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 __visible
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
;
65 printk(KERN_DEFAULT
"RIP: %04lx:[<%016lx>] ", regs
->cs
& 0xffff, regs
->ip
);
66 printk_address(regs
->ip
);
67 printk(KERN_DEFAULT
"RSP: %04lx:%016lx EFLAGS: %08lx\n", regs
->ss
,
68 regs
->sp
, regs
->flags
);
69 printk(KERN_DEFAULT
"RAX: %016lx RBX: %016lx RCX: %016lx\n",
70 regs
->ax
, regs
->bx
, regs
->cx
);
71 printk(KERN_DEFAULT
"RDX: %016lx RSI: %016lx RDI: %016lx\n",
72 regs
->dx
, regs
->si
, regs
->di
);
73 printk(KERN_DEFAULT
"RBP: %016lx R08: %016lx R09: %016lx\n",
74 regs
->bp
, regs
->r8
, regs
->r9
);
75 printk(KERN_DEFAULT
"R10: %016lx R11: %016lx R12: %016lx\n",
76 regs
->r10
, regs
->r11
, regs
->r12
);
77 printk(KERN_DEFAULT
"R13: %016lx R14: %016lx R15: %016lx\n",
78 regs
->r13
, regs
->r14
, regs
->r15
);
80 asm("movl %%ds,%0" : "=r" (ds
));
81 asm("movl %%cs,%0" : "=r" (cs
));
82 asm("movl %%es,%0" : "=r" (es
));
83 asm("movl %%fs,%0" : "=r" (fsindex
));
84 asm("movl %%gs,%0" : "=r" (gsindex
));
86 rdmsrl(MSR_FS_BASE
, fs
);
87 rdmsrl(MSR_GS_BASE
, gs
);
88 rdmsrl(MSR_KERNEL_GS_BASE
, shadowgs
);
98 printk(KERN_DEFAULT
"FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
99 fs
, fsindex
, gs
, gsindex
, shadowgs
);
100 printk(KERN_DEFAULT
"CS: %04x DS: %04x ES: %04x CR0: %016lx\n", cs
, ds
,
102 printk(KERN_DEFAULT
"CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2
, cr3
,
112 /* Only print out debug registers if they are in their non-default state. */
113 if ((d0
== 0) && (d1
== 0) && (d2
== 0) && (d3
== 0) &&
114 (d6
== DR6_RESERVED
) && (d7
== 0x400))
117 printk(KERN_DEFAULT
"DR0: %016lx DR1: %016lx DR2: %016lx\n", d0
, d1
, d2
);
118 printk(KERN_DEFAULT
"DR3: %016lx DR6: %016lx DR7: %016lx\n", d3
, d6
, d7
);
122 void release_thread(struct task_struct
*dead_task
)
125 if (dead_task
->mm
->context
.size
) {
126 pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n",
128 dead_task
->mm
->context
.ldt
,
129 dead_task
->mm
->context
.size
);
135 static inline void set_32bit_tls(struct task_struct
*t
, int tls
, u32 addr
)
137 struct user_desc ud
= {
144 struct desc_struct
*desc
= t
->thread
.tls_array
;
149 static inline u32
read_32bit_tls(struct task_struct
*t
, int tls
)
151 return get_desc_base(&t
->thread
.tls_array
[tls
]);
154 int copy_thread(unsigned long clone_flags
, unsigned long sp
,
155 unsigned long arg
, struct task_struct
*p
)
158 struct pt_regs
*childregs
;
159 struct task_struct
*me
= current
;
161 p
->thread
.sp0
= (unsigned long)task_stack_page(p
) + THREAD_SIZE
;
162 childregs
= task_pt_regs(p
);
163 p
->thread
.sp
= (unsigned long) childregs
;
164 p
->thread
.usersp
= me
->thread
.usersp
;
165 set_tsk_thread_flag(p
, TIF_FORK
);
166 p
->thread
.io_bitmap_ptr
= NULL
;
168 savesegment(gs
, p
->thread
.gsindex
);
169 p
->thread
.gs
= p
->thread
.gsindex
? 0 : me
->thread
.gs
;
170 savesegment(fs
, p
->thread
.fsindex
);
171 p
->thread
.fs
= p
->thread
.fsindex
? 0 : me
->thread
.fs
;
172 savesegment(es
, p
->thread
.es
);
173 savesegment(ds
, p
->thread
.ds
);
174 memset(p
->thread
.ptrace_bps
, 0, sizeof(p
->thread
.ptrace_bps
));
176 if (unlikely(p
->flags
& PF_KTHREAD
)) {
178 memset(childregs
, 0, sizeof(struct pt_regs
));
179 childregs
->sp
= (unsigned long)childregs
;
180 childregs
->ss
= __KERNEL_DS
;
181 childregs
->bx
= sp
; /* function */
183 childregs
->orig_ax
= -1;
184 childregs
->cs
= __KERNEL_CS
| get_kernel_rpl();
185 childregs
->flags
= X86_EFLAGS_IF
| X86_EFLAGS_FIXED
;
188 *childregs
= *current_pt_regs();
195 if (unlikely(test_tsk_thread_flag(me
, TIF_IO_BITMAP
))) {
196 p
->thread
.io_bitmap_ptr
= kmemdup(me
->thread
.io_bitmap_ptr
,
197 IO_BITMAP_BYTES
, GFP_KERNEL
);
198 if (!p
->thread
.io_bitmap_ptr
) {
199 p
->thread
.io_bitmap_max
= 0;
202 set_tsk_thread_flag(p
, TIF_IO_BITMAP
);
206 * Set a new TLS for the child thread?
208 if (clone_flags
& CLONE_SETTLS
) {
209 #ifdef CONFIG_IA32_EMULATION
210 if (test_thread_flag(TIF_IA32
))
211 err
= do_set_thread_area(p
, -1,
212 (struct user_desc __user
*)childregs
->si
, 0);
215 err
= do_arch_prctl(p
, ARCH_SET_FS
, childregs
->r8
);
221 if (err
&& p
->thread
.io_bitmap_ptr
) {
222 kfree(p
->thread
.io_bitmap_ptr
);
223 p
->thread
.io_bitmap_max
= 0;
230 start_thread_common(struct pt_regs
*regs
, unsigned long new_ip
,
231 unsigned long new_sp
,
232 unsigned int _cs
, unsigned int _ss
, unsigned int _ds
)
235 loadsegment(es
, _ds
);
236 loadsegment(ds
, _ds
);
238 current
->thread
.usersp
= new_sp
;
241 this_cpu_write(old_rsp
, new_sp
);
244 regs
->flags
= X86_EFLAGS_IF
;
248 start_thread(struct pt_regs
*regs
, unsigned long new_ip
, unsigned long new_sp
)
250 start_thread_common(regs
, new_ip
, new_sp
,
251 __USER_CS
, __USER_DS
, 0);
254 #ifdef CONFIG_IA32_EMULATION
255 void start_thread_ia32(struct pt_regs
*regs
, u32 new_ip
, u32 new_sp
)
257 start_thread_common(regs
, new_ip
, new_sp
,
258 test_thread_flag(TIF_X32
)
259 ? __USER_CS
: __USER32_CS
,
260 __USER_DS
, __USER_DS
);
265 * switch_to(x,y) should switch tasks from x to y.
267 * This could still be optimized:
268 * - fold all the options into a flag word and test it with a single test.
269 * - could test fs/gs bitsliced
271 * Kprobes not supported here. Set the probe on schedule instead.
272 * Function graph tracer not supported too.
274 __visible __notrace_funcgraph
struct task_struct
*
275 __switch_to(struct task_struct
*prev_p
, struct task_struct
*next_p
)
277 struct thread_struct
*prev
= &prev_p
->thread
;
278 struct thread_struct
*next
= &next_p
->thread
;
279 int cpu
= smp_processor_id();
280 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
281 unsigned fsindex
, gsindex
;
284 fpu
= switch_fpu_prepare(prev_p
, next_p
, cpu
);
287 * Reload esp0, LDT and the page table pointer:
293 * This won't pick up thread selector changes, but I guess that is ok.
295 savesegment(es
, prev
->es
);
296 if (unlikely(next
->es
| prev
->es
))
297 loadsegment(es
, next
->es
);
299 savesegment(ds
, prev
->ds
);
300 if (unlikely(next
->ds
| prev
->ds
))
301 loadsegment(ds
, next
->ds
);
304 /* We must save %fs and %gs before load_TLS() because
305 * %fs and %gs may be cleared by load_TLS().
307 * (e.g. xen_load_tls())
309 savesegment(fs
, fsindex
);
310 savesegment(gs
, gsindex
);
315 * Leave lazy mode, flushing any hypercalls made here.
316 * This must be done before restoring TLS segments so
317 * the GDT and LDT are properly updated, and must be
318 * done before math_state_restore, so the TS bit is up
321 arch_end_context_switch(next_p
);
326 * Segment register != 0 always requires a reload. Also
327 * reload when it has changed. When prev process used 64bit
328 * base always reload to avoid an information leak.
330 if (unlikely(fsindex
| next
->fsindex
| prev
->fs
)) {
331 loadsegment(fs
, next
->fsindex
);
333 * Check if the user used a selector != 0; if yes
334 * clear 64bit base, since overloaded base is always
335 * mapped to the Null selector
340 /* when next process has a 64bit base use it */
342 wrmsrl(MSR_FS_BASE
, next
->fs
);
343 prev
->fsindex
= fsindex
;
345 if (unlikely(gsindex
| next
->gsindex
| prev
->gs
)) {
346 load_gs_index(next
->gsindex
);
351 wrmsrl(MSR_KERNEL_GS_BASE
, next
->gs
);
352 prev
->gsindex
= gsindex
;
354 switch_fpu_finish(next_p
, fpu
);
357 * Switch the PDA and FPU contexts.
359 prev
->usersp
= this_cpu_read(old_rsp
);
360 this_cpu_write(old_rsp
, next
->usersp
);
361 this_cpu_write(current_task
, next_p
);
364 * If it were not for PREEMPT_ACTIVE we could guarantee that the
365 * preempt_count of all tasks was equal here and this would not be
368 task_thread_info(prev_p
)->saved_preempt_count
= this_cpu_read(__preempt_count
);
369 this_cpu_write(__preempt_count
, task_thread_info(next_p
)->saved_preempt_count
);
371 this_cpu_write(kernel_stack
,
372 (unsigned long)task_stack_page(next_p
) +
373 THREAD_SIZE
- KERNEL_STACK_OFFSET
);
376 * Now maybe reload the debug registers and handle I/O bitmaps
378 if (unlikely(task_thread_info(next_p
)->flags
& _TIF_WORK_CTXSW_NEXT
||
379 task_thread_info(prev_p
)->flags
& _TIF_WORK_CTXSW_PREV
))
380 __switch_to_xtra(prev_p
, next_p
, tss
);
385 void set_personality_64bit(void)
387 /* inherit personality from parent */
389 /* Make sure to be in 64bit mode */
390 clear_thread_flag(TIF_IA32
);
391 clear_thread_flag(TIF_ADDR32
);
392 clear_thread_flag(TIF_X32
);
394 /* Ensure the corresponding mm is not marked. */
396 current
->mm
->context
.ia32_compat
= 0;
398 /* TBD: overwrites user setup. Should have two bits.
399 But 64bit processes have always behaved this way,
400 so it's not too bad. The main problem is just that
401 32bit childs are affected again. */
402 current
->personality
&= ~READ_IMPLIES_EXEC
;
405 void set_personality_ia32(bool x32
)
407 /* inherit personality from parent */
409 /* Make sure to be in 32bit mode */
410 set_thread_flag(TIF_ADDR32
);
412 /* Mark the associated mm as containing 32-bit tasks. */
414 clear_thread_flag(TIF_IA32
);
415 set_thread_flag(TIF_X32
);
417 current
->mm
->context
.ia32_compat
= TIF_X32
;
418 current
->personality
&= ~READ_IMPLIES_EXEC
;
419 /* is_compat_task() uses the presence of the x32
420 syscall bit flag to determine compat status */
421 current_thread_info()->status
&= ~TS_COMPAT
;
423 set_thread_flag(TIF_IA32
);
424 clear_thread_flag(TIF_X32
);
426 current
->mm
->context
.ia32_compat
= TIF_IA32
;
427 current
->personality
|= force_personality32
;
428 /* Prepare the first "return" to user space */
429 current_thread_info()->status
|= TS_COMPAT
;
432 EXPORT_SYMBOL_GPL(set_personality_ia32
);
434 unsigned long get_wchan(struct task_struct
*p
)
440 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
)
442 stack
= (unsigned long)task_stack_page(p
);
443 if (p
->thread
.sp
< stack
|| p
->thread
.sp
>= stack
+THREAD_SIZE
)
445 fp
= *(u64
*)(p
->thread
.sp
);
447 if (fp
< (unsigned long)stack
||
448 fp
>= (unsigned long)stack
+THREAD_SIZE
)
451 if (!in_sched_functions(ip
))
454 } while (count
++ < 16);
458 long do_arch_prctl(struct task_struct
*task
, int code
, unsigned long addr
)
461 int doit
= task
== current
;
466 if (addr
>= TASK_SIZE_OF(task
))
469 /* handle small bases via the GDT because that's faster to
471 if (addr
<= 0xffffffff) {
472 set_32bit_tls(task
, GS_TLS
, addr
);
474 load_TLS(&task
->thread
, cpu
);
475 load_gs_index(GS_TLS_SEL
);
477 task
->thread
.gsindex
= GS_TLS_SEL
;
480 task
->thread
.gsindex
= 0;
481 task
->thread
.gs
= addr
;
484 ret
= wrmsrl_safe(MSR_KERNEL_GS_BASE
, addr
);
490 /* Not strictly needed for fs, but do it for symmetry
492 if (addr
>= TASK_SIZE_OF(task
))
495 /* handle small bases via the GDT because that's faster to
497 if (addr
<= 0xffffffff) {
498 set_32bit_tls(task
, FS_TLS
, addr
);
500 load_TLS(&task
->thread
, cpu
);
501 loadsegment(fs
, FS_TLS_SEL
);
503 task
->thread
.fsindex
= FS_TLS_SEL
;
506 task
->thread
.fsindex
= 0;
507 task
->thread
.fs
= addr
;
509 /* set the selector to 0 to not confuse
512 ret
= wrmsrl_safe(MSR_FS_BASE
, addr
);
519 if (task
->thread
.fsindex
== FS_TLS_SEL
)
520 base
= read_32bit_tls(task
, FS_TLS
);
522 rdmsrl(MSR_FS_BASE
, base
);
524 base
= task
->thread
.fs
;
525 ret
= put_user(base
, (unsigned long __user
*)addr
);
531 if (task
->thread
.gsindex
== GS_TLS_SEL
)
532 base
= read_32bit_tls(task
, GS_TLS
);
534 savesegment(gs
, gsindex
);
536 rdmsrl(MSR_KERNEL_GS_BASE
, base
);
538 base
= task
->thread
.gs
;
540 base
= task
->thread
.gs
;
541 ret
= put_user(base
, (unsigned long __user
*)addr
);
553 long sys_arch_prctl(int code
, unsigned long addr
)
555 return do_arch_prctl(current
, code
, addr
);
558 unsigned long KSTK_ESP(struct task_struct
*task
)
560 return (test_tsk_thread_flag(task
, TIF_IA32
)) ?
561 (task_pt_regs(task
)->sp
) : ((task
)->thread
.usersp
);