xref: /openbmc/linux/arch/nios2/kernel/ptrace.c (revision 99a15348)
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/uaccess.h>
19 #include <linux/user.h>
20 
21 static int genregs_get(struct task_struct *target,
22 		       const struct user_regset *regset,
23 		       struct membuf to)
24 {
25 	const struct pt_regs *regs = task_pt_regs(target);
26 	const struct switch_stack *sw = (struct switch_stack *)regs - 1;
27 
28 	membuf_zero(&to, 4); // R0
29 	membuf_write(&to, &regs->r1, 7 * 4); // R1..R7
30 	membuf_write(&to, &regs->r8, 8 * 4); // R8..R15
31 	membuf_write(&to, sw, 8 * 4); // R16..R23
32 	membuf_zero(&to, 2 * 4); /* et and bt */
33 	membuf_store(&to, regs->gp);
34 	membuf_store(&to, regs->sp);
35 	membuf_store(&to, regs->fp);
36 	membuf_store(&to, regs->ea);
37 	membuf_zero(&to, 4); // PTR_BA
38 	membuf_store(&to, regs->ra);
39 	membuf_store(&to, regs->ea); /* use ea for PC */
40 	return membuf_zero(&to, (NUM_PTRACE_REG - PTR_PC) * 4);
41 }
42 
43 /*
44  * Set the thread state from a regset passed in via ptrace
45  */
46 static int genregs_set(struct task_struct *target,
47 		       const struct user_regset *regset,
48 		       unsigned int pos, unsigned int count,
49 		       const void *kbuf, const void __user *ubuf)
50 {
51 	struct pt_regs *regs = task_pt_regs(target);
52 	const struct switch_stack *sw = (struct switch_stack *)regs - 1;
53 	int ret = 0;
54 
55 #define REG_IGNORE_RANGE(START, END)		\
56 	if (!ret)					\
57 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, \
58 			START * 4, (END * 4) + 4);
59 
60 #define REG_IN_ONE(PTR, LOC)	\
61 	if (!ret)			\
62 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
63 			(void *)(PTR), LOC * 4, (LOC * 4) + 4);
64 
65 #define REG_IN_RANGE(PTR, START, END)	\
66 	if (!ret)				\
67 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
68 			(void *)(PTR), START * 4, (END * 4) + 4);
69 
70 	REG_IGNORE_RANGE(PTR_R0, PTR_R0);
71 	REG_IN_RANGE(&regs->r1, PTR_R1, PTR_R7);
72 	REG_IN_RANGE(&regs->r8, PTR_R8, PTR_R15);
73 	REG_IN_RANGE(sw, PTR_R16, PTR_R23);
74 	REG_IGNORE_RANGE(PTR_R24, PTR_R25); /* et and bt */
75 	REG_IN_ONE(&regs->gp, PTR_GP);
76 	REG_IN_ONE(&regs->sp, PTR_SP);
77 	REG_IN_ONE(&regs->fp, PTR_FP);
78 	REG_IN_ONE(&regs->ea, PTR_EA);
79 	REG_IGNORE_RANGE(PTR_BA, PTR_BA);
80 	REG_IN_ONE(&regs->ra, PTR_RA);
81 	REG_IN_ONE(&regs->ea, PTR_PC); /* use ea for PC */
82 	if (!ret)
83 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
84 					 PTR_STATUS * 4, -1);
85 
86 	return ret;
87 }
88 
89 /*
90  * Define the register sets available on Nios2 under Linux
91  */
92 enum nios2_regset {
93 	REGSET_GENERAL,
94 };
95 
96 static const struct user_regset nios2_regsets[] = {
97 	[REGSET_GENERAL] = {
98 		.core_note_type = NT_PRSTATUS,
99 		.n = NUM_PTRACE_REG,
100 		.size = sizeof(unsigned long),
101 		.align = sizeof(unsigned long),
102 		.regset_get = genregs_get,
103 		.set = genregs_set,
104 	}
105 };
106 
107 static const struct user_regset_view nios2_user_view = {
108 	.name = "nios2",
109 	.e_machine = ELF_ARCH,
110 	.ei_osabi = ELF_OSABI,
111 	.regsets = nios2_regsets,
112 	.n = ARRAY_SIZE(nios2_regsets)
113 };
114 
115 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
116 {
117 	return &nios2_user_view;
118 }
119 
120 void ptrace_disable(struct task_struct *child)
121 {
122 
123 }
124 
125 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
126 		 unsigned long data)
127 {
128 	return ptrace_request(child, request, addr, data);
129 }
130 
131 asmlinkage int do_syscall_trace_enter(void)
132 {
133 	int ret = 0;
134 
135 	if (test_thread_flag(TIF_SYSCALL_TRACE))
136 		ret = ptrace_report_syscall_entry(task_pt_regs(current));
137 
138 	return ret;
139 }
140 
141 asmlinkage void do_syscall_trace_exit(void)
142 {
143 	if (test_thread_flag(TIF_SYSCALL_TRACE))
144 		ptrace_report_syscall_exit(task_pt_regs(current), 0);
145 }
146