Fix the I-cache invalidation on ARMv6 and later CPUs

This patch adds the I-cache invalidation in update_mmu_cache if the
corresponding vma is marked as executable. It also invalidates the
I-cache if a thread migrates to a CPU it never ran on.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm/mm/fault-armv.c

@@ -144,13 +144,17 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 	page = pfn_to_page(pfn);
 	mapping = page_mapping(page);
 	if (mapping) {
+#ifndef CONFIG_SMP
 		int dirty = test_and_clear_bit(PG_dcache_dirty, &page->flags);
 
 		if (dirty)
 			__flush_dcache_page(mapping, page);
+#endif
 
 		if (cache_is_vivt())
 			make_coherent(mapping, vma, addr, pfn);
+		else if (vma->vm_flags & VM_EXEC)
+			__flush_icache_all();
 	}
 }
 

arch/arm/mm/flush.c

@@ -199,6 +199,8 @@ void flush_dcache_page(struct page *page)
 		__flush_dcache_page(mapping, page);
 		if (mapping && cache_is_vivt())
 			__flush_dcache_aliases(mapping, page);
+		else if (mapping)
+			__flush_icache_all();
 	}
 }
 EXPORT_SYMBOL(flush_dcache_page);

include/asm-arm/cacheflush.h

@@ -402,6 +402,14 @@ extern void flush_dcache_page(struct page *);
 
 extern void __flush_dcache_page(struct address_space *mapping, struct page *page);
 
+static inline void __flush_icache_all(void)
+{
+	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));
+}
+
 #define ARCH_HAS_FLUSH_ANON_PAGE
 static inline void flush_anon_page(struct vm_area_struct *vma,
 			 struct page *page, unsigned long vmaddr)

include/asm-arm/mmu_context.h

@@ -99,6 +99,11 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
 #ifdef CONFIG_MMU
 	unsigned int cpu = smp_processor_id();
 
+#ifdef CONFIG_SMP
+	/* check for possible thread migration */
+	if (!cpus_empty(next->cpu_vm_mask) && !cpu_isset(cpu, next->cpu_vm_mask))
+		__flush_icache_all();
+#endif
 	if (!cpu_test_and_set(cpu, next->cpu_vm_mask) || prev != next) {
 		check_context(next);
 		cpu_switch_mm(next->pgd, next);