projects / linux-2.6-block.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
[PATCH] xen: x86: Rename usermode macro
[linux-2.6-block.git] / arch / i386 / kernel / process.c
CommitLineData
1da177e4
LT		 1/*
2 * linux/arch/i386/kernel/process.c
3 *
4 * Copyright (C) 1995 Linus Torvalds
5 *
6 * Pentium III FXSR, SSE support
7 * Gareth Hughes <gareth@valinux.com>, May 2000
8 */
9
10/*
11 * This file handles the architecture-dependent parts of process handling..
12 */
13
14#include <stdarg.h>
15
16#include <linux/errno.h>
17#include <linux/sched.h>
18#include <linux/fs.h>
19#include <linux/kernel.h>
20#include <linux/mm.h>
21#include <linux/elfcore.h>
22#include <linux/smp.h>
23#include <linux/smp_lock.h>
24#include <linux/stddef.h>
25#include <linux/slab.h>
26#include <linux/vmalloc.h>
27#include <linux/user.h>
28#include <linux/a.out.h>
29#include <linux/interrupt.h>
30#include <linux/config.h>
31#include <linux/utsname.h>
32#include <linux/delay.h>
33#include <linux/reboot.h>
34#include <linux/init.h>
35#include <linux/mc146818rtc.h>
36#include <linux/module.h>
37#include <linux/kallsyms.h>
38#include <linux/ptrace.h>
39#include <linux/random.h>
40
41#include <asm/uaccess.h>
42#include <asm/pgtable.h>
43#include <asm/system.h>
44#include <asm/io.h>
45#include <asm/ldt.h>
46#include <asm/processor.h>
47#include <asm/i387.h>
48#include <asm/irq.h>
49#include <asm/desc.h>
50#ifdef CONFIG_MATH_EMULATION
51#include <asm/math_emu.h>
52#endif
53
54#include <linux/irq.h>
55#include <linux/err.h>
56
57asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
58
59static int hlt_counter;
60
61unsigned long boot_option_idle_override = 0;
62EXPORT_SYMBOL(boot_option_idle_override);
63
64/*
65 * Return saved PC of a blocked thread.
66 */
67unsigned long thread_saved_pc(struct task_struct *tsk)
68{
69 return ((unsigned long *)tsk->thread.esp)[3];
70}
71
72/*
73 * Powermanagement idle function, if any..
74 */
75void (*pm_idle)(void);
129f6946 76EXPORT_SYMBOL(pm_idle);
1da177e4
LT		 77static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
78
79void disable_hlt(void)
80{
81 hlt_counter++;
82}
83
84EXPORT_SYMBOL(disable_hlt);
85
86void enable_hlt(void)
87{
88 hlt_counter--;
89}
90
91EXPORT_SYMBOL(enable_hlt);
92
93/*
94 * We use this if we don't have any better
95 * idle routine..
96 */
97void default_idle(void)
98{
99 if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
100 local_irq_disable();
101 if (!need_resched())
102 safe_halt();
103 else
104 local_irq_enable();
105 } else {
106 cpu_relax();
107 }
108}
129f6946
AD		 109#ifdef CONFIG_APM_MODULE
110EXPORT_SYMBOL(default_idle);
111#endif
1da177e4
LT		 112
113/*
114 * On SMP it's slightly faster (but much more power-consuming!)
115 * to poll the ->work.need_resched flag instead of waiting for the
116 * cross-CPU IPI to arrive. Use this option with caution.
117 */
118static void poll_idle (void)
119{
120 int oldval;
121
122 local_irq_enable();
123
124 /*
125 * Deal with another CPU just having chosen a thread to
126 * run here:
127 */
128 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
129
130 if (!oldval) {
131 set_thread_flag(TIF_POLLING_NRFLAG);
132 asm volatile(
133 "2:"
134 "testl %0, %1;"
135 "rep; nop;"
136 "je 2b;"
137 : : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));
138
139 clear_thread_flag(TIF_POLLING_NRFLAG);
140 } else {
141 set_need_resched();
142 }
143}
144
145/*
146 * The idle thread. There's no useful work to be
147 * done, so just try to conserve power and have a
148 * low exit latency (ie sit in a loop waiting for
149 * somebody to say that they'd like to reschedule)
150 */
151void cpu_idle (void)
152{
153 /* endless idle loop with no priority at all */
154 while (1) {
155 while (!need_resched()) {
156 void (*idle)(void);
157
158 if (__get_cpu_var(cpu_idle_state))
159 __get_cpu_var(cpu_idle_state) = 0;
160
161 rmb();
162 idle = pm_idle;
163
164 if (!idle)
165 idle = default_idle;
166
167 __get_cpu_var(irq_stat).idle_timestamp = jiffies;
168 idle();
169 }
170 schedule();
171 }
172}
173
174void cpu_idle_wait(void)
175{
176 unsigned int cpu, this_cpu = get_cpu();
177 cpumask_t map;
178
179 set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
180 put_cpu();
181
182 cpus_clear(map);
183 for_each_online_cpu(cpu) {
184 per_cpu(cpu_idle_state, cpu) = 1;
185 cpu_set(cpu, map);
186 }
187
188 __get_cpu_var(cpu_idle_state) = 0;
189
190 wmb();
191 do {
192 ssleep(1);
193 for_each_online_cpu(cpu) {
194 if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu))
195 cpu_clear(cpu, map);
196 }
197 cpus_and(map, map, cpu_online_map);
198 } while (!cpus_empty(map));
199}
200EXPORT_SYMBOL_GPL(cpu_idle_wait);
201
202/*
203 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
204 * which can obviate IPI to trigger checking of need_resched.
205 * We execute MONITOR against need_resched and enter optimized wait state
206 * through MWAIT. Whenever someone changes need_resched, we would be woken
207 * up from MWAIT (without an IPI).
208 */
209static void mwait_idle(void)
210{
211 local_irq_enable();
212
213 if (!need_resched()) {
214 set_thread_flag(TIF_POLLING_NRFLAG);
215 do {
216 __monitor((void *)&current_thread_info()->flags, 0, 0);
217 if (need_resched())
218 break;
219 __mwait(0, 0);
220 } while (!need_resched());
221 clear_thread_flag(TIF_POLLING_NRFLAG);
222 }
223}
224
225void __init select_idle_routine(const struct cpuinfo_x86 *c)
226{
227 if (cpu_has(c, X86_FEATURE_MWAIT)) {
228 printk("monitor/mwait feature present.\n");
229 /*
230 * Skip, if setup has overridden idle.
231 * One CPU supports mwait => All CPUs supports mwait
232 */
233 if (!pm_idle) {
234 printk("using mwait in idle threads.\n");
235 pm_idle = mwait_idle;
236 }
237 }
238}
239
240static int __init idle_setup (char *str)
241{
242 if (!strncmp(str, "poll", 4)) {
243 printk("using polling idle threads.\n");
244 pm_idle = poll_idle;
245#ifdef CONFIG_X86_SMP
246 if (smp_num_siblings > 1)
247 printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
248#endif
249 } else if (!strncmp(str, "halt", 4)) {
250 printk("using halt in idle threads.\n");
251 pm_idle = default_idle;
252 }
253
254 boot_option_idle_override = 1;
255 return 1;
256}
257
258__setup("idle=", idle_setup);
259
260void show_regs(struct pt_regs * regs)
261{
262 unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
263
264 printk("\n");
265 printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
266 printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id());
267 print_symbol("EIP is at %s\n", regs->eip);
268
269 if (regs->xcs & 3)
270 printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp);
271 printk(" EFLAGS: %08lx %s (%s)\n",
272 regs->eflags, print_tainted(), system_utsname.release);
273 printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
274 regs->eax,regs->ebx,regs->ecx,regs->edx);
275 printk("ESI: %08lx EDI: %08lx EBP: %08lx",
276 regs->esi, regs->edi, regs->ebp);
277 printk(" DS: %04x ES: %04x\n",
278 0xffff & regs->xds,0xffff & regs->xes);
279
280 __asm__("movl %%cr0, %0": "=r" (cr0));
281 __asm__("movl %%cr2, %0": "=r" (cr2));
282 __asm__("movl %%cr3, %0": "=r" (cr3));
283 /* This could fault if %cr4 does not exist */
284 __asm__("1: movl %%cr4, %0 \n"
285 "2: \n"
286 ".section __ex_table,\"a\" \n"
287 ".long 1b,2b \n"
288 ".previous \n"
289 : "=r" (cr4): "0" (0));
290 printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
291 show_trace(NULL, &regs->esp);
292}
293
294/*
295 * This gets run with %ebx containing the
296 * function to call, and %edx containing
297 * the "args".
298 */
299extern void kernel_thread_helper(void);
300__asm__(".section .text\n"
301 ".align 4\n"
302 "kernel_thread_helper:\n\t"
303 "movl %edx,%eax\n\t"
304 "pushl %edx\n\t"
305 "call *%ebx\n\t"
306 "pushl %eax\n\t"
307 "call do_exit\n"
308 ".previous");
309
310/*
311 * Create a kernel thread
312 */
313int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
314{
315 struct pt_regs regs;
316
317 memset(&regs, 0, sizeof(regs));
318
319 regs.ebx = (unsigned long) fn;
320 regs.edx = (unsigned long) arg;
321
322 regs.xds = __USER_DS;
323 regs.xes = __USER_DS;
324 regs.orig_eax = -1;
325 regs.eip = (unsigned long) kernel_thread_helper;
326 regs.xcs = __KERNEL_CS;
327 regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2;
328
329 /* Ok, create the new process.. */
330 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
331}
129f6946 332EXPORT_SYMBOL(kernel_thread);
1da177e4
LT		 333
334/*
335 * Free current thread data structures etc..
336 */
337void exit_thread(void)
338{
339 struct task_struct *tsk = current;
340 struct thread_struct *t = &tsk->thread;
341
342 /* The process may have allocated an io port bitmap... nuke it. */
343 if (unlikely(NULL != t->io_bitmap_ptr)) {
344 int cpu = get_cpu();
345 struct tss_struct *tss = &per_cpu(init_tss, cpu);
346
347 kfree(t->io_bitmap_ptr);
348 t->io_bitmap_ptr = NULL;
349 /*
350 * Careful, clear this in the TSS too:
351 */
352 memset(tss->io_bitmap, 0xff, tss->io_bitmap_max);
353 t->io_bitmap_max = 0;
354 tss->io_bitmap_owner = NULL;
355 tss->io_bitmap_max = 0;
356 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
357 put_cpu();
358 }
359}
360
361void flush_thread(void)
362{
363 struct task_struct *tsk = current;
364
365 memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
366 memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
367 /*
368 * Forget coprocessor state..
369 */
370 clear_fpu(tsk);
371 clear_used_math();
372}
373
374void release_thread(struct task_struct *dead_task)
375{
376 if (dead_task->mm) {
377 // temporary debugging check
378 if (dead_task->mm->context.size) {
379 printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
380 dead_task->comm,
381 dead_task->mm->context.ldt,
382 dead_task->mm->context.size);
383 BUG();
384 }
385 }
386
387 release_vm86_irqs(dead_task);
388}
389
390/*
391 * This gets called before we allocate a new thread and copy
392 * the current task into it.
393 */
394void prepare_to_copy(struct task_struct *tsk)
395{
396 unlazy_fpu(tsk);
397}
398
399int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
400 unsigned long unused,
401 struct task_struct * p, struct pt_regs * regs)
402{
403 struct pt_regs * childregs;
404 struct task_struct *tsk;
405 int err;
406
407 childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
5df24082
SS		 408 /*
409 * The below -8 is to reserve 8 bytes on top of the ring0 stack.
410 * This is necessary to guarantee that the entire "struct pt_regs"
411 * is accessable even if the CPU haven't stored the SS/ESP registers
412 * on the stack (interrupt gate does not save these registers
413 * when switching to the same priv ring).
414 * Therefore beware: accessing the xss/esp fields of the
415 * "struct pt_regs" is possible, but they may contain the
416 * completely wrong values.
417 */
f48d9663
AN		 418 childregs = (struct pt_regs *) ((unsigned long) childregs - 8);
419 *childregs = *regs;
420 childregs->eax = 0;
421 childregs->esp = esp;
422
423 p->thread.esp = (unsigned long) childregs;
424 p->thread.esp0 = (unsigned long) (childregs+1);
1da177e4
LT		 425
426 p->thread.eip = (unsigned long) ret_from_fork;
427
428 savesegment(fs,p->thread.fs);
429 savesegment(gs,p->thread.gs);
430
431 tsk = current;
432 if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) {
433 p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
434 if (!p->thread.io_bitmap_ptr) {
435 p->thread.io_bitmap_max = 0;
436 return -ENOMEM;
437 }
438 memcpy(p->thread.io_bitmap_ptr, tsk->thread.io_bitmap_ptr,
439 IO_BITMAP_BYTES);
440 }
441
442 /*
443 * Set a new TLS for the child thread?
444 */
445 if (clone_flags & CLONE_SETTLS) {
446 struct desc_struct *desc;
447 struct user_desc info;
448 int idx;
449
450 err = -EFAULT;
451 if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info)))
452 goto out;
453 err = -EINVAL;
454 if (LDT_empty(&info))
455 goto out;
456
457 idx = info.entry_number;
458 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
459 goto out;
460
461 desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
462 desc->a = LDT_entry_a(&info);
463 desc->b = LDT_entry_b(&info);
464 }
465
466 err = 0;
467 out:
468 if (err && p->thread.io_bitmap_ptr) {
469 kfree(p->thread.io_bitmap_ptr);
470 p->thread.io_bitmap_max = 0;
471 }
472 return err;
473}
474
475/*
476 * fill in the user structure for a core dump..
477 */
478void dump_thread(struct pt_regs * regs, struct user * dump)
479{
480 int i;
481
482/* changed the size calculations - should hopefully work better. lbt */
483 dump->magic = CMAGIC;
484 dump->start_code = 0;
485 dump->start_stack = regs->esp & ~(PAGE_SIZE - 1);
486 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
487 dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
488 dump->u_dsize -= dump->u_tsize;
489 dump->u_ssize = 0;
490 for (i = 0; i < 8; i++)
491 dump->u_debugreg[i] = current->thread.debugreg[i];
492
493 if (dump->start_stack < TASK_SIZE)
494 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
495
496 dump->regs.ebx = regs->ebx;
497 dump->regs.ecx = regs->ecx;
498 dump->regs.edx = regs->edx;
499 dump->regs.esi = regs->esi;
500 dump->regs.edi = regs->edi;
501 dump->regs.ebp = regs->ebp;
502 dump->regs.eax = regs->eax;
503 dump->regs.ds = regs->xds;
504 dump->regs.es = regs->xes;
505 savesegment(fs,dump->regs.fs);
506 savesegment(gs,dump->regs.gs);
507 dump->regs.orig_eax = regs->orig_eax;
508 dump->regs.eip = regs->eip;
509 dump->regs.cs = regs->xcs;
510 dump->regs.eflags = regs->eflags;
511 dump->regs.esp = regs->esp;
512 dump->regs.ss = regs->xss;
513
514 dump->u_fpvalid = dump_fpu (regs, &dump->i387);
515}
129f6946 516EXPORT_SYMBOL(dump_thread);
1da177e4
LT		 517
518/*
519 * Capture the user space registers if the task is not running (in user space)
520 */
521int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
522{
523 struct pt_regs ptregs;
524
525 ptregs = *(struct pt_regs *)
526 ((unsigned long)tsk->thread_info+THREAD_SIZE - sizeof(ptregs));
527 ptregs.xcs &= 0xffff;
528 ptregs.xds &= 0xffff;
529 ptregs.xes &= 0xffff;
530 ptregs.xss &= 0xffff;
531
532 elf_core_copy_regs(regs, &ptregs);
533
534 return 1;
535}
536
537static inline void
538handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss)
539{
540 if (!next->io_bitmap_ptr) {
541 /*
542 * Disable the bitmap via an invalid offset. We still cache
543 * the previous bitmap owner and the IO bitmap contents:
544 */
545 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
546 return;
547 }
548 if (likely(next == tss->io_bitmap_owner)) {
549 /*
550 * Previous owner of the bitmap (hence the bitmap content)
551 * matches the next task, we dont have to do anything but
552 * to set a valid offset in the TSS:
553 */
554 tss->io_bitmap_base = IO_BITMAP_OFFSET;
555 return;
556 }
557 /*
558 * Lazy TSS's I/O bitmap copy. We set an invalid offset here
559 * and we let the task to get a GPF in case an I/O instruction
560 * is performed. The handler of the GPF will verify that the
561 * faulting task has a valid I/O bitmap and, it true, does the
562 * real copy and restart the instruction. This will save us
563 * redundant copies when the currently switched task does not
564 * perform any I/O during its timeslice.
565 */
566 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY;
567}
1da177e4
LT		 568
569/*
570 * switch_to(x,yn) should switch tasks from x to y.
571 *
572 * We fsave/fwait so that an exception goes off at the right time
573 * (as a call from the fsave or fwait in effect) rather than to
574 * the wrong process. Lazy FP saving no longer makes any sense
575 * with modern CPU's, and this simplifies a lot of things (SMP
576 * and UP become the same).
577 *
578 * NOTE! We used to use the x86 hardware context switching. The
579 * reason for not using it any more becomes apparent when you
580 * try to recover gracefully from saved state that is no longer
581 * valid (stale segment register values in particular). With the
582 * hardware task-switch, there is no way to fix up bad state in
583 * a reasonable manner.
584 *
585 * The fact that Intel documents the hardware task-switching to
586 * be slow is a fairly red herring - this code is not noticeably
587 * faster. However, there _is_ some room for improvement here,
588 * so the performance issues may eventually be a valid point.
589 * More important, however, is the fact that this allows us much
590 * more flexibility.
591 *
592 * The return value (in %eax) will be the "prev" task after
593 * the task-switch, and shows up in ret_from_fork in entry.S,
594 * for example.
595 */
596struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
597{
598 struct thread_struct *prev = &prev_p->thread,
599 *next = &next_p->thread;
600 int cpu = smp_processor_id();
601 struct tss_struct *tss = &per_cpu(init_tss, cpu);
602
603 /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
604
605 __unlazy_fpu(prev_p);
606
607 /*
608 * Reload esp0, LDT and the page table pointer:
609 */
610 load_esp0(tss, next);
611
612 /*
613 * Load the per-thread Thread-Local Storage descriptor.
614 */
615 load_TLS(next, cpu);
616
617 /*
618 * Save away %fs and %gs. No need to save %es and %ds, as
619 * those are always kernel segments while inside the kernel.
620 */
fd51f666
L		 621 asm volatile("mov %%fs,%0":"=m" (prev->fs));
622 asm volatile("mov %%gs,%0":"=m" (prev->gs));
1da177e4
LT		 623
624 /*
625 * Restore %fs and %gs if needed.
626 */
627 if (unlikely(prev->fs | prev->gs | next->fs | next->gs)) {
628 loadsegment(fs, next->fs);
629 loadsegment(gs, next->gs);
630 }
631
632 /*
633 * Now maybe reload the debug registers
634 */
635 if (unlikely(next->debugreg[7])) {
1cc6f12e
VH		 636 set_debugreg(current->thread.debugreg[0], 0);
637 set_debugreg(current->thread.debugreg[1], 1);
638 set_debugreg(current->thread.debugreg[2], 2);
639 set_debugreg(current->thread.debugreg[3], 3);
1da177e4 640 /* no 4 and 5 */
1cc6f12e
VH		 641 set_debugreg(current->thread.debugreg[6], 6);
642 set_debugreg(current->thread.debugreg[7], 7);
1da177e4
LT		 643 }
644
645 if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr))
646 handle_io_bitmap(next, tss);
647
648 return prev_p;
649}
650
651asmlinkage int sys_fork(struct pt_regs regs)
652{
653 return do_fork(SIGCHLD, regs.esp, &regs, 0, NULL, NULL);
654}
655
656asmlinkage int sys_clone(struct pt_regs regs)
657{
658 unsigned long clone_flags;
659 unsigned long newsp;
660 int __user *parent_tidptr, *child_tidptr;
661
662 clone_flags = regs.ebx;
663 newsp = regs.ecx;
664 parent_tidptr = (int __user *)regs.edx;
665 child_tidptr = (int __user *)regs.edi;
666 if (!newsp)
667 newsp = regs.esp;
668 return do_fork(clone_flags, newsp, &regs, 0, parent_tidptr, child_tidptr);
669}
670
671/*
672 * This is trivial, and on the face of it looks like it
673 * could equally well be done in user mode.
674 *
675 * Not so, for quite unobvious reasons - register pressure.
676 * In user mode vfork() cannot have a stack frame, and if
677 * done by calling the "clone()" system call directly, you
678 * do not have enough call-clobbered registers to hold all
679 * the information you need.
680 */
681asmlinkage int sys_vfork(struct pt_regs regs)
682{
683 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, &regs, 0, NULL, NULL);
684}
685
686/*
687 * sys_execve() executes a new program.
688 */
689asmlinkage int sys_execve(struct pt_regs regs)
690{
691 int error;
692 char * filename;
693
694 filename = getname((char __user *) regs.ebx);
695 error = PTR_ERR(filename);
696 if (IS_ERR(filename))
697 goto out;
698 error = do_execve(filename,
699 (char __user * __user *) regs.ecx,
700 (char __user * __user *) regs.edx,
701 &regs);
702 if (error == 0) {
703 task_lock(current);
704 current->ptrace &= ~PT_DTRACE;
705 task_unlock(current);
706 /* Make sure we don't return using sysenter.. */
707 set_thread_flag(TIF_IRET);
708 }
709 putname(filename);
710out:
711 return error;
712}
713
714#define top_esp (THREAD_SIZE - sizeof(unsigned long))
715#define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
716
717unsigned long get_wchan(struct task_struct *p)
718{
719 unsigned long ebp, esp, eip;
720 unsigned long stack_page;
721 int count = 0;
722 if (!p || p == current || p->state == TASK_RUNNING)
723 return 0;
724 stack_page = (unsigned long)p->thread_info;
725 esp = p->thread.esp;
726 if (!stack_page || esp < stack_page || esp > top_esp+stack_page)
727 return 0;
728 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
729 ebp = *(unsigned long *) esp;
730 do {
731 if (ebp < stack_page || ebp > top_ebp+stack_page)
732 return 0;
733 eip = *(unsigned long *) (ebp+4);
734 if (!in_sched_functions(eip))
735 return eip;
736 ebp = *(unsigned long *) ebp;
737 } while (count++ < 16);
738 return 0;
739}
129f6946 740EXPORT_SYMBOL(get_wchan);
1da177e4
LT		 741
742/*
743 * sys_alloc_thread_area: get a yet unused TLS descriptor index.
744 */
745static int get_free_idx(void)
746{
747 struct thread_struct *t = &current->thread;
748 int idx;
749
750 for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
751 if (desc_empty(t->tls_array + idx))
752 return idx + GDT_ENTRY_TLS_MIN;
753 return -ESRCH;
754}
755
756/*
757 * Set a given TLS descriptor:
758 */
759asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
760{
761 struct thread_struct *t = &current->thread;
762 struct user_desc info;
763 struct desc_struct *desc;
764 int cpu, idx;
765
766 if (copy_from_user(&info, u_info, sizeof(info)))
767 return -EFAULT;
768 idx = info.entry_number;
769
770 /*
771 * index -1 means the kernel should try to find and
772 * allocate an empty descriptor:
773 */
774 if (idx == -1) {
775 idx = get_free_idx();
776 if (idx < 0)
777 return idx;
778 if (put_user(idx, &u_info->entry_number))
779 return -EFAULT;
780 }
781
782 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
783 return -EINVAL;
784
785 desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;
786
787 /*
788 * We must not get preempted while modifying the TLS.
789 */
790 cpu = get_cpu();
791
792 if (LDT_empty(&info)) {
793 desc->a = 0;
794 desc->b = 0;
795 } else {
796 desc->a = LDT_entry_a(&info);
797 desc->b = LDT_entry_b(&info);
798 }
799 load_TLS(t, cpu);
800
801 put_cpu();
802
803 return 0;
804}
805
806/*
807 * Get the current Thread-Local Storage area:
808 */
809
810#define GET_BASE(desc) ( \
811 (((desc)->a >> 16) & 0x0000ffff) | \
812 (((desc)->b << 16) & 0x00ff0000) | \
813 ( (desc)->b & 0xff000000) )
814
815#define GET_LIMIT(desc) ( \
816 ((desc)->a & 0x0ffff) | \
817 ((desc)->b & 0xf0000) )
818
819#define GET_32BIT(desc) (((desc)->b >> 22) & 1)
820#define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
821#define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
822#define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
823#define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
824#define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
825
826asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
827{
828 struct user_desc info;
829 struct desc_struct *desc;
830 int idx;
831
832 if (get_user(idx, &u_info->entry_number))
833 return -EFAULT;
834 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
835 return -EINVAL;
836
837 desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
838
839 info.entry_number = idx;
840 info.base_addr = GET_BASE(desc);
841 info.limit = GET_LIMIT(desc);
842 info.seg_32bit = GET_32BIT(desc);
843 info.contents = GET_CONTENTS(desc);
844 info.read_exec_only = !GET_WRITABLE(desc);
845 info.limit_in_pages = GET_LIMIT_PAGES(desc);
846 info.seg_not_present = !GET_PRESENT(desc);
847 info.useable = GET_USEABLE(desc);
848
849 if (copy_to_user(u_info, &info, sizeof(info)))
850 return -EFAULT;
851 return 0;
852}
853
854unsigned long arch_align_stack(unsigned long sp)
855{
856 if (randomize_va_space)
857 sp -= get_random_int() % 8192;
858 return sp & ~0xf;
859}
Linux 6.x block layer and io_uring tree(s)