arch/sh/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/mm.h>
   3 #include <linux/kernel.h>
   4 #include <linux/slab.h>
   5 #include <linux/sched/signal.h>
   6 #include <linux/sched/task_stack.h>
   7 #include <linux/export.h>
   8 #include <linux/stackprotector.h>
   9 #include <asm/fpu.h>
  10 #include <asm/ptrace.h>
  11
  12 struct kmem_cache *task_xstate_cachep = NULL;
  13 unsigned int xstate_size;
  14
  15 #ifdef CONFIG_STACKPROTECTOR
  16 unsigned long __stack_chk_guard __read_mostly;
  17 EXPORT_SYMBOL(__stack_chk_guard);
  18 #endif
  19
  20 /*
  21  * this gets called so that we can store lazy state into memory and copy the
  22  * current task into the new thread.
  23  */
  24 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
  25 {
  26         unlazy_fpu(src, task_pt_regs(src));
  27         *dst = *src;
  28
  29         if (src->thread.xstate) {
  30                 dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
  31                                                       GFP_KERNEL);
  32                 if (!dst->thread.xstate)
  33                         return -ENOMEM;
  34                 memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
  35         }
  36
  37         return 0;
  38 }
  39
  40 void free_thread_xstate(struct task_struct *tsk)
  41 {
  42         if (tsk->thread.xstate) {
  43                 kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
  44                 tsk->thread.xstate = NULL;
  45         }
  46 }
  47
  48 void arch_release_task_struct(struct task_struct *tsk)
  49 {
  50         free_thread_xstate(tsk);
  51 }
  52
  53 void arch_task_cache_init(void)
  54 {
  55         if (!xstate_size)
  56                 return;
  57
  58         task_xstate_cachep = kmem_cache_create("task_xstate", xstate_size,
  59                                                __alignof__(union thread_xstate),
  60                                                SLAB_PANIC, NULL);
  61 }
  62
  63 #ifdef CONFIG_SH_FPU_EMU
  64 # define HAVE_SOFTFP    1
  65 #else
  66 # define HAVE_SOFTFP    0
  67 #endif
  68
  69 void init_thread_xstate(void)
  70 {
  71         if (boot_cpu_data.flags & CPU_HAS_FPU)
  72                 xstate_size = sizeof(struct sh_fpu_hard_struct);
  73         else if (HAVE_SOFTFP)
  74                 xstate_size = sizeof(struct sh_fpu_soft_struct);
  75         else
  76                 xstate_size = 0;
  77 }