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1 /*
2  *  arch/arm/include/asm/ptrace.h
3  *
4  *  Copyright (C) 1996-2003 Russell King
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 #ifndef __ASM_ARM_PTRACE_H
11 #define __ASM_ARM_PTRACE_H
12 
13 #include <uapi/asm/ptrace.h>
14 
15 #ifndef __ASSEMBLY__
16 struct pt_regs {
17 	unsigned long uregs[18];
18 };
19 
20 #define user_mode(regs)	\
21 	(((regs)->ARM_cpsr & 0xf) == 0)
22 
23 #ifdef CONFIG_ARM_THUMB
24 #define thumb_mode(regs) \
25 	(((regs)->ARM_cpsr & PSR_T_BIT))
26 #else
27 #define thumb_mode(regs) (0)
28 #endif
29 
30 #ifndef CONFIG_CPU_V7M
31 #define isa_mode(regs) \
32 	((((regs)->ARM_cpsr & PSR_J_BIT) >> (__ffs(PSR_J_BIT) - 1)) | \
33 	 (((regs)->ARM_cpsr & PSR_T_BIT) >> (__ffs(PSR_T_BIT))))
34 #else
35 #define isa_mode(regs) 1 /* Thumb */
36 #endif
37 
38 #define processor_mode(regs) \
39 	((regs)->ARM_cpsr & MODE_MASK)
40 
41 #define interrupts_enabled(regs) \
42 	(!((regs)->ARM_cpsr & PSR_I_BIT))
43 
44 #define fast_interrupts_enabled(regs) \
45 	(!((regs)->ARM_cpsr & PSR_F_BIT))
46 
47 /* Are the current registers suitable for user mode?
48  * (used to maintain security in signal handlers)
49  */
valid_user_regs(struct pt_regs * regs)50 static inline int valid_user_regs(struct pt_regs *regs)
51 {
52 #ifndef CONFIG_CPU_V7M
53 	unsigned long mode = regs->ARM_cpsr & MODE_MASK;
54 
55 	/*
56 	 * Always clear the F (FIQ) and A (delayed abort) bits
57 	 */
58 	regs->ARM_cpsr &= ~(PSR_F_BIT | PSR_A_BIT);
59 
60 	if ((regs->ARM_cpsr & PSR_I_BIT) == 0) {
61 		if (mode == USR_MODE)
62 			return 1;
63 		if (elf_hwcap & HWCAP_26BIT && mode == USR26_MODE)
64 			return 1;
65 	}
66 
67 	/*
68 	 * Force CPSR to something logical...
69 	 */
70 	regs->ARM_cpsr &= PSR_f | PSR_s | PSR_x | PSR_T_BIT | MODE32_BIT;
71 	if (!(elf_hwcap & HWCAP_26BIT))
72 		regs->ARM_cpsr |= USR_MODE;
73 
74 	return 0;
75 #else /* ifndef CONFIG_CPU_V7M */
76 	return 1;
77 #endif
78 }
79 
regs_return_value(struct pt_regs * regs)80 static inline long regs_return_value(struct pt_regs *regs)
81 {
82 	return regs->ARM_r0;
83 }
84 
85 #define instruction_pointer(regs)	(regs)->ARM_pc
86 
87 #ifdef CONFIG_THUMB2_KERNEL
88 #define frame_pointer(regs) (regs)->ARM_r7
89 #else
90 #define frame_pointer(regs) (regs)->ARM_fp
91 #endif
92 
instruction_pointer_set(struct pt_regs * regs,unsigned long val)93 static inline void instruction_pointer_set(struct pt_regs *regs,
94 					   unsigned long val)
95 {
96 	instruction_pointer(regs) = val;
97 }
98 
99 #ifdef CONFIG_SMP
100 extern unsigned long profile_pc(struct pt_regs *regs);
101 #else
102 #define profile_pc(regs) instruction_pointer(regs)
103 #endif
104 
105 #define predicate(x)		((x) & 0xf0000000)
106 #define PREDICATE_ALWAYS	0xe0000000
107 
108 /*
109  * True if instr is a 32-bit thumb instruction. This works if instr
110  * is the first or only half-word of a thumb instruction. It also works
111  * when instr holds all 32-bits of a wide thumb instruction if stored
112  * in the form (first_half<<16)|(second_half)
113  */
114 #define is_wide_instruction(instr)	((unsigned)(instr) >= 0xe800)
115 
116 /*
117  * kprobe-based event tracer support
118  */
119 #include <linux/stddef.h>
120 #include <linux/types.h>
121 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ARM_ORIG_r0))
122 
123 extern int regs_query_register_offset(const char *name);
124 extern const char *regs_query_register_name(unsigned int offset);
125 extern bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr);
126 extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
127 					       unsigned int n);
128 
129 /**
130  * regs_get_register() - get register value from its offset
131  * @regs:	   pt_regs from which register value is gotten
132  * @offset:    offset number of the register.
133  *
134  * regs_get_register returns the value of a register whose offset from @regs.
135  * The @offset is the offset of the register in struct pt_regs.
136  * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
137  */
regs_get_register(struct pt_regs * regs,unsigned int offset)138 static inline unsigned long regs_get_register(struct pt_regs *regs,
139 					      unsigned int offset)
140 {
141 	if (unlikely(offset > MAX_REG_OFFSET))
142 		return 0;
143 	return *(unsigned long *)((unsigned long)regs + offset);
144 }
145 
146 /* Valid only for Kernel mode traps. */
kernel_stack_pointer(struct pt_regs * regs)147 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
148 {
149 	return regs->ARM_sp;
150 }
151 
user_stack_pointer(struct pt_regs * regs)152 static inline unsigned long user_stack_pointer(struct pt_regs *regs)
153 {
154 	return regs->ARM_sp;
155 }
156 
157 #define current_pt_regs(void) ({				\
158 	register unsigned long sp asm ("sp");			\
159 	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) - 7) - 1;	\
160 })
161 
162 #endif /* __ASSEMBLY__ */
163 #endif
164