035cb300d3dcf245b894e86ac39931cbdeee696f
[linux-2.6.git] / arch / sh / kernel / ptrace_32.c
1 /*
2  * linux/arch/sh/kernel/ptrace.c
3  *
4  * Original x86 implementation:
5  *      By Ross Biro 1/23/92
6  *      edited by Linus Torvalds
7  *
8  * SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
9  * Audit support: Yuichi Nakamura <ynakam@hitachisoft.jp>
10  */
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/smp.h>
15 #include <linux/errno.h>
16 #include <linux/ptrace.h>
17 #include <linux/user.h>
18 #include <linux/slab.h>
19 #include <linux/security.h>
20 #include <linux/signal.h>
21 #include <linux/io.h>
22 #include <linux/audit.h>
23 #include <linux/seccomp.h>
24 #include <linux/tracehook.h>
25 #include <asm/uaccess.h>
26 #include <asm/pgtable.h>
27 #include <asm/system.h>
28 #include <asm/processor.h>
29 #include <asm/mmu_context.h>
30
31 /*
32  * does not yet catch signals sent when the child dies.
33  * in exit.c or in signal.c.
34  */
35
36 /*
37  * This routine will get a word off of the process kernel stack.
38  */
39 static inline int get_stack_long(struct task_struct *task, int offset)
40 {
41         unsigned char *stack;
42
43         stack = (unsigned char *)task_pt_regs(task);
44         stack += offset;
45         return (*((int *)stack));
46 }
47
48 /*
49  * This routine will put a word on the process kernel stack.
50  */
51 static inline int put_stack_long(struct task_struct *task, int offset,
52                                  unsigned long data)
53 {
54         unsigned char *stack;
55
56         stack = (unsigned char *)task_pt_regs(task);
57         stack += offset;
58         *(unsigned long *) stack = data;
59         return 0;
60 }
61
62 void user_enable_single_step(struct task_struct *child)
63 {
64         struct pt_regs *regs = task_pt_regs(child);
65         long pc;
66
67         pc = get_stack_long(child, (long)&regs->pc);
68
69         /* Next scheduling will set up UBC */
70         if (child->thread.ubc_pc == 0)
71                 ubc_usercnt += 1;
72
73         child->thread.ubc_pc = pc;
74
75         set_tsk_thread_flag(child, TIF_SINGLESTEP);
76 }
77
78 void user_disable_single_step(struct task_struct *child)
79 {
80         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
81
82         /*
83          * Ensure the UBC is not programmed at the next context switch.
84          *
85          * Normally this is not needed but there are sequences such as
86          * singlestep, signal delivery, and continue that leave the
87          * ubc_pc non-zero leading to spurious SIGTRAPs.
88          */
89         if (child->thread.ubc_pc != 0) {
90                 ubc_usercnt -= 1;
91                 child->thread.ubc_pc = 0;
92         }
93 }
94
95 /*
96  * Called by kernel/ptrace.c when detaching..
97  *
98  * Make sure single step bits etc are not set.
99  */
100 void ptrace_disable(struct task_struct *child)
101 {
102         user_disable_single_step(child);
103 }
104
105 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
106 {
107         struct user * dummy = NULL;
108         int ret;
109
110         switch (request) {
111         /* read the word at location addr in the USER area. */
112         case PTRACE_PEEKUSR: {
113                 unsigned long tmp;
114
115                 ret = -EIO;
116                 if ((addr & 3) || addr < 0 ||
117                     addr > sizeof(struct user) - 3)
118                         break;
119
120                 if (addr < sizeof(struct pt_regs))
121                         tmp = get_stack_long(child, addr);
122                 else if (addr >= (long) &dummy->fpu &&
123                          addr < (long) &dummy->u_fpvalid) {
124                         if (!tsk_used_math(child)) {
125                                 if (addr == (long)&dummy->fpu.fpscr)
126                                         tmp = FPSCR_INIT;
127                                 else
128                                         tmp = 0;
129                         } else
130                                 tmp = ((long *)&child->thread.fpu)
131                                         [(addr - (long)&dummy->fpu) >> 2];
132                 } else if (addr == (long) &dummy->u_fpvalid)
133                         tmp = !!tsk_used_math(child);
134                 else
135                         tmp = 0;
136                 ret = put_user(tmp, (unsigned long __user *)data);
137                 break;
138         }
139
140         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
141                 ret = -EIO;
142                 if ((addr & 3) || addr < 0 ||
143                     addr > sizeof(struct user) - 3)
144                         break;
145
146                 if (addr < sizeof(struct pt_regs))
147                         ret = put_stack_long(child, addr, data);
148                 else if (addr >= (long) &dummy->fpu &&
149                          addr < (long) &dummy->u_fpvalid) {
150                         set_stopped_child_used_math(child);
151                         ((long *)&child->thread.fpu)
152                                 [(addr - (long)&dummy->fpu) >> 2] = data;
153                         ret = 0;
154                 } else if (addr == (long) &dummy->u_fpvalid) {
155                         conditional_stopped_child_used_math(data, child);
156                         ret = 0;
157                 }
158                 break;
159
160 #ifdef CONFIG_SH_DSP
161         case PTRACE_GETDSPREGS: {
162                 unsigned long dp;
163
164                 ret = -EIO;
165                 dp = ((unsigned long) child) + THREAD_SIZE -
166                          sizeof(struct pt_dspregs);
167                 if (*((int *) (dp - 4)) == SR_FD) {
168                         copy_to_user((void *)addr, (void *) dp,
169                                 sizeof(struct pt_dspregs));
170                         ret = 0;
171                 }
172                 break;
173         }
174
175         case PTRACE_SETDSPREGS: {
176                 unsigned long dp;
177
178                 ret = -EIO;
179                 dp = ((unsigned long) child) + THREAD_SIZE -
180                          sizeof(struct pt_dspregs);
181                 if (*((int *) (dp - 4)) == SR_FD) {
182                         copy_from_user((void *) dp, (void *)addr,
183                                 sizeof(struct pt_dspregs));
184                         ret = 0;
185                 }
186                 break;
187         }
188 #endif
189 #ifdef CONFIG_BINFMT_ELF_FDPIC
190         case PTRACE_GETFDPIC: {
191                 unsigned long tmp = 0;
192
193                 switch (addr) {
194                 case PTRACE_GETFDPIC_EXEC:
195                         tmp = child->mm->context.exec_fdpic_loadmap;
196                         break;
197                 case PTRACE_GETFDPIC_INTERP:
198                         tmp = child->mm->context.interp_fdpic_loadmap;
199                         break;
200                 default:
201                         break;
202                 }
203
204                 ret = 0;
205                 if (put_user(tmp, (unsigned long *) data)) {
206                         ret = -EFAULT;
207                         break;
208                 }
209                 break;
210         }
211 #endif
212         default:
213                 ret = ptrace_request(child, request, addr, data);
214                 break;
215         }
216
217         return ret;
218 }
219
220 static inline int audit_arch(void)
221 {
222         int arch = EM_SH;
223
224 #ifdef CONFIG_CPU_LITTLE_ENDIAN
225         arch |= __AUDIT_ARCH_LE;
226 #endif
227
228         return arch;
229 }
230
231 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
232 {
233         long ret = 0;
234
235         secure_computing(regs->regs[0]);
236
237         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
238             tracehook_report_syscall_entry(regs))
239                 /*
240                  * Tracing decided this syscall should not happen.
241                  * We'll return a bogus call number to get an ENOSYS
242                  * error, but leave the original number in regs->regs[0].
243                  */
244                 ret = -1L;
245
246         if (unlikely(current->audit_context))
247                 audit_syscall_entry(audit_arch(), regs->regs[3],
248                                     regs->regs[4], regs->regs[5],
249                                     regs->regs[6], regs->regs[7]);
250
251         return ret ?: regs->regs[0];
252 }
253
254 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
255 {
256         int step;
257
258         if (unlikely(current->audit_context))
259                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
260                                    regs->regs[0]);
261
262         step = test_thread_flag(TIF_SINGLESTEP);
263         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
264                 tracehook_report_syscall_exit(regs, step);
265 }