ptrace.h

  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	/* Saved syscall stack arguments; entries 0-3 unused. */
 31	unsigned long args[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 \
 69	(offsetof(struct pt_regs, __last) - sizeof(unsigned long))
 70
 71/**
 72 * regs_get_register() - get register value from its offset
 73 * @regs:       pt_regs from which register value is gotten.
 74 * @offset:     offset number of the register.
 75 *
 76 * regs_get_register returns the value of a register. The @offset is the
 77 * offset of the register in struct pt_regs address which specified by @regs.
 78 * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
 79 */
 80static inline unsigned long regs_get_register(struct pt_regs *regs,
 81                                              unsigned int offset)
 82{
 83	if (unlikely(offset > MAX_REG_OFFSET))
 84		return 0;
 85
 86	return *(unsigned long *)((unsigned long)regs + offset);
 87}
 88
 89/**
 90 * regs_within_kernel_stack() - check the address in the stack
 91 * @regs:       pt_regs which contains kernel stack pointer.
 92 * @addr:       address which is checked.
 93 *
 94 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 95 * If @addr is within the kernel stack, it returns true. If not, returns false.
 96 */
 97static inline int regs_within_kernel_stack(struct pt_regs *regs,
 98                                           unsigned long addr)
 99{
100	return ((addr & ~(THREAD_SIZE - 1))  ==
101		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
102}
103
104/**
105 * regs_get_kernel_stack_nth() - get Nth entry of the stack
106 * @regs:       pt_regs which contains kernel stack pointer.
107 * @n:          stack entry number.
108 *
109 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
110 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
111 * this returns 0.
112 */
113static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
114                                                      unsigned int n)
115{
116	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
117
118	addr += n;
119	if (regs_within_kernel_stack(regs, (unsigned long)addr))
120		return *addr;
121	else
122		return 0;
123}
124
125struct task_struct;
126
127extern int ptrace_getregs(struct task_struct *child,
128	struct user_pt_regs __user *data);
129extern int ptrace_setregs(struct task_struct *child,
130	struct user_pt_regs __user *data);
131
132extern int ptrace_getfpregs(struct task_struct *child, __u32 __user *data);
133extern int ptrace_setfpregs(struct task_struct *child, __u32 __user *data);
134
135extern int ptrace_get_watch_regs(struct task_struct *child,
136	struct pt_watch_regs __user *addr);
137extern int ptrace_set_watch_regs(struct task_struct *child,
138	struct pt_watch_regs __user *addr);
139
140/*
141 * Does the process account for user or for system time?
142 */
143#define user_mode(regs) (((regs)->cp0_status & KU_MASK) == KU_USER)
144
145static inline int is_syscall_success(struct pt_regs *regs)
146{
147	return !regs->regs[7];
148}
149
150static inline long regs_return_value(struct pt_regs *regs)
151{
152	if (is_syscall_success(regs) || !user_mode(regs))
153		return regs->regs[2];
154	else
155		return -regs->regs[2];
156}
157
158#define instruction_pointer(regs) ((regs)->cp0_epc)
159extern unsigned long exception_ip(struct pt_regs *regs);
160#define exception_ip(regs) exception_ip(regs)
161#define profile_pc(regs) instruction_pointer(regs)
162
163extern asmlinkage long syscall_trace_enter(struct pt_regs *regs);
164extern asmlinkage void syscall_trace_leave(struct pt_regs *regs);
165
166extern void die(const char *, struct pt_regs *) __noreturn;
167
168static inline void die_if_kernel(const char *str, struct pt_regs *regs)
169{
170	if (unlikely(!user_mode(regs)))
171		die(str, regs);
172}
173
174#define current_pt_regs()						\
175({									\
176	unsigned long sp = (unsigned long)__builtin_frame_address(0);	\
177	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1 - 32) - 1;	\
178})
179
180/* Helpers for working with the user stack pointer */
181
182static inline unsigned long user_stack_pointer(struct pt_regs *regs)
183{
184	return regs->regs[29];
185}
186
187static inline void user_stack_pointer_set(struct pt_regs *regs,
188	unsigned long val)
189{
190	regs->regs[29] = val;
191}
192
193#endif /* _ASM_PTRACE_H */