGUMENTS) { 327 n -= NR_REG_ARGUMENTS - 1; 328 return regs_get_kernel_stack_nth(regs, n); 329 } else 330 return regs_get_register(regs, argument_offs[n]); 331 } 332 333 #define arch_has_single_step() (1) 334 #ifdef CONFIG_X86_DEBUGCTLMSR 335 #define arch_has_block_step() (1) 336 #else 337 #define arch_has_block_step() (boot_cpu_data.x86 >= 6) 338 #endif 339 340 #define ARCH_HAS_USER_SINGLE_STEP_REPORT 341 342 /* 343 * When hitting ptrace_stop(), we cannot return using SYSRET because 344 * that does not restore the full CPU state, only a minimal set. The 345 * ptracer can change arbitrary register values, which is usually okay 346 * because the usual ptrace stops run off the signal delivery path which 347 * forces IRET; however, ptrace_event() stops happen in arbitrary places 348 * in the kernel and don't force IRET path. 349 * 350 * So force IRET path after a ptrace stop. 351 */ 352 #define arch_ptrace_stop_needed(code, info) \ 353 ({ \ 354 force_iret(); \ 355 false; \ 356 }) 357 358 struct user_desc; 359 extern int do_get_thread_area(struct task_struct *p, int idx, 360 struct user_desc __user *info); 361 extern int do_set_thread_area(struct task_struct *p, int idx, 362 struct user_desc __user *info, int can_allocate); 363 364 #ifdef CONFIG_X86_64 365 # define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t) 366 #else 367 # define do_set_thread_area_64(p, s, t) (0) 368 #endif 369 370 #endif /* !__ASSEMBLY__ */ 371 #endif /* _ASM_X86_PTRACE_H */ 372