Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/alpha/kernel/process.c |
| 3 | * |
| 4 | * Copyright (C) 1995 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * This file handles the architecture-dependent parts of process handling. |
| 9 | */ |
| 10 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/errno.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/sched.h> |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/mm.h> |
| 16 | #include <linux/smp.h> |
| 17 | #include <linux/smp_lock.h> |
| 18 | #include <linux/stddef.h> |
| 19 | #include <linux/unistd.h> |
| 20 | #include <linux/ptrace.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/user.h> |
| 23 | #include <linux/a.out.h> |
| 24 | #include <linux/utsname.h> |
| 25 | #include <linux/time.h> |
| 26 | #include <linux/major.h> |
| 27 | #include <linux/stat.h> |
Jon Smirl | a8f340e | 2006-07-10 04:44:12 -0700 | [diff] [blame] | 28 | #include <linux/vt.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/mman.h> |
| 30 | #include <linux/elfcore.h> |
| 31 | #include <linux/reboot.h> |
| 32 | #include <linux/tty.h> |
| 33 | #include <linux/console.h> |
| 34 | |
| 35 | #include <asm/reg.h> |
| 36 | #include <asm/uaccess.h> |
| 37 | #include <asm/system.h> |
| 38 | #include <asm/io.h> |
| 39 | #include <asm/pgtable.h> |
| 40 | #include <asm/hwrpb.h> |
| 41 | #include <asm/fpu.h> |
| 42 | |
| 43 | #include "proto.h" |
| 44 | #include "pci_impl.h" |
| 45 | |
Eric W. Biederman | 5e38291 | 2006-01-08 01:03:46 -0800 | [diff] [blame] | 46 | /* |
| 47 | * Power off function, if any |
| 48 | */ |
| 49 | void (*pm_power_off)(void) = machine_power_off; |
Al Viro | 89eb169 | 2007-01-30 13:23:25 +0000 | [diff] [blame] | 50 | EXPORT_SYMBOL(pm_power_off); |
Eric W. Biederman | 5e38291 | 2006-01-08 01:03:46 -0800 | [diff] [blame] | 51 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | void |
| 53 | cpu_idle(void) |
| 54 | { |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 55 | set_thread_flag(TIF_POLLING_NRFLAG); |
| 56 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | while (1) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | /* FIXME -- EV6 and LCA45 know how to power down |
| 59 | the CPU. */ |
| 60 | |
| 61 | while (!need_resched()) |
Nick Piggin | 64c7c8f | 2005-11-08 21:39:04 -0800 | [diff] [blame] | 62 | cpu_relax(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | schedule(); |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | |
| 68 | struct halt_info { |
| 69 | int mode; |
| 70 | char *restart_cmd; |
| 71 | }; |
| 72 | |
| 73 | static void |
| 74 | common_shutdown_1(void *generic_ptr) |
| 75 | { |
| 76 | struct halt_info *how = (struct halt_info *)generic_ptr; |
| 77 | struct percpu_struct *cpup; |
| 78 | unsigned long *pflags, flags; |
| 79 | int cpuid = smp_processor_id(); |
| 80 | |
| 81 | /* No point in taking interrupts anymore. */ |
| 82 | local_irq_disable(); |
| 83 | |
| 84 | cpup = (struct percpu_struct *) |
| 85 | ((unsigned long)hwrpb + hwrpb->processor_offset |
| 86 | + hwrpb->processor_size * cpuid); |
| 87 | pflags = &cpup->flags; |
| 88 | flags = *pflags; |
| 89 | |
| 90 | /* Clear reason to "default"; clear "bootstrap in progress". */ |
| 91 | flags &= ~0x00ff0001UL; |
| 92 | |
| 93 | #ifdef CONFIG_SMP |
| 94 | /* Secondaries halt here. */ |
| 95 | if (cpuid != boot_cpuid) { |
| 96 | flags |= 0x00040000UL; /* "remain halted" */ |
| 97 | *pflags = flags; |
Ivan Kokshaysky | c7d2d28 | 2006-06-04 02:51:34 -0700 | [diff] [blame] | 98 | cpu_clear(cpuid, cpu_present_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | halt(); |
| 100 | } |
| 101 | #endif |
| 102 | |
| 103 | if (how->mode == LINUX_REBOOT_CMD_RESTART) { |
| 104 | if (!how->restart_cmd) { |
| 105 | flags |= 0x00020000UL; /* "cold bootstrap" */ |
| 106 | } else { |
| 107 | /* For SRM, we could probably set environment |
| 108 | variables to get this to work. We'd have to |
| 109 | delay this until after srm_paging_stop unless |
| 110 | we ever got srm_fixup working. |
| 111 | |
| 112 | At the moment, SRM will use the last boot device, |
| 113 | but the file and flags will be the defaults, when |
| 114 | doing a "warm" bootstrap. */ |
| 115 | flags |= 0x00030000UL; /* "warm bootstrap" */ |
| 116 | } |
| 117 | } else { |
| 118 | flags |= 0x00040000UL; /* "remain halted" */ |
| 119 | } |
| 120 | *pflags = flags; |
| 121 | |
| 122 | #ifdef CONFIG_SMP |
| 123 | /* Wait for the secondaries to halt. */ |
Ivan Kokshaysky | c7d2d28 | 2006-06-04 02:51:34 -0700 | [diff] [blame] | 124 | cpu_clear(boot_cpuid, cpu_present_map); |
| 125 | while (cpus_weight(cpu_present_map)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | barrier(); |
| 127 | #endif |
| 128 | |
| 129 | /* If booted from SRM, reset some of the original environment. */ |
| 130 | if (alpha_using_srm) { |
| 131 | #ifdef CONFIG_DUMMY_CONSOLE |
Ivan Kokshaysky | 4b3c86a | 2005-09-22 21:43:57 -0700 | [diff] [blame] | 132 | /* If we've gotten here after SysRq-b, leave interrupt |
| 133 | context before taking over the console. */ |
| 134 | if (in_interrupt()) |
| 135 | irq_exit(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | /* This has the effect of resetting the VGA video origin. */ |
| 137 | take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1); |
| 138 | #endif |
| 139 | pci_restore_srm_config(); |
| 140 | set_hae(srm_hae); |
| 141 | } |
| 142 | |
| 143 | if (alpha_mv.kill_arch) |
| 144 | alpha_mv.kill_arch(how->mode); |
| 145 | |
| 146 | if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) { |
| 147 | /* Unfortunately, since MILO doesn't currently understand |
| 148 | the hwrpb bits above, we can't reliably halt the |
| 149 | processor and keep it halted. So just loop. */ |
| 150 | return; |
| 151 | } |
| 152 | |
| 153 | if (alpha_using_srm) |
| 154 | srm_paging_stop(); |
| 155 | |
| 156 | halt(); |
| 157 | } |
| 158 | |
| 159 | static void |
| 160 | common_shutdown(int mode, char *restart_cmd) |
| 161 | { |
| 162 | struct halt_info args; |
| 163 | args.mode = mode; |
| 164 | args.restart_cmd = restart_cmd; |
| 165 | on_each_cpu(common_shutdown_1, &args, 1, 0); |
| 166 | } |
| 167 | |
| 168 | void |
| 169 | machine_restart(char *restart_cmd) |
| 170 | { |
| 171 | common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd); |
| 172 | } |
| 173 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | |
| 175 | void |
| 176 | machine_halt(void) |
| 177 | { |
| 178 | common_shutdown(LINUX_REBOOT_CMD_HALT, NULL); |
| 179 | } |
| 180 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | |
| 182 | void |
| 183 | machine_power_off(void) |
| 184 | { |
| 185 | common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL); |
| 186 | } |
| 187 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | |
| 189 | /* Used by sysrq-p, among others. I don't believe r9-r15 are ever |
| 190 | saved in the context it's used. */ |
| 191 | |
| 192 | void |
| 193 | show_regs(struct pt_regs *regs) |
| 194 | { |
| 195 | dik_show_regs(regs, NULL); |
| 196 | } |
| 197 | |
| 198 | /* |
| 199 | * Re-start a thread when doing execve() |
| 200 | */ |
| 201 | void |
| 202 | start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) |
| 203 | { |
| 204 | set_fs(USER_DS); |
| 205 | regs->pc = pc; |
| 206 | regs->ps = 8; |
| 207 | wrusp(sp); |
| 208 | } |
Al Viro | cff52da | 2006-10-11 17:40:22 +0100 | [diff] [blame] | 209 | EXPORT_SYMBOL(start_thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | |
| 211 | /* |
| 212 | * Free current thread data structures etc.. |
| 213 | */ |
| 214 | void |
| 215 | exit_thread(void) |
| 216 | { |
| 217 | } |
| 218 | |
| 219 | void |
| 220 | flush_thread(void) |
| 221 | { |
| 222 | /* Arrange for each exec'ed process to start off with a clean slate |
| 223 | with respect to the FPU. This is all exceptions disabled. */ |
| 224 | current_thread_info()->ieee_state = 0; |
| 225 | wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0)); |
| 226 | |
| 227 | /* Clean slate for TLS. */ |
| 228 | current_thread_info()->pcb.unique = 0; |
| 229 | } |
| 230 | |
| 231 | void |
| 232 | release_thread(struct task_struct *dead_task) |
| 233 | { |
| 234 | } |
| 235 | |
| 236 | /* |
| 237 | * "alpha_clone()".. By the time we get here, the |
| 238 | * non-volatile registers have also been saved on the |
| 239 | * stack. We do some ugly pointer stuff here.. (see |
| 240 | * also copy_thread) |
| 241 | * |
| 242 | * Notice that "fork()" is implemented in terms of clone, |
| 243 | * with parameters (SIGCHLD, 0). |
| 244 | */ |
| 245 | int |
| 246 | alpha_clone(unsigned long clone_flags, unsigned long usp, |
| 247 | int __user *parent_tid, int __user *child_tid, |
| 248 | unsigned long tls_value, struct pt_regs *regs) |
| 249 | { |
| 250 | if (!usp) |
| 251 | usp = rdusp(); |
| 252 | |
| 253 | return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid); |
| 254 | } |
| 255 | |
| 256 | int |
| 257 | alpha_vfork(struct pt_regs *regs) |
| 258 | { |
| 259 | return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), |
| 260 | regs, 0, NULL, NULL); |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * Copy an alpha thread.. |
| 265 | * |
| 266 | * Note the "stack_offset" stuff: when returning to kernel mode, we need |
| 267 | * to have some extra stack-space for the kernel stack that still exists |
| 268 | * after the "ret_from_fork". When returning to user mode, we only want |
| 269 | * the space needed by the syscall stack frame (ie "struct pt_regs"). |
| 270 | * Use the passed "regs" pointer to determine how much space we need |
| 271 | * for a kernel fork(). |
| 272 | */ |
| 273 | |
| 274 | int |
| 275 | copy_thread(int nr, unsigned long clone_flags, unsigned long usp, |
| 276 | unsigned long unused, |
| 277 | struct task_struct * p, struct pt_regs * regs) |
| 278 | { |
| 279 | extern void ret_from_fork(void); |
| 280 | |
Al Viro | 27f4513 | 2006-01-12 01:05:36 -0800 | [diff] [blame] | 281 | struct thread_info *childti = task_thread_info(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | struct pt_regs * childregs; |
| 283 | struct switch_stack * childstack, *stack; |
| 284 | unsigned long stack_offset, settls; |
| 285 | |
| 286 | stack_offset = PAGE_SIZE - sizeof(struct pt_regs); |
| 287 | if (!(regs->ps & 8)) |
| 288 | stack_offset = (PAGE_SIZE-1) & (unsigned long) regs; |
| 289 | childregs = (struct pt_regs *) |
Al Viro | 27f4513 | 2006-01-12 01:05:36 -0800 | [diff] [blame] | 290 | (stack_offset + PAGE_SIZE + task_stack_page(p)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | |
| 292 | *childregs = *regs; |
| 293 | settls = regs->r20; |
| 294 | childregs->r0 = 0; |
| 295 | childregs->r19 = 0; |
| 296 | childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */ |
| 297 | regs->r20 = 0; |
| 298 | stack = ((struct switch_stack *) regs) - 1; |
| 299 | childstack = ((struct switch_stack *) childregs) - 1; |
| 300 | *childstack = *stack; |
| 301 | childstack->r26 = (unsigned long) ret_from_fork; |
| 302 | childti->pcb.usp = usp; |
| 303 | childti->pcb.ksp = (unsigned long) childstack; |
| 304 | childti->pcb.flags = 1; /* set FEN, clear everything else */ |
| 305 | |
| 306 | /* Set a new TLS for the child thread? Peek back into the |
| 307 | syscall arguments that we saved on syscall entry. Oops, |
| 308 | except we'd have clobbered it with the parent/child set |
| 309 | of r20. Read the saved copy. */ |
| 310 | /* Note: if CLONE_SETTLS is not set, then we must inherit the |
| 311 | value from the parent, which will have been set by the block |
| 312 | copy in dup_task_struct. This is non-intuitive, but is |
| 313 | required for proper operation in the case of a threaded |
| 314 | application calling fork. */ |
| 315 | if (clone_flags & CLONE_SETTLS) |
| 316 | childti->pcb.unique = settls; |
| 317 | |
| 318 | return 0; |
| 319 | } |
| 320 | |
| 321 | /* |
| 322 | * Fill in the user structure for an ECOFF core dump. |
| 323 | */ |
| 324 | void |
| 325 | dump_thread(struct pt_regs * pt, struct user * dump) |
| 326 | { |
| 327 | /* switch stack follows right below pt_regs: */ |
| 328 | struct switch_stack * sw = ((struct switch_stack *) pt) - 1; |
| 329 | |
| 330 | dump->magic = CMAGIC; |
| 331 | dump->start_code = current->mm->start_code; |
| 332 | dump->start_data = current->mm->start_data; |
| 333 | dump->start_stack = rdusp() & ~(PAGE_SIZE - 1); |
| 334 | dump->u_tsize = ((current->mm->end_code - dump->start_code) |
| 335 | >> PAGE_SHIFT); |
| 336 | dump->u_dsize = ((current->mm->brk + PAGE_SIZE-1 - dump->start_data) |
| 337 | >> PAGE_SHIFT); |
| 338 | dump->u_ssize = (current->mm->start_stack - dump->start_stack |
| 339 | + PAGE_SIZE-1) >> PAGE_SHIFT; |
| 340 | |
| 341 | /* |
| 342 | * We store the registers in an order/format that is |
| 343 | * compatible with DEC Unix/OSF/1 as this makes life easier |
| 344 | * for gdb. |
| 345 | */ |
| 346 | dump->regs[EF_V0] = pt->r0; |
| 347 | dump->regs[EF_T0] = pt->r1; |
| 348 | dump->regs[EF_T1] = pt->r2; |
| 349 | dump->regs[EF_T2] = pt->r3; |
| 350 | dump->regs[EF_T3] = pt->r4; |
| 351 | dump->regs[EF_T4] = pt->r5; |
| 352 | dump->regs[EF_T5] = pt->r6; |
| 353 | dump->regs[EF_T6] = pt->r7; |
| 354 | dump->regs[EF_T7] = pt->r8; |
| 355 | dump->regs[EF_S0] = sw->r9; |
| 356 | dump->regs[EF_S1] = sw->r10; |
| 357 | dump->regs[EF_S2] = sw->r11; |
| 358 | dump->regs[EF_S3] = sw->r12; |
| 359 | dump->regs[EF_S4] = sw->r13; |
| 360 | dump->regs[EF_S5] = sw->r14; |
| 361 | dump->regs[EF_S6] = sw->r15; |
| 362 | dump->regs[EF_A3] = pt->r19; |
| 363 | dump->regs[EF_A4] = pt->r20; |
| 364 | dump->regs[EF_A5] = pt->r21; |
| 365 | dump->regs[EF_T8] = pt->r22; |
| 366 | dump->regs[EF_T9] = pt->r23; |
| 367 | dump->regs[EF_T10] = pt->r24; |
| 368 | dump->regs[EF_T11] = pt->r25; |
| 369 | dump->regs[EF_RA] = pt->r26; |
| 370 | dump->regs[EF_T12] = pt->r27; |
| 371 | dump->regs[EF_AT] = pt->r28; |
| 372 | dump->regs[EF_SP] = rdusp(); |
| 373 | dump->regs[EF_PS] = pt->ps; |
| 374 | dump->regs[EF_PC] = pt->pc; |
| 375 | dump->regs[EF_GP] = pt->gp; |
| 376 | dump->regs[EF_A0] = pt->r16; |
| 377 | dump->regs[EF_A1] = pt->r17; |
| 378 | dump->regs[EF_A2] = pt->r18; |
| 379 | memcpy((char *)dump->regs + EF_SIZE, sw->fp, 32 * 8); |
| 380 | } |
Al Viro | cff52da | 2006-10-11 17:40:22 +0100 | [diff] [blame] | 381 | EXPORT_SYMBOL(dump_thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | |
| 383 | /* |
| 384 | * Fill in the user structure for a ELF core dump. |
| 385 | */ |
| 386 | void |
| 387 | dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti) |
| 388 | { |
| 389 | /* switch stack follows right below pt_regs: */ |
| 390 | struct switch_stack * sw = ((struct switch_stack *) pt) - 1; |
| 391 | |
| 392 | dest[ 0] = pt->r0; |
| 393 | dest[ 1] = pt->r1; |
| 394 | dest[ 2] = pt->r2; |
| 395 | dest[ 3] = pt->r3; |
| 396 | dest[ 4] = pt->r4; |
| 397 | dest[ 5] = pt->r5; |
| 398 | dest[ 6] = pt->r6; |
| 399 | dest[ 7] = pt->r7; |
| 400 | dest[ 8] = pt->r8; |
| 401 | dest[ 9] = sw->r9; |
| 402 | dest[10] = sw->r10; |
| 403 | dest[11] = sw->r11; |
| 404 | dest[12] = sw->r12; |
| 405 | dest[13] = sw->r13; |
| 406 | dest[14] = sw->r14; |
| 407 | dest[15] = sw->r15; |
| 408 | dest[16] = pt->r16; |
| 409 | dest[17] = pt->r17; |
| 410 | dest[18] = pt->r18; |
| 411 | dest[19] = pt->r19; |
| 412 | dest[20] = pt->r20; |
| 413 | dest[21] = pt->r21; |
| 414 | dest[22] = pt->r22; |
| 415 | dest[23] = pt->r23; |
| 416 | dest[24] = pt->r24; |
| 417 | dest[25] = pt->r25; |
| 418 | dest[26] = pt->r26; |
| 419 | dest[27] = pt->r27; |
| 420 | dest[28] = pt->r28; |
| 421 | dest[29] = pt->gp; |
| 422 | dest[30] = rdusp(); |
| 423 | dest[31] = pt->pc; |
| 424 | |
| 425 | /* Once upon a time this was the PS value. Which is stupid |
| 426 | since that is always 8 for usermode. Usurped for the more |
| 427 | useful value of the thread's UNIQUE field. */ |
| 428 | dest[32] = ti->pcb.unique; |
| 429 | } |
Al Viro | cff52da | 2006-10-11 17:40:22 +0100 | [diff] [blame] | 430 | EXPORT_SYMBOL(dump_elf_thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | |
| 432 | int |
| 433 | dump_elf_task(elf_greg_t *dest, struct task_struct *task) |
| 434 | { |
akpm@osdl.org | e52f4ca | 2006-01-12 01:05:37 -0800 | [diff] [blame] | 435 | dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | return 1; |
| 437 | } |
Al Viro | cff52da | 2006-10-11 17:40:22 +0100 | [diff] [blame] | 438 | EXPORT_SYMBOL(dump_elf_task); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 439 | |
| 440 | int |
| 441 | dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task) |
| 442 | { |
akpm@osdl.org | e52f4ca | 2006-01-12 01:05:37 -0800 | [diff] [blame] | 443 | struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | memcpy(dest, sw->fp, 32 * 8); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | return 1; |
| 446 | } |
Al Viro | cff52da | 2006-10-11 17:40:22 +0100 | [diff] [blame] | 447 | EXPORT_SYMBOL(dump_elf_task_fp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 448 | |
| 449 | /* |
| 450 | * sys_execve() executes a new program. |
| 451 | */ |
| 452 | asmlinkage int |
| 453 | do_sys_execve(char __user *ufilename, char __user * __user *argv, |
| 454 | char __user * __user *envp, struct pt_regs *regs) |
| 455 | { |
| 456 | int error; |
| 457 | char *filename; |
| 458 | |
| 459 | filename = getname(ufilename); |
| 460 | error = PTR_ERR(filename); |
| 461 | if (IS_ERR(filename)) |
| 462 | goto out; |
| 463 | error = do_execve(filename, argv, envp, regs); |
| 464 | putname(filename); |
| 465 | out: |
| 466 | return error; |
| 467 | } |
| 468 | |
| 469 | /* |
| 470 | * Return saved PC of a blocked thread. This assumes the frame |
| 471 | * pointer is the 6th saved long on the kernel stack and that the |
| 472 | * saved return address is the first long in the frame. This all |
| 473 | * holds provided the thread blocked through a call to schedule() ($15 |
| 474 | * is the frame pointer in schedule() and $15 is saved at offset 48 by |
| 475 | * entry.S:do_switch_stack). |
| 476 | * |
| 477 | * Under heavy swap load I've seen this lose in an ugly way. So do |
| 478 | * some extra sanity checking on the ranges we expect these pointers |
| 479 | * to be in so that we can fail gracefully. This is just for ps after |
| 480 | * all. -- r~ |
| 481 | */ |
| 482 | |
| 483 | unsigned long |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 484 | thread_saved_pc(struct task_struct *t) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | { |
Al Viro | 27f4513 | 2006-01-12 01:05:36 -0800 | [diff] [blame] | 486 | unsigned long base = (unsigned long)task_stack_page(t); |
Al Viro | 37bfbaf | 2006-01-12 01:05:36 -0800 | [diff] [blame] | 487 | unsigned long fp, sp = task_thread_info(t)->pcb.ksp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | |
| 489 | if (sp > base && sp+6*8 < base + 16*1024) { |
| 490 | fp = ((unsigned long*)sp)[6]; |
| 491 | if (fp > sp && fp < base + 16*1024) |
| 492 | return *(unsigned long *)fp; |
| 493 | } |
| 494 | |
| 495 | return 0; |
| 496 | } |
| 497 | |
| 498 | unsigned long |
| 499 | get_wchan(struct task_struct *p) |
| 500 | { |
| 501 | unsigned long schedule_frame; |
| 502 | unsigned long pc; |
| 503 | if (!p || p == current || p->state == TASK_RUNNING) |
| 504 | return 0; |
| 505 | /* |
| 506 | * This one depends on the frame size of schedule(). Do a |
| 507 | * "disass schedule" in gdb to find the frame size. Also, the |
| 508 | * code assumes that sleep_on() follows immediately after |
| 509 | * interruptible_sleep_on() and that add_timer() follows |
| 510 | * immediately after interruptible_sleep(). Ugly, isn't it? |
| 511 | * Maybe adding a wchan field to task_struct would be better, |
| 512 | * after all... |
| 513 | */ |
| 514 | |
| 515 | pc = thread_saved_pc(p); |
| 516 | if (in_sched_functions(pc)) { |
Al Viro | 37bfbaf | 2006-01-12 01:05:36 -0800 | [diff] [blame] | 517 | schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | return ((unsigned long *)schedule_frame)[12]; |
| 519 | } |
| 520 | return pc; |
| 521 | } |