xref: /linux/arch/nios2/kernel/ptrace.c (revision ca853314e78b0a65c20b6a889a23c31f918d4aa2)
1 /*
2  * Copyright (C) 2014 Altera Corporation
3  * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
4  *
5  * This file is subject to the terms and conditions of the GNU General
6  * Public License.  See the file COPYING in the main directory of this
7  * archive for more details.
8  */
9 
10 #include <linux/elf.h>
11 #include <linux/errno.h>
12 #include <linux/kernel.h>
13 #include <linux/mm.h>
14 #include <linux/ptrace.h>
15 #include <linux/regset.h>
16 #include <linux/sched.h>
17 #include <linux/sched/task_stack.h>
18 #include <linux/tracehook.h>
19 #include <linux/uaccess.h>
20 #include <linux/user.h>
21 
22 static int genregs_get(struct task_struct *target,
23 		       const struct user_regset *regset,
24 		       struct membuf to)
25 {
26 	const struct pt_regs *regs = task_pt_regs(target);
27 	const struct switch_stack *sw = (struct switch_stack *)regs - 1;
28 
29 	membuf_zero(&to, 4); // R0
30 	membuf_write(&to, &regs->r1, 7 * 4); // R1..R7
31 	membuf_write(&to, &regs->r8, 8 * 4); // R8..R15
32 	membuf_write(&to, sw, 8 * 4); // R16..R23
33 	membuf_zero(&to, 2 * 4); /* et and bt */
34 	membuf_store(&to, regs->gp);
35 	membuf_store(&to, regs->sp);
36 	membuf_store(&to, regs->fp);
37 	membuf_store(&to, regs->ea);
38 	membuf_zero(&to, 4); // PTR_BA
39 	membuf_store(&to, regs->ra);
40 	membuf_store(&to, regs->ea); /* use ea for PC */
41 	return membuf_zero(&to, (NUM_PTRACE_REG - PTR_PC) * 4);
42 }
43 
44 /*
45  * Set the thread state from a regset passed in via ptrace
46  */
47 static int genregs_set(struct task_struct *target,
48 		       const struct user_regset *regset,
49 		       unsigned int pos, unsigned int count,
50 		       const void *kbuf, const void __user *ubuf)
51 {
52 	struct pt_regs *regs = task_pt_regs(target);
53 	const struct switch_stack *sw = (struct switch_stack *)regs - 1;
54 	int ret = 0;
55 
56 #define REG_IGNORE_RANGE(START, END)		\
57 	if (!ret)					\
58 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, \
59 			START * 4, (END * 4) + 4);
60 
61 #define REG_IN_ONE(PTR, LOC)	\
62 	if (!ret)			\
63 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
64 			(void *)(PTR), LOC * 4, (LOC * 4) + 4);
65 
66 #define REG_IN_RANGE(PTR, START, END)	\
67 	if (!ret)				\
68 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
69 			(void *)(PTR), START * 4, (END * 4) + 4);
70 
71 	REG_IGNORE_RANGE(PTR_R0, PTR_R0);
72 	REG_IN_RANGE(&regs->r1, PTR_R1, PTR_R7);
73 	REG_IN_RANGE(&regs->r8, PTR_R8, PTR_R15);
74 	REG_IN_RANGE(sw, PTR_R16, PTR_R23);
75 	REG_IGNORE_RANGE(PTR_R24, PTR_R25); /* et and bt */
76 	REG_IN_ONE(&regs->gp, PTR_GP);
77 	REG_IN_ONE(&regs->sp, PTR_SP);
78 	REG_IN_ONE(&regs->fp, PTR_FP);
79 	REG_IN_ONE(&regs->ea, PTR_EA);
80 	REG_IGNORE_RANGE(PTR_BA, PTR_BA);
81 	REG_IN_ONE(&regs->ra, PTR_RA);
82 	REG_IN_ONE(&regs->ea, PTR_PC); /* use ea for PC */
83 	if (!ret)
84 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
85 					 PTR_STATUS * 4, -1);
86 
87 	return ret;
88 }
89 
90 /*
91  * Define the register sets available on Nios2 under Linux
92  */
93 enum nios2_regset {
94 	REGSET_GENERAL,
95 };
96 
97 static const struct user_regset nios2_regsets[] = {
98 	[REGSET_GENERAL] = {
99 		.core_note_type = NT_PRSTATUS,
100 		.n = NUM_PTRACE_REG,
101 		.size = sizeof(unsigned long),
102 		.align = sizeof(unsigned long),
103 		.regset_get = genregs_get,
104 		.set = genregs_set,
105 	}
106 };
107 
108 static const struct user_regset_view nios2_user_view = {
109 	.name = "nios2",
110 	.e_machine = ELF_ARCH,
111 	.ei_osabi = ELF_OSABI,
112 	.regsets = nios2_regsets,
113 	.n = ARRAY_SIZE(nios2_regsets)
114 };
115 
116 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
117 {
118 	return &nios2_user_view;
119 }
120 
121 void ptrace_disable(struct task_struct *child)
122 {
123 
124 }
125 
126 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
127 		 unsigned long data)
128 {
129 	return ptrace_request(child, request, addr, data);
130 }
131 
132 asmlinkage int do_syscall_trace_enter(void)
133 {
134 	int ret = 0;
135 
136 	if (test_thread_flag(TIF_SYSCALL_TRACE))
137 		ret = tracehook_report_syscall_entry(task_pt_regs(current));
138 
139 	return ret;
140 }
141 
142 asmlinkage void do_syscall_trace_exit(void)
143 {
144 	if (test_thread_flag(TIF_SYSCALL_TRACE))
145 		tracehook_report_syscall_exit(task_pt_regs(current), 0);
146 }
147