1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000 by Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 */
9#ifndef _ASM_PTRACE_H
10#define _ASM_PTRACE_H
11
12
13#include <linux/compiler.h>
14#include <linux/linkage.h>
15#include <linux/types.h>
16#include <asm/isadep.h>
17#include <asm/page.h>
18#include <asm/thread_info.h>
19#include <uapi/asm/ptrace.h>
20
21/*
22 * This struct defines the way the registers are stored on the stack during a
23 * system call/exception. As usual the registers k0/k1 aren't being saved.
24 *
25 * If you add a register here, also add it to regoffset_table[] in
26 * arch/mips/kernel/ptrace.c.
27 */
28struct pt_regs {
29#ifdef CONFIG_32BIT
30	/* Pad bytes for argument save space on the stack. */
31	unsigned long pad0[8];
32#endif
33
34	/* Saved main processor registers. */
35	unsigned long regs[32];
36
37	/* Saved special registers. */
38	unsigned long cp0_status;
39	unsigned long hi;
40	unsigned long lo;
41#ifdef CONFIG_CPU_HAS_SMARTMIPS
42	unsigned long acx;
43#endif
44	unsigned long cp0_badvaddr;
45	unsigned long cp0_cause;
46	unsigned long cp0_epc;
47#ifdef CONFIG_CPU_CAVIUM_OCTEON
48	unsigned long long mpl[6];        /* MTM{0-5} */
49	unsigned long long mtp[6];        /* MTP{0-5} */
50#endif
51	unsigned long __last[0];
52} __aligned(8);
53
54static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
55{
56	return regs->regs[29];
57}
58
59static inline void instruction_pointer_set(struct pt_regs *regs,
60                                           unsigned long val)
61{
62	regs->cp0_epc = val;
63	regs->cp0_cause &= ~CAUSEF_BD;
64}
65
66/* Query offset/name of register from its name/offset */
67extern int regs_query_register_offset(const char *name);
68#define MAX_REG_OFFSET (offsetof(struct pt_regs, __last))
69
70/**
71 * regs_get_register() - get register value from its offset
72 * @regs:       pt_regs from which register value is gotten.
73 * @offset:     offset number of the register.
74 *
75 * regs_get_register returns the value of a register. The @offset is the
76 * offset of the register in struct pt_regs address which specified by @regs.
77 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
78 */
79static inline unsigned long regs_get_register(struct pt_regs *regs,
80                                              unsigned int offset)
81{
82	if (unlikely(offset > MAX_REG_OFFSET))
83		return 0;
84
85	return *(unsigned long *)((unsigned long)regs + offset);
86}
87
88/**
89 * regs_within_kernel_stack() - check the address in the stack
90 * @regs:       pt_regs which contains kernel stack pointer.
91 * @addr:       address which is checked.
92 *
93 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
94 * If @addr is within the kernel stack, it returns true. If not, returns false.
95 */
96static inline int regs_within_kernel_stack(struct pt_regs *regs,
97                                           unsigned long addr)
98{
99	return ((addr & ~(THREAD_SIZE - 1))  ==
100		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
101}
102
103/**
104 * regs_get_kernel_stack_nth() - get Nth entry of the stack
105 * @regs:       pt_regs which contains kernel stack pointer.
106 * @n:          stack entry number.
107 *
108 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
109 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
110 * this returns 0.
111 */
112static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
113                                                      unsigned int n)
114{
115	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
116
117	addr += n;
118	if (regs_within_kernel_stack(regs, (unsigned long)addr))
119		return *addr;
120	else
121		return 0;
122}
123
124struct task_struct;
125
126extern int ptrace_getregs(struct task_struct *child,
127	struct user_pt_regs __user *data);
128extern int ptrace_setregs(struct task_struct *child,
129	struct user_pt_regs __user *data);
130
131extern int ptrace_getfpregs(struct task_struct *child, __u32 __user *data);
132extern int ptrace_setfpregs(struct task_struct *child, __u32 __user *data);
133
134extern int ptrace_get_watch_regs(struct task_struct *child,
135	struct pt_watch_regs __user *addr);
136extern int ptrace_set_watch_regs(struct task_struct *child,
137	struct pt_watch_regs __user *addr);
138
139/*
140 * Does the process account for user or for system time?
141 */
142#define user_mode(regs) (((regs)->cp0_status & KU_MASK) == KU_USER)
143
144static inline int is_syscall_success(struct pt_regs *regs)
145{
146	return !regs->regs[7];
147}
148
149static inline long regs_return_value(struct pt_regs *regs)
150{
151	if (is_syscall_success(regs) || !user_mode(regs))
152		return regs->regs[2];
153	else
154		return -regs->regs[2];
155}
156
157#define instruction_pointer(regs) ((regs)->cp0_epc)
158extern unsigned long exception_ip(struct pt_regs *regs);
159#define exception_ip(regs) exception_ip(regs)
160#define profile_pc(regs) instruction_pointer(regs)
161
162extern asmlinkage long syscall_trace_enter(struct pt_regs *regs);
163extern asmlinkage void syscall_trace_leave(struct pt_regs *regs);
164
165extern void die(const char *, struct pt_regs *) __noreturn;
166
167static inline void die_if_kernel(const char *str, struct pt_regs *regs)
168{
169	if (unlikely(!user_mode(regs)))
170		die(str, regs);
171}
172
173#define current_pt_regs()						\
174({									\
175	unsigned long sp = (unsigned long)__builtin_frame_address(0);	\
176	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1 - 32) - 1;	\
177})
178
179/* Helpers for working with the user stack pointer */
180
181static inline unsigned long user_stack_pointer(struct pt_regs *regs)
182{
183	return regs->regs[29];
184}
185
186static inline void user_stack_pointer_set(struct pt_regs *regs,
187	unsigned long val)
188{
189	regs->regs[29] = val;
190}
191
192#endif /* _ASM_PTRACE_H */
193