arch/powerpc/include/asm/kprobes.h

   1 #ifndef _ASM_POWERPC_KPROBES_H
   2 #define _ASM_POWERPC_KPROBES_H
   3
   4 #include <asm-generic/kprobes.h>
   5
   6 #ifdef __KERNEL__
   7 /*
   8  *  Kernel Probes (KProbes)
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23  *
  24  * Copyright (C) IBM Corporation, 2002, 2004
  25  *
  26  * 2002-Oct     Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
  27  *              Probes initial implementation ( includes suggestions from
  28  *              Rusty Russell).
  29  * 2004-Nov     Modified for PPC64 by Ananth N Mavinakayanahalli
  30  *              <ananth@in.ibm.com>
  31  */
  32 #include <linux/types.h>
  33 #include <linux/ptrace.h>
  34 #include <linux/percpu.h>
  35 #include <linux/module.h>
  36 #include <asm/probes.h>
  37 #include <asm/code-patching.h>
  38
  39 #ifdef CONFIG_KPROBES
  40 #define  __ARCH_WANT_KPROBES_INSN_SLOT
  41
  42 struct pt_regs;
  43 struct kprobe;
  44
  45 typedef ppc_opcode_t kprobe_opcode_t;
  46
  47 extern kprobe_opcode_t optinsn_slot;
  48
  49 /* Optinsn template address */
  50 extern kprobe_opcode_t optprobe_template_entry[];
  51 extern kprobe_opcode_t optprobe_template_op_address[];
  52 extern kprobe_opcode_t optprobe_template_call_handler[];
  53 extern kprobe_opcode_t optprobe_template_insn[];
  54 extern kprobe_opcode_t optprobe_template_call_emulate[];
  55 extern kprobe_opcode_t optprobe_template_ret[];
  56 extern kprobe_opcode_t optprobe_template_end[];
  57
  58 /* Fixed instruction size for powerpc */
  59 #define MAX_INSN_SIZE           1
  60 #define MAX_OPTIMIZED_LENGTH    sizeof(kprobe_opcode_t) /* 4 bytes */
  61 #define MAX_OPTINSN_SIZE        (optprobe_template_end - optprobe_template_entry)
  62 #define RELATIVEJUMP_SIZE       sizeof(kprobe_opcode_t) /* 4 bytes */
  63
  64 #ifdef PPC64_ELF_ABI_v2
  65 /* PPC64 ABIv2 needs local entry point */
  66 #define kprobe_lookup_name(name, addr)                                  \
  67 {                                                                       \
  68         addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);           \
  69         if (addr)                                                       \
  70                 addr = (kprobe_opcode_t *)ppc_function_entry(addr);     \
  71 }
  72 #elif defined(PPC64_ELF_ABI_v1)
  73 /*
  74  * 64bit powerpc ABIv1 uses function descriptors:
  75  * - Check for the dot variant of the symbol first.
  76  * - If that fails, try looking up the symbol provided.
  77  *
  78  * This ensures we always get to the actual symbol and not the descriptor.
  79  * Also handle <module:symbol> format.
  80  */
  81 #define kprobe_lookup_name(name, addr)                                  \
  82 {                                                                       \
  83         char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];             \
  84         const char *modsym;                                                     \
  85         bool dot_appended = false;                                      \
  86         if ((modsym = strchr(name, ':')) != NULL) {                     \
  87                 modsym++;                                               \
  88                 if (*modsym != '\0' && *modsym != '.') {                \
  89                         /* Convert to <module:.symbol> */               \
  90                         strncpy(dot_name, name, modsym - name);         \
  91                         dot_name[modsym - name] = '.';                  \
  92                         dot_name[modsym - name + 1] = '\0';             \
  93                         strncat(dot_name, modsym,                       \
  94                                 sizeof(dot_name) - (modsym - name) - 2);\
  95                         dot_appended = true;                            \
  96                 } else {                                                \
  97                         dot_name[0] = '\0';                             \
  98                         strncat(dot_name, name, sizeof(dot_name) - 1);  \
  99                 }                                                       \
 100         } else if (name[0] != '.') {                                    \
 101                 dot_name[0] = '.';                                      \
 102                 dot_name[1] = '\0';                                     \
 103                 strncat(dot_name, name, KSYM_NAME_LEN - 2);             \
 104                 dot_appended = true;                                    \
 105         } else {                                                        \
 106                 dot_name[0] = '\0';                                     \
 107                 strncat(dot_name, name, KSYM_NAME_LEN - 1);             \
 108         }                                                               \
 109         addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name);       \
 110         if (!addr && dot_appended) {                                    \
 111                 /* Let's try the original non-dot symbol lookup */      \
 112                 addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);   \
 113         }                                                               \
 114 }
 115 #endif
 116
 117 #define flush_insn_slot(p)      do { } while (0)
 118 #define kretprobe_blacklist_size 0
 119
 120 void kretprobe_trampoline(void);
 121 extern void arch_remove_kprobe(struct kprobe *p);
 122
 123 /* Architecture specific copy of original instruction */
 124 struct arch_specific_insn {
 125         /* copy of original instruction */
 126         kprobe_opcode_t *insn;
 127         /*
 128          * Set in kprobes code, initially to 0. If the instruction can be
 129          * eumulated, this is set to 1, if not, to -1.
 130          */
 131         int boostable;
 132 };
 133
 134 struct prev_kprobe {
 135         struct kprobe *kp;
 136         unsigned long status;
 137         unsigned long saved_msr;
 138 };
 139
 140 /* per-cpu kprobe control block */
 141 struct kprobe_ctlblk {
 142         unsigned long kprobe_status;
 143         unsigned long kprobe_saved_msr;
 144         struct pt_regs jprobe_saved_regs;
 145         struct prev_kprobe prev_kprobe;
 146 };
 147
 148 struct arch_optimized_insn {
 149         kprobe_opcode_t copied_insn[1];
 150         /* detour buffer */
 151         kprobe_opcode_t *insn;
 152 };
 153
 154 extern int kprobe_exceptions_notify(struct notifier_block *self,
 155                                         unsigned long val, void *data);
 156 extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
 157 extern int kprobe_handler(struct pt_regs *regs);
 158 extern int kprobe_post_handler(struct pt_regs *regs);
 159 #else
 160 static inline int kprobe_handler(struct pt_regs *regs) { return 0; }
 161 static inline int kprobe_post_handler(struct pt_regs *regs) { return 0; }
 162 #endif /* CONFIG_KPROBES */
 163 #endif /* __KERNEL__ */
 164 #endif  /* _ASM_POWERPC_KPROBES_H */