LXR linux/arch/x86/include/asm/ptrace.h

   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
  12struct 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        /*
  41         * On interrupt, gs and __gsh store the vector number.  They never
  42         * store gs any more.
  43         */
  44        unsigned short gs;
  45        unsigned short __gsh;
  46        /* On interrupt, this is the error code. */
  47        unsigned long orig_ax;
  48        unsigned long ip;
  49        unsigned short cs;
  50        unsigned short __csh;
  51        unsigned long flags;
  52        unsigned long sp;
  53        unsigned short ss;
  54        unsigned short __ssh;
  55};
  56
  57#else /* __i386__ */
  58
  59struct pt_regs {
  60/*
  61 * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
  62 * unless syscall needs a complete, fully filled "struct pt_regs".
  63 */
  64        unsigned long r15;
  65        unsigned long r14;
  66        unsigned long r13;
  67        unsigned long r12;
  68        unsigned long bp;
  69        unsigned long bx;
  70/* These regs are callee-clobbered. Always saved on kernel entry. */
  71        unsigned long r11;
  72        unsigned long r10;
  73        unsigned long r9;
  74        unsigned long r8;
  75        unsigned long ax;
  76        unsigned long cx;
  77        unsigned long dx;
  78        unsigned long si;
  79        unsigned long di;
  80/*
  81 * On syscall entry, this is syscall#. On CPU exception, this is error code.
  82 * On hw interrupt, it's IRQ number:
  83 */
  84        unsigned long orig_ax;
  85/* Return frame for iretq */
  86        unsigned long ip;
  87        unsigned long cs;
  88        unsigned long flags;
  89        unsigned long sp;
  90        unsigned long ss;
  91/* top of stack page */
  92};
  93
  94#endif /* !__i386__ */
  95
  96#ifdef CONFIG_PARAVIRT
  97#include <asm/paravirt_types.h>
  98#endif
  99
 100#include <asm/proto.h>
 101
 102struct cpuinfo_x86;
 103struct task_struct;
 104
 105extern unsigned long profile_pc(struct pt_regs *regs);
 106
 107extern unsigned long
 108convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
 109extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code);
 110
 111
 112static inline unsigned long regs_return_value(struct pt_regs *regs)
 113{
 114        return regs->ax;
 115}
 116
 117static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
 118{
 119        regs->ax = rc;
 120}
 121
 122/*
 123 * user_mode(regs) determines whether a register set came from user
 124 * mode.  On x86_32, this is true if V8086 mode was enabled OR if the
 125 * register set was from protected mode with RPL-3 CS value.  This
 126 * tricky test checks that with one comparison.
 127 *
 128 * On x86_64, vm86 mode is mercifully nonexistent, and we don't need
 129 * the extra check.
 130 */
 131static __always_inline int user_mode(struct pt_regs *regs)
 132{
 133#ifdef CONFIG_X86_32
 134        return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL;
 135#else
 136        return !!(regs->cs & 3);
 137#endif
 138}
 139
 140static inline int v8086_mode(struct pt_regs *regs)
 141{
 142#ifdef CONFIG_X86_32
 143        return (regs->flags & X86_VM_MASK);
 144#else
 145        return 0;       /* No V86 mode support in long mode */
 146#endif
 147}
 148
 149static inline bool user_64bit_mode(struct pt_regs *regs)
 150{
 151#ifdef CONFIG_X86_64
 152#ifndef CONFIG_PARAVIRT_XXL
 153        /*
 154         * On non-paravirt systems, this is the only long mode CPL 3
 155         * selector.  We do not allow long mode selectors in the LDT.
 156         */
 157        return regs->cs == __USER_CS;
 158#else
 159        /* Headers are too twisted for this to go in paravirt.h. */
 160        return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;
 161#endif
 162#else /* !CONFIG_X86_64 */
 163        return false;
 164#endif
 165}
 166
 167/*
 168 * Determine whether the register set came from any context that is running in
 169 * 64-bit mode.
 170 */
 171static inline bool any_64bit_mode(struct pt_regs *regs)
 172{
 173#ifdef CONFIG_X86_64
 174        return !user_mode(regs) || user_64bit_mode(regs);
 175#else
 176        return false;
 177#endif
 178}
 179
 180#ifdef CONFIG_X86_64
 181#define current_user_stack_pointer()    current_pt_regs()->sp
 182#define compat_user_stack_pointer()     current_pt_regs()->sp
 183
 184static __always_inline bool ip_within_syscall_gap(struct pt_regs *regs)
 185{
 186        bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
 187                    regs->ip <  (unsigned long)entry_SYSCALL_64_safe_stack);
 188
 189#ifdef CONFIG_IA32_EMULATION
 190        ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat &&
 191                      regs->ip <  (unsigned long)entry_SYSCALL_compat_safe_stack);
 192#endif
 193
 194        return ret;
 195}
 196#endif
 197
 198static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 199{
 200        return regs->sp;
 201}
 202
 203static inline unsigned long instruction_pointer(struct pt_regs *regs)
 204{
 205        return regs->ip;
 206}
 207
 208static inline void instruction_pointer_set(struct pt_regs *regs,
 209                unsigned long val)
 210{
 211        regs->ip = val;
 212}
 213
 214static inline unsigned long frame_pointer(struct pt_regs *regs)
 215{
 216        return regs->bp;
 217}
 218
 219static inline unsigned long user_stack_pointer(struct pt_regs *regs)
 220{
 221        return regs->sp;
 222}
 223
 224static inline void user_stack_pointer_set(struct pt_regs *regs,
 225                unsigned long val)
 226{
 227        regs->sp = val;
 228}
 229
 230static __always_inline bool regs_irqs_disabled(struct pt_regs *regs)
 231{
 232        return !(regs->flags & X86_EFLAGS_IF);
 233}
 234
 235/* Query offset/name of register from its name/offset */
 236extern int regs_query_register_offset(const char *name);
 237extern const char *regs_query_register_name(unsigned int offset);
 238#define MAX_REG_OFFSET (offsetof(struct pt_regs, ss))
 239
 240/**
 241 * regs_get_register() - get register value from its offset
 242 * @regs:       pt_regs from which register value is gotten.
 243 * @offset:     offset number of the register.
 244 *
 245 * regs_get_register returns the value of a register. The @offset is the
 246 * offset of the register in struct pt_regs address which specified by @regs.
 247 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
 248 */
 249static inline unsigned long regs_get_register(struct pt_regs *regs,
 250                                              unsigned int offset)
 251{
 252        if (unlikely(offset > MAX_REG_OFFSET))
 253                return 0;
 254#ifdef CONFIG_X86_32
 255        /* The selector fields are 16-bit. */
 256        if (offset == offsetof(struct pt_regs, cs) ||
 257            offset == offsetof(struct pt_regs, ss) ||
 258            offset == offsetof(struct pt_regs, ds) ||
 259            offset == offsetof(struct pt_regs, es) ||
 260            offset == offsetof(struct pt_regs, fs) ||
 261            offset == offsetof(struct pt_regs, gs)) {
 262                return *(u16 *)((unsigned long)regs + offset);
 263
 264        }
 265#endif
 266        return *(unsigned long *)((unsigned long)regs + offset);
 267}
 268
 269/**
 270 * regs_within_kernel_stack() - check the address in the stack
 271 * @regs:       pt_regs which contains kernel stack pointer.
 272 * @addr:       address which is checked.
 273 *
 274 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 275 * If @addr is within the kernel stack, it returns true. If not, returns false.
 276 */
 277static inline int regs_within_kernel_stack(struct pt_regs *regs,
 278                                           unsigned long addr)
 279{
 280        return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1)));
 281}
 282
 283/**
 284 * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack
 285 * @regs:       pt_regs which contains kernel stack pointer.
 286 * @n:          stack entry number.
 287 *
 288 * regs_get_kernel_stack_nth() returns the address of the @n th entry of the
 289 * kernel stack which is specified by @regs. If the @n th entry is NOT in
 290 * the kernel stack, this returns NULL.
 291 */
 292static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n)
 293{
 294        unsigned long *addr = (unsigned long *)regs->sp;
 295
 296        addr += n;
 297        if (regs_within_kernel_stack(regs, (unsigned long)addr))
 298                return addr;
 299        else
 300                return NULL;
 301}
 302
 303/* To avoid include hell, we can't include uaccess.h */
 304extern long copy_from_kernel_nofault(void *dst, const void *src, size_t size);
 305
 306/**
 307 * regs_get_kernel_stack_nth() - get Nth entry of the stack
 308 * @regs:       pt_regs which contains kernel stack pointer.
 309 * @n:          stack entry number.
 310 *
 311 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 312 * is specified by @regs. If the @n th entry is NOT in the kernel stack
 313 * this returns 0.
 314 */
 315static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
 316                                                      unsigned int n)
 317{
 318        unsigned long *addr;
 319        unsigned long val;
 320        long ret;
 321
 322        addr = regs_get_kernel_stack_nth_addr(regs, n);
 323        if (addr) {
 324                ret = copy_from_kernel_nofault(&val, addr, sizeof(val));
 325                if (!ret)
 326                        return val;
 327        }
 328        return 0;
 329}
 330
 331/**
 332 * regs_get_kernel_argument() - get Nth function argument in kernel
 333 * @regs:       pt_regs of that context
 334 * @n:          function argument number (start from 0)
 335 *
 336 * regs_get_argument() returns @n th argument of the function call.
 337 * Note that this chooses most probably assignment, in some case
 338 * it can be incorrect.
 339 * This is expected to be called from kprobes or ftrace with regs
 340 * where the top of stack is the return address.
 341 */
 342static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
 343                                                     unsigned int n)
 344{
 345        static const unsigned int argument_offs[] = {
 346#ifdef __i386__
 347                offsetof(struct pt_regs, ax),
 348                offsetof(struct pt_regs, dx),
 349                offsetof(struct pt_regs, cx),
 350#define NR_REG_ARGUMENTS 3
 351#else
 352                offsetof(struct pt_regs, di),
 353                offsetof(struct pt_regs, si),
 354                offsetof(struct pt_regs, dx),
 355                offsetof(struct pt_regs, cx),
 356                offsetof(struct pt_regs, r8),
 357                offsetof(struct pt_regs, r9),
 358#define NR_REG_ARGUMENTS 6
 359#endif
 360        };
 361
 362        if (n >= NR_REG_ARGUMENTS) {
 363                n -= NR_REG_ARGUMENTS - 1;
 364                return regs_get_kernel_stack_nth(regs, n);
 365        } else
 366                return regs_get_register(regs, argument_offs[n]);
 367}
 368
 369#define arch_has_single_step()  (1)
 370#ifdef CONFIG_X86_DEBUGCTLMSR
 371#define arch_has_block_step()   (1)
 372#else
 373#define arch_has_block_step()   (boot_cpu_data.x86 >= 6)
 374#endif
 375
 376#define ARCH_HAS_USER_SINGLE_STEP_REPORT
 377
 378struct user_desc;
 379extern int do_get_thread_area(struct task_struct *p, int idx,
 380                              struct user_desc __user *info);
 381extern int do_set_thread_area(struct task_struct *p, int idx,
 382                              struct user_desc __user *info, int can_allocate);
 383
 384#ifdef CONFIG_X86_64
 385# define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t)
 386#else
 387# define do_set_thread_area_64(p, s, t) (0)
 388#endif
 389
 390#endif /* !__ASSEMBLY__ */
 391#endif /* _ASM_X86_PTRACE_H */
 392