xref: /linux/arch/powerpc/include/asm/kprobes.h (revision cc04a46f11ea046ed53e2c832ae29e4790f7e35f)
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 <asm/probes.h>
33 #include <asm/code-patching.h>
34 
35 #define  __ARCH_WANT_KPROBES_INSN_SLOT
36 
37 struct pt_regs;
38 struct kprobe;
39 
40 typedef ppc_opcode_t kprobe_opcode_t;
41 #define MAX_INSN_SIZE 1
42 
43 #ifdef CONFIG_PPC64
44 #if defined(_CALL_ELF) && _CALL_ELF == 2
45 /* PPC64 ABIv2 needs local entry point */
46 #define kprobe_lookup_name(name, addr)					\
47 {									\
48 	addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);		\
49 	if (addr)							\
50 		addr = (kprobe_opcode_t *)ppc_function_entry(addr);	\
51 }
52 #else
53 /*
54  * 64bit powerpc ABIv1 uses function descriptors:
55  * - Check for the dot variant of the symbol first.
56  * - If that fails, try looking up the symbol provided.
57  *
58  * This ensures we always get to the actual symbol and not the descriptor.
59  * Also handle <module:symbol> format.
60  */
61 #define kprobe_lookup_name(name, addr)					\
62 {									\
63 	char dot_name[MODULE_NAME_LEN + 1 + KSYM_NAME_LEN];		\
64 	char *modsym;							\
65 	bool dot_appended = false;					\
66 	if ((modsym = strchr(name, ':')) != NULL) {			\
67 		modsym++;						\
68 		if (*modsym != '\0' && *modsym != '.') {		\
69 			/* Convert to <module:.symbol> */		\
70 			strncpy(dot_name, name, modsym - name);		\
71 			dot_name[modsym - name] = '.';			\
72 			dot_name[modsym - name + 1] = '\0';		\
73 			strncat(dot_name, modsym,			\
74 				sizeof(dot_name) - (modsym - name) - 2);\
75 			dot_appended = true;				\
76 		} else {						\
77 			dot_name[0] = '\0';				\
78 			strncat(dot_name, name, sizeof(dot_name) - 1);	\
79 		}							\
80 	} else if (name[0] != '.') {					\
81 		dot_name[0] = '.';					\
82 		dot_name[1] = '\0';					\
83 		strncat(dot_name, name, KSYM_NAME_LEN - 2);		\
84 		dot_appended = true;					\
85 	} else {							\
86 		dot_name[0] = '\0';					\
87 		strncat(dot_name, name, KSYM_NAME_LEN - 1);		\
88 	}								\
89 	addr = (kprobe_opcode_t *)kallsyms_lookup_name(dot_name);	\
90 	if (!addr && dot_appended) {					\
91 		/* Let's try the original non-dot symbol lookup	*/	\
92 		addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);	\
93 	}								\
94 }
95 #endif /* defined(_CALL_ELF) && _CALL_ELF == 2 */
96 #endif /* CONFIG_PPC64 */
97 
98 #define flush_insn_slot(p)	do { } while (0)
99 #define kretprobe_blacklist_size 0
100 
101 void kretprobe_trampoline(void);
102 extern void arch_remove_kprobe(struct kprobe *p);
103 
104 /* Architecture specific copy of original instruction */
105 struct arch_specific_insn {
106 	/* copy of original instruction */
107 	kprobe_opcode_t *insn;
108 	/*
109 	 * Set in kprobes code, initially to 0. If the instruction can be
110 	 * eumulated, this is set to 1, if not, to -1.
111 	 */
112 	int boostable;
113 };
114 
115 struct prev_kprobe {
116 	struct kprobe *kp;
117 	unsigned long status;
118 	unsigned long saved_msr;
119 };
120 
121 /* per-cpu kprobe control block */
122 struct kprobe_ctlblk {
123 	unsigned long kprobe_status;
124 	unsigned long kprobe_saved_msr;
125 	struct pt_regs jprobe_saved_regs;
126 	struct prev_kprobe prev_kprobe;
127 };
128 
129 extern int kprobe_exceptions_notify(struct notifier_block *self,
130 					unsigned long val, void *data);
131 extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
132 #endif /* __KERNEL__ */
133 #endif	/* _ASM_POWERPC_KPROBES_H */
134