int init_fpu(struct task_struct *tsk)
{
if (tsk_used_math(tsk)) {
if ((boot_cpu_data.flags & CPU_HAS_FPU) && tsk == current)
unlazy_fpu(tsk, task_pt_regs(tsk));
return 0;
}
/*
* Memory allocation at the first usage of the FPU and other state.
*/
if (!tsk->thread.xstate) {
tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
GFP_KERNEL);
if (!tsk->thread.xstate)
return -ENOMEM;
}
if (boot_cpu_data.flags & CPU_HAS_FPU) {
struct sh_fpu_hard_struct *fp = &tsk->thread.xstate->hardfpu;
memset(fp, 0, xstate_size);
fp->fpscr = FPSCR_INIT;
} else {
struct sh_fpu_soft_struct *fp = &tsk->thread.xstate->softfpu;
memset(fp, 0, xstate_size);
fp->fpscr = FPSCR_INIT;
}
set_stopped_child_used_math(tsk);
return 0;
}
static void init_fp_ctx(struct task_struct *target)
{
/* If FP has been used then the target already has context */
if (tsk_used_math(target))
return;
/* Begin with data registers set to all 1s... */
memset(&target->thread.fpu.fpr, ~0, sizeof(target->thread.fpu.fpr));
/* FCSR has been preset by `mips_set_personality_nan'. */
/*
* Record that the target has "used" math, such that the context
* just initialised, and any modifications made by the caller,
* aren't discarded.
*/
set_stopped_child_used_math(target);
}
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
int ret;
*dst = *src;
if (fpu_allocated(&src->thread.fpu)) {
memset(&dst->thread.fpu, 0, sizeof(dst->thread.fpu));
ret = fpu_alloc(&dst->thread.fpu);
if (ret)
return ret;
fpu_copy(&dst->thread.fpu, &src->thread.fpu);
}
#ifdef CONFIG_X86_EARLYMIC
if (dst->thread.fpu.state) {
/*
* No need to set this flag ? it should be inherited from the
* parent thread since the threadinfo is copied from the
* parent in setup_thread_stack()
*/
set_stopped_child_used_math(dst);
/*
* Simulate FPU DNA
* Undo the effects of unlazy_fpu in prepare_to_copy()
*/
preempt_disable();
clts();
#ifdef CONFIG_ML1OM
__math_state_restore();
#else
restore_mask_regs();
stts();
#endif
preempt_enable();
}
#endif
return 0;
}
