arch/powerpc/include/asm/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 #include <linux/module.h>
  33 #include <asm/probes.h>
  34 #include <asm/code-patching.h>
  35
  36 #ifdef CONFIG_KPROBES
  37 #define  __ARCH_WANT_KPROBES_INSN_SLOT
  38
  39 struct pt_regs;
  40 struct kprobe;
  41
  42 typedef ppc_opcode_t kprobe_opcode_t;
  43
  44 extern kprobe_opcode_t optinsn_slot;
  45
  46 /* Optinsn template address */
  47 extern kprobe_opcode_t optprobe_template_entry[];
  48 extern kprobe_opcode_t optprobe_template_op_address[];
  49 extern kprobe_opcode_t optprobe_template_call_handler[];
  50 extern kprobe_opcode_t optprobe_template_insn[];
  51 extern kprobe_opcode_t optprobe_template_call_emulate[];
  52 extern kprobe_opcode_t optprobe_template_ret[];
  53 extern kprobe_opcode_t optprobe_template_end[];
  54
  55 /* Fixed instruction size for powerpc */
  56 #define MAX_INSN_SIZE           1
  57 #define MAX_OPTIMIZED_LENGTH    sizeof(kprobe_opcode_t) /* 4 bytes */
  58 #define MAX_OPTINSN_SIZE        (optprobe_template_end - optprobe_template_entry)
  59 #define RELATIVEJUMP_SIZE       sizeof(kprobe_opcode_t) /* 4 bytes */
  60
  61 #ifdef PPC64_ELF_ABI_v2
  62 /* PPC64 ABIv2 needs local entry point */
  63 #define kprobe_lookup_name(name, addr)                                  \
  64 {                                                                       \
  65         addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);           \
  66         if (addr)                                                       \
  67                 addr = (kprobe_opcode_t *)ppc_function_entry(addr);     \
  68 }
  69 #elif defined(PPC64_ELF_ABI_v1)
  70 /*
  71  * 64bit powerpc ABIv1 uses function descriptors:
  72  * - Check for the dot variant of the symbol first.
  73  * - If that fails, try looking up the symbol provided.
  74  *
  75  * This ensures we always get to the actual symbol and not the descriptor.
  76  * Also handle <module:symbol> format.
  77  */
  78 #define kprobe_lookup_name(name, addr)                                  \
  79 {                                                                       \
  80         char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];             \
  81         const char *modsym;                                                     \
  82         bool dot_appended = false;                                      \
  83         if ((modsym = strchr(name, ':')) != NULL) {                     \
  84                 modsym++;                                               \
  85                 if (*modsym != '\0' && *modsym != '.') {                \
  86                         /* Convert to <module:.symbol> */               \
  87                         strncpy(dot_name, name, modsym - name);         \
  88                         dot_name[modsym - name] = '.';                  \
  89                         dot_name[modsym - name + 1] = '\0';             \
  90                         strncat(dot_name, modsym,                       \
  91                                 sizeof(dot_name) - (modsym - name) - 2);\
  92                         dot_appended = true;                            \
  93                 } else {                                                \
  94                         dot_name[0] = '\0';                             \
  95                         strncat(dot_name, name, sizeof(dot_name) - 1);  \
  96                 }                                                       \
  97         } else if (name[0] != '.') {                                    \
  98                 dot_name[0] = '.';                                      \
  99                 dot_name[1] = '\0';                                     \
 100                 strncat(dot_name, name, KSYM_NAME_LEN - 2);             \
 101                 dot_appended = true;                                    \
 102         } else {                                                        \
 103                 dot_name[0] = '\0';                                     \
 104                 strncat(dot_name, name, KSYM_NAME_LEN - 1);             \
 105         }                                                               \
 106         addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name);       \
 107         if (!addr && dot_appended) {                                    \
 108                 /* Let's try the original non-dot symbol lookup */      \
 109                 addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);   \
 110         }                                                               \
 111 }
 112 #endif
 113
 114 #define flush_insn_slot(p)      do { } while (0)
 115 #define kretprobe_blacklist_size 0
 116
 117 void kretprobe_trampoline(void);
 118 extern void arch_remove_kprobe(struct kprobe *p);
 119
 120 /* Architecture specific copy of original instruction */
 121 struct arch_specific_insn {
 122         /* copy of original instruction */
 123         kprobe_opcode_t *insn;
 124         /*
 125          * Set in kprobes code, initially to 0. If the instruction can be
 126          * eumulated, this is set to 1, if not, to -1.
 127          */
 128         int boostable;
 129 };
 130
 131 struct prev_kprobe {
 132         struct kprobe *kp;
 133         unsigned long status;
 134         unsigned long saved_msr;
 135 };
 136
 137 /* per-cpu kprobe control block */
 138 struct kprobe_ctlblk {
 139         unsigned long kprobe_status;
 140         unsigned long kprobe_saved_msr;
 141         struct pt_regs jprobe_saved_regs;
 142         struct prev_kprobe prev_kprobe;
 143 };
 144
 145 struct arch_optimized_insn {
 146         kprobe_opcode_t copied_insn[1];
 147         /* detour buffer */
 148         kprobe_opcode_t *insn;
 149 };
 150
 151 extern int kprobe_exceptions_notify(struct notifier_block *self,
 152                                         unsigned long val, void *data);
 153 extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
 154 extern int kprobe_handler(struct pt_regs *regs);
 155 extern int kprobe_post_handler(struct pt_regs *regs);
 156 #else
 157 static inline int kprobe_handler(struct pt_regs *regs) { return 0; }
 158 static inline int kprobe_post_handler(struct pt_regs *regs) { return 0; }
 159 #endif /* CONFIG_KPROBES */
 160 #endif /* __KERNEL__ */
 161 #endif  /* _ASM_POWERPC_KPROBES_H */