Subject: [PATCH] powerpc: remove fpscr use from [kvm_]cvt_{fd,df}

From: Andreas Schwab <[email-masked]>
Date: Sat, 21 Aug 2010 23:43:20 +0200

Neither lfs nor stfs touch the fpscr, so remove the restore/save of it
around them.

Signed-off-by: Andreas Schwab <[email-masked]>
---
 arch/powerpc/include/asm/kvm_fpu.h       |    4 +-
 arch/powerpc/include/asm/system.h        |    4 +-
 arch/powerpc/kernel/align.c              |    4 +-
 arch/powerpc/kernel/fpu.S                |   10 -------
 arch/powerpc/kvm/book3s_paired_singles.c |   44 +++++++++++++----------------
 arch/powerpc/kvm/fpu.S                   |    8 -----
 6 files changed, 26 insertions(+), 48 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_fpu.h b/arch/powerpc/include/asm/kvm_fpu.h
index c3d4f05..92daae1 100644
--- a/arch/powerpc/include/asm/kvm_fpu.h
+++ b/arch/powerpc/include/asm/kvm_fpu.h
@@ -82,7 +82,7 @@ FPD_THREE_IN(fmadd)
 FPD_THREE_IN(fnmsub)
 FPD_THREE_IN(fnmadd)
 
-extern void kvm_cvt_fd(u32 *from, u64 *to, u64 *fpscr);
-extern void kvm_cvt_df(u64 *from, u32 *to, u64 *fpscr);
+extern void kvm_cvt_fd(u32 *from, u64 *to);
+extern void kvm_cvt_df(u64 *from, u32 *to);
 
 #endif
diff --git a/arch/powerpc/include/asm/system.h b/arch/powerpc/include/asm/system.h
index 6c294ac..0b3fe78 100644
--- a/arch/powerpc/include/asm/system.h
+++ b/arch/powerpc/include/asm/system.h
@@ -154,8 +154,8 @@ extern void enable_kernel_spe(void);
 extern void giveup_spe(struct task_struct *);
 extern void load_up_spe(struct task_struct *);
 extern int fix_alignment(struct pt_regs *);
-extern void cvt_fd(float *from, double *to, struct thread_struct *thread);
-extern void cvt_df(double *from, float *to, struct thread_struct *thread);
+extern void cvt_fd(float *from, double *to);
+extern void cvt_df(double *from, float *to);
 
 #ifndef CONFIG_SMP
 extern void discard_lazy_cpu_state(void);
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index b876e98..8184ee9 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -889,7 +889,7 @@ int fix_alignment(struct pt_regs *regs)
 #ifdef CONFIG_PPC_FPU
 			preempt_disable();
 			enable_kernel_fp();
-			cvt_df(&data.dd, (float *)&data.v[4], &current->thread);
+			cvt_df(&data.dd, (float *)&data.v[4]);
 			preempt_enable();
 #else
 			return 0;
@@ -933,7 +933,7 @@ int fix_alignment(struct pt_regs *regs)
 #ifdef CONFIG_PPC_FPU
 		preempt_disable();
 		enable_kernel_fp();
-		cvt_fd((float *)&data.v[4], &data.dd, &current->thread);
+		cvt_fd((float *)&data.v[4], &data.dd);
 		preempt_enable();
 #else
 		return 0;
diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S
index fc8f5b1..e86c040 100644
--- a/arch/powerpc/kernel/fpu.S
+++ b/arch/powerpc/kernel/fpu.S
@@ -163,24 +163,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
 /*
  * These are used in the alignment trap handler when emulating
  * single-precision loads and stores.
- * We restore and save the fpscr so the task gets the same result
- * and exceptions as if the cpu had performed the load or store.
  */
 
 _GLOBAL(cvt_fd)
-	lfd	0,THREAD_FPSCR(r5)	/* load up fpscr value */
-	MTFSF_L(0)
 	lfs	0,0(r3)
 	stfd	0,0(r4)
-	mffs	0
-	stfd	0,THREAD_FPSCR(r5)	/* save new fpscr value */
 	blr
 
 _GLOBAL(cvt_df)
-	lfd	0,THREAD_FPSCR(r5)	/* load up fpscr value */
-	MTFSF_L(0)
 	lfd	0,0(r3)
 	stfs	0,0(r4)
-	mffs	0
-	stfd	0,THREAD_FPSCR(r5)	/* save new fpscr value */
 	blr
diff --git a/arch/powerpc/kvm/book3s_paired_singles.c b/arch/powerpc/kvm/book3s_paired_singles.c
index 474f2e2..35a701f 100644
--- a/arch/powerpc/kvm/book3s_paired_singles.c
+++ b/arch/powerpc/kvm/book3s_paired_singles.c
@@ -159,7 +159,7 @@
 
 static inline void kvmppc_sync_qpr(struct kvm_vcpu *vcpu, int rt)
 {
-	kvm_cvt_df(&vcpu->arch.fpr[rt], &vcpu->arch.qpr[rt], &vcpu->arch.fpscr);
+	kvm_cvt_df(&vcpu->arch.fpr[rt], &vcpu->arch.qpr[rt]);
 }
 
 static void kvmppc_inject_pf(struct kvm_vcpu *vcpu, ulong eaddr, bool is_store)
@@ -204,7 +204,7 @@ static int kvmppc_emulate_fpr_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	/* put in registers */
 	switch (ls_type) {
 	case FPU_LS_SINGLE:
-		kvm_cvt_fd((u32*)tmp, &vcpu->arch.fpr[rs], &vcpu->arch.fpscr);
+		kvm_cvt_fd((u32*)tmp, &vcpu->arch.fpr[rs]);
 		vcpu->arch.qpr[rs] = *((u32*)tmp);
 		break;
 	case FPU_LS_DOUBLE:
@@ -230,7 +230,7 @@ static int kvmppc_emulate_fpr_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
 
 	switch (ls_type) {
 	case FPU_LS_SINGLE:
-		kvm_cvt_df(&vcpu->arch.fpr[rs], (u32*)tmp, &vcpu->arch.fpscr);
+		kvm_cvt_df(&vcpu->arch.fpr[rs], (u32*)tmp);
 		val = *((u32*)tmp);
 		len = sizeof(u32);
 		break;
@@ -296,7 +296,7 @@ static int kvmppc_emulate_psq_load(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	emulated = EMULATE_DONE;
 
 	/* put in registers */
-	kvm_cvt_fd(&tmp[0], &vcpu->arch.fpr[rs], &vcpu->arch.fpscr);
+	kvm_cvt_fd(&tmp[0], &vcpu->arch.fpr[rs]);
 	vcpu->arch.qpr[rs] = tmp[1];
 
 	dprintk(KERN_INFO "KVM: PSQ_LD [0x%x, 0x%x] at 0x%lx (%d)\n", tmp[0],
@@ -314,7 +314,7 @@ static int kvmppc_emulate_psq_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	u32 tmp[2];
 	int len = w ? sizeof(u32) : sizeof(u64);
 
-	kvm_cvt_df(&vcpu->arch.fpr[rs], &tmp[0], &vcpu->arch.fpscr);
+	kvm_cvt_df(&vcpu->arch.fpr[rs], &tmp[0]);
 	tmp[1] = vcpu->arch.qpr[rs];
 
 	r = kvmppc_st(vcpu, &addr, len, tmp, true);
@@ -516,9 +516,9 @@ static int kvmppc_ps_three_in(struct kvm_vcpu *vcpu, bool rc,
 	WARN_ON(rc);
 
 	/* PS0 */
-	kvm_cvt_df(&fpr[reg_in1], &ps0_in1, &vcpu->arch.fpscr);
-	kvm_cvt_df(&fpr[reg_in2], &ps0_in2, &vcpu->arch.fpscr);
-	kvm_cvt_df(&fpr[reg_in3], &ps0_in3, &vcpu->arch.fpscr);
+	kvm_cvt_df(&fpr[reg_in1], &ps0_in1);
+	kvm_cvt_df(&fpr[reg_in2], &ps0_in2);
+	kvm_cvt_df(&fpr[reg_in3], &ps0_in3);
 
 	if (scalar & SCALAR_LOW)
 		ps0_in2 = qpr[reg_in2];
@@ -529,7 +529,7 @@ static int kvmppc_ps_three_in(struct kvm_vcpu *vcpu, bool rc,
 			  ps0_in1, ps0_in2, ps0_in3, ps0_out);
 
 	if (!(scalar & SCALAR_NO_PS0))
-		kvm_cvt_fd(&ps0_out, &fpr[reg_out], &vcpu->arch.fpscr);
+		kvm_cvt_fd(&ps0_out, &fpr[reg_out]);
 
 	/* PS1 */
 	ps1_in1 = qpr[reg_in1];
@@ -566,12 +566,12 @@ static int kvmppc_ps_two_in(struct kvm_vcpu *vcpu, bool rc,
 	WARN_ON(rc);
 
 	/* PS0 */
-	kvm_cvt_df(&fpr[reg_in1], &ps0_in1, &vcpu->arch.fpscr);
+	kvm_cvt_df(&fpr[reg_in1], &ps0_in1);
 
 	if (scalar & SCALAR_LOW)
 		ps0_in2 = qpr[reg_in2];
 	else
-		kvm_cvt_df(&fpr[reg_in2], &ps0_in2, &vcpu->arch.fpscr);
+		kvm_cvt_df(&fpr[reg_in2], &ps0_in2);
 
 	func(&vcpu->arch.fpscr, &ps0_out, &ps0_in1, &ps0_in2);
 
@@ -579,7 +579,7 @@ static int kvmppc_ps_two_in(struct kvm_vcpu *vcpu, bool rc,
 		dprintk(KERN_INFO "PS2 ps0 -> f(0x%x, 0x%x) = 0x%x\n",
 				  ps0_in1, ps0_in2, ps0_out);
 
-		kvm_cvt_fd(&ps0_out, &fpr[reg_out], &vcpu->arch.fpscr);
+		kvm_cvt_fd(&ps0_out, &fpr[reg_out]);
 	}
 
 	/* PS1 */
@@ -615,13 +615,13 @@ static int kvmppc_ps_one_in(struct kvm_vcpu *vcpu, bool rc,
 	WARN_ON(rc);
 
 	/* PS0 */
-	kvm_cvt_df(&fpr[reg_in], &ps0_in, &vcpu->arch.fpscr);
+	kvm_cvt_df(&fpr[reg_in], &ps0_in);
 	func(&vcpu->arch.fpscr, &ps0_out, &ps0_in);
 
 	dprintk(KERN_INFO "PS1 ps0 -> f(0x%x) = 0x%x\n",
 			  ps0_in, ps0_out);
 
-	kvm_cvt_fd(&ps0_out, &fpr[reg_out], &vcpu->arch.fpscr);
+	kvm_cvt_fd(&ps0_out, &fpr[reg_out]);
 
 	/* PS1 */
 	ps1_in = qpr[reg_in];
@@ -671,7 +671,7 @@ int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu)
 #ifdef DEBUG
 	for (i = 0; i < ARRAY_SIZE(vcpu->arch.fpr); i++) {
 		u32 f;
-		kvm_cvt_df(&vcpu->arch.fpr[i], &f, &vcpu->arch.fpscr);
+		kvm_cvt_df(&vcpu->arch.fpr[i], &f);
 		dprintk(KERN_INFO "FPR[%d] = 0x%x / 0x%llx    QPR[%d] = 0x%x\n",
 			i, f, vcpu->arch.fpr[i], i, vcpu->arch.qpr[i]);
 	}
@@ -796,8 +796,7 @@ int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu)
 			vcpu->arch.fpr[ax_rd] = vcpu->arch.fpr[ax_ra];
 			/* vcpu->arch.qpr[ax_rd] = vcpu->arch.fpr[ax_rb]; */
 			kvm_cvt_df(&vcpu->arch.fpr[ax_rb],
-				   &vcpu->arch.qpr[ax_rd],
-				   &vcpu->arch.fpscr);
+				   &vcpu->arch.qpr[ax_rd]);
 			break;
 		case OP_4X_PS_MERGE01:
 			WARN_ON(rcomp);
@@ -808,19 +807,16 @@ int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu)
 			WARN_ON(rcomp);
 			/* vcpu->arch.fpr[ax_rd] = vcpu->arch.qpr[ax_ra]; */
 			kvm_cvt_fd(&vcpu->arch.qpr[ax_ra],
-				   &vcpu->arch.fpr[ax_rd],
-				   &vcpu->arch.fpscr);
+				   &vcpu->arch.fpr[ax_rd]);
 			/* vcpu->arch.qpr[ax_rd] = vcpu->arch.fpr[ax_rb]; */
 			kvm_cvt_df(&vcpu->arch.fpr[ax_rb],
-				   &vcpu->arch.qpr[ax_rd],
-				   &vcpu->arch.fpscr);
+				   &vcpu->arch.qpr[ax_rd]);
 			break;
 		case OP_4X_PS_MERGE11:
 			WARN_ON(rcomp);
 			/* vcpu->arch.fpr[ax_rd] = vcpu->arch.qpr[ax_ra]; */
 			kvm_cvt_fd(&vcpu->arch.qpr[ax_ra],
-				   &vcpu->arch.fpr[ax_rd],
-				   &vcpu->arch.fpscr);
+				   &vcpu->arch.fpr[ax_rd]);
 			vcpu->arch.qpr[ax_rd] = vcpu->arch.qpr[ax_rb];
 			break;
 		}
@@ -1255,7 +1251,7 @@ int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu)
 #ifdef DEBUG
 	for (i = 0; i < ARRAY_SIZE(vcpu->arch.fpr); i++) {
 		u32 f;
-		kvm_cvt_df(&vcpu->arch.fpr[i], &f, &vcpu->arch.fpscr);
+		kvm_cvt_df(&vcpu->arch.fpr[i], &f);
 		dprintk(KERN_INFO "FPR[%d] = 0x%x\n", i, f);
 	}
 #endif
diff --git a/arch/powerpc/kvm/fpu.S b/arch/powerpc/kvm/fpu.S
index cb34bbe..bf68d59 100644
--- a/arch/powerpc/kvm/fpu.S
+++ b/arch/powerpc/kvm/fpu.S
@@ -273,19 +273,11 @@ FPD_THREE_IN(fnmsub)
 FPD_THREE_IN(fnmadd)
 
 _GLOBAL(kvm_cvt_fd)
-	lfd	0,0(r5)			/* load up fpscr value */
-	MTFSF_L(0)
 	lfs	0,0(r3)
 	stfd	0,0(r4)
-	mffs	0
-	stfd	0,0(r5)			/* save new fpscr value */
 	blr
 
 _GLOBAL(kvm_cvt_df)
-	lfd	0,0(r5)			/* load up fpscr value */
-	MTFSF_L(0)
 	lfd	0,0(r3)
 	stfs	0,0(r4)
-	mffs	0
-	stfd	0,0(r5)			/* save new fpscr value */
 	blr
-- 
1.7.2.2

-- 
Andreas Schwab, [email-masked]
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."