diff options
Diffstat (limited to 'arch/x86/kernel/fpu/core.c')
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 36df548acc40..422c98ca6eb8 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -60,9 +60,16 @@ bool irq_fpu_usable(void) if (WARN_ON_ONCE(in_nmi())) return false; - /* In kernel FPU usage already active? */ - if (this_cpu_read(in_kernel_fpu)) + /* + * In kernel FPU usage already active? This detects any explicitly + * nested usage in task or softirq context, which is unsupported. It + * also detects attempted usage in a hardirq that has interrupted a + * kernel-mode FPU section. + */ + if (this_cpu_read(in_kernel_fpu)) { + WARN_ON_FPU(!in_hardirq()); return false; + } /* * When not in NMI or hard interrupt context, FPU can be used in: @@ -420,7 +427,8 @@ EXPORT_SYMBOL_GPL(fpu_copy_uabi_to_guest_fpstate); void kernel_fpu_begin_mask(unsigned int kfpu_mask) { - preempt_disable(); + if (!irqs_disabled()) + fpregs_lock(); WARN_ON_FPU(!irq_fpu_usable()); WARN_ON_FPU(this_cpu_read(in_kernel_fpu)); @@ -448,7 +456,8 @@ void kernel_fpu_end(void) WARN_ON_FPU(!this_cpu_read(in_kernel_fpu)); this_cpu_write(in_kernel_fpu, false); - preempt_enable(); + if (!irqs_disabled()) + fpregs_unlock(); } EXPORT_SYMBOL_GPL(kernel_fpu_end); |