Linux Kernel  3.7.1
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process.c
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1 #include <linux/mm.h>
2 #include <linux/kernel.h>
3 #include <linux/slab.h>
4 #include <linux/sched.h>
5 #include <linux/export.h>
6 #include <linux/stackprotector.h>
7 #include <asm/fpu.h>
8 
10 unsigned int xstate_size;
11 
12 #ifdef CONFIG_CC_STACKPROTECTOR
13 unsigned long __stack_chk_guard __read_mostly;
14 EXPORT_SYMBOL(__stack_chk_guard);
15 #endif
16 
17 /*
18  * this gets called so that we can store lazy state into memory and copy the
19  * current task into the new thread.
20  */
22 {
23 #ifdef CONFIG_SUPERH32
24  unlazy_fpu(src, task_pt_regs(src));
25 #endif
26  *dst = *src;
27 
28  if (src->thread.xstate) {
29  dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
30  GFP_KERNEL);
31  if (!dst->thread.xstate)
32  return -ENOMEM;
33  memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
34  }
35 
36  return 0;
37 }
38 
40 {
41  if (tsk->thread.xstate) {
42  kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
43  tsk->thread.xstate = NULL;
44  }
45 }
46 
48 {
49  free_thread_xstate(tsk);
50 }
51 
53 {
54  if (!xstate_size)
55  return;
56 
57  task_xstate_cachep = kmem_cache_create("task_xstate", xstate_size,
58  __alignof__(union thread_xstate),
60 }
61 
62 #ifdef CONFIG_SH_FPU_EMU
63 # define HAVE_SOFTFP 1
64 #else
65 # define HAVE_SOFTFP 0
66 #endif
67 
69 {
70  if (boot_cpu_data.flags & CPU_HAS_FPU)
71  xstate_size = sizeof(struct sh_fpu_hard_struct);
72  else if (HAVE_SOFTFP)
73  xstate_size = sizeof(struct sh_fpu_soft_struct);
74  else
75  xstate_size = 0;
76 }