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
  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         unsigned short gs;
  41         unsigned short __gsh;
  42         unsigned long orig_ax;
  43         unsigned long ip;
  44         unsigned short cs;
  45         unsigned short __csh;
  46         unsigned long flags;
  47         unsigned long sp;
  48         unsigned short ss;
  49         unsigned short __ssh;
  50 };
  51
  52 #else /* __i386__ */
  53
  54 struct pt_regs {
  55 /*
  56  * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
  57  * unless syscall needs a complete, fully filled "struct pt_regs".
  58  */
  59         unsigned long r15;
  60         unsigned long r14;
  61         unsigned long r13;
  62         unsigned long r12;
  63         unsigned long bp;
  64         unsigned long bx;
  65 /* These regs are callee-clobbered. Always saved on kernel entry. */
  66         unsigned long r11;
  67         unsigned long r10;
  68         unsigned long r9;
  69         unsigned long r8;
  70         unsigned long ax;
  71         unsigned long cx;
  72         unsigned long dx;
  73         unsigned long si;
  74         unsigned long di;
  75 /*
  76  * On syscall entry, this is syscall#. On CPU exception, this is error code.
  77  * On hw interrupt, it's IRQ number:
  78  */
  79         unsigned long orig_ax;
  80 /* Return frame for iretq */
  81         unsigned long ip;
  82         unsigned long cs;
  83         unsigned long flags;
  84         unsigned long sp;
  85         unsigned long ss;
  86 /* top of stack page */
  87 };
  88
  89 #endif /* !__i386__ */
  90
  91 #ifdef CONFIG_PARAVIRT
  92 #include <asm/paravirt_types.h>
  93 #endif
  94
  95 struct cpuinfo_x86;
  96 struct task_struct;
  97
  98 extern unsigned long profile_pc(struct pt_regs *regs);
  99 #define profile_pc profile_pc
 100
 101 extern unsigned long
 102 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
 103 extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
 104                          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
 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 #ifdef CONFIG_X86_32
 168 extern unsigned long kernel_stack_pointer(struct pt_regs *regs);
 169 #else
 170 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 171 {
 172         return regs->sp;
 173 }
 174 #endif
 175
 176 #define GET_IP(regs) ((regs)->ip)
 177 #define GET_FP(regs) ((regs)->bp)
 178 #define GET_USP(regs) ((regs)->sp)
 179
 180 #include <asm-generic/ptrace.h>
 181
 182 /* Query offset/name of register from its name/offset */
 183 extern int regs_query_register_offset(const char *name);
 184 extern const char *regs_query_register_name(unsigned int offset);
 185 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ss))
 186
 187 /**
 188  * regs_get_register() - get register value from its offset
 189  * @regs:       pt_regs from which register value is gotten.
 190  * @offset:     offset number of the register.
 191  *
 192  * regs_get_register returns the value of a register. The @offset is the
 193  * offset of the register in struct pt_regs address which specified by @regs.
 194  * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
 195  */
 196 static inline unsigned long regs_get_register(struct pt_regs *regs,
 197                                               unsigned int offset)
 198 {
 199         if (unlikely(offset > MAX_REG_OFFSET))
 200                 return 0;
 201 #ifdef CONFIG_X86_32
 202         /*
 203          * Traps from the kernel do not save sp and ss.
 204          * Use the helper function to retrieve sp.
 205          */
 206         if (offset == offsetof(struct pt_regs, sp) &&
 207             regs->cs == __KERNEL_CS)
 208                 return kernel_stack_pointer(regs);
 209
 210         /* The selector fields are 16-bit. */
 211         if (offset == offsetof(struct pt_regs, cs) ||
 212             offset == offsetof(struct pt_regs, ss) ||
 213             offset == offsetof(struct pt_regs, ds) ||
 214             offset == offsetof(struct pt_regs, es) ||
 215             offset == offsetof(struct pt_regs, fs) ||
 216             offset == offsetof(struct pt_regs, gs)) {
 217                 return *(u16 *)((unsigned long)regs + offset);
 218
 219         }
 220 #endif
 221         return *(unsigned long *)((unsigned long)regs + offset);
 222 }
 223
 224 /**
 225  * regs_within_kernel_stack() - check the address in the stack
 226  * @regs:       pt_regs which contains kernel stack pointer.
 227  * @addr:       address which is checked.
 228  *
 229  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 230  * If @addr is within the kernel stack, it returns true. If not, returns false.
 231  */
 232 static inline int regs_within_kernel_stack(struct pt_regs *regs,
 233                                            unsigned long addr)
 234 {
 235         return ((addr & ~(THREAD_SIZE - 1))  ==
 236                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 237 }
 238
 239 /**
 240  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 241  * @regs:       pt_regs which contains kernel stack pointer.
 242  * @n:          stack entry number.
 243  *
 244  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 245  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 246  * this returns 0.
 247  */
 248 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
 249                                                       unsigned int n)
 250 {
 251         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 252         addr += n;
 253         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 254                 return *addr;
 255         else
 256                 return 0;
 257 }
 258
 259 #define arch_has_single_step()  (1)
 260 #ifdef CONFIG_X86_DEBUGCTLMSR
 261 #define arch_has_block_step()   (1)
 262 #else
 263 #define arch_has_block_step()   (boot_cpu_data.x86 >= 6)
 264 #endif
 265
 266 #define ARCH_HAS_USER_SINGLE_STEP_INFO
 267
 268 /*
 269  * When hitting ptrace_stop(), we cannot return using SYSRET because
 270  * that does not restore the full CPU state, only a minimal set.  The
 271  * ptracer can change arbitrary register values, which is usually okay
 272  * because the usual ptrace stops run off the signal delivery path which
 273  * forces IRET; however, ptrace_event() stops happen in arbitrary places
 274  * in the kernel and don't force IRET path.
 275  *
 276  * So force IRET path after a ptrace stop.
 277  */
 278 #define arch_ptrace_stop_needed(code, info)                             \
 279 ({                                                                      \
 280         force_iret();                                                   \
 281         false;                                                          \
 282 })
 283
 284 struct user_desc;
 285 extern int do_get_thread_area(struct task_struct *p, int idx,
 286                               struct user_desc __user *info);
 287 extern int do_set_thread_area(struct task_struct *p, int idx,
 288                               struct user_desc __user *info, int can_allocate);
 289
 290 #endif /* !__ASSEMBLY__ */
 291 #endif /* _ASM_X86_PTRACE_H */