xref: /openbmc/linux/arch/arc/kernel/ptrace.c (revision 12eb4683)
1 /*
2  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/ptrace.h>
10 #include <linux/tracehook.h>
11 #include <linux/regset.h>
12 #include <linux/unistd.h>
13 #include <linux/elf.h>
14 
15 static struct callee_regs *task_callee_regs(struct task_struct *tsk)
16 {
17 	struct callee_regs *tmp = (struct callee_regs *)tsk->thread.callee_reg;
18 	return tmp;
19 }
20 
21 static int genregs_get(struct task_struct *target,
22 		       const struct user_regset *regset,
23 		       unsigned int pos, unsigned int count,
24 		       void *kbuf, void __user *ubuf)
25 {
26 	const struct pt_regs *ptregs = task_pt_regs(target);
27 	const struct callee_regs *cregs = task_callee_regs(target);
28 	int ret = 0;
29 	unsigned int stop_pc_val;
30 
31 #define REG_O_CHUNK(START, END, PTR)	\
32 	if (!ret)	\
33 		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
34 			offsetof(struct user_regs_struct, START), \
35 			offsetof(struct user_regs_struct, END));
36 
37 #define REG_O_ONE(LOC, PTR)	\
38 	if (!ret)		\
39 		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
40 			offsetof(struct user_regs_struct, LOC), \
41 			offsetof(struct user_regs_struct, LOC) + 4);
42 
43 #define REG_O_ZERO(LOC)		\
44 	if (!ret)		\
45 		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, \
46 			offsetof(struct user_regs_struct, LOC), \
47 			offsetof(struct user_regs_struct, LOC) + 4);
48 
49 	REG_O_ZERO(pad);
50 	REG_O_CHUNK(scratch, callee, ptregs);
51 	REG_O_ZERO(pad2);
52 	REG_O_CHUNK(callee, efa, cregs);
53 	REG_O_CHUNK(efa, stop_pc, &target->thread.fault_address);
54 
55 	if (!ret) {
56 		if (in_brkpt_trap(ptregs)) {
57 			stop_pc_val = target->thread.fault_address;
58 			pr_debug("\t\tstop_pc (brk-pt)\n");
59 		} else {
60 			stop_pc_val = ptregs->ret;
61 			pr_debug("\t\tstop_pc (others)\n");
62 		}
63 
64 		REG_O_ONE(stop_pc, &stop_pc_val);
65 	}
66 
67 	return ret;
68 }
69 
70 static int genregs_set(struct task_struct *target,
71 		       const struct user_regset *regset,
72 		       unsigned int pos, unsigned int count,
73 		       const void *kbuf, const void __user *ubuf)
74 {
75 	const struct pt_regs *ptregs = task_pt_regs(target);
76 	const struct callee_regs *cregs = task_callee_regs(target);
77 	int ret = 0;
78 
79 #define REG_IN_CHUNK(FIRST, NEXT, PTR)	\
80 	if (!ret)			\
81 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
82 			(void *)(PTR), \
83 			offsetof(struct user_regs_struct, FIRST), \
84 			offsetof(struct user_regs_struct, NEXT));
85 
86 #define REG_IN_ONE(LOC, PTR)		\
87 	if (!ret)			\
88 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
89 			(void *)(PTR), \
90 			offsetof(struct user_regs_struct, LOC), \
91 			offsetof(struct user_regs_struct, LOC) + 4);
92 
93 #define REG_IGNORE_ONE(LOC)		\
94 	if (!ret)			\
95 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, \
96 			offsetof(struct user_regs_struct, LOC), \
97 			offsetof(struct user_regs_struct, LOC) + 4);
98 
99 	REG_IGNORE_ONE(pad);
100 	/* TBD: disallow updates to STATUS32 etc*/
101 	REG_IN_CHUNK(scratch, pad2, ptregs);	/* pt_regs[bta..sp] */
102 	REG_IGNORE_ONE(pad2);
103 	REG_IN_CHUNK(callee, efa, cregs);	/* callee_regs[r25..r13] */
104 	REG_IGNORE_ONE(efa);			/* efa update invalid */
105 	REG_IGNORE_ONE(stop_pc);			/* PC updated via @ret */
106 
107 	return ret;
108 }
109 
110 enum arc_getset {
111 	REGSET_GENERAL,
112 };
113 
114 static const struct user_regset arc_regsets[] = {
115 	[REGSET_GENERAL] = {
116 	       .core_note_type = NT_PRSTATUS,
117 	       .n = ELF_NGREG,
118 	       .size = sizeof(unsigned long),
119 	       .align = sizeof(unsigned long),
120 	       .get = genregs_get,
121 	       .set = genregs_set,
122 	}
123 };
124 
125 static const struct user_regset_view user_arc_view = {
126 	.name		= UTS_MACHINE,
127 	.e_machine	= EM_ARCOMPACT,
128 	.regsets	= arc_regsets,
129 	.n		= ARRAY_SIZE(arc_regsets)
130 };
131 
132 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
133 {
134 	return &user_arc_view;
135 }
136 
137 void ptrace_disable(struct task_struct *child)
138 {
139 }
140 
141 long arch_ptrace(struct task_struct *child, long request,
142 		 unsigned long addr, unsigned long data)
143 {
144 	int ret = -EIO;
145 
146 	pr_debug("REQ=%ld: ADDR =0x%lx, DATA=0x%lx)\n", request, addr, data);
147 
148 	switch (request) {
149 	default:
150 		ret = ptrace_request(child, request, addr, data);
151 		break;
152 	}
153 
154 	return ret;
155 }
156 
157 asmlinkage int syscall_trace_entry(struct pt_regs *regs)
158 {
159 	if (tracehook_report_syscall_entry(regs))
160 		return ULONG_MAX;
161 
162 	return regs->r8;
163 }
164 
165 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
166 {
167 	tracehook_report_syscall_exit(regs, 0);
168 }
169