xref: /openbmc/linux/arch/powerpc/include/asm/kprobes.h (revision 63dc02bd)
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-existent 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 is_trap(instr)	(IS_TW(instr) || IS_TD(instr) || \
77 			IS_TWI(instr) || IS_TDI(instr))
78 #else
79 /* Use stock kprobe_lookup_name since ppc32 doesn't use function descriptors */
80 #define is_trap(instr)	(IS_TW(instr) || IS_TWI(instr))
81 #endif
82 
83 #define flush_insn_slot(p)	do { } while (0)
84 #define kretprobe_blacklist_size 0
85 
86 void kretprobe_trampoline(void);
87 extern void arch_remove_kprobe(struct kprobe *p);
88 
89 /* Architecture specific copy of original instruction */
90 struct arch_specific_insn {
91 	/* copy of original instruction */
92 	kprobe_opcode_t *insn;
93 	/*
94 	 * Set in kprobes code, initially to 0. If the instruction can be
95 	 * eumulated, this is set to 1, if not, to -1.
96 	 */
97 	int boostable;
98 };
99 
100 struct prev_kprobe {
101 	struct kprobe *kp;
102 	unsigned long status;
103 	unsigned long saved_msr;
104 };
105 
106 /* per-cpu kprobe control block */
107 struct kprobe_ctlblk {
108 	unsigned long kprobe_status;
109 	unsigned long kprobe_saved_msr;
110 	struct pt_regs jprobe_saved_regs;
111 	struct prev_kprobe prev_kprobe;
112 };
113 
114 extern int kprobe_exceptions_notify(struct notifier_block *self,
115 					unsigned long val, void *data);
116 extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
117 #endif /* __KERNEL__ */
118 #endif	/* _ASM_POWERPC_KPROBES_H */
119