x86/asm: Add _ASM_BYTES() macro for a .byte ... opcode sequence

Make it easy to create a sequence of bytes that can be used in either
assembly proper on in a C asm() statement.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210510090940.924953-3-hpa@zytor.com

arch/x86/include/asm/asm.h

@@ -13,6 +13,8 @@
 # define __ASM_FORM_COMMA(x, ...)	" " __stringify(x,##__VA_ARGS__) ","
 #endif
 
+#define _ASM_BYTES(x, ...)	__ASM_FORM(.byte x,##__VA_ARGS__ ;)
+
 #ifndef __x86_64__
 /* 32 bit */
 # define __ASM_SEL(a,b)		__ASM_FORM(a)