[PATCH 02/20] x86/tdx: Add macros to generate TDVMCALL wrappers

[Kirill A. Shutemov]

Introduce a set of macros that allow to generate wrappers for TDVMCALL
leafs. The macros uses tdvmcall_trmapoline() and provides SYSV-complaint
ABI on top of it.

There are three macros differentiated by number of return parameters.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/shared/tdx.h | 54 +++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h
index 89f7fcade8ae..ddf2cc4a45da 100644
--- a/arch/x86/include/asm/shared/tdx.h
+++ b/arch/x86/include/asm/shared/tdx.h
@@ -76,6 +76,60 @@
 
 #include <linux/compiler_attributes.h>
 
+#define TDVMCALL_0(reason, in_r12, in_r13, in_r14, in_r15)			\
+({										\
+	long __ret;								\
+										\
+	asm(									\
+		"call	tdvmcall_trampoline\n\t"				\
+		"movq	%%r10, %[r10_out]\n\t"					\
+		: [r10_out] "=r" (__ret), ASM_CALL_CONSTRAINT			\
+		: "a" (TDX_HYPERCALL_STANDARD), "b" (reason),			\
+		  "D" (in_r12), "S"(in_r13), "d"(in_r14), "c" (in_r15)		\
+		: "r12", "r13", "r14", "r15"					\
+	);									\
+	__ret;									\
+})
+
+#define TDVMCALL_1(reason, in_r12, in_r13, in_r14, in_r15, out_r11)		\
+({										\
+	long __ret;								\
+										\
+	asm(									\
+		"call	tdvmcall_trampoline\n\t"				\
+		"movq	%%r10, %[r10_out]\n\t"					\
+		"movq	%%r11, %[r11_out]\n\t"					\
+		: [r10_out] "=r" (__ret), [r11_out] "=r" (out_r11),		\
+		  ASM_CALL_CONSTRAINT						\
+		: "a" (TDX_HYPERCALL_STANDARD), "b" (reason),			\
+		  "D" (in_r12), "S"(in_r13), "d"(in_r14), "c" (in_r15)		\
+		: "r10", "r11", "r12", "r13", "r14", "r15"			\
+	);									\
+	__ret;									\
+})
+
+#define TDVMCALL_4(reason, in_r12, in_r13, in_r14, in_r15,			\
+		   out_r12, out_r13, out_r14, out_r15)				\
+({										\
+	long __ret;								\
+										\
+	asm(									\
+		"call	tdvmcall_trampoline\n\t"				\
+		"movq	%%r10, %[r10_out]\n\t"					\
+		"movq	%%r12, %[r12_out]\n\t"					\
+		"movq	%%r13, %[r13_out]\n\t"					\
+		"movq	%%r14, %[r14_out]\n\t"					\
+		"movq	%%r15, %[r15_out]\n\t"					\
+		: [r10_out] "=r" (__ret), ASM_CALL_CONSTRAINT,			\
+		  [r12_out] "=r" (out_r12), [r13_out] "=r" (out_r13),		\
+		  [r14_out] "=r" (out_r14), [r15_out] "=r" (out_r15)		\
+		: "a" (TDX_HYPERCALL_STANDARD), "b" (reason),			\
+		  "D" (in_r12), "S"(in_r13), "d"(in_r14), "c" (in_r15)		\
+		: "r10", "r12", "r13", "r14", "r15"				\
+	);									\
+	__ret;									\
+})
+
 /*
  * Used in __tdcall*() to gather the input/output registers' values of the
  * TDCALL instruction when requesting services from the TDX module. This is a
-- 
2.43.0