x86: Make cpu_tss available to external modules

[mirror_ubuntu-bionic-kernel.git] / arch / x86 / kernel / process.c

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 0c8992dbead5e9ccdf00f1b87dfe3ec72d58c7fc..bfc99b3b6522078ba2aea707b24d6aa513e1bf7d 100644 (file)
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -57,7 +57,7 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
        .io_bitmap              = { [0 ... IO_BITMAP_LONGS] = ~0 },
 #endif
 };
-EXPORT_PER_CPU_SYMBOL_GPL(cpu_tss);
+EXPORT_PER_CPU_SYMBOL(cpu_tss);
 
 #ifdef CONFIG_X86_64
 static DEFINE_PER_CPU(unsigned char, is_idle);
@@ -89,8 +89,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 
        dst->thread.fpu_counter = 0;
        dst->thread.fpu.has_fpu = 0;
-       dst->thread.fpu.last_cpu = ~0;
        dst->thread.fpu.state = NULL;
+       task_disable_lazy_fpu_restore(dst);
        if (tsk_used_math(src)) {
                int err = fpu_alloc(&dst->thread.fpu);
                if (err)
@@ -151,13 +151,18 @@ void flush_thread(void)
 
        flush_ptrace_hw_breakpoint(tsk);
        memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
-       drop_init_fpu(tsk);
-       /*
-        * Free the FPU state for non xsave platforms. They get reallocated
-        * lazily at the first use.
-        */
-       if (!use_eager_fpu())
+
+       if (!use_eager_fpu()) {
+               /* FPU state will be reallocated lazily at the first use. */
+               drop_fpu(tsk);
                free_thread_xstate(tsk);
+       } else if (!used_math()) {
+               /* kthread execs. TODO: cleanup this horror. */
+               if (WARN_ON(init_fpu(tsk)))
+                       force_sig(SIGKILL, tsk);
+               user_fpu_begin();
+               restore_init_xstate();
+       }
 }
 
 static void hard_disable_TSC(void)