~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/avr32/kernel/ptrace.c

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.77 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (C) 2004-2006 Atmel Corporation
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License version 2 as
  6  * published by the Free Software Foundation.
  7  */
  8 #undef DEBUG
  9 #include <linux/kernel.h>
 10 #include <linux/sched.h>
 11 #include <linux/mm.h>
 12 #include <linux/ptrace.h>
 13 #include <linux/errno.h>
 14 #include <linux/user.h>
 15 #include <linux/security.h>
 16 #include <linux/unistd.h>
 17 #include <linux/notifier.h>
 18 
 19 #include <asm/traps.h>
 20 #include <asm/uaccess.h>
 21 #include <asm/ocd.h>
 22 #include <asm/mmu_context.h>
 23 #include <linux/kdebug.h>
 24 
 25 static struct pt_regs *get_user_regs(struct task_struct *tsk)
 26 {
 27         return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
 28                                   THREAD_SIZE - sizeof(struct pt_regs));
 29 }
 30 
 31 void user_enable_single_step(struct task_struct *tsk)
 32 {
 33         pr_debug("user_enable_single_step: pid=%u, PC=0x%08lx, SR=0x%08lx\n",
 34                  tsk->pid, task_pt_regs(tsk)->pc, task_pt_regs(tsk)->sr);
 35 
 36         /*
 37          * We can't schedule in Debug mode, so when TIF_BREAKPOINT is
 38          * set, the system call or exception handler will do a
 39          * breakpoint to enter monitor mode before returning to
 40          * userspace.
 41          *
 42          * The monitor code will then notice that TIF_SINGLE_STEP is
 43          * set and return to userspace with single stepping enabled.
 44          * The CPU will then enter monitor mode again after exactly
 45          * one instruction has been executed, and the monitor code
 46          * will then send a SIGTRAP to the process.
 47          */
 48         set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
 49         set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
 50 }
 51 
 52 void user_disable_single_step(struct task_struct *child)
 53 {
 54         /* XXX(hch): a no-op here seems wrong.. */
 55 }
 56 
 57 /*
 58  * Called by kernel/ptrace.c when detaching
 59  *
 60  * Make sure any single step bits, etc. are not set
 61  */
 62 void ptrace_disable(struct task_struct *child)
 63 {
 64         clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
 65         clear_tsk_thread_flag(child, TIF_BREAKPOINT);
 66         ocd_disable(child);
 67 }
 68 
 69 /*
 70  * Read the word at offset "offset" into the task's "struct user". We
 71  * actually access the pt_regs struct stored on the kernel stack.
 72  */
 73 static int ptrace_read_user(struct task_struct *tsk, unsigned long offset,
 74                             unsigned long __user *data)
 75 {
 76         unsigned long *regs;
 77         unsigned long value;
 78 
 79         if (offset & 3 || offset >= sizeof(struct user)) {
 80                 printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
 81                 return -EIO;
 82         }
 83 
 84         regs = (unsigned long *)get_user_regs(tsk);
 85 
 86         value = 0;
 87         if (offset < sizeof(struct pt_regs))
 88                 value = regs[offset / sizeof(regs[0])];
 89 
 90         pr_debug("ptrace_read_user(%s[%u], %#lx, %p) -> %#lx\n",
 91                  tsk->comm, tsk->pid, offset, data, value);
 92 
 93         return put_user(value, data);
 94 }
 95 
 96 /*
 97  * Write the word "value" to offset "offset" into the task's "struct
 98  * user". We actually access the pt_regs struct stored on the kernel
 99  * stack.
100  */
101 static int ptrace_write_user(struct task_struct *tsk, unsigned long offset,
102                              unsigned long value)
103 {
104         unsigned long *regs;
105 
106         pr_debug("ptrace_write_user(%s[%u], %#lx, %#lx)\n",
107                         tsk->comm, tsk->pid, offset, value);
108 
109         if (offset & 3 || offset >= sizeof(struct user)) {
110                 pr_debug("  invalid offset 0x%08lx\n", offset);
111                 return -EIO;
112         }
113 
114         if (offset >= sizeof(struct pt_regs))
115                 return 0;
116 
117         regs = (unsigned long *)get_user_regs(tsk);
118         regs[offset / sizeof(regs[0])] = value;
119 
120         return 0;
121 }
122 
123 static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
124 {
125         struct pt_regs *regs = get_user_regs(tsk);
126 
127         return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0;
128 }
129 
130 static int ptrace_setregs(struct task_struct *tsk, const void __user *uregs)
131 {
132         struct pt_regs newregs;
133         int ret;
134 
135         ret = -EFAULT;
136         if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) {
137                 struct pt_regs *regs = get_user_regs(tsk);
138 
139                 ret = -EINVAL;
140                 if (valid_user_regs(&newregs)) {
141                         *regs = newregs;
142                         ret = 0;
143                 }
144         }
145 
146         return ret;
147 }
148 
149 long arch_ptrace(struct task_struct *child, long request,
150                  unsigned long addr, unsigned long data)
151 {
152         int ret;
153         void __user *datap = (void __user *) data;
154 
155         switch (request) {
156         /* Read the word at location addr in the child process */
157         case PTRACE_PEEKTEXT:
158         case PTRACE_PEEKDATA:
159                 ret = generic_ptrace_peekdata(child, addr, data);
160                 break;
161 
162         case PTRACE_PEEKUSR:
163                 ret = ptrace_read_user(child, addr, datap);
164                 break;
165 
166         /* Write the word in data at location addr */
167         case PTRACE_POKETEXT:
168         case PTRACE_POKEDATA:
169                 ret = generic_ptrace_pokedata(child, addr, data);
170                 break;
171 
172         case PTRACE_POKEUSR:
173                 ret = ptrace_write_user(child, addr, data);
174                 break;
175 
176         case PTRACE_GETREGS:
177                 ret = ptrace_getregs(child, datap);
178                 break;
179 
180         case PTRACE_SETREGS:
181                 ret = ptrace_setregs(child, datap);
182                 break;
183 
184         default:
185                 ret = ptrace_request(child, request, addr, data);
186                 break;
187         }
188 
189         return ret;
190 }
191 
192 asmlinkage void syscall_trace(void)
193 {
194         if (!test_thread_flag(TIF_SYSCALL_TRACE))
195                 return;
196         if (!(current->ptrace & PT_PTRACED))
197                 return;
198 
199         /* The 0x80 provides a way for the tracing parent to
200          * distinguish between a syscall stop and SIGTRAP delivery */
201         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
202                                  ? 0x80 : 0));
203 
204         /*
205          * this isn't the same as continuing with a signal, but it
206          * will do for normal use.  strace only continues with a
207          * signal if the stopping signal is not SIGTRAP.  -brl
208          */
209         if (current->exit_code) {
210                 pr_debug("syscall_trace: sending signal %d to PID %u\n",
211                          current->exit_code, current->pid);
212                 send_sig(current->exit_code, current, 1);
213                 current->exit_code = 0;
214         }
215 }
216 
217 /*
218  * debug_trampoline() is an assembly stub which will store all user
219  * registers on the stack and execute a breakpoint instruction.
220  *
221  * If we single-step into an exception handler which runs with
222  * interrupts disabled the whole time so it doesn't have to check for
223  * pending work, its return address will be modified so that it ends
224  * up returning to debug_trampoline.
225  *
226  * If the exception handler decides to store the user context and
227  * enable interrupts after all, it will restore the original return
228  * address and status register value. Before it returns, it will
229  * notice that TIF_BREAKPOINT is set and execute a breakpoint
230  * instruction.
231  */
232 extern void debug_trampoline(void);
233 
234 asmlinkage struct pt_regs *do_debug(struct pt_regs *regs)
235 {
236         struct thread_info      *ti;
237         unsigned long           trampoline_addr;
238         u32                     status;
239         u32                     ctrl;
240         int                     code;
241 
242         status = ocd_read(DS);
243         ti = current_thread_info();
244         code = TRAP_BRKPT;
245 
246         pr_debug("do_debug: status=0x%08x PC=0x%08lx SR=0x%08lx tif=0x%08lx\n",
247                         status, regs->pc, regs->sr, ti->flags);
248 
249         if (!user_mode(regs)) {
250                 unsigned long   die_val = DIE_BREAKPOINT;
251 
252                 if (status & (1 << OCD_DS_SSS_BIT))
253                         die_val = DIE_SSTEP;
254 
255                 if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP)
256                                 == NOTIFY_STOP)
257                         return regs;
258 
259                 if ((status & (1 << OCD_DS_SWB_BIT))
260                                 && test_and_clear_ti_thread_flag(
261                                         ti, TIF_BREAKPOINT)) {
262                         /*
263                          * Explicit breakpoint from trampoline or
264                          * exception/syscall/interrupt handler.
265                          *
266                          * The real saved regs are on the stack right
267                          * after the ones we saved on entry.
268                          */
269                         regs++;
270                         pr_debug("  -> TIF_BREAKPOINT done, adjusted regs:"
271                                         "PC=0x%08lx SR=0x%08lx\n",
272                                         regs->pc, regs->sr);
273                         BUG_ON(!user_mode(regs));
274 
275                         if (test_thread_flag(TIF_SINGLE_STEP)) {
276                                 pr_debug("Going to do single step...\n");
277                                 return regs;
278                         }
279 
280                         /*
281                          * No TIF_SINGLE_STEP means we're done
282                          * stepping over a syscall. Do the trap now.
283                          */
284                         code = TRAP_TRACE;
285                 } else if ((status & (1 << OCD_DS_SSS_BIT))
286                                 && test_ti_thread_flag(ti, TIF_SINGLE_STEP)) {
287 
288                         pr_debug("Stepped into something, "
289                                         "setting TIF_BREAKPOINT...\n");
290                         set_ti_thread_flag(ti, TIF_BREAKPOINT);
291 
292                         /*
293                          * We stepped into an exception, interrupt or
294                          * syscall handler. Some exception handlers
295                          * don't check for pending work, so we need to
296                          * set up a trampoline just in case.
297                          *
298                          * The exception entry code will undo the
299                          * trampoline stuff if it does a full context
300                          * save (which also means that it'll check for
301                          * pending work later.)
302                          */
303                         if ((regs->sr & MODE_MASK) == MODE_EXCEPTION) {
304                                 trampoline_addr
305                                         = (unsigned long)&debug_trampoline;
306 
307                                 pr_debug("Setting up trampoline...\n");
308                                 ti->rar_saved = sysreg_read(RAR_EX);
309                                 ti->rsr_saved = sysreg_read(RSR_EX);
310                                 sysreg_write(RAR_EX, trampoline_addr);
311                                 sysreg_write(RSR_EX, (MODE_EXCEPTION
312                                                         | SR_EM | SR_GM));
313                                 BUG_ON(ti->rsr_saved & MODE_MASK);
314                         }
315 
316                         /*
317                          * If we stepped into a system call, we
318                          * shouldn't do a single step after we return
319                          * since the return address is right after the
320                          * "scall" instruction we were told to step
321                          * over.
322                          */
323                         if ((regs->sr & MODE_MASK) == MODE_SUPERVISOR) {
324                                 pr_debug("Supervisor; no single step\n");
325                                 clear_ti_thread_flag(ti, TIF_SINGLE_STEP);
326                         }
327 
328                         ctrl = ocd_read(DC);
329                         ctrl &= ~(1 << OCD_DC_SS_BIT);
330                         ocd_write(DC, ctrl);
331 
332                         return regs;
333                 } else {
334                         printk(KERN_ERR "Unexpected OCD_DS value: 0x%08x\n",
335                                         status);
336                         printk(KERN_ERR "Thread flags: 0x%08lx\n", ti->flags);
337                         die("Unhandled debug trap in kernel mode",
338                                         regs, SIGTRAP);
339                 }
340         } else if (status & (1 << OCD_DS_SSS_BIT)) {
341                 /* Single step in user mode */
342                 code = TRAP_TRACE;
343 
344                 ctrl = ocd_read(DC);
345                 ctrl &= ~(1 << OCD_DC_SS_BIT);
346                 ocd_write(DC, ctrl);
347         }
348 
349         pr_debug("Sending SIGTRAP: code=%d PC=0x%08lx SR=0x%08lx\n",
350                         code, regs->pc, regs->sr);
351 
352         clear_thread_flag(TIF_SINGLE_STEP);
353         _exception(SIGTRAP, regs, code, instruction_pointer(regs));
354 
355         return regs;
356 }
357 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp