diff options
Diffstat (limited to 'arch/x86/kernel/fpu/core.c')
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 1209c7aebb21..91d6341f281f 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: @@ -220,7 +227,7 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) struct fpstate *fpstate; unsigned int size; - size = fpu_user_cfg.default_size + ALIGN(offsetof(struct fpstate, regs), 64); + size = fpu_kernel_cfg.default_size + ALIGN(offsetof(struct fpstate, regs), 64); fpstate = vzalloc(size); if (!fpstate) return false; @@ -232,8 +239,8 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) fpstate->is_guest = true; gfpu->fpstate = fpstate; - gfpu->xfeatures = fpu_user_cfg.default_features; - gfpu->perm = fpu_user_cfg.default_features; + gfpu->xfeatures = fpu_kernel_cfg.default_features; + gfpu->perm = fpu_kernel_cfg.default_features; /* * KVM sets the FP+SSE bits in the XSAVE header when copying FPU state @@ -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); @@ -499,7 +508,7 @@ static inline void fpstate_init_fstate(struct fpstate *fpstate) /* * Used in two places: * 1) Early boot to setup init_fpstate for non XSAVE systems - * 2) fpu_init_fpstate_user() which is invoked from KVM + * 2) fpu_alloc_guest_fpstate() which is invoked from KVM */ void fpstate_init_user(struct fpstate *fpstate) { |