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Commit | Line | Data |
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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 | ||
f3705136 | 12 | #include <linux/cpu.h> |
1da177e4 LT |
13 | #include <linux/errno.h> |
14 | #include <linux/sched.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/elfcore.h> | |
19 | #include <linux/smp.h> | |
1da177e4 LT |
20 | #include <linux/stddef.h> |
21 | #include <linux/slab.h> | |
22 | #include <linux/vmalloc.h> | |
23 | #include <linux/user.h> | |
1da177e4 | 24 | #include <linux/interrupt.h> |
1da177e4 LT |
25 | #include <linux/delay.h> |
26 | #include <linux/reboot.h> | |
1da177e4 LT |
27 | #include <linux/mc146818rtc.h> |
28 | #include <linux/module.h> | |
29 | #include <linux/kallsyms.h> | |
30 | #include <linux/ptrace.h> | |
c16b63e0 | 31 | #include <linux/personality.h> |
7c3576d2 | 32 | #include <linux/percpu.h> |
529e25f6 | 33 | #include <linux/prctl.h> |
8b96f011 | 34 | #include <linux/ftrace.h> |
befa9e78 JSR |
35 | #include <linux/uaccess.h> |
36 | #include <linux/io.h> | |
37 | #include <linux/kdebug.h> | |
1da177e4 | 38 | |
1da177e4 | 39 | #include <asm/pgtable.h> |
1da177e4 LT |
40 | #include <asm/ldt.h> |
41 | #include <asm/processor.h> | |
78f7f1e5 | 42 | #include <asm/fpu/internal.h> |
1da177e4 LT |
43 | #include <asm/desc.h> |
44 | #ifdef CONFIG_MATH_EMULATION | |
45 | #include <asm/math_emu.h> | |
46 | #endif | |
47 | ||
1da177e4 LT |
48 | #include <linux/err.h> |
49 | ||
f3705136 ZM |
50 | #include <asm/tlbflush.h> |
51 | #include <asm/cpu.h> | |
1eda8149 | 52 | #include <asm/idle.h> |
bbc1f698 | 53 | #include <asm/syscalls.h> |
66cb5917 | 54 | #include <asm/debugreg.h> |
f05e798a | 55 | #include <asm/switch_to.h> |
ba3e127e | 56 | #include <asm/vm86.h> |
f3705136 | 57 | |
1da177e4 | 58 | asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); |
7076aada | 59 | asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread"); |
1da177e4 | 60 | |
1da177e4 LT |
61 | /* |
62 | * Return saved PC of a blocked thread. | |
63 | */ | |
64 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
65 | { | |
faca6227 | 66 | return ((unsigned long *)tsk->thread.sp)[3]; |
1da177e4 LT |
67 | } |
68 | ||
e2ce07c8 | 69 | void __show_regs(struct pt_regs *regs, int all) |
1da177e4 LT |
70 | { |
71 | unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; | |
bb1995d5 | 72 | unsigned long d0, d1, d2, d3, d6, d7; |
65ea5b03 | 73 | unsigned long sp; |
9d975ebd PE |
74 | unsigned short ss, gs; |
75 | ||
f39b6f0e | 76 | if (user_mode(regs)) { |
65ea5b03 PA |
77 | sp = regs->sp; |
78 | ss = regs->ss & 0xffff; | |
d9a89a26 | 79 | gs = get_user_gs(regs); |
9d975ebd | 80 | } else { |
def3c5d0 | 81 | sp = kernel_stack_pointer(regs); |
9d975ebd PE |
82 | savesegment(ss, ss); |
83 | savesegment(gs, gs); | |
84 | } | |
1da177e4 | 85 | |
d015a092 | 86 | printk(KERN_DEFAULT "EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n", |
92bc2056 | 87 | (u16)regs->cs, regs->ip, regs->flags, |
9d975ebd | 88 | smp_processor_id()); |
65ea5b03 | 89 | print_symbol("EIP is at %s\n", regs->ip); |
1da177e4 | 90 | |
d015a092 | 91 | printk(KERN_DEFAULT "EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n", |
65ea5b03 | 92 | regs->ax, regs->bx, regs->cx, regs->dx); |
d015a092 | 93 | printk(KERN_DEFAULT "ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n", |
65ea5b03 | 94 | regs->si, regs->di, regs->bp, sp); |
d015a092 | 95 | printk(KERN_DEFAULT " DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n", |
92bc2056 | 96 | (u16)regs->ds, (u16)regs->es, (u16)regs->fs, gs, ss); |
9d975ebd PE |
97 | |
98 | if (!all) | |
99 | return; | |
1da177e4 | 100 | |
4bb0d3ec ZA |
101 | cr0 = read_cr0(); |
102 | cr2 = read_cr2(); | |
103 | cr3 = read_cr3(); | |
1e02ce4c | 104 | cr4 = __read_cr4_safe(); |
d015a092 | 105 | printk(KERN_DEFAULT "CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", |
9d975ebd | 106 | cr0, cr2, cr3, cr4); |
bb1995d5 AS |
107 | |
108 | get_debugreg(d0, 0); | |
109 | get_debugreg(d1, 1); | |
110 | get_debugreg(d2, 2); | |
111 | get_debugreg(d3, 3); | |
bb1995d5 AS |
112 | get_debugreg(d6, 6); |
113 | get_debugreg(d7, 7); | |
4338774c DJ |
114 | |
115 | /* Only print out debug registers if they are in their non-default state. */ | |
116 | if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && | |
117 | (d6 == DR6_RESERVED) && (d7 == 0x400)) | |
118 | return; | |
119 | ||
120 | printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", | |
121 | d0, d1, d2, d3); | |
d015a092 | 122 | printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n", |
9d975ebd PE |
123 | d6, d7); |
124 | } | |
bb1995d5 | 125 | |
1da177e4 LT |
126 | void release_thread(struct task_struct *dead_task) |
127 | { | |
2684927c | 128 | BUG_ON(dead_task->mm); |
1da177e4 LT |
129 | release_vm86_irqs(dead_task); |
130 | } | |
131 | ||
c1bd55f9 JT |
132 | int copy_thread_tls(unsigned long clone_flags, unsigned long sp, |
133 | unsigned long arg, struct task_struct *p, unsigned long tls) | |
1da177e4 | 134 | { |
7076aada | 135 | struct pt_regs *childregs = task_pt_regs(p); |
1da177e4 LT |
136 | struct task_struct *tsk; |
137 | int err; | |
138 | ||
7076aada AV |
139 | p->thread.sp = (unsigned long) childregs; |
140 | p->thread.sp0 = (unsigned long) (childregs+1); | |
6f46b3ae | 141 | memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); |
7076aada | 142 | |
1d4b4b29 | 143 | if (unlikely(p->flags & PF_KTHREAD)) { |
7076aada AV |
144 | /* kernel thread */ |
145 | memset(childregs, 0, sizeof(struct pt_regs)); | |
146 | p->thread.ip = (unsigned long) ret_from_kernel_thread; | |
147 | task_user_gs(p) = __KERNEL_STACK_CANARY; | |
148 | childregs->ds = __USER_DS; | |
149 | childregs->es = __USER_DS; | |
150 | childregs->fs = __KERNEL_PERCPU; | |
151 | childregs->bx = sp; /* function */ | |
152 | childregs->bp = arg; | |
153 | childregs->orig_ax = -1; | |
154 | childregs->cs = __KERNEL_CS | get_kernel_rpl(); | |
1adfa76a | 155 | childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED; |
7076aada | 156 | p->thread.io_bitmap_ptr = NULL; |
7076aada AV |
157 | return 0; |
158 | } | |
1d4b4b29 | 159 | *childregs = *current_pt_regs(); |
65ea5b03 | 160 | childregs->ax = 0; |
1d4b4b29 AV |
161 | if (sp) |
162 | childregs->sp = sp; | |
f48d9663 | 163 | |
faca6227 | 164 | p->thread.ip = (unsigned long) ret_from_fork; |
1d4b4b29 | 165 | task_user_gs(p) = get_user_gs(current_pt_regs()); |
1da177e4 | 166 | |
66cb5917 | 167 | p->thread.io_bitmap_ptr = NULL; |
1da177e4 | 168 | tsk = current; |
66cb5917 | 169 | err = -ENOMEM; |
24f1e32c | 170 | |
b3cf2576 | 171 | if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { |
52978be6 AD |
172 | p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr, |
173 | IO_BITMAP_BYTES, GFP_KERNEL); | |
1da177e4 LT |
174 | if (!p->thread.io_bitmap_ptr) { |
175 | p->thread.io_bitmap_max = 0; | |
176 | return -ENOMEM; | |
177 | } | |
b3cf2576 | 178 | set_tsk_thread_flag(p, TIF_IO_BITMAP); |
1da177e4 LT |
179 | } |
180 | ||
efd1ca52 RM |
181 | err = 0; |
182 | ||
1da177e4 LT |
183 | /* |
184 | * Set a new TLS for the child thread? | |
185 | */ | |
efd1ca52 RM |
186 | if (clone_flags & CLONE_SETTLS) |
187 | err = do_set_thread_area(p, -1, | |
c1bd55f9 | 188 | (struct user_desc __user *)tls, 0); |
1da177e4 | 189 | |
1da177e4 LT |
190 | if (err && p->thread.io_bitmap_ptr) { |
191 | kfree(p->thread.io_bitmap_ptr); | |
192 | p->thread.io_bitmap_max = 0; | |
193 | } | |
194 | return err; | |
195 | } | |
196 | ||
513ad84b IM |
197 | void |
198 | start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) | |
199 | { | |
d9a89a26 | 200 | set_user_gs(regs, 0); |
513ad84b | 201 | regs->fs = 0; |
513ad84b IM |
202 | regs->ds = __USER_DS; |
203 | regs->es = __USER_DS; | |
204 | regs->ss = __USER_DS; | |
205 | regs->cs = __USER_CS; | |
206 | regs->ip = new_ip; | |
207 | regs->sp = new_sp; | |
6783eaa2 | 208 | regs->flags = X86_EFLAGS_IF; |
1daeaa31 | 209 | force_iret(); |
513ad84b IM |
210 | } |
211 | EXPORT_SYMBOL_GPL(start_thread); | |
212 | ||
1da177e4 LT |
213 | |
214 | /* | |
ea70ef3d | 215 | * switch_to(x,y) should switch tasks from x to y. |
1da177e4 LT |
216 | * |
217 | * We fsave/fwait so that an exception goes off at the right time | |
218 | * (as a call from the fsave or fwait in effect) rather than to | |
219 | * the wrong process. Lazy FP saving no longer makes any sense | |
220 | * with modern CPU's, and this simplifies a lot of things (SMP | |
221 | * and UP become the same). | |
222 | * | |
223 | * NOTE! We used to use the x86 hardware context switching. The | |
224 | * reason for not using it any more becomes apparent when you | |
225 | * try to recover gracefully from saved state that is no longer | |
226 | * valid (stale segment register values in particular). With the | |
227 | * hardware task-switch, there is no way to fix up bad state in | |
228 | * a reasonable manner. | |
229 | * | |
230 | * The fact that Intel documents the hardware task-switching to | |
231 | * be slow is a fairly red herring - this code is not noticeably | |
232 | * faster. However, there _is_ some room for improvement here, | |
233 | * so the performance issues may eventually be a valid point. | |
234 | * More important, however, is the fact that this allows us much | |
235 | * more flexibility. | |
236 | * | |
65ea5b03 | 237 | * The return value (in %ax) will be the "prev" task after |
1da177e4 LT |
238 | * the task-switch, and shows up in ret_from_fork in entry.S, |
239 | * for example. | |
240 | */ | |
35ea7903 | 241 | __visible __notrace_funcgraph struct task_struct * |
8b96f011 | 242 | __switch_to(struct task_struct *prev_p, struct task_struct *next_p) |
1da177e4 LT |
243 | { |
244 | struct thread_struct *prev = &prev_p->thread, | |
384a23f9 IM |
245 | *next = &next_p->thread; |
246 | struct fpu *prev_fpu = &prev->fpu; | |
247 | struct fpu *next_fpu = &next->fpu; | |
1da177e4 | 248 | int cpu = smp_processor_id(); |
24933b82 | 249 | struct tss_struct *tss = &per_cpu(cpu_tss, cpu); |
384a23f9 | 250 | fpu_switch_t fpu_switch; |
1da177e4 LT |
251 | |
252 | /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ | |
253 | ||
384a23f9 | 254 | fpu_switch = switch_fpu_prepare(prev_fpu, next_fpu, cpu); |
acc20761 | 255 | |
1da177e4 | 256 | /* |
464d1a78 | 257 | * Save away %gs. No need to save %fs, as it was saved on the |
f95d47ca JF |
258 | * stack on entry. No need to save %es and %ds, as those are |
259 | * always kernel segments while inside the kernel. Doing this | |
260 | * before setting the new TLS descriptors avoids the situation | |
261 | * where we temporarily have non-reloadable segments in %fs | |
262 | * and %gs. This could be an issue if the NMI handler ever | |
263 | * used %fs or %gs (it does not today), or if the kernel is | |
264 | * running inside of a hypervisor layer. | |
1da177e4 | 265 | */ |
ccbeed3a | 266 | lazy_save_gs(prev->gs); |
1da177e4 LT |
267 | |
268 | /* | |
e7a2ff59 | 269 | * Load the per-thread Thread-Local Storage descriptor. |
1da177e4 | 270 | */ |
e7a2ff59 | 271 | load_TLS(next, cpu); |
1da177e4 | 272 | |
8b151144 ZA |
273 | /* |
274 | * Restore IOPL if needed. In normal use, the flags restore | |
275 | * in the switch assembly will handle this. But if the kernel | |
276 | * is running virtualized at a non-zero CPL, the popf will | |
277 | * not restore flags, so it must be done in a separate step. | |
278 | */ | |
279 | if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl)) | |
280 | set_iopl_mask(next->iopl); | |
281 | ||
1da177e4 | 282 | /* |
b3cf2576 | 283 | * Now maybe handle debug registers and/or IO bitmaps |
1da177e4 | 284 | */ |
cf99abac AA |
285 | if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV || |
286 | task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT)) | |
287 | __switch_to_xtra(prev_p, next_p, tss); | |
ffaa8bd6 | 288 | |
9226d125 ZA |
289 | /* |
290 | * Leave lazy mode, flushing any hypercalls made here. | |
291 | * This must be done before restoring TLS segments so | |
292 | * the GDT and LDT are properly updated, and must be | |
3a0aee48 | 293 | * done before fpu__restore(), so the TS bit is up |
9226d125 ZA |
294 | * to date. |
295 | */ | |
224101ed | 296 | arch_end_context_switch(next_p); |
9226d125 | 297 | |
b27559a4 | 298 | /* |
fed7c3f0 | 299 | * Reload esp0 and cpu_current_top_of_stack. This changes |
a7fcf28d | 300 | * current_thread_info(). |
b27559a4 AL |
301 | */ |
302 | load_sp0(tss, next); | |
a7fcf28d AL |
303 | this_cpu_write(cpu_current_top_of_stack, |
304 | (unsigned long)task_stack_page(next_p) + | |
305 | THREAD_SIZE); | |
198d208d | 306 | |
9226d125 ZA |
307 | /* |
308 | * Restore %gs if needed (which is common) | |
309 | */ | |
310 | if (prev->gs | next->gs) | |
ccbeed3a | 311 | lazy_load_gs(next->gs); |
9226d125 | 312 | |
384a23f9 | 313 | switch_fpu_finish(next_fpu, fpu_switch); |
34ddc81a | 314 | |
c6ae41e7 | 315 | this_cpu_write(current_task, next_p); |
9226d125 | 316 | |
1da177e4 LT |
317 | return prev_p; |
318 | } |