arch/powerpc/include/asm/ptrace.h

   1 /*
   2  * Copyright (C) 2001 PPC64 Team, IBM Corp
   3  *
   4  * This struct defines the way the registers are stored on the
   5  * kernel stack during a system call or other kernel entry.
   6  *
   7  * this should only contain volatile regs
   8  * since we can keep non-volatile in the thread_struct
   9  * should set this up when only volatiles are saved
  10  * by intr code.
  11  *
  12  * Since this is going on the stack, *CARE MUST BE TAKEN* to insure
  13  * that the overall structure is a multiple of 16 bytes in length.
  14  *
  15  * Note that the offsets of the fields in this struct correspond with
  16  * the PT_* values below.  This simplifies arch/powerpc/kernel/ptrace.c.
  17  *
  18  * This program is free software; you can redistribute it and/or
  19  * modify it under the terms of the GNU General Public License
  20  * as published by the Free Software Foundation; either version
  21  * 2 of the License, or (at your option) any later version.
  22  */
  23 #ifndef _ASM_POWERPC_PTRACE_H
  24 #define _ASM_POWERPC_PTRACE_H
  25
  26 #include <uapi/asm/ptrace.h>
  27
  28
  29 #ifdef __powerpc64__
  30
  31 /*
  32  * Size of redzone that userspace is allowed to use below the stack
  33  * pointer.  This is 288 in the 64-bit big-endian ELF ABI, and 512 in
  34  * the new ELFv2 little-endian ABI, so we allow the larger amount.
  35  *
  36  * For kernel code we allow a 288-byte redzone, in order to conserve
  37  * kernel stack space; gcc currently only uses 288 bytes, and will
  38  * hopefully allow explicit control of the redzone size in future.
  39  */
  40 #define USER_REDZONE_SIZE       512
  41 #define KERNEL_REDZONE_SIZE     288
  42
  43 #define STACK_FRAME_OVERHEAD    112     /* size of minimum stack frame */
  44 #define STACK_FRAME_LR_SAVE     2       /* Location of LR in stack frame */
  45 #define STACK_FRAME_REGS_MARKER ASM_CONST(0x7265677368657265)
  46 #define STACK_INT_FRAME_SIZE    (sizeof(struct pt_regs) + \
  47                                  STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
  48 #define STACK_FRAME_MARKER      12
  49
  50 #ifdef PPC64_ELF_ABI_v2
  51 #define STACK_FRAME_MIN_SIZE    32
  52 #else
  53 #define STACK_FRAME_MIN_SIZE    STACK_FRAME_OVERHEAD
  54 #endif
  55
  56 /* Size of dummy stack frame allocated when calling signal handler. */
  57 #define __SIGNAL_FRAMESIZE      128
  58 #define __SIGNAL_FRAMESIZE32    64
  59
  60 #else /* __powerpc64__ */
  61
  62 #define USER_REDZONE_SIZE       0
  63 #define KERNEL_REDZONE_SIZE     0
  64 #define STACK_FRAME_OVERHEAD    16      /* size of minimum stack frame */
  65 #define STACK_FRAME_LR_SAVE     1       /* Location of LR in stack frame */
  66 #define STACK_FRAME_REGS_MARKER ASM_CONST(0x72656773)
  67 #define STACK_INT_FRAME_SIZE    (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
  68 #define STACK_FRAME_MARKER      2
  69 #define STACK_FRAME_MIN_SIZE    STACK_FRAME_OVERHEAD
  70
  71 /* Size of stack frame allocated when calling signal handler. */
  72 #define __SIGNAL_FRAMESIZE      64
  73
  74 #endif /* __powerpc64__ */
  75
  76 #ifndef __ASSEMBLY__
  77
  78 #define GET_IP(regs)            ((regs)->nip)
  79 #define GET_USP(regs)           ((regs)->gpr[1])
  80 #define GET_FP(regs)            (0)
  81 #define SET_FP(regs, val)
  82
  83 #ifdef CONFIG_SMP
  84 extern unsigned long profile_pc(struct pt_regs *regs);
  85 #define profile_pc profile_pc
  86 #endif
  87
  88 #include <asm-generic/ptrace.h>
  89
  90 #define kernel_stack_pointer(regs) ((regs)->gpr[1])
  91 static inline int is_syscall_success(struct pt_regs *regs)
  92 {
  93         return !(regs->ccr & 0x10000000);
  94 }
  95
  96 static inline long regs_return_value(struct pt_regs *regs)
  97 {
  98         if (is_syscall_success(regs))
  99                 return regs->gpr[3];
 100         else
 101                 return -regs->gpr[3];
 102 }
 103
 104 #ifdef __powerpc64__
 105 #define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1)
 106 #else
 107 #define user_mode(regs) (((regs)->msr & MSR_PR) != 0)
 108 #endif
 109
 110 #define force_successful_syscall_return()   \
 111         do { \
 112                 set_thread_flag(TIF_NOERROR); \
 113         } while(0)
 114
 115 struct task_struct;
 116 extern int ptrace_get_reg(struct task_struct *task, int regno,
 117                           unsigned long *data);
 118 extern int ptrace_put_reg(struct task_struct *task, int regno,
 119                           unsigned long data);
 120
 121 #define current_pt_regs() \
 122         ((struct pt_regs *)((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
 123 /*
 124  * We use the least-significant bit of the trap field to indicate
 125  * whether we have saved the full set of registers, or only a
 126  * partial set.  A 1 there means the partial set.
 127  * On 4xx we use the next bit to indicate whether the exception
 128  * is a critical exception (1 means it is).
 129  */
 130 #define FULL_REGS(regs)         (((regs)->trap & 1) == 0)
 131 #ifndef __powerpc64__
 132 #define IS_CRITICAL_EXC(regs)   (((regs)->trap & 2) != 0)
 133 #define IS_MCHECK_EXC(regs)     (((regs)->trap & 4) != 0)
 134 #define IS_DEBUG_EXC(regs)      (((regs)->trap & 8) != 0)
 135 #endif /* ! __powerpc64__ */
 136 #define TRAP(regs)              ((regs)->trap & ~0xF)
 137 #ifdef __powerpc64__
 138 #define NV_REG_POISON           0xdeadbeefdeadbeefUL
 139 #define CHECK_FULL_REGS(regs)   BUG_ON(regs->trap & 1)
 140 #else
 141 #define NV_REG_POISON           0xdeadbeef
 142 #define CHECK_FULL_REGS(regs)                                                 \
 143 do {                                                                          \
 144         if ((regs)->trap & 1)                                                 \
 145                 printk(KERN_CRIT "%s: partial register set\n", __func__); \
 146 } while (0)
 147 #endif /* __powerpc64__ */
 148
 149 #define arch_has_single_step()  (1)
 150 #define arch_has_block_step()   (!cpu_has_feature(CPU_FTR_601))
 151 #define ARCH_HAS_USER_SINGLE_STEP_INFO
 152
 153 /*
 154  * kprobe-based event tracer support
 155  */
 156
 157 #include <linux/stddef.h>
 158 #include <linux/thread_info.h>
 159 extern int regs_query_register_offset(const char *name);
 160 extern const char *regs_query_register_name(unsigned int offset);
 161 #define MAX_REG_OFFSET (offsetof(struct pt_regs, dsisr))
 162
 163 /**
 164  * regs_get_register() - get register value from its offset
 165  * @regs:          pt_regs from which register value is gotten
 166  * @offset:    offset number of the register.
 167  *
 168  * regs_get_register returns the value of a register whose offset from @regs.
 169  * The @offset is the offset of the register in struct pt_regs.
 170  * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
 171  */
 172 static inline unsigned long regs_get_register(struct pt_regs *regs,
 173                                                 unsigned int offset)
 174 {
 175         if (unlikely(offset > MAX_REG_OFFSET))
 176                 return 0;
 177         return *(unsigned long *)((unsigned long)regs + offset);
 178 }
 179
 180 /**
 181  * regs_within_kernel_stack() - check the address in the stack
 182  * @regs:      pt_regs which contains kernel stack pointer.
 183  * @addr:      address which is checked.
 184  *
 185  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 186  * If @addr is within the kernel stack, it returns true. If not, returns false.
 187  */
 188
 189 static inline bool regs_within_kernel_stack(struct pt_regs *regs,
 190                                                 unsigned long addr)
 191 {
 192         return ((addr & ~(THREAD_SIZE - 1))  ==
 193                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 194 }
 195
 196 /**
 197  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 198  * @regs:       pt_regs which contains kernel stack pointer.
 199  * @n:          stack entry number.
 200  *
 201  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 202  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 203  * this returns 0.
 204  */
 205 static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
 206                                                       unsigned int n)
 207 {
 208         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 209         addr += n;
 210         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 211                 return *addr;
 212         else
 213                 return 0;
 214 }
 215
 216 #endif /* __ASSEMBLY__ */
 217
 218 #ifndef __powerpc64__
 219 #else /* __powerpc64__ */
 220 #define PT_FPSCR32 (PT_FPR0 + 2*32 + 1) /* each FP reg occupies 2 32-bit userspace slots */
 221 #define PT_VR0_32 164   /* each Vector reg occupies 4 slots in 32-bit */
 222 #define PT_VSCR_32 (PT_VR0 + 32*4 + 3)
 223 #define PT_VRSAVE_32 (PT_VR0 + 33*4)
 224 #define PT_VSR0_32 300  /* each VSR reg occupies 4 slots in 32-bit */
 225 #endif /* __powerpc64__ */
 226 #endif /* _ASM_POWERPC_PTRACE_H */