[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>

arch/arm/mm/context.c

@@ -47,6 +47,13 @@ void __new_context(struct mm_struct *mm)
 		    : "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;

include/asm-arm/cacheflush.h

@@ -438,6 +438,7 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
 #define __cacheid_vipt(val)			(__cacheid_type_v7(val) ? 1 : __cacheid_vipt_prev7(val))
 #define __cacheid_vipt_nonaliasing(val)		(__cacheid_type_v7(val) ? 1 : __cacheid_vipt_nonaliasing_prev7(val))
 #define __cacheid_vipt_aliasing(val)		(__cacheid_type_v7(val) ? 0 : __cacheid_vipt_aliasing_prev7(val))
+#define __cacheid_vivt_asid_tagged_instr(val)	(__cacheid_type_v7(val) ? ((val & (3 << 14)) == (1 << 14)) : 0)
 
 #if defined(CONFIG_CPU_CACHE_VIVT) && !defined(CONFIG_CPU_CACHE_VIPT)
 
@@ -445,6 +446,7 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
 #define cache_is_vipt()			0
 #define cache_is_vipt_nonaliasing()	0
 #define cache_is_vipt_aliasing()	0
+#define icache_is_vivt_asid_tagged()	0
 
 #elif defined(CONFIG_CPU_CACHE_VIPT)
 
@@ -462,6 +464,12 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
 		__cacheid_vipt_aliasing(__val);				\
 	})
 
+#define icache_is_vivt_asid_tagged()					\
+	({								\
+		unsigned int __val = read_cpuid(CPUID_CACHETYPE);	\
+		__cacheid_vivt_asid_tagged_instr(__val);		\
+	})
+
 #else
 
 #define cache_is_vivt()							\
@@ -490,6 +498,13 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
 		 __cacheid_vipt_aliasing(__val);			\
 	})
 
+#define icache_is_vivt_asid_tagged()					\
+	({								\
+		unsigned int __val = read_cpuid(CPUID_CACHETYPE);	\
+		__cacheid_present(__val) &&				\
+		 __cacheid_vivt_asid_tagged_instr(__val);		\
+	})
+
 #endif
 
 #endif