1 files changed, 48 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
new file mode 100644
index 000000000..952f6cb9c
--- /dev/null
+++ b/arch/arm64/kvm/hyp.S
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2012,2013 - 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/alternative.h>
+#include <asm/assembler.h>
+#include <asm/cpufeature.h>
+
+/*
+ * u64 __kvm_call_hyp(void *hypfn, ...);
+ *
+ * This is not really a variadic function in the classic C-way and care must
+ * be taken when calling this to ensure parameters are passed in registers
+ * only, since the stack will change between the caller and the callee.
+ *
+ * Call the function with the first argument containing a pointer to the
+ * function you wish to call in Hyp mode, and subsequent arguments will be
+ * passed as x0, x1, and x2 (a maximum of 3 arguments in addition to the
+ * function pointer can be passed).  The function being called must be mapped
+ * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
+ * passed in x0.
+ *
+ * A function pointer with a value less than 0xfff has a special meaning,
+ * and is used to implement hyp stubs in the same way as in
+ * arch/arm64/kernel/hyp_stub.S.
+ */
+ENTRY(__kvm_call_hyp)
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+	hvc	#0
+	ret
+alternative_else_nop_endif
+	b	__vhe_hyp_call
+ENDPROC(__kvm_call_hyp)