arch/powerpc/include/asm/ptrace.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * Copyright (C) 2001 PPC64 Team, IBM Corp
   4  *
   5  * This struct defines the way the registers are stored on the
   6  * kernel stack during a system call or other kernel entry.
   7  *
   8  * this should only contain volatile regs
   9  * since we can keep non-volatile in the thread_struct
  10  * should set this up when only volatiles are saved
  11  * by intr code.
  12  *
  13  * Since this is going on the stack, *CARE MUST BE TAKEN* to insure
  14  * that the overall structure is a multiple of 16 bytes in length.
  15  *
  16  * Note that the offsets of the fields in this struct correspond with
  17  * the PT_* values below.  This simplifies arch/powerpc/kernel/ptrace.c.
  18  */
  19 #ifndef _ASM_POWERPC_PTRACE_H
  20 #define _ASM_POWERPC_PTRACE_H
  21
  22 #include <uapi/asm/ptrace.h>
  23 #include <asm/asm-const.h>
  24
  25 #ifndef __ASSEMBLY__
  26 struct pt_regs
  27 {
  28         union {
  29                 struct user_pt_regs user_regs;
  30                 struct {
  31                         unsigned long gpr[32];
  32                         unsigned long nip;
  33                         unsigned long msr;
  34                         unsigned long orig_gpr3;
  35                         unsigned long ctr;
  36                         unsigned long link;
  37                         unsigned long xer;
  38                         unsigned long ccr;
  39 #ifdef CONFIG_PPC64
  40                         unsigned long softe;
  41 #else
  42                         unsigned long mq;
  43 #endif
  44                         unsigned long trap;
  45                         unsigned long dar;
  46                         unsigned long dsisr;
  47                         unsigned long result;
  48                 };
  49         };
  50
  51         union {
  52                 struct {
  53 #ifdef CONFIG_PPC64
  54                         unsigned long ppr;
  55 #endif
  56 #ifdef CONFIG_PPC_KUAP
  57                         unsigned long kuap;
  58 #endif
  59                 };
  60                 unsigned long __pad[2]; /* Maintain 16 byte interrupt stack alignment */
  61         };
  62 };
  63 #endif
  64
  65 #ifdef __powerpc64__
  66
  67 /*
  68  * Size of redzone that userspace is allowed to use below the stack
  69  * pointer.  This is 288 in the 64-bit big-endian ELF ABI, and 512 in
  70  * the new ELFv2 little-endian ABI, so we allow the larger amount.
  71  *
  72  * For kernel code we allow a 288-byte redzone, in order to conserve
  73  * kernel stack space; gcc currently only uses 288 bytes, and will
  74  * hopefully allow explicit control of the redzone size in future.
  75  */
  76 #define USER_REDZONE_SIZE       512
  77 #define KERNEL_REDZONE_SIZE     288
  78
  79 #define STACK_FRAME_OVERHEAD    112     /* size of minimum stack frame */
  80 #define STACK_FRAME_LR_SAVE     2       /* Location of LR in stack frame */
  81 #define STACK_FRAME_REGS_MARKER ASM_CONST(0x7265677368657265)
  82 #define STACK_INT_FRAME_SIZE    (sizeof(struct pt_regs) + \
  83                                  STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
  84 #define STACK_FRAME_MARKER      12
  85
  86 #ifdef PPC64_ELF_ABI_v2
  87 #define STACK_FRAME_MIN_SIZE    32
  88 #else
  89 #define STACK_FRAME_MIN_SIZE    STACK_FRAME_OVERHEAD
  90 #endif
  91
  92 /* Size of dummy stack frame allocated when calling signal handler. */
  93 #define __SIGNAL_FRAMESIZE      128
  94 #define __SIGNAL_FRAMESIZE32    64
  95
  96 #else /* __powerpc64__ */
  97
  98 #define USER_REDZONE_SIZE       0
  99 #define KERNEL_REDZONE_SIZE     0
 100 #define STACK_FRAME_OVERHEAD    16      /* size of minimum stack frame */
 101 #define STACK_FRAME_LR_SAVE     1       /* Location of LR in stack frame */
 102 #define STACK_FRAME_REGS_MARKER ASM_CONST(0x72656773)
 103 #define STACK_INT_FRAME_SIZE    (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 104 #define STACK_FRAME_MARKER      2
 105 #define STACK_FRAME_MIN_SIZE    STACK_FRAME_OVERHEAD
 106
 107 /* Size of stack frame allocated when calling signal handler. */
 108 #define __SIGNAL_FRAMESIZE      64
 109
 110 #endif /* __powerpc64__ */
 111
 112 #ifndef __ASSEMBLY__
 113
 114 static inline unsigned long instruction_pointer(struct pt_regs *regs)
 115 {
 116         return regs->nip;
 117 }
 118
 119 static inline void instruction_pointer_set(struct pt_regs *regs,
 120                 unsigned long val)
 121 {
 122         regs->nip = val;
 123 }
 124
 125 static inline unsigned long user_stack_pointer(struct pt_regs *regs)
 126 {
 127         return regs->gpr[1];
 128 }
 129
 130 static inline unsigned long frame_pointer(struct pt_regs *regs)
 131 {
 132         return 0;
 133 }
 134
 135 #ifdef CONFIG_SMP
 136 extern unsigned long profile_pc(struct pt_regs *regs);
 137 #else
 138 #define profile_pc(regs) instruction_pointer(regs)
 139 #endif
 140
 141 #define kernel_stack_pointer(regs) ((regs)->gpr[1])
 142 static inline int is_syscall_success(struct pt_regs *regs)
 143 {
 144         return !(regs->ccr & 0x10000000);
 145 }
 146
 147 static inline long regs_return_value(struct pt_regs *regs)
 148 {
 149         if (is_syscall_success(regs))
 150                 return regs->gpr[3];
 151         else
 152                 return -regs->gpr[3];
 153 }
 154
 155 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
 156 {
 157         regs->gpr[3] = rc;
 158 }
 159
 160 #ifdef __powerpc64__
 161 #define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1)
 162 #else
 163 #define user_mode(regs) (((regs)->msr & MSR_PR) != 0)
 164 #endif
 165
 166 #define force_successful_syscall_return()   \
 167         do { \
 168                 set_thread_flag(TIF_NOERROR); \
 169         } while(0)
 170
 171 struct task_struct;
 172 extern int ptrace_get_reg(struct task_struct *task, int regno,
 173                           unsigned long *data);
 174 extern int ptrace_put_reg(struct task_struct *task, int regno,
 175                           unsigned long data);
 176
 177 #define current_pt_regs() \
 178         ((struct pt_regs *)((unsigned long)task_stack_page(current) + THREAD_SIZE) - 1)
 179 /*
 180  * We use the least-significant bit of the trap field to indicate
 181  * whether we have saved the full set of registers, or only a
 182  * partial set.  A 1 there means the partial set.
 183  * On 4xx we use the next bit to indicate whether the exception
 184  * is a critical exception (1 means it is).
 185  */
 186 #define FULL_REGS(regs)         (((regs)->trap & 1) == 0)
 187 #ifndef __powerpc64__
 188 #define IS_CRITICAL_EXC(regs)   (((regs)->trap & 2) != 0)
 189 #define IS_MCHECK_EXC(regs)     (((regs)->trap & 4) != 0)
 190 #define IS_DEBUG_EXC(regs)      (((regs)->trap & 8) != 0)
 191 #endif /* ! __powerpc64__ */
 192 #define TRAP(regs)              ((regs)->trap & ~0xF)
 193 #ifdef __powerpc64__
 194 #define NV_REG_POISON           0xdeadbeefdeadbeefUL
 195 #define CHECK_FULL_REGS(regs)   BUG_ON(regs->trap & 1)
 196 #else
 197 #define NV_REG_POISON           0xdeadbeef
 198 #define CHECK_FULL_REGS(regs)                                                 \
 199 do {                                                                          \
 200         if ((regs)->trap & 1)                                                 \
 201                 printk(KERN_CRIT "%s: partial register set\n", __func__); \
 202 } while (0)
 203 #endif /* __powerpc64__ */
 204
 205 #define arch_has_single_step()  (1)
 206 #ifndef CONFIG_BOOK3S_601
 207 #define arch_has_block_step()   (true)
 208 #else
 209 #define arch_has_block_step()   (false)
 210 #endif
 211 #define ARCH_HAS_USER_SINGLE_STEP_REPORT
 212
 213 /*
 214  * kprobe-based event tracer support
 215  */
 216
 217 #include <linux/stddef.h>
 218 #include <linux/thread_info.h>
 219 extern int regs_query_register_offset(const char *name);
 220 extern const char *regs_query_register_name(unsigned int offset);
 221 #define MAX_REG_OFFSET (offsetof(struct pt_regs, dsisr))
 222
 223 /**
 224  * regs_get_register() - get register value from its offset
 225  * @regs:          pt_regs from which register value is gotten
 226  * @offset:    offset number of the register.
 227  *
 228  * regs_get_register returns the value of a register whose offset from @regs.
 229  * The @offset is the offset of the register in struct pt_regs.
 230  * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
 231  */
 232 static inline unsigned long regs_get_register(struct pt_regs *regs,
 233                                                 unsigned int offset)
 234 {
 235         if (unlikely(offset > MAX_REG_OFFSET))
 236                 return 0;
 237         return *(unsigned long *)((unsigned long)regs + offset);
 238 }
 239
 240 /**
 241  * regs_within_kernel_stack() - check the address in the stack
 242  * @regs:      pt_regs which contains kernel stack pointer.
 243  * @addr:      address which is checked.
 244  *
 245  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 246  * If @addr is within the kernel stack, it returns true. If not, returns false.
 247  */
 248
 249 static inline bool regs_within_kernel_stack(struct pt_regs *regs,
 250                                                 unsigned long addr)
 251 {
 252         return ((addr & ~(THREAD_SIZE - 1))  ==
 253                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 254 }
 255
 256 /**
 257  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 258  * @regs:       pt_regs which contains kernel stack pointer.
 259  * @n:          stack entry number.
 260  *
 261  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 262  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 263  * this returns 0.
 264  */
 265 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
 266                                                       unsigned int n)
 267 {
 268         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 269         addr += n;
 270         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 271                 return *addr;
 272         else
 273                 return 0;
 274 }
 275
 276 #endif /* __ASSEMBLY__ */
 277
 278 #ifndef __powerpc64__
 279 #else /* __powerpc64__ */
 280 #define PT_FPSCR32 (PT_FPR0 + 2*32 + 1) /* each FP reg occupies 2 32-bit userspace slots */
 281 #define PT_VR0_32 164   /* each Vector reg occupies 4 slots in 32-bit */
 282 #define PT_VSCR_32 (PT_VR0 + 32*4 + 3)
 283 #define PT_VRSAVE_32 (PT_VR0 + 33*4)
 284 #define PT_VSR0_32 300  /* each VSR reg occupies 4 slots in 32-bit */
 285 #endif /* __powerpc64__ */
 286 #endif /* _ASM_POWERPC_PTRACE_H */