Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Kernel support for the ptrace() and syscall tracing interfaces. | |
3 | * | |
4 | * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc. | |
5 | * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx> | |
6 | * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org> | |
81e192d6 | 7 | * Copyright (C) 2008 Helge Deller <deller@gmx.de> |
1da177e4 LT |
8 | */ |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/sched.h> | |
12 | #include <linux/mm.h> | |
13 | #include <linux/smp.h> | |
1da177e4 LT |
14 | #include <linux/errno.h> |
15 | #include <linux/ptrace.h> | |
d6b58772 | 16 | #include <linux/tracehook.h> |
1da177e4 LT |
17 | #include <linux/user.h> |
18 | #include <linux/personality.h> | |
19 | #include <linux/security.h> | |
fe5c8734 | 20 | #include <linux/seccomp.h> |
1da177e4 | 21 | #include <linux/compat.h> |
7ed20e1a | 22 | #include <linux/signal.h> |
527973c8 | 23 | #include <linux/audit.h> |
1da177e4 LT |
24 | |
25 | #include <asm/uaccess.h> | |
26 | #include <asm/pgtable.h> | |
1da177e4 | 27 | #include <asm/processor.h> |
0013a854 | 28 | #include <asm/asm-offsets.h> |
1da177e4 LT |
29 | |
30 | /* PSW bits we allow the debugger to modify */ | |
34360f08 | 31 | #define USER_PSW_BITS (PSW_N | PSW_B | PSW_V | PSW_CB) |
1da177e4 | 32 | |
81e192d6 HD |
33 | /* |
34 | * Called by kernel/ptrace.c when detaching.. | |
35 | * | |
36 | * Make sure single step bits etc are not set. | |
37 | */ | |
38 | void ptrace_disable(struct task_struct *task) | |
39 | { | |
ecd3d4bc KM |
40 | clear_tsk_thread_flag(task, TIF_SINGLESTEP); |
41 | clear_tsk_thread_flag(task, TIF_BLOCKSTEP); | |
1da177e4 | 42 | |
81e192d6 HD |
43 | /* make sure the trap bits are not set */ |
44 | pa_psw(task)->r = 0; | |
45 | pa_psw(task)->t = 0; | |
46 | pa_psw(task)->h = 0; | |
47 | pa_psw(task)->l = 0; | |
48 | } | |
49 | ||
50 | /* | |
51 | * The following functions are called by ptrace_resume() when | |
52 | * enabling or disabling single/block tracing. | |
53 | */ | |
54 | void user_disable_single_step(struct task_struct *task) | |
55 | { | |
56 | ptrace_disable(task); | |
57 | } | |
58 | ||
59 | void user_enable_single_step(struct task_struct *task) | |
60 | { | |
ecd3d4bc KM |
61 | clear_tsk_thread_flag(task, TIF_BLOCKSTEP); |
62 | set_tsk_thread_flag(task, TIF_SINGLESTEP); | |
81e192d6 HD |
63 | |
64 | if (pa_psw(task)->n) { | |
65 | struct siginfo si; | |
66 | ||
67 | /* Nullified, just crank over the queue. */ | |
68 | task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1]; | |
69 | task_regs(task)->iasq[0] = task_regs(task)->iasq[1]; | |
70 | task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4; | |
71 | pa_psw(task)->n = 0; | |
72 | pa_psw(task)->x = 0; | |
73 | pa_psw(task)->y = 0; | |
74 | pa_psw(task)->z = 0; | |
75 | pa_psw(task)->b = 0; | |
76 | ptrace_disable(task); | |
77 | /* Don't wake up the task, but let the | |
78 | parent know something happened. */ | |
79 | si.si_code = TRAP_TRACE; | |
80 | si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3); | |
81 | si.si_signo = SIGTRAP; | |
82 | si.si_errno = 0; | |
83 | force_sig_info(SIGTRAP, &si, task); | |
84 | /* notify_parent(task, SIGCHLD); */ | |
85 | return; | |
86 | } | |
87 | ||
88 | /* Enable recovery counter traps. The recovery counter | |
89 | * itself will be set to zero on a task switch. If the | |
90 | * task is suspended on a syscall then the syscall return | |
91 | * path will overwrite the recovery counter with a suitable | |
92 | * value such that it traps once back in user space. We | |
93 | * disable interrupts in the tasks PSW here also, to avoid | |
94 | * interrupts while the recovery counter is decrementing. | |
95 | */ | |
96 | pa_psw(task)->r = 1; | |
97 | pa_psw(task)->t = 0; | |
98 | pa_psw(task)->h = 0; | |
99 | pa_psw(task)->l = 0; | |
100 | } | |
101 | ||
102 | void user_enable_block_step(struct task_struct *task) | |
103 | { | |
ecd3d4bc KM |
104 | clear_tsk_thread_flag(task, TIF_SINGLESTEP); |
105 | set_tsk_thread_flag(task, TIF_BLOCKSTEP); | |
81e192d6 HD |
106 | |
107 | /* Enable taken branch trap. */ | |
108 | pa_psw(task)->r = 0; | |
109 | pa_psw(task)->t = 1; | |
110 | pa_psw(task)->h = 0; | |
111 | pa_psw(task)->l = 0; | |
112 | } | |
113 | ||
9b05a69e NK |
114 | long arch_ptrace(struct task_struct *child, long request, |
115 | unsigned long addr, unsigned long data) | |
81e192d6 HD |
116 | { |
117 | unsigned long tmp; | |
118 | long ret = -EIO; | |
1da177e4 | 119 | |
81e192d6 HD |
120 | switch (request) { |
121 | ||
122 | /* Read the word at location addr in the USER area. For ptraced | |
123 | processes, the kernel saves all regs on a syscall. */ | |
124 | case PTRACE_PEEKUSR: | |
9b05a69e NK |
125 | if ((addr & (sizeof(unsigned long)-1)) || |
126 | addr >= sizeof(struct pt_regs)) | |
81e192d6 HD |
127 | break; |
128 | tmp = *(unsigned long *) ((char *) task_regs(child) + addr); | |
1cb4953c | 129 | ret = put_user(tmp, (unsigned long __user *) data); |
81e192d6 HD |
130 | break; |
131 | ||
132 | /* Write the word at location addr in the USER area. This will need | |
133 | to change when the kernel no longer saves all regs on a syscall. | |
134 | FIXME. There is a problem at the moment in that r3-r18 are only | |
135 | saved if the process is ptraced on syscall entry, and even then | |
136 | those values are overwritten by actual register values on syscall | |
137 | exit. */ | |
138 | case PTRACE_POKEUSR: | |
139 | /* Some register values written here may be ignored in | |
140 | * entry.S:syscall_restore_rfi; e.g. iaoq is written with | |
141 | * r31/r31+4, and not with the values in pt_regs. | |
142 | */ | |
143 | if (addr == PT_PSW) { | |
144 | /* Allow writing to Nullify, Divide-step-correction, | |
145 | * and carry/borrow bits. | |
146 | * BEWARE, if you set N, and then single step, it won't | |
147 | * stop on the nullified instruction. | |
148 | */ | |
149 | data &= USER_PSW_BITS; | |
150 | task_regs(child)->gr[0] &= ~USER_PSW_BITS; | |
151 | task_regs(child)->gr[0] |= data; | |
152 | ret = 0; | |
153 | break; | |
154 | } | |
155 | ||
9b05a69e NK |
156 | if ((addr & (sizeof(unsigned long)-1)) || |
157 | addr >= sizeof(struct pt_regs)) | |
81e192d6 HD |
158 | break; |
159 | if ((addr >= PT_GR1 && addr <= PT_GR31) || | |
160 | addr == PT_IAOQ0 || addr == PT_IAOQ1 || | |
161 | (addr >= PT_FR0 && addr <= PT_FR31 + 4) || | |
162 | addr == PT_SAR) { | |
163 | *(unsigned long *) ((char *) task_regs(child) + addr) = data; | |
164 | ret = 0; | |
165 | } | |
166 | break; | |
167 | ||
168 | default: | |
169 | ret = ptrace_request(child, request, addr, data); | |
170 | break; | |
171 | } | |
172 | ||
173 | return ret; | |
174 | } | |
175 | ||
176 | ||
177 | #ifdef CONFIG_COMPAT | |
1da177e4 LT |
178 | |
179 | /* This function is needed to translate 32 bit pt_regs offsets in to | |
180 | * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel | |
181 | * will request offset 12 if it wants gr3, but the lower 32 bits of | |
182 | * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4). | |
183 | * This code relies on a 32 bit pt_regs being comprised of 32 bit values | |
184 | * except for the fp registers which (a) are 64 bits, and (b) follow | |
185 | * the gr registers at the start of pt_regs. The 32 bit pt_regs should | |
186 | * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[] | |
187 | * being 64 bit in both cases. | |
188 | */ | |
189 | ||
ed79b86d | 190 | static compat_ulong_t translate_usr_offset(compat_ulong_t offset) |
1da177e4 LT |
191 | { |
192 | if (offset < 0) | |
ed79b86d | 193 | return sizeof(struct pt_regs); |
1da177e4 LT |
194 | else if (offset <= 32*4) /* gr[0..31] */ |
195 | return offset * 2 + 4; | |
196 | else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */ | |
197 | return offset + 32*4; | |
198 | else if (offset < sizeof(struct pt_regs)/2 + 32*4) | |
199 | return offset * 2 + 4 - 32*8; | |
200 | else | |
ed79b86d | 201 | return sizeof(struct pt_regs); |
1da177e4 | 202 | } |
1da177e4 | 203 | |
81e192d6 HD |
204 | long compat_arch_ptrace(struct task_struct *child, compat_long_t request, |
205 | compat_ulong_t addr, compat_ulong_t data) | |
1da177e4 | 206 | { |
81e192d6 HD |
207 | compat_uint_t tmp; |
208 | long ret = -EIO; | |
1da177e4 | 209 | |
1da177e4 | 210 | switch (request) { |
1da177e4 | 211 | |
81e192d6 HD |
212 | case PTRACE_PEEKUSR: |
213 | if (addr & (sizeof(compat_uint_t)-1)) | |
214 | break; | |
215 | addr = translate_usr_offset(addr); | |
ed79b86d | 216 | if (addr >= sizeof(struct pt_regs)) |
81e192d6 | 217 | break; |
1da177e4 | 218 | |
81e192d6 HD |
219 | tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr); |
220 | ret = put_user(tmp, (compat_uint_t *) (unsigned long) data); | |
221 | break; | |
1da177e4 LT |
222 | |
223 | /* Write the word at location addr in the USER area. This will need | |
224 | to change when the kernel no longer saves all regs on a syscall. | |
225 | FIXME. There is a problem at the moment in that r3-r18 are only | |
226 | saved if the process is ptraced on syscall entry, and even then | |
227 | those values are overwritten by actual register values on syscall | |
228 | exit. */ | |
229 | case PTRACE_POKEUSR: | |
1da177e4 LT |
230 | /* Some register values written here may be ignored in |
231 | * entry.S:syscall_restore_rfi; e.g. iaoq is written with | |
232 | * r31/r31+4, and not with the values in pt_regs. | |
233 | */ | |
1da177e4 | 234 | if (addr == PT_PSW) { |
81e192d6 HD |
235 | /* Since PT_PSW==0, it is valid for 32 bit processes |
236 | * under 64 bit kernels as well. | |
1da177e4 | 237 | */ |
81e192d6 HD |
238 | ret = arch_ptrace(child, request, addr, data); |
239 | } else { | |
240 | if (addr & (sizeof(compat_uint_t)-1)) | |
241 | break; | |
242 | addr = translate_usr_offset(addr); | |
ed79b86d | 243 | if (addr >= sizeof(struct pt_regs)) |
81e192d6 | 244 | break; |
1da177e4 LT |
245 | if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { |
246 | /* Special case, fp regs are 64 bits anyway */ | |
81e192d6 | 247 | *(__u64 *) ((char *) task_regs(child) + addr) = data; |
1da177e4 LT |
248 | ret = 0; |
249 | } | |
250 | else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) || | |
251 | addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 || | |
252 | addr == PT_SAR+4) { | |
253 | /* Zero the top 32 bits */ | |
81e192d6 HD |
254 | *(__u32 *) ((char *) task_regs(child) + addr - 4) = 0; |
255 | *(__u32 *) ((char *) task_regs(child) + addr) = data; | |
1da177e4 LT |
256 | ret = 0; |
257 | } | |
1da177e4 | 258 | } |
81e192d6 | 259 | break; |
1da177e4 LT |
260 | |
261 | default: | |
81e192d6 HD |
262 | ret = compat_ptrace_request(child, request, addr, data); |
263 | break; | |
1da177e4 LT |
264 | } |
265 | ||
1da177e4 LT |
266 | return ret; |
267 | } | |
81e192d6 HD |
268 | #endif |
269 | ||
2798af1a KM |
270 | long do_syscall_trace_enter(struct pt_regs *regs) |
271 | { | |
c90f0694 | 272 | /* Do the secure computing check first. */ |
910cd32e HD |
273 | if (secure_computing() == -1) |
274 | return -1; | |
c90f0694 | 275 | |
2798af1a | 276 | if (test_thread_flag(TIF_SYSCALL_TRACE) && |
98e8b6c9 HD |
277 | tracehook_report_syscall_entry(regs)) { |
278 | /* | |
279 | * Tracing decided this syscall should not happen or the | |
280 | * debugger stored an invalid system call number. Skip | |
281 | * the system call and the system call restart handling. | |
282 | */ | |
283 | regs->gr[20] = -1UL; | |
284 | goto out; | |
285 | } | |
527973c8 HD |
286 | |
287 | #ifdef CONFIG_64BIT | |
288 | if (!is_compat_task()) | |
91397401 EP |
289 | audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25], |
290 | regs->gr[24], regs->gr[23]); | |
527973c8 HD |
291 | else |
292 | #endif | |
91397401 | 293 | audit_syscall_entry(regs->gr[20] & 0xffffffff, |
527973c8 HD |
294 | regs->gr[26] & 0xffffffff, |
295 | regs->gr[25] & 0xffffffff, | |
296 | regs->gr[24] & 0xffffffff, | |
297 | regs->gr[23] & 0xffffffff); | |
298 | ||
98e8b6c9 | 299 | out: |
910cd32e HD |
300 | /* |
301 | * Sign extend the syscall number to 64bit since it may have been | |
302 | * modified by a compat ptrace call | |
303 | */ | |
304 | return (int) ((u32) regs->gr[20]); | |
2798af1a | 305 | } |
1da177e4 | 306 | |
2798af1a | 307 | void do_syscall_trace_exit(struct pt_regs *regs) |
1da177e4 | 308 | { |
ecd3d4bc KM |
309 | int stepping = test_thread_flag(TIF_SINGLESTEP) || |
310 | test_thread_flag(TIF_BLOCKSTEP); | |
d6b58772 | 311 | |
527973c8 HD |
312 | audit_syscall_exit(regs); |
313 | ||
2798af1a KM |
314 | if (stepping || test_thread_flag(TIF_SYSCALL_TRACE)) |
315 | tracehook_report_syscall_exit(regs, stepping); | |
1da177e4 | 316 | } |