include/asm-powerpc/kprobes.h

   1 #ifndef _ASM_POWERPC_KPROBES_H
   2 #define _ASM_POWERPC_KPROBES_H
   3 #ifdef __KERNEL__
   4 /*
   5  *  Kernel Probes (KProbes)
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20  *
  21  * Copyright (C) IBM Corporation, 2002, 2004
  22  *
  23  * 2002-Oct     Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
  24  *              Probes initial implementation ( includes suggestions from
  25  *              Rusty Russell).
  26  * 2004-Nov     Modified for PPC64 by Ananth N Mavinakayanahalli
  27  *              <ananth@in.ibm.com>
  28  */
  29 #include <linux/types.h>
  30 #include <linux/ptrace.h>
  31 #include <linux/percpu.h>
  32
  33 #define  __ARCH_WANT_KPROBES_INSN_SLOT
  34
  35 struct pt_regs;
  36 struct kprobe;
  37
  38 typedef unsigned int kprobe_opcode_t;
  39 #define BREAKPOINT_INSTRUCTION  0x7fe00008      /* trap */
  40 #define MAX_INSN_SIZE 1
  41
  42 #define IS_TW(instr)            (((instr) & 0xfc0007fe) == 0x7c000008)
  43 #define IS_TD(instr)            (((instr) & 0xfc0007fe) == 0x7c000088)
  44 #define IS_TDI(instr)           (((instr) & 0xfc000000) == 0x08000000)
  45 #define IS_TWI(instr)           (((instr) & 0xfc000000) == 0x0c000000)
  46
  47 #ifdef CONFIG_PPC64
  48 /*
  49  * 64bit powerpc uses function descriptors.
  50  * Handle cases where:
  51  *              - User passes a <.symbol> or <module:.symbol>
  52  *              - User passes a <symbol> or <module:symbol>
  53  *              - User passes a non-existant symbol, kallsyms_lookup_name
  54  *                returns 0. Don't deref the NULL pointer in that case
  55  */
  56 #define kprobe_lookup_name(name, addr)                                  \
  57 {                                                                       \
  58         addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);           \
  59         if (addr) {                                                     \
  60                 char *colon;                                            \
  61                 if ((colon = strchr(name, ':')) != NULL) {              \
  62                         colon++;                                        \
  63                         if (*colon != '\0' && *colon != '.')            \
  64                                 addr = *(kprobe_opcode_t **)addr;       \
  65                 } else if (name[0] != '.')                              \
  66                         addr = *(kprobe_opcode_t **)addr;               \
  67         } else {                                                        \
  68                 char dot_name[KSYM_NAME_LEN];                           \
  69                 dot_name[0] = '.';                                      \
  70                 dot_name[1] = '\0';                                     \
  71                 strncat(dot_name, name, KSYM_NAME_LEN - 2);             \
  72                 addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name); \
  73         }                                                               \
  74 }
  75
  76 #define JPROBE_ENTRY(pentry)    (kprobe_opcode_t *)((func_descr_t *)pentry)
  77 #define is_trap(instr)  (IS_TW(instr) || IS_TD(instr) || \
  78                         IS_TWI(instr) || IS_TDI(instr))
  79 #else
  80 /* Use stock kprobe_lookup_name since ppc32 doesn't use function descriptors */
  81 #define JPROBE_ENTRY(pentry)    (kprobe_opcode_t *)(pentry)
  82 #define is_trap(instr)  (IS_TW(instr) || IS_TWI(instr))
  83 #endif
  84
  85 #define ARCH_SUPPORTS_KRETPROBES
  86 #define  ARCH_INACTIVE_KPROBE_COUNT 1
  87 #define flush_insn_slot(p)      do { } while (0)
  88
  89 void kretprobe_trampoline(void);
  90 extern void arch_remove_kprobe(struct kprobe *p);
  91
  92 /* Architecture specific copy of original instruction */
  93 struct arch_specific_insn {
  94         /* copy of original instruction */
  95         kprobe_opcode_t *insn;
  96         /*
  97          * Set in kprobes code, initially to 0. If the instruction can be
  98          * eumulated, this is set to 1, if not, to -1.
  99          */
 100         int boostable;
 101 };
 102
 103 struct prev_kprobe {
 104         struct kprobe *kp;
 105         unsigned long status;
 106         unsigned long saved_msr;
 107 };
 108
 109 /* per-cpu kprobe control block */
 110 struct kprobe_ctlblk {
 111         unsigned long kprobe_status;
 112         unsigned long kprobe_saved_msr;
 113         struct pt_regs jprobe_saved_regs;
 114         struct prev_kprobe prev_kprobe;
 115 };
 116
 117 extern int kprobe_exceptions_notify(struct notifier_block *self,
 118                                         unsigned long val, void *data);
 119 extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
 120 #endif /* __KERNEL__ */
 121 #endif  /* _ASM_POWERPC_KPROBES_H */