[PATCH v2 03/11] arm64: gunyah: Add Gunyah hypercalls ABI

[Elliot Berman]

Add initial support to perform Gunyah hypercalls. The arm64 ABI for
Gunyah hypercalls generally follows the SMC Calling Convention.

Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
 MAINTAINERS                     |   1 +
 arch/arm64/include/asm/gunyah.h | 134 ++++++++++++++++++++++++++++++++
 2 files changed, 135 insertions(+)
 create mode 100644 arch/arm64/include/asm/gunyah.h

diff --git a/MAINTAINERS b/MAINTAINERS
index b36bd47bcaaa..1d098bdba5c9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8742,6 +8742,7 @@ L:	linux-arm-msm@xxxxxxxxxxxxxxx
 S:	Maintained
 F:	Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
 F:	Documentation/virt/gunyah/
+F:	arch/arm64/include/asm/gunyah.h
 
 HABANALABS PCI DRIVER
 M:	Oded Gabbay <ogabbay@xxxxxxxxxx>
diff --git a/arch/arm64/include/asm/gunyah.h b/arch/arm64/include/asm/gunyah.h
new file mode 100644
index 000000000000..2dbef08d58d7
--- /dev/null
+++ b/arch/arm64/include/asm/gunyah.h
@@ -0,0 +1,134 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+#ifndef __ASM_GUNYAH_H
+#define __ASM_GUNYAH_H
+
+#include <linux/arm-smccc.h>
+#include <linux/types.h>
+
+#define GH_CALL_TYPE_PLATFORM_CALL		0
+#define GH_CALL_TYPE_HYPERCALL			2
+#define GH_CALL_TYPE_SERVICE			3
+#define GH_CALL_TYPE_SHIFT			14
+#define GH_CALL_FUNCTION_NUM_MASK		0x3fff
+
+#define GH_SERVICE(fn)		ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_32, \
+						   ARM_SMCCC_OWNER_VENDOR_HYP, \
+						   (GH_CALL_TYPE_SERVICE << GH_CALL_TYPE_SHIFT) \
+							| ((fn) & GH_CALL_FUNCTION_NUM_MASK))
+
+#define GH_HYPERCALL(fn)	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \
+						   ARM_SMCCC_OWNER_VENDOR_HYP, \
+						   (GH_CALL_TYPE_HYPERCALL << GH_CALL_TYPE_SHIFT) \
+							| ((fn) & GH_CALL_FUNCTION_NUM_MASK))
+
+#define ___gh_count_args(_0, _1, _2, _3, _4, _5, _6, _7, _8, x, ...) x
+
+#define __gh_count_args(...)						\
+	___gh_count_args(_, ## __VA_ARGS__, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+
+#define __gh_skip_0(...)		__VA_ARGS__
+#define __gh_skip_1(a, ...)	__VA_ARGS__
+#define __gh_skip_2(a, b, ...)	__VA_ARGS__
+#define __gh_skip_3(a, b, c, ...)	__VA_ARGS__
+#define __gh_skip_4(a, b, c, d, ...)	__VA_ARGS__
+#define __gh_skip_5(a, b, c, d, e, ...)	__VA_ARGS__
+#define __gh_skip_6(a, b, c, d, e, f, ...)	__VA_ARGS__
+#define __gh_skip_7(a, b, c, d, e, f, g, ...)	__VA_ARGS__
+#define __gh_skip_8(a, b, c, d, e, f, g, h, ...)	__VA_ARGS__
+#define __gh_to_res(nargs, ...)		__gh_skip_ ## nargs (__VA_ARGS__)
+
+#define __gh_declare_arg_0(...)
+
+#define __gh_declare_arg_1(arg1, ...)						\
+	.a1 = (arg1)
+
+#define __gh_declare_arg_2(arg1, arg2, ...)					\
+	__gh_declare_arg_1(arg1),						\
+	.a2 = (arg2)
+
+#define __gh_declare_arg_3(arg1, arg2, arg3, ...)				\
+	__gh_declare_arg_2(arg1, arg2),						\
+	.a3 = (arg3)
+
+#define __gh_declare_arg_4(arg1, arg2, arg3, arg4, ...)				\
+	__gh_declare_arg_3(arg1, arg2, arg3),					\
+	.a4 = (arg4)
+
+#define __gh_declare_arg_5(arg1, arg2, arg3, arg4, arg5, ...)			\
+	__gh_declare_arg_4(arg1, arg2, arg3, arg4),				\
+	.a5 = (arg5)
+
+#define __gh_declare_arg_6(arg1, arg2, arg3, arg4, arg5, arg6, ...)		\
+	__gh_declare_arg_5(arg1, arg2, arg3, arg4, arg5),			\
+	.a6 = (arg6)
+
+#define __gh_declare_arg_7(arg1, arg2, arg3, arg4, arg5, arg6, arg7, ...)	\
+	__gh_declare_arg_6(arg1, arg2, arg3, arg4, arg5, arg6),			\
+	.a7 = (arg7)
+
+#define __gh_declare_arg_8(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, ...)	\
+	__gh_declare_arg_7(arg1, arg2, arg3, arg4, arg5, arg6, arg7),		\
+	.a8 = (arg8)
+
+#define ___gh_declare_args(nargs)	__gh_declare_arg_ ## nargs
+#define __gh_declare_args(nargs)	___gh_declare_args(nargs)
+#define _gh_declare_args(nargs, ...) __gh_declare_args(nargs)(__VA_ARGS__)
+
+#define __gh_assign_res_0(...)
+
+#define __gh_assign_res_1(r1)					\
+	r1 = res.a0
+
+#define __gh_assign_res_2(r1, r2)				\
+	__gh_assign_res_1(r1);					\
+	r2 = res.a1
+
+#define __gh_assign_res_3(r1, r2, r3)				\
+	__gh_assign_res_2(r1, r2);				\
+	r3 = res.a2
+
+#define __gh_assign_res_4(r1, r2, r3, r4)			\
+	__gh_assign_res_3(r1, r2, r3);				\
+	r4 = res.a3
+
+#define __gh_assign_res_5(r1, r2, r3, r4, r5)			\
+	__gh_assign_res_4(r1, r2, r3, r4);			\
+	r5 = res.a4
+
+#define __gh_assign_res_6(r1, r2, r3, r4, r5, r6)		\
+	__gh_assign_res_5(r1, r2, r3, r4, r5);			\
+	r6 = res.a5
+
+#define __gh_assign_res_7(r1, r2, r3, r4, r5, r6, r7)		\
+	__gh_assign_res_6(r1, r2, r3, r4, r5, r6);		\
+	r7 = res.a6
+
+#define __gh_assign_res_8(r1, r2, r3, r4, r5, r6, r7, r8)	\
+	__gh_assign_res_7(r1, r2, r3, r4, r5, r6, r7);		\
+	r8 = res.a7
+
+#define ___gh_assign_res(nargs)	__gh_assign_res_ ## nargs
+#define __gh_assign_res(nargs)	___gh_assign_res(nargs)
+#define _gh_assign_res(...) __gh_assign_res(__gh_count_args(__VA_ARGS__))(__VA_ARGS__)
+
+/**
+ * arch_gh_hypercall() - Performs an AArch64-specific call into hypervisor using Gunyah ABI
+ * @hcall_num: Hypercall function ID to invoke
+ * @nargs: Number of input arguments
+ * @...: First nargs are the input arguments. Remaining arguments are output variables.
+ */
+#define arch_gh_hypercall(hcall_num, nargs, ...)				\
+	do {									\
+		struct arm_smccc_1_2_regs res;					\
+		struct arm_smccc_1_2_regs args = {				\
+			.a0 = hcall_num,					\
+			_gh_declare_args(nargs, __VA_ARGS__)			\
+		};								\
+		arm_smccc_1_2_hvc(&args, &res);					\
+		_gh_assign_res(__gh_to_res(nargs, __VA_ARGS__));		\
+	} while (0)
+
+#endif
-- 
2.25.1