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 #define profile_pc profile_pc 102 103 extern unsigned long 104 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs); 105 extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, 106 int error_code, int si_code); 107 108 109 static inline unsigned long regs_return_value(struct pt_regs *regs) 110 { 111 return regs->ax; 112 } 113 114 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) 115 { 116 regs->ax = rc; 117 } 118 119 /* 120 * user_mode(regs) determines whether a register set came from user 121 * mode. On x86_32, this is true if V8086 mode was enabled OR if the 122 * register set was from protected mode with RPL-3 CS value. This 123 * tricky test checks that with one comparison. 124 * 125 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need 126 * the extra check. 127 */ 128 static inline int user_mode(struct pt_regs *regs) 129 { 130 #ifdef CONFIG_X86_32 131 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; 132 #else 133 return !!(regs->cs & 3); 134 #endif 135 } 136 137 static inline int v8086_mode(struct pt_regs *regs) 138 { 139 #ifdef CONFIG_X86_32 140 return (regs->flags & X86_VM_MASK); 141 #else 142 return 0; /* No V86 mode support in long mode */ 143 #endif 144 } 145 146 static inline bool user_64bit_mode(struct pt_regs *regs) 147 { 148 #ifdef CONFIG_X86_64 149 #ifndef CONFIG_PARAVIRT_XXL 150 /* 151 * On non-paravirt systems, this is the only long mode CPL 3 152 * selector. We do not allow long mode selectors in the LDT. 153 */ 154 return regs->cs == __USER_CS; 155 #else 156 /* Headers are too twisted for this to go in paravirt.h. */ 157 return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs; 158 #endif 159 #else /* !CONFIG_X86_64 */ 160 return false; 161 #endif 162 } 163 164 #ifdef CONFIG_X86_64 165 #define current_user_stack_pointer() current_pt_regs()->sp 166 #define compat_user_stack_pointer() current_pt_regs()->sp 167 #endif 168 169 #ifdef CONFIG_X86_32 170 extern unsigned long kernel_stack_pointer(struct pt_regs *regs); 171 #else 172 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) 173 { 174 return regs->sp; 175 } 176 #endif 177 178 #define GET_IP(regs) ((regs)->ip) 179 #define GET_FP(regs) ((regs)->bp) 180 #define GET_USP(regs) ((regs)->sp) 181 182 #include <asm-generic/ptrace.h> 183 184 /* Query offset/name of register from its name/offset */ 185 extern int regs_query_register_offset(const char *name); 186 extern const char *regs_query_register_name(unsigned int offset); 187 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) 188 189 /** 190 * regs_get_register() - get register value from its offset 191 * @regs: pt_regs from which register value is gotten. 192 * @offset: offset number of the register. 193 * 194 * regs_get_register returns the value of a register. The @offset is the 195 * offset of the register in struct pt_regs address which specified by @regs. 196 * If @offset is bigger than MAX_REG_OFFSET, this returns 0. 197 */ 198 static inline unsigned long regs_get_register(struct pt_regs *regs, 199 unsigned int offset) 200 { 201 if (unlikely(offset > MAX_REG_OFFSET)) 202 return 0; 203 #ifdef CONFIG_X86_32 204 /* 205 * Traps from the kernel do not save sp and ss. 206 * Use the helper function to retrieve sp. 207 */ 208 if (offset == offsetof(struct pt_regs, sp) && 209 regs->cs == __KERNEL_CS) 210 return kernel_stack_pointer(regs); 211 212 /* The selector fields are 16-bit. */ 213 if (offset == offsetof(struct pt_regs, cs) || 214 offset == offsetof(struct pt_regs, ss) || 215 offset == offsetof(struct pt_regs, ds) || 216 offset == offsetof(struct pt_regs, es) || 217 offset == offsetof(struct pt_regs, fs) || 218 offset == offsetof(struct pt_regs, gs)) { 219 return *(u16 *)((unsigned long)regs + offset); 220 221 } 222 #endif 223 return *(unsigned long *)((unsigned long)regs + offset); 224 } 225 226 /** 227 * regs_within_kernel_stack() - check the address in the stack 228 * @regs: pt_regs which contains kernel stack pointer. 229 * @addr: address which is checked. 230 * 231 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s). 232 * If @addr is within the kernel stack, it returns true. If not, returns false. 233 */ 234 static inline int regs_within_kernel_stack(struct pt_regs *regs, 235 unsigned long addr) 236 { 237 return ((addr & ~(THREAD_SIZE - 1)) == 238 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))); 239 } 240 241 /** 242 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack 243 * @regs: pt_regs which contains kernel stack pointer. 244 * @n: stack entry number. 245 * 246 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the 247 * kernel stack which is specified by @regs. If the @n th entry is NOT in 248 * the kernel stack, this returns NULL. 249 */ 250 static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n) 251 { 252 unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs); 253 254 addr += n; 255 if (regs_within_kernel_stack(regs, (unsigned long)addr)) 256 return addr; 257 else 258 return NULL; 259 } 260 261 /* To avoid include hell, we can't include uaccess.h */ 262 extern long probe_kernel_read(void *dst, const void *src, size_t size); 263 264 /** 265 * regs_get_kernel_stack_nth() - get Nth entry of the stack 266 * @regs: pt_regs which contains kernel stack pointer. 267 * @n: stack entry number. 268 * 269 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which 270 * is specified by @regs. If the @n th entry is NOT in the kernel stack 271 * this returns 0. 272 */ 273 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, 274 unsigned int n) 275 { 276 unsigned long *addr; 277 unsigned long val; 278 long ret; 279 280 addr = regs_get_kernel_stack_nth_addr(regs, n); 281 if (addr) { 282 ret = probe_kernel_read(&val, addr, sizeof(val)); 283 if (!ret) 284 return val; 285 } 286 return 0; 287 } 288 289 /** 290 * regs_get_kernel_argument() - get Nth function argument in kernel 291 * @regs: pt_regs of that context 292 * @n: function argument number (start from 0) 293 * 294 * regs_get_argument() returns @n th argument of the function call. 295 * Note that this chooses most probably assignment, in some case 296 * it can be incorrect. 297 * This is expected to be called from kprobes or ftrace with regs 298 * where the top of stack is the return address. 299 */ 300 static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, 301 unsigned int n) 302 { 303 static const unsigned int argument_offs[] = { 304 #ifdef __i386__ 305 offsetof(struct pt_regs, ax), 306 offsetof(struct pt_regs, cx), 307 offsetof(struct pt_regs, dx), 308 #define NR_REG_ARGUMENTS 3 309 #else 310 offsetof(struct pt_regs, di), 311 offsetof(struct pt_regs, si), 312 offsetof(struct pt_regs, dx), 313 offsetof(struct pt_regs, cx), 314 offsetof(struct pt_regs, r8), 315 offsetof(struct pt_regs, r9), 316 #define NR_REG_ARGUMENTS 6 317 #endif 318 }; 319 320 if (n >= NR_REG_ARGUMENTS) { 321 n -= NR_REG_ARGUMENTS - 1; 322 return regs_get_kernel_stack_nth(regs, n); 323 } else 324 return regs_get_register(regs, argument_offs[n]); 325 } 326 327 #define arch_has_single_step() (1) 328 #ifdef CONFIG_X86_DEBUGCTLMSR 329 #define arch_has_block_step() (1) 330 #else 331 #define arch_has_block_step() (boot_cpu_data.x86 >= 6) 332 #endif 333 334 #define ARCH_HAS_USER_SINGLE_STEP_REPORT 335 336 /* 337 * When hitting ptrace_stop(), we cannot return using SYSRET because 338 * that does not restore the full CPU state, only a minimal set. The 339 * ptracer can change arbitrary register values, which is usually okay 340 * because the usual ptrace stops run off the signal delivery path which 341 * forces IRET; however, ptrace_event() stops happen in arbitrary places 342 * in the kernel and don't force IRET path. 343 * 344 * So force IRET path after a ptrace stop. 345 */ 346 #define arch_ptrace_stop_needed(code, info) \ 347 ({ \ 348 force_iret(); \ 349 false; \ 350 }) 351 352 struct user_desc; 353 extern int do_get_thread_area(struct task_struct *p, int idx, 354 struct user_desc __user *info); 355 extern int do_set_thread_area(struct task_struct *p, int idx, 356 struct user_desc __user *info, int can_allocate); 357 358 #endif /* !__ASSEMBLY__ */ 359 #endif /* _ASM_X86_PTRACE_H */ 360