[ARM] armv7: add support for asid-tagged VIVT I-cache

ARMv7 can have VIPT, PIPT or ASID-tagged VIVT I-cache. This patch
adds the necessary invalidation of the I-cache when the ASID numbers
are re-used.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 9da43a0..c9e9a558 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -47,6 +47,13 @@
 		    : "r" (0));
 		isb();
 		flush_tlb_all();
+		if (icache_is_vivt_asid_tagged()) {
+			asm("mcr	p15, 0, %0, c7, c5, 0	@ invalidate I-cache\n"
+			    "mcr	p15, 0, %0, c7, c5, 6	@ flush BTAC/BTB\n"
+			    :
+			    : "r" (0));
+			dsb();
+		}
 	}
 
 	mm->context.id = asid;