diff options
| -rw-r--r-- | arch/mips/kernel/process.c | 40 |
1 files changed, 17 insertions, 23 deletions
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index dcccc6d..a6b3dc5 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -576,11 +576,19 @@ int mips_get_process_fp_mode(struct task_struct *task) return value; } +static void prepare_for_fp_mode_switch(void *info) +{ + struct mm_struct *mm = info; + + if (current->mm == mm) + lose_fpu(1); +} + int mips_set_process_fp_mode(struct task_struct *task, unsigned int value) { const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE; - unsigned long switch_count; struct task_struct *t; + int max_users; /* Check the value is valid */ if (value & ~known_bits) @@ -609,31 +617,17 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value) smp_mb__after_atomic(); /* - * If there are multiple online CPUs then wait until all threads whose - * FP mode is about to change have been context switched. This approach - * allows us to only worry about whether an FP mode switch is in - * progress when FP is first used in a tasks time slice. Pretty much all - * of the mode switch overhead can thus be confined to cases where mode - * switches are actually occurring. That is, to here. However for the - * thread performing the mode switch it may take a while... + * If there are multiple online CPUs then force any which are running + * threads in this process to lose their FPU context, which they can't + * regain until fp_mode_switching is cleared later. */ if (num_online_cpus() > 1) { - spin_lock_irq(&task->sighand->siglock); - - for_each_thread(task, t) { - if (t == current) - continue; - - switch_count = t->nvcsw + t->nivcsw; - - do { - spin_unlock_irq(&task->sighand->siglock); - cond_resched(); - spin_lock_irq(&task->sighand->siglock); - } while ((t->nvcsw + t->nivcsw) == switch_count); - } + /* No need to send an IPI for the local CPU */ + max_users = (task->mm == current->mm) ? 1 : 0; - spin_unlock_irq(&task->sighand->siglock); + if (atomic_read(¤t->mm->mm_users) > max_users) + smp_call_function(prepare_for_fp_mode_switch, + (void *)current->mm, 1); } /* |
