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+/*
+ * Copyright (C) 2016 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.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/asm-offsets.h>
+#include <asm/kvm_arm.h>
+
+ .arch_extension virt
+
+ .text
+ .pushsection .hyp.text, "ax"
+
+#define USR_REGS_OFFSET (CPU_CTXT_GP_REGS + GP_REGS_USR)
+
+/* int __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host) */
+ENTRY(__guest_enter)
+ @ Save host registers
+ add r1, r1, #(USR_REGS_OFFSET + S_R4)
+ stm r1!, {r4-r12}
+ str lr, [r1, #4] @ Skip SP_usr (already saved)
+
+ @ Restore guest registers
+ add r0, r0, #(VCPU_GUEST_CTXT + USR_REGS_OFFSET + S_R0)
+ ldr lr, [r0, #S_LR]
+ ldm r0, {r0-r12}
+
+ clrex
+ eret
+ENDPROC(__guest_enter)
+
+ENTRY(__guest_exit)
+ /*
+ * return convention:
+ * guest r0, r1, r2 saved on the stack
+ * r0: vcpu pointer
+ * r1: exception code
+ */
+
+ add r2, r0, #(VCPU_GUEST_CTXT + USR_REGS_OFFSET + S_R3)
+ stm r2!, {r3-r12}
+ str lr, [r2, #4]
+ add r2, r0, #(VCPU_GUEST_CTXT + USR_REGS_OFFSET + S_R0)
+ pop {r3, r4, r5} @ r0, r1, r2
+ stm r2, {r3-r5}
+
+ ldr r0, [r0, #VCPU_HOST_CTXT]
+ add r0, r0, #(USR_REGS_OFFSET + S_R4)
+ ldm r0!, {r4-r12}
+ ldr lr, [r0, #4]
+
+ mov r0, r1
+ bx lr
+ENDPROC(__guest_exit)
+
+/*
+ * If VFPv3 support is not available, then we will not switch the VFP
+ * registers; however cp10 and cp11 accesses will still trap and fallback
+ * to the regular coprocessor emulation code, which currently will
+ * inject an undefined exception to the guest.
+ */
+#ifdef CONFIG_VFPv3
+ENTRY(__vfp_guest_restore)
+ push {r3, r4, lr}
+
+ @ NEON/VFP used. Turn on VFP access.
+ mrc p15, 4, r1, c1, c1, 2 @ HCPTR
+ bic r1, r1, #(HCPTR_TCP(10) | HCPTR_TCP(11))
+ mcr p15, 4, r1, c1, c1, 2 @ HCPTR
+ isb
+
+ @ Switch VFP/NEON hardware state to the guest's
+ mov r4, r0
+ ldr r0, [r0, #VCPU_HOST_CTXT]
+ add r0, r0, #CPU_CTXT_VFP
+ bl __vfp_save_state
+ add r0, r4, #(VCPU_GUEST_CTXT + CPU_CTXT_VFP)
+ bl __vfp_restore_state
+
+ pop {r3, r4, lr}
+ pop {r0, r1, r2}
+ clrex
+ eret
+ENDPROC(__vfp_guest_restore)
+#endif
+
+ .popsection
+
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