Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 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> |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 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> |
Christoph Hellwig | 1eeb66a | 2007-05-08 00:27:03 -0700 | [diff] [blame] | 23 | #include <linux/kdebug.h> |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 24 | |
| 25 | static struct pt_regs *get_user_regs(struct task_struct *tsk) |
| 26 | { |
Roman Zippel | c9f4f06 | 2007-05-09 02:35:16 -0700 | [diff] [blame] | 27 | return (struct pt_regs *)((unsigned long)task_stack_page(tsk) + |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 28 | THREAD_SIZE - sizeof(struct pt_regs)); |
| 29 | } |
| 30 | |
| 31 | static void ptrace_single_step(struct task_struct *tsk) |
| 32 | { |
| 33 | pr_debug("ptrace_single_step: pid=%u, SR=0x%08lx\n", |
| 34 | tsk->pid, tsk->thread.cpu_context.sr); |
| 35 | if (!(tsk->thread.cpu_context.sr & SR_D)) { |
| 36 | /* |
| 37 | * Set a breakpoint at the current pc to force the |
| 38 | * process into debug mode. The syscall/exception |
| 39 | * exit code will set a breakpoint at the return |
| 40 | * address when this flag is set. |
| 41 | */ |
| 42 | pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n"); |
| 43 | set_tsk_thread_flag(tsk, TIF_BREAKPOINT); |
| 44 | } |
| 45 | |
| 46 | /* The monitor code will do the actual step for us */ |
| 47 | set_tsk_thread_flag(tsk, TIF_SINGLE_STEP); |
| 48 | } |
| 49 | |
| 50 | /* |
| 51 | * Called by kernel/ptrace.c when detaching |
| 52 | * |
| 53 | * Make sure any single step bits, etc. are not set |
| 54 | */ |
| 55 | void ptrace_disable(struct task_struct *child) |
| 56 | { |
| 57 | clear_tsk_thread_flag(child, TIF_SINGLE_STEP); |
| 58 | } |
| 59 | |
| 60 | /* |
| 61 | * Handle hitting a breakpoint |
| 62 | */ |
| 63 | static void ptrace_break(struct task_struct *tsk, struct pt_regs *regs) |
| 64 | { |
| 65 | siginfo_t info; |
| 66 | |
| 67 | info.si_signo = SIGTRAP; |
| 68 | info.si_errno = 0; |
| 69 | info.si_code = TRAP_BRKPT; |
| 70 | info.si_addr = (void __user *)instruction_pointer(regs); |
| 71 | |
| 72 | pr_debug("ptrace_break: Sending SIGTRAP to PID %u (pc = 0x%p)\n", |
| 73 | tsk->pid, info.si_addr); |
| 74 | force_sig_info(SIGTRAP, &info, tsk); |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * Read the word at offset "offset" into the task's "struct user". We |
| 79 | * actually access the pt_regs struct stored on the kernel stack. |
| 80 | */ |
| 81 | static int ptrace_read_user(struct task_struct *tsk, unsigned long offset, |
| 82 | unsigned long __user *data) |
| 83 | { |
| 84 | unsigned long *regs; |
| 85 | unsigned long value; |
| 86 | |
| 87 | pr_debug("ptrace_read_user(%p, %#lx, %p)\n", |
| 88 | tsk, offset, data); |
| 89 | |
| 90 | if (offset & 3 || offset >= sizeof(struct user)) { |
| 91 | printk("ptrace_read_user: invalid offset 0x%08lx\n", offset); |
| 92 | return -EIO; |
| 93 | } |
| 94 | |
| 95 | regs = (unsigned long *)get_user_regs(tsk); |
| 96 | |
| 97 | value = 0; |
| 98 | if (offset < sizeof(struct pt_regs)) |
| 99 | value = regs[offset / sizeof(regs[0])]; |
| 100 | |
| 101 | return put_user(value, data); |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * Write the word "value" to offset "offset" into the task's "struct |
| 106 | * user". We actually access the pt_regs struct stored on the kernel |
| 107 | * stack. |
| 108 | */ |
| 109 | static int ptrace_write_user(struct task_struct *tsk, unsigned long offset, |
| 110 | unsigned long value) |
| 111 | { |
| 112 | unsigned long *regs; |
| 113 | |
| 114 | if (offset & 3 || offset >= sizeof(struct user)) { |
| 115 | printk("ptrace_write_user: invalid offset 0x%08lx\n", offset); |
| 116 | return -EIO; |
| 117 | } |
| 118 | |
| 119 | if (offset >= sizeof(struct pt_regs)) |
| 120 | return 0; |
| 121 | |
| 122 | regs = (unsigned long *)get_user_regs(tsk); |
| 123 | regs[offset / sizeof(regs[0])] = value; |
| 124 | |
| 125 | return 0; |
| 126 | } |
| 127 | |
| 128 | static int ptrace_getregs(struct task_struct *tsk, void __user *uregs) |
| 129 | { |
| 130 | struct pt_regs *regs = get_user_regs(tsk); |
| 131 | |
| 132 | return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0; |
| 133 | } |
| 134 | |
| 135 | static int ptrace_setregs(struct task_struct *tsk, const void __user *uregs) |
| 136 | { |
| 137 | struct pt_regs newregs; |
| 138 | int ret; |
| 139 | |
| 140 | ret = -EFAULT; |
| 141 | if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) { |
| 142 | struct pt_regs *regs = get_user_regs(tsk); |
| 143 | |
| 144 | ret = -EINVAL; |
| 145 | if (valid_user_regs(&newregs)) { |
| 146 | *regs = newregs; |
| 147 | ret = 0; |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | return ret; |
| 152 | } |
| 153 | |
| 154 | long arch_ptrace(struct task_struct *child, long request, long addr, long data) |
| 155 | { |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 156 | int ret; |
| 157 | |
Haavard Skinnemoen | 6ea850b | 2006-10-24 10:12:40 +0200 | [diff] [blame] | 158 | pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n", |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 159 | request, child->pid, addr, data); |
| 160 | |
| 161 | pr_debug("ptrace: Enabling monitor mode...\n"); |
| 162 | __mtdr(DBGREG_DC, __mfdr(DBGREG_DC) | DC_MM | DC_DBE); |
| 163 | |
| 164 | switch (request) { |
| 165 | /* Read the word at location addr in the child process */ |
| 166 | case PTRACE_PEEKTEXT: |
| 167 | case PTRACE_PEEKDATA: |
Alexey Dobriyan | 7664732 | 2007-07-17 04:03:43 -0700 | [diff] [blame] | 168 | ret = generic_ptrace_peekdata(child, addr, data); |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 169 | break; |
| 170 | |
| 171 | case PTRACE_PEEKUSR: |
| 172 | ret = ptrace_read_user(child, addr, |
| 173 | (unsigned long __user *)data); |
| 174 | break; |
| 175 | |
| 176 | /* Write the word in data at location addr */ |
| 177 | case PTRACE_POKETEXT: |
| 178 | case PTRACE_POKEDATA: |
Alexey Dobriyan | f284ce7 | 2007-07-17 04:03:44 -0700 | [diff] [blame^] | 179 | ret = generic_ptrace_pokedata(child, addr, data); |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 180 | break; |
| 181 | |
| 182 | case PTRACE_POKEUSR: |
| 183 | ret = ptrace_write_user(child, addr, data); |
| 184 | break; |
| 185 | |
| 186 | /* continue and stop at next (return from) syscall */ |
| 187 | case PTRACE_SYSCALL: |
| 188 | /* restart after signal */ |
| 189 | case PTRACE_CONT: |
| 190 | ret = -EIO; |
| 191 | if (!valid_signal(data)) |
| 192 | break; |
| 193 | if (request == PTRACE_SYSCALL) |
| 194 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
| 195 | else |
| 196 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
| 197 | child->exit_code = data; |
| 198 | /* XXX: Are we sure no breakpoints are active here? */ |
| 199 | wake_up_process(child); |
| 200 | ret = 0; |
| 201 | break; |
| 202 | |
| 203 | /* |
| 204 | * Make the child exit. Best I can do is send it a |
| 205 | * SIGKILL. Perhaps it should be put in the status that it |
| 206 | * wants to exit. |
| 207 | */ |
| 208 | case PTRACE_KILL: |
| 209 | ret = 0; |
| 210 | if (child->exit_state == EXIT_ZOMBIE) |
| 211 | break; |
| 212 | child->exit_code = SIGKILL; |
| 213 | wake_up_process(child); |
| 214 | break; |
| 215 | |
| 216 | /* |
| 217 | * execute single instruction. |
| 218 | */ |
| 219 | case PTRACE_SINGLESTEP: |
| 220 | ret = -EIO; |
| 221 | if (!valid_signal(data)) |
| 222 | break; |
| 223 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
| 224 | ptrace_single_step(child); |
| 225 | child->exit_code = data; |
| 226 | wake_up_process(child); |
| 227 | ret = 0; |
| 228 | break; |
| 229 | |
| 230 | /* Detach a process that was attached */ |
| 231 | case PTRACE_DETACH: |
| 232 | ret = ptrace_detach(child, data); |
| 233 | break; |
| 234 | |
| 235 | case PTRACE_GETREGS: |
| 236 | ret = ptrace_getregs(child, (void __user *)data); |
| 237 | break; |
| 238 | |
| 239 | case PTRACE_SETREGS: |
| 240 | ret = ptrace_setregs(child, (const void __user *)data); |
| 241 | break; |
| 242 | |
| 243 | default: |
| 244 | ret = ptrace_request(child, request, addr, data); |
| 245 | break; |
| 246 | } |
| 247 | |
| 248 | pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC)); |
| 249 | return ret; |
| 250 | } |
| 251 | |
| 252 | asmlinkage void syscall_trace(void) |
| 253 | { |
| 254 | pr_debug("syscall_trace called\n"); |
| 255 | if (!test_thread_flag(TIF_SYSCALL_TRACE)) |
| 256 | return; |
| 257 | if (!(current->ptrace & PT_PTRACED)) |
| 258 | return; |
| 259 | |
| 260 | pr_debug("syscall_trace: notifying parent\n"); |
| 261 | /* The 0x80 provides a way for the tracing parent to |
| 262 | * distinguish between a syscall stop and SIGTRAP delivery */ |
| 263 | ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) |
| 264 | ? 0x80 : 0)); |
| 265 | |
| 266 | /* |
| 267 | * this isn't the same as continuing with a signal, but it |
| 268 | * will do for normal use. strace only continues with a |
| 269 | * signal if the stopping signal is not SIGTRAP. -brl |
| 270 | */ |
| 271 | if (current->exit_code) { |
| 272 | pr_debug("syscall_trace: sending signal %d to PID %u\n", |
| 273 | current->exit_code, current->pid); |
| 274 | send_sig(current->exit_code, current, 1); |
| 275 | current->exit_code = 0; |
| 276 | } |
| 277 | } |
| 278 | |
| 279 | asmlinkage void do_debug_priv(struct pt_regs *regs) |
| 280 | { |
| 281 | unsigned long dc, ds; |
| 282 | unsigned long die_val; |
| 283 | |
| 284 | ds = __mfdr(DBGREG_DS); |
| 285 | |
| 286 | pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds); |
| 287 | |
| 288 | if (ds & DS_SSS) |
| 289 | die_val = DIE_SSTEP; |
| 290 | else |
| 291 | die_val = DIE_BREAKPOINT; |
| 292 | |
Christoph Hellwig | 1eeb66a | 2007-05-08 00:27:03 -0700 | [diff] [blame] | 293 | if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP) == NOTIFY_STOP) |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 294 | return; |
| 295 | |
| 296 | if (likely(ds & DS_SSS)) { |
| 297 | extern void itlb_miss(void); |
| 298 | extern void tlb_miss_common(void); |
| 299 | struct thread_info *ti; |
| 300 | |
| 301 | dc = __mfdr(DBGREG_DC); |
| 302 | dc &= ~DC_SS; |
| 303 | __mtdr(DBGREG_DC, dc); |
| 304 | |
| 305 | ti = current_thread_info(); |
Haavard Skinnemoen | a19b4a1 | 2007-03-01 10:37:35 +0100 | [diff] [blame] | 306 | set_ti_thread_flag(ti, TIF_BREAKPOINT); |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 307 | |
| 308 | /* The TLB miss handlers don't check thread flags */ |
| 309 | if ((regs->pc >= (unsigned long)&itlb_miss) |
| 310 | && (regs->pc <= (unsigned long)&tlb_miss_common)) { |
| 311 | __mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX)); |
| 312 | __mtdr(DBGREG_BWC2A, 0x40000001 | (get_asid() << 1)); |
| 313 | } |
| 314 | |
| 315 | /* |
| 316 | * If we're running in supervisor mode, the breakpoint |
| 317 | * will take us where we want directly, no need to |
| 318 | * single step. |
| 319 | */ |
| 320 | if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR) |
Haavard Skinnemoen | a19b4a1 | 2007-03-01 10:37:35 +0100 | [diff] [blame] | 321 | set_ti_thread_flag(ti, TIF_SINGLE_STEP); |
Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 322 | } else { |
| 323 | panic("Unable to handle debug trap at pc = %08lx\n", |
| 324 | regs->pc); |
| 325 | } |
| 326 | } |
| 327 | |
| 328 | /* |
| 329 | * Handle breakpoints, single steps and other debuggy things. To keep |
| 330 | * things simple initially, we run with interrupts and exceptions |
| 331 | * disabled all the time. |
| 332 | */ |
| 333 | asmlinkage void do_debug(struct pt_regs *regs) |
| 334 | { |
| 335 | unsigned long dc, ds; |
| 336 | |
| 337 | ds = __mfdr(DBGREG_DS); |
| 338 | pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds); |
| 339 | |
| 340 | if (test_thread_flag(TIF_BREAKPOINT)) { |
| 341 | pr_debug("TIF_BREAKPOINT set\n"); |
| 342 | /* We're taking care of it */ |
| 343 | clear_thread_flag(TIF_BREAKPOINT); |
| 344 | __mtdr(DBGREG_BWC2A, 0); |
| 345 | } |
| 346 | |
| 347 | if (test_thread_flag(TIF_SINGLE_STEP)) { |
| 348 | pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds); |
| 349 | if (ds & DS_SSS) { |
| 350 | dc = __mfdr(DBGREG_DC); |
| 351 | dc &= ~DC_SS; |
| 352 | __mtdr(DBGREG_DC, dc); |
| 353 | |
| 354 | clear_thread_flag(TIF_SINGLE_STEP); |
| 355 | ptrace_break(current, regs); |
| 356 | } |
| 357 | } else { |
| 358 | /* regular breakpoint */ |
| 359 | ptrace_break(current, regs); |
| 360 | } |
| 361 | } |