x86/cpu: Use INVPCID mnemonic in invpcid.h

The current minimum required version of binutils is 2.23, which supports
the INVPCID instruction mnemonic. Replace the byte-wise specification of
INVPCID with the proper mnemonic.

 [ bp: Add symbolic operand names for increased readability and flip
   their order like the insn expects them for the AT&T syntax. ]

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200508092247.132147-1-ubizjak@gmail.com

Signed-off-by: Borislav Petkov <bp@suse.de>

arch/x86/include/asm/invpcid.h

@@ -12,12 +12,9 @@ static inline void __invpcid(unsigned long pcid, unsigned long addr,
 	 * stale TLB entries and, especially if we're flushing global
 	 * mappings, we don't want the compiler to reorder any subsequent
 	 * memory accesses before the TLB flush.
-	 *
-	 * The hex opcode is invpcid (%ecx), %eax in 32-bit mode and
-	 * invpcid (%rcx), %rax in long mode.
 	 */
-	asm volatile (".byte 0x66, 0x0f, 0x38, 0x82, 0x01"
-		      : : "m" (desc), "a" (type), "c" (&desc) : "memory");
+	asm volatile("invpcid %[desc], %[type]"
+		     :: [desc] "m" (desc), [type] "r" (type) : "memory");
 }
 
 #define INVPCID_TYPE_INDIV_ADDR		0