2 * Kernel support for the ptrace() and syscall tracing interfaces.
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>
7 * Copyright (C) 2008 Helge Deller <deller@gmx.de>
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
13 #include <linux/smp.h>
14 #include <linux/errno.h>
15 #include <linux/ptrace.h>
16 #include <linux/tracehook.h>
17 #include <linux/user.h>
18 #include <linux/personality.h>
19 #include <linux/security.h>
20 #include <linux/seccomp.h>
21 #include <linux/compat.h>
22 #include <linux/signal.h>
23 #include <linux/audit.h>
25 #include <asm/uaccess.h>
26 #include <asm/pgtable.h>
27 #include <asm/processor.h>
28 #include <asm/asm-offsets.h>
30 /* PSW bits we allow the debugger to modify */
31 #define USER_PSW_BITS (PSW_N | PSW_B | PSW_V | PSW_CB)
34 * Called by kernel/ptrace.c when detaching..
36 * Make sure single step bits etc are not set.
38 void ptrace_disable(struct task_struct *task)
40 clear_tsk_thread_flag(task, TIF_SINGLESTEP);
41 clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
43 /* make sure the trap bits are not set */
51 * The following functions are called by ptrace_resume() when
52 * enabling or disabling single/block tracing.
54 void user_disable_single_step(struct task_struct *task)
59 void user_enable_single_step(struct task_struct *task)
61 clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
62 set_tsk_thread_flag(task, TIF_SINGLESTEP);
64 if (pa_psw(task)->n) {
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;
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;
83 force_sig_info(SIGTRAP, &si, task);
84 /* notify_parent(task, SIGCHLD); */
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.
102 void user_enable_block_step(struct task_struct *task)
104 clear_tsk_thread_flag(task, TIF_SINGLESTEP);
105 set_tsk_thread_flag(task, TIF_BLOCKSTEP);
107 /* Enable taken branch trap. */
114 long arch_ptrace(struct task_struct *child, long request,
115 unsigned long addr, unsigned long data)
122 /* Read the word at location addr in the USER area. For ptraced
123 processes, the kernel saves all regs on a syscall. */
125 if ((addr & (sizeof(unsigned long)-1)) ||
126 addr >= sizeof(struct pt_regs))
128 tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
129 ret = put_user(tmp, (unsigned long __user *) data);
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
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.
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.
149 data &= USER_PSW_BITS;
150 task_regs(child)->gr[0] &= ~USER_PSW_BITS;
151 task_regs(child)->gr[0] |= data;
156 if ((addr & (sizeof(unsigned long)-1)) ||
157 addr >= sizeof(struct pt_regs))
159 if (addr == PT_IAOQ0 || addr == PT_IAOQ1) {
160 data |= 3; /* ensure userspace privilege */
162 if ((addr >= PT_GR1 && addr <= PT_GR31) ||
163 addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
164 (addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
166 *(unsigned long *) ((char *) task_regs(child) + addr) = data;
172 ret = ptrace_request(child, request, addr, data);
182 /* This function is needed to translate 32 bit pt_regs offsets in to
183 * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel
184 * will request offset 12 if it wants gr3, but the lower 32 bits of
185 * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
186 * This code relies on a 32 bit pt_regs being comprised of 32 bit values
187 * except for the fp registers which (a) are 64 bits, and (b) follow
188 * the gr registers at the start of pt_regs. The 32 bit pt_regs should
189 * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
190 * being 64 bit in both cases.
193 static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
197 if (offset < 32*4) /* gr[0..31] */
198 pos = offset * 2 + 4;
199 else if (offset < 32*4+32*8) /* fr[0] ... fr[31] */
200 pos = (offset - 32*4) + PT_FR0;
201 else if (offset < sizeof(struct pt_regs)/2 + 32*4) /* sr[0] ... ipsw */
202 pos = (offset - 32*4 - 32*8) * 2 + PT_SR0 + 4;
204 pos = sizeof(struct pt_regs);
209 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
210 compat_ulong_t addr, compat_ulong_t data)
218 if (addr & (sizeof(compat_uint_t)-1))
220 addr = translate_usr_offset(addr);
221 if (addr >= sizeof(struct pt_regs))
224 tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
225 ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
228 /* Write the word at location addr in the USER area. This will need
229 to change when the kernel no longer saves all regs on a syscall.
230 FIXME. There is a problem at the moment in that r3-r18 are only
231 saved if the process is ptraced on syscall entry, and even then
232 those values are overwritten by actual register values on syscall
235 /* Some register values written here may be ignored in
236 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
237 * r31/r31+4, and not with the values in pt_regs.
239 if (addr == PT_PSW) {
240 /* Since PT_PSW==0, it is valid for 32 bit processes
241 * under 64 bit kernels as well.
243 ret = arch_ptrace(child, request, addr, data);
245 if (addr & (sizeof(compat_uint_t)-1))
247 addr = translate_usr_offset(addr);
248 if (addr >= sizeof(struct pt_regs))
250 if (addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4) {
251 data |= 3; /* ensure userspace privilege */
253 if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
254 /* Special case, fp regs are 64 bits anyway */
255 *(__u32 *) ((char *) task_regs(child) + addr) = data;
258 else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
259 addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
261 /* Zero the top 32 bits */
262 *(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
263 *(__u32 *) ((char *) task_regs(child) + addr) = data;
270 ret = compat_ptrace_request(child, request, addr, data);
278 long do_syscall_trace_enter(struct pt_regs *regs)
280 /* Do the secure computing check first. */
281 secure_computing_strict(regs->gr[20]);
283 if (test_thread_flag(TIF_SYSCALL_TRACE) &&
284 tracehook_report_syscall_entry(regs)) {
286 * Tracing decided this syscall should not happen or the
287 * debugger stored an invalid system call number. Skip
288 * the system call and the system call restart handling.
295 if (!is_compat_task())
296 audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
297 regs->gr[24], regs->gr[23]);
300 audit_syscall_entry(regs->gr[20] & 0xffffffff,
301 regs->gr[26] & 0xffffffff,
302 regs->gr[25] & 0xffffffff,
303 regs->gr[24] & 0xffffffff,
304 regs->gr[23] & 0xffffffff);
310 void do_syscall_trace_exit(struct pt_regs *regs)
312 int stepping = test_thread_flag(TIF_SINGLESTEP) ||
313 test_thread_flag(TIF_BLOCKSTEP);
315 audit_syscall_exit(regs);
317 if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
318 tracehook_report_syscall_exit(regs, stepping);