x86/mm: Carve out INVLPG inline asm for use by others

BugLink: https://bugs.launchpad.net/bugs/2101915

commit f1d84b59cbb9547c243d93991acf187fdbe9fbe9 upstream.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/ZyulbYuvrkshfsd2@antipodes
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

arch/x86/include/asm/tlb.h

@@ -34,4 +34,8 @@ static inline void __tlb_remove_table(void *table)
 	free_page_and_swap_cache(table);
 }
 
+static inline void invlpg(unsigned long addr)
+{
+	asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
+}
 #endif /* _ASM_X86_TLB_H */

arch/x86/mm/tlb.c

@@ -19,6 +19,7 @@
 #include <asm/cacheflush.h>
 #include <asm/apic.h>
 #include <asm/perf_event.h>
+#include <asm/tlb.h>
 
 #include "mm_internal.h"
 
@@ -1145,7 +1146,7 @@ STATIC_NOPV void native_flush_tlb_one_user(unsigned long addr)
 	bool cpu_pcide;
 
 	/* Flush 'addr' from the kernel PCID: */
-	asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
+	invlpg(addr);
 
 	/* If PTI is off there is no user PCID and nothing to flush. */
 	if (!static_cpu_has(X86_FEATURE_PTI))