[patch 07/31] x86/process: Clone FPU in copy_thread()

Thomas Gleixner
2021-10-12T00:07:31Z

There is no reason to clone FPU in arch_dup_task_struct(). Quite the
contrary it prevents optimizations. Move it to copy_thread()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/process.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -87,7 +87,7 @@ int arch_dup_task_struct(struct task_str
#ifdef CONFIG_VM86
dst->thread.vm86 = NULL;
#endif
- return fpu_clone(dst);
+ return 0;
}

/*
@@ -154,6 +154,8 @@ int copy_thread(unsigned long clone_flag
frame->flags = X86_EFLAGS_FIXED;
#endif

+ fpu_clone(p);
+
/* Kernel thread ? */
if (unlikely(p->flags & PF_KTHREAD)) {
p->thread.pkru = pkru_get_init_value();