Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 1995 Linus Torvalds |
3 | * | |
4 | * Pentium III FXSR, SSE support | |
5 | * Gareth Hughes <gareth@valinux.com>, May 2000 | |
6 | */ | |
7 | ||
8 | /* | |
9 | * This file handles the architecture-dependent parts of process handling.. | |
10 | */ | |
11 | ||
5c79d2a5 | 12 | #include <linux/stackprotector.h> |
f3705136 | 13 | #include <linux/cpu.h> |
1da177e4 LT |
14 | #include <linux/errno.h> |
15 | #include <linux/sched.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/elfcore.h> | |
20 | #include <linux/smp.h> | |
1da177e4 LT |
21 | #include <linux/stddef.h> |
22 | #include <linux/slab.h> | |
23 | #include <linux/vmalloc.h> | |
24 | #include <linux/user.h> | |
1da177e4 | 25 | #include <linux/interrupt.h> |
1da177e4 LT |
26 | #include <linux/utsname.h> |
27 | #include <linux/delay.h> | |
28 | #include <linux/reboot.h> | |
29 | #include <linux/init.h> | |
30 | #include <linux/mc146818rtc.h> | |
31 | #include <linux/module.h> | |
32 | #include <linux/kallsyms.h> | |
33 | #include <linux/ptrace.h> | |
c16b63e0 | 34 | #include <linux/personality.h> |
74167347 | 35 | #include <linux/tick.h> |
7c3576d2 | 36 | #include <linux/percpu.h> |
529e25f6 | 37 | #include <linux/prctl.h> |
90f7d25c | 38 | #include <linux/dmi.h> |
8b96f011 | 39 | #include <linux/ftrace.h> |
befa9e78 JSR |
40 | #include <linux/uaccess.h> |
41 | #include <linux/io.h> | |
42 | #include <linux/kdebug.h> | |
1da177e4 | 43 | |
1da177e4 LT |
44 | #include <asm/pgtable.h> |
45 | #include <asm/system.h> | |
1da177e4 LT |
46 | #include <asm/ldt.h> |
47 | #include <asm/processor.h> | |
48 | #include <asm/i387.h> | |
1da177e4 LT |
49 | #include <asm/desc.h> |
50 | #ifdef CONFIG_MATH_EMULATION | |
51 | #include <asm/math_emu.h> | |
52 | #endif | |
53 | ||
1da177e4 LT |
54 | #include <linux/err.h> |
55 | ||
f3705136 ZM |
56 | #include <asm/tlbflush.h> |
57 | #include <asm/cpu.h> | |
1eda8149 | 58 | #include <asm/idle.h> |
bbc1f698 | 59 | #include <asm/syscalls.h> |
bf53de90 | 60 | #include <asm/ds.h> |
f3705136 | 61 | |
1da177e4 LT |
62 | asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); |
63 | ||
1da177e4 LT |
64 | /* |
65 | * Return saved PC of a blocked thread. | |
66 | */ | |
67 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
68 | { | |
faca6227 | 69 | return ((unsigned long *)tsk->thread.sp)[3]; |
1da177e4 LT |
70 | } |
71 | ||
913da64b AN |
72 | #ifndef CONFIG_SMP |
73 | static inline void play_dead(void) | |
74 | { | |
75 | BUG(); | |
76 | } | |
77 | #endif | |
78 | ||
1da177e4 LT |
79 | /* |
80 | * The idle thread. There's no useful work to be | |
81 | * done, so just try to conserve power and have a | |
82 | * low exit latency (ie sit in a loop waiting for | |
83 | * somebody to say that they'd like to reschedule) | |
84 | */ | |
f3705136 | 85 | void cpu_idle(void) |
1da177e4 | 86 | { |
5bfb5d69 | 87 | int cpu = smp_processor_id(); |
f3705136 | 88 | |
5c79d2a5 TH |
89 | /* |
90 | * If we're the non-boot CPU, nothing set the stack canary up | |
91 | * for us. CPU0 already has it initialized but no harm in | |
92 | * doing it again. This is a good place for updating it, as | |
93 | * we wont ever return from this function (so the invalid | |
94 | * canaries already on the stack wont ever trigger). | |
95 | */ | |
96 | boot_init_stack_canary(); | |
97 | ||
495ab9c0 | 98 | current_thread_info()->status |= TS_POLLING; |
64c7c8f8 | 99 | |
1da177e4 LT |
100 | /* endless idle loop with no priority at all */ |
101 | while (1) { | |
b8f8c3cf | 102 | tick_nohz_stop_sched_tick(1); |
1da177e4 | 103 | while (!need_resched()) { |
1da177e4 | 104 | |
f1d1a842 | 105 | check_pgt_cache(); |
1da177e4 | 106 | rmb(); |
1da177e4 | 107 | |
f3705136 ZM |
108 | if (cpu_is_offline(cpu)) |
109 | play_dead(); | |
110 | ||
7f424a8b | 111 | local_irq_disable(); |
6cd8a4bb SR |
112 | /* Don't trace irqs off for idle */ |
113 | stop_critical_timings(); | |
6ddd2a27 | 114 | pm_idle(); |
6cd8a4bb | 115 | start_critical_timings(); |
1da177e4 | 116 | } |
74167347 | 117 | tick_nohz_restart_sched_tick(); |
5bfb5d69 | 118 | preempt_enable_no_resched(); |
1da177e4 | 119 | schedule(); |
5bfb5d69 | 120 | preempt_disable(); |
1da177e4 LT |
121 | } |
122 | } | |
123 | ||
e2ce07c8 | 124 | void __show_regs(struct pt_regs *regs, int all) |
1da177e4 LT |
125 | { |
126 | unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; | |
bb1995d5 | 127 | unsigned long d0, d1, d2, d3, d6, d7; |
65ea5b03 | 128 | unsigned long sp; |
9d975ebd | 129 | unsigned short ss, gs; |
90f7d25c | 130 | const char *board; |
9d975ebd PE |
131 | |
132 | if (user_mode_vm(regs)) { | |
65ea5b03 PA |
133 | sp = regs->sp; |
134 | ss = regs->ss & 0xffff; | |
d9a89a26 | 135 | gs = get_user_gs(regs); |
9d975ebd | 136 | } else { |
65ea5b03 | 137 | sp = (unsigned long) (®s->sp); |
9d975ebd PE |
138 | savesegment(ss, ss); |
139 | savesegment(gs, gs); | |
140 | } | |
1da177e4 LT |
141 | |
142 | printk("\n"); | |
90f7d25c AV |
143 | |
144 | board = dmi_get_system_info(DMI_PRODUCT_NAME); | |
145 | if (!board) | |
146 | board = ""; | |
147 | printk("Pid: %d, comm: %s %s (%s %.*s) %s\n", | |
60812a4a | 148 | task_pid_nr(current), current->comm, |
9d975ebd PE |
149 | print_tainted(), init_utsname()->release, |
150 | (int)strcspn(init_utsname()->version, " "), | |
90f7d25c | 151 | init_utsname()->version, board); |
9d975ebd PE |
152 | |
153 | printk("EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n", | |
92bc2056 | 154 | (u16)regs->cs, regs->ip, regs->flags, |
9d975ebd | 155 | smp_processor_id()); |
65ea5b03 | 156 | print_symbol("EIP is at %s\n", regs->ip); |
1da177e4 | 157 | |
1da177e4 | 158 | printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n", |
65ea5b03 | 159 | regs->ax, regs->bx, regs->cx, regs->dx); |
9d975ebd | 160 | printk("ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n", |
65ea5b03 | 161 | regs->si, regs->di, regs->bp, sp); |
9d975ebd | 162 | printk(" DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n", |
92bc2056 | 163 | (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss); |
9d975ebd PE |
164 | |
165 | if (!all) | |
166 | return; | |
1da177e4 | 167 | |
4bb0d3ec ZA |
168 | cr0 = read_cr0(); |
169 | cr2 = read_cr2(); | |
170 | cr3 = read_cr3(); | |
ff6e8c0d | 171 | cr4 = read_cr4_safe(); |
9d975ebd PE |
172 | printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", |
173 | cr0, cr2, cr3, cr4); | |
bb1995d5 AS |
174 | |
175 | get_debugreg(d0, 0); | |
176 | get_debugreg(d1, 1); | |
177 | get_debugreg(d2, 2); | |
178 | get_debugreg(d3, 3); | |
179 | printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", | |
180 | d0, d1, d2, d3); | |
9d975ebd | 181 | |
bb1995d5 AS |
182 | get_debugreg(d6, 6); |
183 | get_debugreg(d7, 7); | |
9d975ebd PE |
184 | printk("DR6: %08lx DR7: %08lx\n", |
185 | d6, d7); | |
186 | } | |
bb1995d5 | 187 | |
9d975ebd PE |
188 | void show_regs(struct pt_regs *regs) |
189 | { | |
e2ce07c8 | 190 | __show_regs(regs, 1); |
5bc27dc2 | 191 | show_trace(NULL, regs, ®s->sp, regs->bp); |
1da177e4 LT |
192 | } |
193 | ||
194 | /* | |
65ea5b03 PA |
195 | * This gets run with %bx containing the |
196 | * function to call, and %dx containing | |
1da177e4 LT |
197 | * the "args". |
198 | */ | |
199 | extern void kernel_thread_helper(void); | |
1da177e4 LT |
200 | |
201 | /* | |
202 | * Create a kernel thread | |
203 | */ | |
befa9e78 | 204 | int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) |
1da177e4 LT |
205 | { |
206 | struct pt_regs regs; | |
207 | ||
208 | memset(®s, 0, sizeof(regs)); | |
209 | ||
65ea5b03 PA |
210 | regs.bx = (unsigned long) fn; |
211 | regs.dx = (unsigned long) arg; | |
1da177e4 | 212 | |
65ea5b03 PA |
213 | regs.ds = __USER_DS; |
214 | regs.es = __USER_DS; | |
215 | regs.fs = __KERNEL_PERCPU; | |
60a5317f | 216 | regs.gs = __KERNEL_STACK_CANARY; |
65ea5b03 PA |
217 | regs.orig_ax = -1; |
218 | regs.ip = (unsigned long) kernel_thread_helper; | |
219 | regs.cs = __KERNEL_CS | get_kernel_rpl(); | |
220 | regs.flags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2; | |
1da177e4 LT |
221 | |
222 | /* Ok, create the new process.. */ | |
8cf2c519 | 223 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); |
1da177e4 | 224 | } |
129f6946 | 225 | EXPORT_SYMBOL(kernel_thread); |
1da177e4 | 226 | |
1da177e4 LT |
227 | void release_thread(struct task_struct *dead_task) |
228 | { | |
2684927c | 229 | BUG_ON(dead_task->mm); |
1da177e4 LT |
230 | release_vm86_irqs(dead_task); |
231 | } | |
232 | ||
233 | /* | |
234 | * This gets called before we allocate a new thread and copy | |
235 | * the current task into it. | |
236 | */ | |
237 | void prepare_to_copy(struct task_struct *tsk) | |
238 | { | |
239 | unlazy_fpu(tsk); | |
240 | } | |
241 | ||
6f2c55b8 | 242 | int copy_thread(unsigned long clone_flags, unsigned long sp, |
1da177e4 | 243 | unsigned long unused, |
befa9e78 | 244 | struct task_struct *p, struct pt_regs *regs) |
1da177e4 | 245 | { |
befa9e78 | 246 | struct pt_regs *childregs; |
1da177e4 LT |
247 | struct task_struct *tsk; |
248 | int err; | |
249 | ||
07b047fc | 250 | childregs = task_pt_regs(p); |
f48d9663 | 251 | *childregs = *regs; |
65ea5b03 PA |
252 | childregs->ax = 0; |
253 | childregs->sp = sp; | |
f48d9663 | 254 | |
faca6227 PA |
255 | p->thread.sp = (unsigned long) childregs; |
256 | p->thread.sp0 = (unsigned long) (childregs+1); | |
1da177e4 | 257 | |
faca6227 | 258 | p->thread.ip = (unsigned long) ret_from_fork; |
1da177e4 | 259 | |
d9a89a26 | 260 | task_user_gs(p) = get_user_gs(regs); |
1da177e4 LT |
261 | |
262 | tsk = current; | |
b3cf2576 | 263 | if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { |
52978be6 AD |
264 | p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr, |
265 | IO_BITMAP_BYTES, GFP_KERNEL); | |
1da177e4 LT |
266 | if (!p->thread.io_bitmap_ptr) { |
267 | p->thread.io_bitmap_max = 0; | |
268 | return -ENOMEM; | |
269 | } | |
b3cf2576 | 270 | set_tsk_thread_flag(p, TIF_IO_BITMAP); |
1da177e4 LT |
271 | } |
272 | ||
efd1ca52 RM |
273 | err = 0; |
274 | ||
1da177e4 LT |
275 | /* |
276 | * Set a new TLS for the child thread? | |
277 | */ | |
efd1ca52 RM |
278 | if (clone_flags & CLONE_SETTLS) |
279 | err = do_set_thread_area(p, -1, | |
65ea5b03 | 280 | (struct user_desc __user *)childregs->si, 0); |
1da177e4 | 281 | |
1da177e4 LT |
282 | if (err && p->thread.io_bitmap_ptr) { |
283 | kfree(p->thread.io_bitmap_ptr); | |
284 | p->thread.io_bitmap_max = 0; | |
285 | } | |
bf53de90 | 286 | |
2311f0de MM |
287 | clear_tsk_thread_flag(p, TIF_DS_AREA_MSR); |
288 | p->thread.ds_ctx = NULL; | |
bf53de90 MM |
289 | |
290 | clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR); | |
291 | p->thread.debugctlmsr = 0; | |
292 | ||
1da177e4 LT |
293 | return err; |
294 | } | |
295 | ||
513ad84b IM |
296 | void |
297 | start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) | |
298 | { | |
d9a89a26 | 299 | set_user_gs(regs, 0); |
513ad84b IM |
300 | regs->fs = 0; |
301 | set_fs(USER_DS); | |
302 | regs->ds = __USER_DS; | |
303 | regs->es = __USER_DS; | |
304 | regs->ss = __USER_DS; | |
305 | regs->cs = __USER_CS; | |
306 | regs->ip = new_ip; | |
307 | regs->sp = new_sp; | |
aa283f49 SS |
308 | /* |
309 | * Free the old FP and other extended state | |
310 | */ | |
311 | free_thread_xstate(current); | |
513ad84b IM |
312 | } |
313 | EXPORT_SYMBOL_GPL(start_thread); | |
314 | ||
1da177e4 LT |
315 | |
316 | /* | |
317 | * switch_to(x,yn) should switch tasks from x to y. | |
318 | * | |
319 | * We fsave/fwait so that an exception goes off at the right time | |
320 | * (as a call from the fsave or fwait in effect) rather than to | |
321 | * the wrong process. Lazy FP saving no longer makes any sense | |
322 | * with modern CPU's, and this simplifies a lot of things (SMP | |
323 | * and UP become the same). | |
324 | * | |
325 | * NOTE! We used to use the x86 hardware context switching. The | |
326 | * reason for not using it any more becomes apparent when you | |
327 | * try to recover gracefully from saved state that is no longer | |
328 | * valid (stale segment register values in particular). With the | |
329 | * hardware task-switch, there is no way to fix up bad state in | |
330 | * a reasonable manner. | |
331 | * | |
332 | * The fact that Intel documents the hardware task-switching to | |
333 | * be slow is a fairly red herring - this code is not noticeably | |
334 | * faster. However, there _is_ some room for improvement here, | |
335 | * so the performance issues may eventually be a valid point. | |
336 | * More important, however, is the fact that this allows us much | |
337 | * more flexibility. | |
338 | * | |
65ea5b03 | 339 | * The return value (in %ax) will be the "prev" task after |
1da177e4 LT |
340 | * the task-switch, and shows up in ret_from_fork in entry.S, |
341 | * for example. | |
342 | */ | |
8b96f011 FW |
343 | __notrace_funcgraph struct task_struct * |
344 | __switch_to(struct task_struct *prev_p, struct task_struct *next_p) | |
1da177e4 LT |
345 | { |
346 | struct thread_struct *prev = &prev_p->thread, | |
347 | *next = &next_p->thread; | |
348 | int cpu = smp_processor_id(); | |
349 | struct tss_struct *tss = &per_cpu(init_tss, cpu); | |
2fcddce1 | 350 | bool preload_fpu; |
1da177e4 LT |
351 | |
352 | /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ | |
353 | ||
2fcddce1 JF |
354 | /* |
355 | * If the task has used fpu the last 5 timeslices, just do a full | |
356 | * restore of the math state immediately to avoid the trap; the | |
357 | * chances of needing FPU soon are obviously high now | |
358 | */ | |
359 | preload_fpu = tsk_used_math(next_p) && next_p->fpu_counter > 5; | |
1da177e4 | 360 | |
2fcddce1 | 361 | __unlazy_fpu(prev_p); |
acc20761 CE |
362 | |
363 | /* we're going to use this soon, after a few expensive things */ | |
2fcddce1 | 364 | if (preload_fpu) |
61c4628b | 365 | prefetch(next->xstate); |
acc20761 | 366 | |
1da177e4 | 367 | /* |
e7a2ff59 | 368 | * Reload esp0. |
1da177e4 | 369 | */ |
faca6227 | 370 | load_sp0(tss, next); |
1da177e4 LT |
371 | |
372 | /* | |
464d1a78 | 373 | * Save away %gs. No need to save %fs, as it was saved on the |
f95d47ca JF |
374 | * stack on entry. No need to save %es and %ds, as those are |
375 | * always kernel segments while inside the kernel. Doing this | |
376 | * before setting the new TLS descriptors avoids the situation | |
377 | * where we temporarily have non-reloadable segments in %fs | |
378 | * and %gs. This could be an issue if the NMI handler ever | |
379 | * used %fs or %gs (it does not today), or if the kernel is | |
380 | * running inside of a hypervisor layer. | |
1da177e4 | 381 | */ |
ccbeed3a | 382 | lazy_save_gs(prev->gs); |
1da177e4 LT |
383 | |
384 | /* | |
e7a2ff59 | 385 | * Load the per-thread Thread-Local Storage descriptor. |
1da177e4 | 386 | */ |
e7a2ff59 | 387 | load_TLS(next, cpu); |
1da177e4 | 388 | |
8b151144 ZA |
389 | /* |
390 | * Restore IOPL if needed. In normal use, the flags restore | |
391 | * in the switch assembly will handle this. But if the kernel | |
392 | * is running virtualized at a non-zero CPL, the popf will | |
393 | * not restore flags, so it must be done in a separate step. | |
394 | */ | |
395 | if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl)) | |
396 | set_iopl_mask(next->iopl); | |
397 | ||
1da177e4 | 398 | /* |
b3cf2576 | 399 | * Now maybe handle debug registers and/or IO bitmaps |
1da177e4 | 400 | */ |
cf99abac AA |
401 | if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV || |
402 | task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT)) | |
403 | __switch_to_xtra(prev_p, next_p, tss); | |
ffaa8bd6 | 404 | |
2fcddce1 JF |
405 | /* If we're going to preload the fpu context, make sure clts |
406 | is run while we're batching the cpu state updates. */ | |
407 | if (preload_fpu) | |
408 | clts(); | |
409 | ||
9226d125 ZA |
410 | /* |
411 | * Leave lazy mode, flushing any hypercalls made here. | |
412 | * This must be done before restoring TLS segments so | |
413 | * the GDT and LDT are properly updated, and must be | |
414 | * done before math_state_restore, so the TS bit is up | |
415 | * to date. | |
416 | */ | |
224101ed | 417 | arch_end_context_switch(next_p); |
9226d125 | 418 | |
2fcddce1 JF |
419 | if (preload_fpu) |
420 | __math_state_restore(); | |
acc20761 | 421 | |
9226d125 ZA |
422 | /* |
423 | * Restore %gs if needed (which is common) | |
424 | */ | |
425 | if (prev->gs | next->gs) | |
ccbeed3a | 426 | lazy_load_gs(next->gs); |
9226d125 | 427 | |
6dbde353 | 428 | percpu_write(current_task, next_p); |
9226d125 | 429 | |
1da177e4 LT |
430 | return prev_p; |
431 | } | |
432 | ||
b12bdaf1 | 433 | int sys_clone(struct pt_regs *regs) |
1da177e4 | 434 | { |
b12bdaf1 BG |
435 | unsigned long clone_flags; |
436 | unsigned long newsp; | |
437 | int __user *parent_tidptr, *child_tidptr; | |
438 | ||
439 | clone_flags = regs->bx; | |
440 | newsp = regs->cx; | |
441 | parent_tidptr = (int __user *)regs->dx; | |
442 | child_tidptr = (int __user *)regs->di; | |
1da177e4 | 443 | if (!newsp) |
253f29a4 BG |
444 | newsp = regs->sp; |
445 | return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr); | |
1da177e4 LT |
446 | } |
447 | ||
1da177e4 LT |
448 | /* |
449 | * sys_execve() executes a new program. | |
450 | */ | |
b12bdaf1 | 451 | int sys_execve(struct pt_regs *regs) |
1da177e4 LT |
452 | { |
453 | int error; | |
befa9e78 | 454 | char *filename; |
1da177e4 | 455 | |
b12bdaf1 | 456 | filename = getname((char __user *) regs->bx); |
1da177e4 LT |
457 | error = PTR_ERR(filename); |
458 | if (IS_ERR(filename)) | |
459 | goto out; | |
b12bdaf1 BG |
460 | error = do_execve(filename, |
461 | (char __user * __user *) regs->cx, | |
462 | (char __user * __user *) regs->dx, | |
463 | regs); | |
1da177e4 | 464 | if (error == 0) { |
1da177e4 LT |
465 | /* Make sure we don't return using sysenter.. */ |
466 | set_thread_flag(TIF_IRET); | |
467 | } | |
468 | putname(filename); | |
469 | out: | |
470 | return error; | |
471 | } | |
472 | ||
473 | #define top_esp (THREAD_SIZE - sizeof(unsigned long)) | |
474 | #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long)) | |
475 | ||
476 | unsigned long get_wchan(struct task_struct *p) | |
477 | { | |
65ea5b03 | 478 | unsigned long bp, sp, ip; |
1da177e4 LT |
479 | unsigned long stack_page; |
480 | int count = 0; | |
481 | if (!p || p == current || p->state == TASK_RUNNING) | |
482 | return 0; | |
65e0fdff | 483 | stack_page = (unsigned long)task_stack_page(p); |
faca6227 | 484 | sp = p->thread.sp; |
65ea5b03 | 485 | if (!stack_page || sp < stack_page || sp > top_esp+stack_page) |
1da177e4 | 486 | return 0; |
65ea5b03 PA |
487 | /* include/asm-i386/system.h:switch_to() pushes bp last. */ |
488 | bp = *(unsigned long *) sp; | |
1da177e4 | 489 | do { |
65ea5b03 | 490 | if (bp < stack_page || bp > top_ebp+stack_page) |
1da177e4 | 491 | return 0; |
65ea5b03 PA |
492 | ip = *(unsigned long *) (bp+4); |
493 | if (!in_sched_functions(ip)) | |
494 | return ip; | |
495 | bp = *(unsigned long *) bp; | |
1da177e4 LT |
496 | } while (count++ < 16); |
497 | return 0; | |
498 | } | |
499 |