xref: /openbmc/linux/arch/riscv/kernel/ptrace.c (revision 8bd1369b)
1 /*
2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
3  * Copyright 2015 Regents of the University of California
4  * Copyright 2017 SiFive
5  *
6  *   This program is free software; you can redistribute it and/or
7  *   modify it under the terms of the GNU General Public License
8  *   as published by the Free Software Foundation, version 2.
9  *
10  *   This program is distributed in the hope that it will be useful,
11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  *   GNU General Public License for more details.
14  *
15  * Copied from arch/tile/kernel/ptrace.c
16  */
17 
18 #include <asm/ptrace.h>
19 #include <asm/syscall.h>
20 #include <asm/thread_info.h>
21 #include <linux/ptrace.h>
22 #include <linux/elf.h>
23 #include <linux/regset.h>
24 #include <linux/sched.h>
25 #include <linux/sched/task_stack.h>
26 #include <linux/tracehook.h>
27 #include <trace/events/syscalls.h>
28 
29 enum riscv_regset {
30 	REGSET_X,
31 };
32 
33 static int riscv_gpr_get(struct task_struct *target,
34 			 const struct user_regset *regset,
35 			 unsigned int pos, unsigned int count,
36 			 void *kbuf, void __user *ubuf)
37 {
38 	struct pt_regs *regs;
39 
40 	regs = task_pt_regs(target);
41 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
42 }
43 
44 static int riscv_gpr_set(struct task_struct *target,
45 			 const struct user_regset *regset,
46 			 unsigned int pos, unsigned int count,
47 			 const void *kbuf, const void __user *ubuf)
48 {
49 	int ret;
50 	struct pt_regs *regs;
51 
52 	regs = task_pt_regs(target);
53 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
54 	return ret;
55 }
56 
57 
58 static const struct user_regset riscv_user_regset[] = {
59 	[REGSET_X] = {
60 		.core_note_type = NT_PRSTATUS,
61 		.n = ELF_NGREG,
62 		.size = sizeof(elf_greg_t),
63 		.align = sizeof(elf_greg_t),
64 		.get = &riscv_gpr_get,
65 		.set = &riscv_gpr_set,
66 	},
67 };
68 
69 static const struct user_regset_view riscv_user_native_view = {
70 	.name = "riscv",
71 	.e_machine = EM_RISCV,
72 	.regsets = riscv_user_regset,
73 	.n = ARRAY_SIZE(riscv_user_regset),
74 };
75 
76 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
77 {
78 	return &riscv_user_native_view;
79 }
80 
81 void ptrace_disable(struct task_struct *child)
82 {
83 	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
84 }
85 
86 long arch_ptrace(struct task_struct *child, long request,
87 		 unsigned long addr, unsigned long data)
88 {
89 	long ret = -EIO;
90 
91 	switch (request) {
92 	default:
93 		ret = ptrace_request(child, request, addr, data);
94 		break;
95 	}
96 
97 	return ret;
98 }
99 
100 /*
101  * Allows PTRACE_SYSCALL to work.  These are called from entry.S in
102  * {handle,ret_from}_syscall.
103  */
104 void do_syscall_trace_enter(struct pt_regs *regs)
105 {
106 	if (test_thread_flag(TIF_SYSCALL_TRACE))
107 		if (tracehook_report_syscall_entry(regs))
108 			syscall_set_nr(current, regs, -1);
109 
110 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
111 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
112 		trace_sys_enter(regs, syscall_get_nr(current, regs));
113 #endif
114 }
115 
116 void do_syscall_trace_exit(struct pt_regs *regs)
117 {
118 	if (test_thread_flag(TIF_SYSCALL_TRACE))
119 		tracehook_report_syscall_exit(regs, 0);
120 
121 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
122 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
123 		trace_sys_exit(regs, regs->regs[0]);
124 #endif
125 }
126