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