From 59cbcdb5d83b49d1d2e161f3468f850f9fa4b968 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 4 Jan 2016 15:41:51 +0000 Subject: [PATCH] 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: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm/kvm/hyp/Makefile | 1 + arch/arm/kvm/hyp/hyp.h | 13 ++++++++ arch/arm/kvm/hyp/vfp.S | 68 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 82 insertions(+) create mode 100644 arch/arm/kvm/hyp/vfp.S diff --git a/arch/arm/kvm/hyp/Makefile b/arch/arm/kvm/hyp/Makefile index d8acbb691249..5a45f4c21f83 100644 --- a/arch/arm/kvm/hyp/Makefile +++ b/arch/arm/kvm/hyp/Makefile @@ -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 diff --git a/arch/arm/kvm/hyp/hyp.h b/arch/arm/kvm/hyp/hyp.h index 7eb1c21d2d21..dce0f7305cf5 100644 --- a/arch/arm/kvm/hyp/hyp.h +++ b/arch/arm/kvm/hyp/hyp.h @@ -21,6 +21,7 @@ #include #include #include +#include #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__ */ diff --git a/arch/arm/kvm/hyp/vfp.S b/arch/arm/kvm/hyp/vfp.S new file mode 100644 index 000000000000..7c297e87eb8b --- /dev/null +++ b/arch/arm/kvm/hyp/vfp.S @@ -0,0 +1,68 @@ +/* + * Copyright (C) 2012 - Virtual Open Systems and Columbia University + * Author: Christoffer Dall + * + * 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 . + */ + +#include +#include + + .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 -- 2.39.5