[ARM] 4129/1: Add barriers after the TLB operations

The architecture specification states that TLB operations are
guaranteed to be complete only after the execution of a DSB (Data
Synchronisation Barrier, former Data Write Barrier or Drain Write
Buffer). The branch target cache invalidation is also needed. The ISB
(Instruction Synchronisation Barrier, formerly Prefetch Flush) is
needed unless there will be a return from exception before the
corresponding mapping is used (i.e. user mappings).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 42 insertions, 12 deletions

diff --git a/arch/arm/mm/tlb-v6.S b/arch/arm/mm/tlb-v6.S
index fd6adde39091..20f84bbaa9bb 100644
--- a/arch/arm/mm/tlb-v6.S
+++ b/arch/arm/mm/tlb-v6.S
@@ -53,6 +53,8 @@ ENTRY(v6wbi_flush_user_tlb_range)
 	add	r0, r0, #PAGE_SZ
 	cmp	r0, r1
 	blo	1b
+	mcr	p15, 0, ip, c7, c5, 6		@ flush BTAC/BTB
+	mcr	p15, 0, ip, c7, c10, 4		@ data synchronization barrier
 	mov	pc, lr
 
 /*
@@ -80,7 +82,9 @@ ENTRY(v6wbi_flush_kern_tlb_range)
 	add	r0, r0, #PAGE_SZ
 	cmp	r0, r1
 	blo	1b
+	mcr	p15, 0, r2, c7, c5, 6		@ flush BTAC/BTB
 	mcr	p15, 0, r2, c7, c10, 4		@ data synchronization barrier
+	mcr	p15, 0, r2, c7, c5, 4		@ prefetch flush
 	mov	pc, lr
 
 	.section ".text.init", #alloc, #execinstr
diff --git a/include/asm-arm/tlbflush.h b/include/asm-arm/tlbflush.h
index cd10a0b5f8ae..08c6991dc9c9 100644
--- a/include/asm-arm/tlbflush.h
+++ b/include/asm-arm/tlbflush.h
@@ -247,7 +247,7 @@ static inline void local_flush_tlb_all(void)
 	const unsigned int __tlb_flag = __cpu_tlb_flags;
 
 	if (tlb_flag(TLB_WB))
-		asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (zero) : "cc");
+		dsb();
 
 	if (tlb_flag(TLB_V3_FULL))
 		asm("mcr p15, 0, %0, c6, c0, 0" : : "r" (zero) : "cc");
@@ -257,6 +257,15 @@ static inline void local_flush_tlb_all(void)
 		asm("mcr p15, 0, %0, c8, c6, 0" : : "r" (zero) : "cc");
 	if (tlb_flag(TLB_V4_I_FULL | TLB_V6_I_FULL))
 		asm("mcr p15, 0, %0, c8, c5, 0" : : "r" (zero) : "cc");
+
+	if (tlb_flag(TLB_V6_I_FULL | TLB_V6_D_FULL |
+		     TLB_V6_I_PAGE | TLB_V6_D_PAGE |
+		     TLB_V6_I_ASID | TLB_V6_D_ASID)) {
+		/* flush the branch target cache */
+		asm("mcr p15, 0, %0, c7, c5, 6" : : "r" (zero) : "cc");
+		dsb();
+		isb();
+	}
 }
 
 static inline void local_flush_tlb_mm(struct mm_struct *mm)
@@ -266,7 +275,7 @@ static inline void local_flush_tlb_mm(struct mm_struct *mm)
 	const unsigned int __tlb_flag = __cpu_tlb_flags;
 
 	if (tlb_flag(TLB_WB))
-		asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (zero) : "cc");
+		dsb();
 
 	if (cpu_isset(smp_processor_id(), mm->cpu_vm_mask)) {
 		if (tlb_flag(TLB_V3_FULL))
@@ -285,6 +294,14 @@ static inline void local_flush_tlb_mm(struct mm_struct *mm)
 		asm("mcr p15, 0, %0, c8, c6, 2" : : "r" (asid) : "cc");
 	if (tlb_flag(TLB_V6_I_ASID))
 		asm("mcr p15, 0, %0, c8, c5, 2" : : "r" (asid) : "cc");
+
+	if (tlb_flag(TLB_V6_I_FULL | TLB_V6_D_FULL |
+		     TLB_V6_I_PAGE | TLB_V6_D_PAGE |
+		     TLB_V6_I_ASID | TLB_V6_D_ASID)) {
+		/* flush the branch target cache */
+		asm("mcr p15, 0, %0, c7, c5, 6" : : "r" (zero) : "cc");
+		dsb();
+	}
 }
 
 static inline void
@@ -296,7 +313,7 @@ local_flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
 	uaddr = (uaddr & PAGE_MASK) | ASID(vma->vm_mm);
 
 	if (tlb_flag(TLB_WB))
-		asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (zero));
+		dsb();
 
 	if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
 		if (tlb_flag(TLB_V3_PAGE))
@@ -317,6 +334,14 @@ local_flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
 		asm("mcr p15, 0, %0, c8, c6, 1" : : "r" (uaddr) : "cc");
 	if (tlb_flag(TLB_V6_I_PAGE))
 		asm("mcr p15, 0, %0, c8, c5, 1" : : "r" (uaddr) : "cc");
+
+	if (tlb_flag(TLB_V6_I_FULL | TLB_V6_D_FULL |
+		     TLB_V6_I_PAGE | TLB_V6_D_PAGE |
+		     TLB_V6_I_ASID | TLB_V6_D_ASID)) {
+		/* flush the branch target cache */
+		asm("mcr p15, 0, %0, c7, c5, 6" : : "r" (zero) : "cc");
+		dsb();
+	}
 }
 
 static inline void local_flush_tlb_kernel_page(unsigned long kaddr)
@@ -327,7 +352,7 @@ static inline void local_flush_tlb_kernel_page(unsigned long kaddr)
 	kaddr &= PAGE_MASK;
 
 	if (tlb_flag(TLB_WB))
-		asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (zero) : "cc");
+		dsb();
 
 	if (tlb_flag(TLB_V3_PAGE))
 		asm("mcr p15, 0, %0, c6, c0, 0" : : "r" (kaddr) : "cc");
@@ -347,11 +372,14 @@ static inline void local_flush_tlb_kernel_page(unsigned long kaddr)
 	if (tlb_flag(TLB_V6_I_PAGE))
 		asm("mcr p15, 0, %0, c8, c5, 1" : : "r" (kaddr) : "cc");
 
-	/* The ARM ARM states that the completion of a TLB maintenance
-	 * operation is only guaranteed by a DSB instruction
-	 */
-	if (tlb_flag(TLB_V6_U_PAGE | TLB_V6_D_PAGE | TLB_V6_I_PAGE))
-		asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (zero) : "cc");
+	if (tlb_flag(TLB_V6_I_FULL | TLB_V6_D_FULL |
+		     TLB_V6_I_PAGE | TLB_V6_D_PAGE |
+		     TLB_V6_I_ASID | TLB_V6_D_ASID)) {
+		/* flush the branch target cache */
+		asm("mcr p15, 0, %0, c7, c5, 6" : : "r" (zero) : "cc");
+		dsb();
+		isb();
+	}
 }
 
 /*
@@ -369,15 +397,13 @@ static inline void local_flush_tlb_kernel_page(unsigned long kaddr)
  */
 static inline void flush_pmd_entry(pmd_t *pmd)
 {
-	const unsigned int zero = 0;
 	const unsigned int __tlb_flag = __cpu_tlb_flags;
 
 	if (tlb_flag(TLB_DCLEAN))
 		asm("mcr	p15, 0, %0, c7, c10, 1	@ flush_pmd"
 			: : "r" (pmd) : "cc");
 	if (tlb_flag(TLB_WB))
-		asm("mcr	p15, 0, %0, c7, c10, 4	@ flush_pmd"
-			: : "r" (zero) : "cc");
+		dsb();
 }
 
 static inline void clean_pmd_entry(pmd_t *pmd)