powerpc: Create disable_kernel_{fp,altivec,vsx,spe}()

The enable_kernel_*() functions leave the relevant MSR bits enabled
until we exit the kernel sometime later. Create disable versions
that wrap the kernel use of FP, Altivec VSX or SPE.

While we don't want to disable it normally for performance reasons
(MSR writes are slow), it will be used for a debug boot option that
does this and catches bad uses in other areas of the kernel.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

10 files changed, 25 insertions, 0 deletions

diff --git a/arch/powerpc/crypto/aes-spe-glue.c b/arch/powerpc/crypto/aes-spe-glue.c
index bd5e63f..93ee046 100644
--- a/arch/powerpc/crypto/aes-spe-glue.c
+++ b/arch/powerpc/crypto/aes-spe-glue.c
@@ -85,6 +85,7 @@ static void spe_begin(void)
 
 static void spe_end(void)
 {
+	disable_kernel_spe();
 	/* reenable preemption */
 	preempt_enable();
 }
diff --git a/arch/powerpc/crypto/sha1-spe-glue.c b/arch/powerpc/crypto/sha1-spe-glue.c
index 3e1d222..f9ebc38 100644
--- a/arch/powerpc/crypto/sha1-spe-glue.c
+++ b/arch/powerpc/crypto/sha1-spe-glue.c
@@ -46,6 +46,7 @@ static void spe_begin(void)
 
 static void spe_end(void)
 {
+	disable_kernel_spe();
 	/* reenable preemption */
 	preempt_enable();
 }
diff --git a/arch/powerpc/crypto/sha256-spe-glue.c b/arch/powerpc/crypto/sha256-spe-glue.c
index f4a616f..718a079 100644
--- a/arch/powerpc/crypto/sha256-spe-glue.c
+++ b/arch/powerpc/crypto/sha256-spe-glue.c
@@ -47,6 +47,7 @@ static void spe_begin(void)
 
 static void spe_end(void)
 {
+	disable_kernel_spe();
 	/* reenable preemption */
 	preempt_enable();
 }
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index c2678b9..438502f 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -26,6 +26,11 @@ extern void enable_kernel_spe(void);
 extern void load_up_spe(struct task_struct *);
 extern void switch_booke_debug_regs(struct debug_reg *new_debug);
 
+static inline void disable_kernel_fp(void) { }
+static inline void disable_kernel_altivec(void) { }
+static inline void disable_kernel_spe(void) { }
+static inline void disable_kernel_vsx(void) { }
+
 #ifdef CONFIG_PPC_FPU
 extern void flush_fp_to_thread(struct task_struct *);
 extern void giveup_fpu(struct task_struct *);
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index 86150fb..8e7cb8e 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -960,6 +960,7 @@ int fix_alignment(struct pt_regs *regs)
 			preempt_disable();
 			enable_kernel_fp();
 			cvt_df(&data.dd, (float *)&data.x32.low32);
+			disable_kernel_fp();
 			preempt_enable();
 #else
 			return 0;
@@ -1000,6 +1001,7 @@ int fix_alignment(struct pt_regs *regs)
 		preempt_disable();
 		enable_kernel_fp();
 		cvt_fd((float *)&data.x32.low32, &data.dd);
+		disable_kernel_fp();
 		preempt_enable();
 #else
 		return 0;
diff --git a/arch/powerpc/kvm/book3s_paired_singles.c b/arch/powerpc/kvm/book3s_paired_singles.c
index a759d9a..eab96cf 100644
--- a/arch/powerpc/kvm/book3s_paired_singles.c
+++ b/arch/powerpc/kvm/book3s_paired_singles.c
@@ -1265,6 +1265,7 @@ int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu)
 	if (rcomp)
 		kvmppc_set_cr(vcpu, cr);
 
+	disable_kernel_fp();
 	preempt_enable();
 
 	return emulated;
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 64891b0..49f5dad 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -751,6 +751,7 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
 		preempt_disable();
 		enable_kernel_fp();
 		load_fp_state(&vcpu->arch.fp);
+		disable_kernel_fp();
 		t->fp_save_area = &vcpu->arch.fp;
 		preempt_enable();
 	}
@@ -760,6 +761,7 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
 		preempt_disable();
 		enable_kernel_altivec();
 		load_vr_state(&vcpu->arch.vr);
+		disable_kernel_altivec();
 		t->vr_save_area = &vcpu->arch.vr;
 		preempt_enable();
 #endif
@@ -788,6 +790,7 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu)
 		preempt_disable();
 		enable_kernel_fp();
 		load_fp_state(&vcpu->arch.fp);
+		disable_kernel_fp();
 		preempt_enable();
 	}
 #ifdef CONFIG_ALTIVEC
@@ -795,6 +798,7 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu)
 		preempt_disable();
 		enable_kernel_altivec();
 		load_vr_state(&vcpu->arch.vr);
+		disable_kernel_altivec();
 		preempt_enable();
 	}
 #endif
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index fd58751..778ef86 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -98,6 +98,7 @@ void kvmppc_vcpu_disable_spe(struct kvm_vcpu *vcpu)
 	preempt_disable();
 	enable_kernel_spe();
 	kvmppc_save_guest_spe(vcpu);
+	disable_kernel_spe();
 	vcpu->arch.shadow_msr &= ~MSR_SPE;
 	preempt_enable();
 }
@@ -107,6 +108,7 @@ static void kvmppc_vcpu_enable_spe(struct kvm_vcpu *vcpu)
 	preempt_disable();
 	enable_kernel_spe();
 	kvmppc_load_guest_spe(vcpu);
+	disable_kernel_spe();
 	vcpu->arch.shadow_msr |= MSR_SPE;
 	preempt_enable();
 }
@@ -141,6 +143,7 @@ static inline void kvmppc_load_guest_fp(struct kvm_vcpu *vcpu)
 	if (!(current->thread.regs->msr & MSR_FP)) {
 		enable_kernel_fp();
 		load_fp_state(&vcpu->arch.fp);
+		disable_kernel_fp();
 		current->thread.fp_save_area = &vcpu->arch.fp;
 		current->thread.regs->msr |= MSR_FP;
 	}
@@ -182,6 +185,7 @@ static inline void kvmppc_load_guest_altivec(struct kvm_vcpu *vcpu)
 		if (!(current->thread.regs->msr & MSR_VEC)) {
 			enable_kernel_altivec();
 			load_vr_state(&vcpu->arch.vr);
+			disable_kernel_altivec();
 			current->thread.vr_save_area = &vcpu->arch.vr;
 			current->thread.regs->msr |= MSR_VEC;
 		}
diff --git a/arch/powerpc/lib/vmx-helper.c b/arch/powerpc/lib/vmx-helper.c
index ac93a3b..b27e030 100644
--- a/arch/powerpc/lib/vmx-helper.c
+++ b/arch/powerpc/lib/vmx-helper.c
@@ -46,6 +46,7 @@ int enter_vmx_usercopy(void)
  */
 int exit_vmx_usercopy(void)
 {
+	disable_kernel_altivec();
 	pagefault_enable();
 	preempt_enable();
 	return 0;
@@ -70,6 +71,7 @@ int enter_vmx_copy(void)
  */
 void *exit_vmx_copy(void *dest)
 {
+	disable_kernel_altivec();
 	preempt_enable();
 	return dest;
 }
diff --git a/arch/powerpc/lib/xor_vmx.c b/arch/powerpc/lib/xor_vmx.c
index e905f7c..07f49f1 100644
--- a/arch/powerpc/lib/xor_vmx.c
+++ b/arch/powerpc/lib/xor_vmx.c
@@ -74,6 +74,7 @@ void xor_altivec_2(unsigned long bytes, unsigned long *v1_in,
 		v2 += 4;
 	} while (--lines > 0);
 
+	disable_kernel_altivec();
 	preempt_enable();
 }
 EXPORT_SYMBOL(xor_altivec_2);
@@ -102,6 +103,7 @@ void xor_altivec_3(unsigned long bytes, unsigned long *v1_in,
 		v3 += 4;
 	} while (--lines > 0);
 
+	disable_kernel_altivec();
 	preempt_enable();
 }
 EXPORT_SYMBOL(xor_altivec_3);
@@ -135,6 +137,7 @@ void xor_altivec_4(unsigned long bytes, unsigned long *v1_in,
 		v4 += 4;
 	} while (--lines > 0);
 
+	disable_kernel_altivec();
 	preempt_enable();
 }
 EXPORT_SYMBOL(xor_altivec_4);
@@ -172,6 +175,7 @@ void xor_altivec_5(unsigned long bytes, unsigned long *v1_in,
 		v5 += 4;
 	} while (--lines > 0);
 
+	disable_kernel_altivec();
 	preempt_enable();
 }
 EXPORT_SYMBOL(xor_altivec_5);