2 * Copyright (C) 1995 Linus Torvalds
4 * Pentium III FXSR, SSE support
5 * Gareth Hughes <gareth@valinux.com>, May 2000
10 * CPU hotplug support - ashok.raj@intel.com
14 * This file handles the architecture-dependent parts of process handling..
17 #include <linux/cpu.h>
18 #include <linux/errno.h>
19 #include <linux/sched.h>
21 #include <linux/kernel.h>
23 #include <linux/elfcore.h>
24 #include <linux/smp.h>
25 #include <linux/slab.h>
26 #include <linux/user.h>
27 #include <linux/interrupt.h>
28 #include <linux/delay.h>
29 #include <linux/module.h>
30 #include <linux/ptrace.h>
31 #include <linux/notifier.h>
32 #include <linux/kprobes.h>
33 #include <linux/kdebug.h>
34 #include <linux/prctl.h>
35 #include <linux/uaccess.h>
37 #include <linux/ftrace.h>
39 #include <asm/pgtable.h>
40 #include <asm/processor.h>
42 #include <asm/fpu-internal.h>
43 #include <asm/mmu_context.h>
44 #include <asm/prctl.h>
46 #include <asm/proto.h>
49 #include <asm/syscalls.h>
50 #include <asm/debugreg.h>
51 #include <asm/switch_to.h>
53 asmlinkage extern void ret_from_fork(void);
55 DEFINE_PER_CPU(unsigned long, old_rsp);
57 /* Prints also some state that isn't saved in the pt_regs */
58 void __show_regs(struct pt_regs *regs, int all)
60 unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
61 unsigned long d0, d1, d2, d3, d6, d7;
62 unsigned int fsindex, gsindex;
63 unsigned int ds, cs, es;
66 printk(KERN_DEFAULT "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
67 printk_address(regs->ip, 1);
68 printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx\n", regs->ss,
69 regs->sp, regs->flags);
70 printk(KERN_DEFAULT "RAX: %016lx RBX: %016lx RCX: %016lx\n",
71 regs->ax, regs->bx, regs->cx);
72 printk(KERN_DEFAULT "RDX: %016lx RSI: %016lx RDI: %016lx\n",
73 regs->dx, regs->si, regs->di);
74 printk(KERN_DEFAULT "RBP: %016lx R08: %016lx R09: %016lx\n",
75 regs->bp, regs->r8, regs->r9);
76 printk(KERN_DEFAULT "R10: %016lx R11: %016lx R12: %016lx\n",
77 regs->r10, regs->r11, regs->r12);
78 printk(KERN_DEFAULT "R13: %016lx R14: %016lx R15: %016lx\n",
79 regs->r13, regs->r14, regs->r15);
81 asm("movl %%ds,%0" : "=r" (ds));
82 asm("movl %%cs,%0" : "=r" (cs));
83 asm("movl %%es,%0" : "=r" (es));
84 asm("movl %%fs,%0" : "=r" (fsindex));
85 asm("movl %%gs,%0" : "=r" (gsindex));
87 rdmsrl(MSR_FS_BASE, fs);
88 rdmsrl(MSR_GS_BASE, gs);
89 rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
99 printk(KERN_DEFAULT "FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
100 fs, fsindex, gs, gsindex, shadowgs);
101 printk(KERN_DEFAULT "CS: %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds,
103 printk(KERN_DEFAULT "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3,
109 printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
113 printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
116 void release_thread(struct task_struct *dead_task)
119 if (dead_task->mm->context.size) {
120 printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
122 dead_task->mm->context.ldt,
123 dead_task->mm->context.size);
129 static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
131 struct user_desc ud = {
138 struct desc_struct *desc = t->thread.tls_array;
143 static inline u32 read_32bit_tls(struct task_struct *t, int tls)
145 return get_desc_base(&t->thread.tls_array[tls]);
149 * This gets called before we allocate a new thread and copy
150 * the current task into it.
152 void prepare_to_copy(struct task_struct *tsk)
157 int copy_thread(unsigned long clone_flags, unsigned long sp,
158 unsigned long unused,
159 struct task_struct *p, struct pt_regs *regs)
162 struct pt_regs *childregs;
163 struct task_struct *me = current;
165 childregs = ((struct pt_regs *)
166 (THREAD_SIZE + task_stack_page(p))) - 1;
173 childregs->sp = (unsigned long)childregs;
175 p->thread.sp = (unsigned long) childregs;
176 p->thread.sp0 = (unsigned long) (childregs+1);
177 p->thread.usersp = me->thread.usersp;
179 set_tsk_thread_flag(p, TIF_FORK);
182 p->thread.io_bitmap_ptr = NULL;
184 savesegment(gs, p->thread.gsindex);
185 p->thread.gs = p->thread.gsindex ? 0 : me->thread.gs;
186 savesegment(fs, p->thread.fsindex);
187 p->thread.fs = p->thread.fsindex ? 0 : me->thread.fs;
188 savesegment(es, p->thread.es);
189 savesegment(ds, p->thread.ds);
192 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
194 if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
195 p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
196 IO_BITMAP_BYTES, GFP_KERNEL);
197 if (!p->thread.io_bitmap_ptr) {
198 p->thread.io_bitmap_max = 0;
201 set_tsk_thread_flag(p, TIF_IO_BITMAP);
205 * Set a new TLS for the child thread?
207 if (clone_flags & CLONE_SETTLS) {
208 #ifdef CONFIG_IA32_EMULATION
209 if (test_thread_flag(TIF_IA32))
210 err = do_set_thread_area(p, -1,
211 (struct user_desc __user *)childregs->si, 0);
214 err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
220 if (err && p->thread.io_bitmap_ptr) {
221 kfree(p->thread.io_bitmap_ptr);
222 p->thread.io_bitmap_max = 0;
229 start_thread_common(struct pt_regs *regs, unsigned long new_ip,
230 unsigned long new_sp,
231 unsigned int _cs, unsigned int _ss, unsigned int _ds)
234 loadsegment(es, _ds);
235 loadsegment(ds, _ds);
237 current->thread.usersp = new_sp;
240 percpu_write(old_rsp, new_sp);
243 regs->flags = X86_EFLAGS_IF;
245 * Free the old FP and other extended state
247 free_thread_xstate(current);
251 start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
253 start_thread_common(regs, new_ip, new_sp,
254 __USER_CS, __USER_DS, 0);
257 #ifdef CONFIG_IA32_EMULATION
258 void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
260 start_thread_common(regs, new_ip, new_sp,
261 __USER32_CS, __USER32_DS, __USER32_DS);
266 * switch_to(x,y) should switch tasks from x to y.
268 * This could still be optimized:
269 * - fold all the options into a flag word and test it with a single test.
270 * - could test fs/gs bitsliced
272 * Kprobes not supported here. Set the probe on schedule instead.
273 * Function graph tracer not supported too.
275 __notrace_funcgraph struct task_struct *
276 __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
278 struct thread_struct *prev = &prev_p->thread;
279 struct thread_struct *next = &next_p->thread;
280 int cpu = smp_processor_id();
281 struct tss_struct *tss = &per_cpu(init_tss, cpu);
282 unsigned fsindex, gsindex;
285 fpu = switch_fpu_prepare(prev_p, next_p, cpu);
288 * Reload esp0, LDT and the page table pointer:
294 * This won't pick up thread selector changes, but I guess that is ok.
296 savesegment(es, prev->es);
297 if (unlikely(next->es | prev->es))
298 loadsegment(es, next->es);
300 savesegment(ds, prev->ds);
301 if (unlikely(next->ds | prev->ds))
302 loadsegment(ds, next->ds);
305 /* We must save %fs and %gs before load_TLS() because
306 * %fs and %gs may be cleared by load_TLS().
308 * (e.g. xen_load_tls())
310 savesegment(fs, fsindex);
311 savesegment(gs, gsindex);
316 * Leave lazy mode, flushing any hypercalls made here.
317 * This must be done before restoring TLS segments so
318 * the GDT and LDT are properly updated, and must be
319 * done before math_state_restore, so the TS bit is up
322 arch_end_context_switch(next_p);
327 * Segment register != 0 always requires a reload. Also
328 * reload when it has changed. When prev process used 64bit
329 * base always reload to avoid an information leak.
331 if (unlikely(fsindex | next->fsindex | prev->fs)) {
332 loadsegment(fs, next->fsindex);
334 * Check if the user used a selector != 0; if yes
335 * clear 64bit base, since overloaded base is always
336 * mapped to the Null selector
341 /* when next process has a 64bit base use it */
343 wrmsrl(MSR_FS_BASE, next->fs);
344 prev->fsindex = fsindex;
346 if (unlikely(gsindex | next->gsindex | prev->gs)) {
347 load_gs_index(next->gsindex);
352 wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
353 prev->gsindex = gsindex;
355 switch_fpu_finish(next_p, fpu);
358 * Switch the PDA and FPU contexts.
360 prev->usersp = percpu_read(old_rsp);
361 percpu_write(old_rsp, next->usersp);
362 percpu_write(current_task, next_p);
364 percpu_write(kernel_stack,
365 (unsigned long)task_stack_page(next_p) +
366 THREAD_SIZE - KERNEL_STACK_OFFSET);
369 * Now maybe reload the debug registers and handle I/O bitmaps
371 if (unlikely(task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT ||
372 task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
373 __switch_to_xtra(prev_p, next_p, tss);
378 void set_personality_64bit(void)
380 /* inherit personality from parent */
382 /* Make sure to be in 64bit mode */
383 clear_thread_flag(TIF_IA32);
385 /* Ensure the corresponding mm is not marked. */
387 current->mm->context.ia32_compat = 0;
389 /* TBD: overwrites user setup. Should have two bits.
390 But 64bit processes have always behaved this way,
391 so it's not too bad. The main problem is just that
392 32bit childs are affected again. */
393 current->personality &= ~READ_IMPLIES_EXEC;
396 void set_personality_ia32(void)
398 /* inherit personality from parent */
400 /* Make sure to be in 32bit mode */
401 set_thread_flag(TIF_IA32);
402 current->personality |= force_personality32;
404 /* Mark the associated mm as containing 32-bit tasks. */
406 current->mm->context.ia32_compat = 1;
408 /* Prepare the first "return" to user space */
409 current_thread_info()->status |= TS_COMPAT;
412 unsigned long get_wchan(struct task_struct *p)
418 if (!p || p == current || p->state == TASK_RUNNING)
420 stack = (unsigned long)task_stack_page(p);
421 if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE)
423 fp = *(u64 *)(p->thread.sp);
425 if (fp < (unsigned long)stack ||
426 fp >= (unsigned long)stack+THREAD_SIZE)
429 if (!in_sched_functions(ip))
432 } while (count++ < 16);
436 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
439 int doit = task == current;
444 if (addr >= TASK_SIZE_OF(task))
447 /* handle small bases via the GDT because that's faster to
449 if (addr <= 0xffffffff) {
450 set_32bit_tls(task, GS_TLS, addr);
452 load_TLS(&task->thread, cpu);
453 load_gs_index(GS_TLS_SEL);
455 task->thread.gsindex = GS_TLS_SEL;
458 task->thread.gsindex = 0;
459 task->thread.gs = addr;
462 ret = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr);
468 /* Not strictly needed for fs, but do it for symmetry
470 if (addr >= TASK_SIZE_OF(task))
473 /* handle small bases via the GDT because that's faster to
475 if (addr <= 0xffffffff) {
476 set_32bit_tls(task, FS_TLS, addr);
478 load_TLS(&task->thread, cpu);
479 loadsegment(fs, FS_TLS_SEL);
481 task->thread.fsindex = FS_TLS_SEL;
484 task->thread.fsindex = 0;
485 task->thread.fs = addr;
487 /* set the selector to 0 to not confuse
490 ret = checking_wrmsrl(MSR_FS_BASE, addr);
497 if (task->thread.fsindex == FS_TLS_SEL)
498 base = read_32bit_tls(task, FS_TLS);
500 rdmsrl(MSR_FS_BASE, base);
502 base = task->thread.fs;
503 ret = put_user(base, (unsigned long __user *)addr);
509 if (task->thread.gsindex == GS_TLS_SEL)
510 base = read_32bit_tls(task, GS_TLS);
512 savesegment(gs, gsindex);
514 rdmsrl(MSR_KERNEL_GS_BASE, base);
516 base = task->thread.gs;
518 base = task->thread.gs;
519 ret = put_user(base, (unsigned long __user *)addr);
531 long sys_arch_prctl(int code, unsigned long addr)
533 return do_arch_prctl(current, code, addr);
536 unsigned long KSTK_ESP(struct task_struct *task)
538 return (test_tsk_thread_flag(task, TIF_IA32)) ?
539 (task_pt_regs(task)->sp) : ((task)->thread.usersp);