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Commit 59cbcdb5 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

ARM: KVM: Add VFP save/restore 



This is almost a copy/paste of the existing version, with a couple
of subtle differences:
- Only write to FPEXC once on the save path
- Add an isb when enabling VFP access

The patch also defines a few sysreg accessors and a __vfp_enabled
predicate that test the VFP trapping state.

Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent c0c2cdbf

arch/arm/kvm/hyp/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,3 +6,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += tlb.o 
obj-$(CONFIG_KVM_ARM_HOST) += cp15-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += vfp.o

arch/arm/kvm/hyp/hyp.h

+13 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/compiler.h>

#include <linux/kvm_host.h>

#include <asm/kvm_mmu.h>

#include <asm/vfp.h>



#define __hyp_text __section(.hyp.text) notrace
@@ -31,6 +32,8 @@ 
	"mrc", "mcr", __stringify(p15, Op1, %0, CRn, CRm, Op2), u32

#define __ACCESS_CP15_64(Op1, CRm)		\

	"mrrc", "mcrr", __stringify(p15, Op1, %Q0, %R0, CRm), u64

#define __ACCESS_VFP(CRn)			\

	"mrc", "mcr", __stringify(p10, 7, %0, CRn, cr0, 0), u32



#define __write_sysreg(v, r, w, c, t)	asm volatile(w " " c : : "r" ((t)(v)))

#define write_sysreg(v, ...)		__write_sysreg(v, __VA_ARGS__)
@@ -53,6 +56,7 @@ 
#define VMPIDR		__ACCESS_CP15(c0, 4, c0, 5)

#define SCTLR		__ACCESS_CP15(c1, 0, c0, 0)

#define CPACR		__ACCESS_CP15(c1, 0, c0, 2)

#define HCPTR		__ACCESS_CP15(c1, 4, c1, 2)

#define TTBCR		__ACCESS_CP15(c2, 0, c0, 2)

#define DACR		__ACCESS_CP15(c3, 0, c0, 0)

#define DFSR		__ACCESS_CP15(c5, 0, c0, 0)
@@ -77,6 +81,8 @@ 
#define CNTV_CTL	__ACCESS_CP15(c14, 0, c3, 1)

#define CNTHCTL		__ACCESS_CP15(c14, 4, c1, 0)



#define VFP_FPEXC	__ACCESS_VFP(FPEXC)



void __timer_save_state(struct kvm_vcpu *vcpu);

void __timer_restore_state(struct kvm_vcpu *vcpu);
@@ -86,4 +92,11 @@ void __vgic_v2_restore_state(struct kvm_vcpu *vcpu); 
void __sysreg_save_state(struct kvm_cpu_context *ctxt);

void __sysreg_restore_state(struct kvm_cpu_context *ctxt);



void asmlinkage __vfp_save_state(struct vfp_hard_struct *vfp);

void asmlinkage __vfp_restore_state(struct vfp_hard_struct *vfp);

static inline bool __vfp_enabled(void)

{

	return !(read_sysreg(HCPTR) & (HCPTR_TCP(11) | HCPTR_TCP(10)));

}



#endif /* __ARM_KVM_HYP_H__ */

arch/arm/kvm/hyp/vfp.S

0 → 100644
+68 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2012 - Virtual Open Systems and Columbia University

 * Author: Christoffer Dall <c.dall@virtualopensystems.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */



#include <linux/linkage.h>

#include <asm/vfpmacros.h>



	.text

	.pushsection	.hyp.text, "ax"



/* void __vfp_save_state(struct vfp_hard_struct *vfp); */

ENTRY(__vfp_save_state)

	push	{r4, r5}

	VFPFMRX	r1, FPEXC



	@ Make sure *really* VFP is enabled so we can touch the registers.

	orr	r5, r1, #FPEXC_EN

	tst	r5, #FPEXC_EX		@ Check for VFP Subarchitecture

	bic	r5, r5, #FPEXC_EX	@ FPEXC_EX disable

	VFPFMXR	FPEXC, r5

	isb



	VFPFMRX	r2, FPSCR

	beq	1f



	@ If FPEXC_EX is 0, then FPINST/FPINST2 reads are upredictable, so

	@ we only need to save them if FPEXC_EX is set.

	VFPFMRX r3, FPINST

	tst	r5, #FPEXC_FP2V

	VFPFMRX r4, FPINST2, ne		@ vmrsne

1:

	VFPFSTMIA r0, r5		@ Save VFP registers

	stm	r0, {r1-r4}		@ Save FPEXC, FPSCR, FPINST, FPINST2

	pop	{r4, r5}

	bx	lr

ENDPROC(__vfp_save_state)



/* void __vfp_restore_state(struct vfp_hard_struct *vfp);

 * Assume FPEXC_EN is on and FPEXC_EX is off */

ENTRY(__vfp_restore_state)

	VFPFLDMIA r0, r1		@ Load VFP registers

	ldm	r0, {r0-r3}		@ Load FPEXC, FPSCR, FPINST, FPINST2



	VFPFMXR FPSCR, r1

	tst	r0, #FPEXC_EX		@ Check for VFP Subarchitecture

	beq	1f

	VFPFMXR FPINST, r2

	tst	r0, #FPEXC_FP2V

	VFPFMXR FPINST2, r3, ne

1:

	VFPFMXR FPEXC, r0		@ FPEXC	(last, in case !EN)

	bx	lr

ENDPROC(__vfp_restore_state)



	.popsection