MIPS: cache: Provide cache flush operations for XFS

Until now flush_kernel_vmap_range() and invalidate_kernel_vmap_range() did
not exist on MIPS resulting in heavy cache corruption on XFS filesystems.

Left for the post-3.0 time: optimization and make this work with highmem,
too.  Since the combination of highmem + cache aliases atm doesn't work
this isn't a regression.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/2505/

arch/mips/include/asm/cacheflush.h

@@ -114,4 +114,28 @@ unsigned long run_uncached(void *func);
 extern void *kmap_coherent(struct page *page, unsigned long addr);
 extern void kunmap_coherent(void);
 
+#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
+static inline void flush_kernel_dcache_page(struct page *page)
+{
+	BUG_ON(cpu_has_dc_aliases && PageHighMem(page));
+}
+
+/*
+ * For now flush_kernel_vmap_range and invalidate_kernel_vmap_range both do a
+ * cache writeback and invalidate operation.
+ */
+extern void (*__flush_kernel_vmap_range)(unsigned long vaddr, int size);
+
+static inline void flush_kernel_vmap_range(void *vaddr, int size)
+{
+	if (cpu_has_dc_aliases)
+		__flush_kernel_vmap_range((unsigned long) vaddr, size);
+}
+
+static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
+{
+	if (cpu_has_dc_aliases)
+		__flush_kernel_vmap_range((unsigned long) vaddr, size);
+}
+
 #endif /* _ASM_CACHEFLUSH_H */

arch/mips/mm/c-octeon.c

@@ -169,6 +169,10 @@ static void octeon_flush_cache_page(struct vm_area_struct *vma,
 		octeon_flush_icache_all_cores(vma);
 }
 
+static void octeon_flush_kernel_vmap_range(unsigned long vaddr, int size)
+{
+	BUG();
+}
 
 /**
  * Probe Octeon's caches
@@ -273,6 +277,8 @@ void __cpuinit octeon_cache_init(void)
 	flush_icache_range		= octeon_flush_icache_range;
 	local_flush_icache_range	= local_octeon_flush_icache_range;
 
+	__flush_kernel_vmap_range	= octeon_flush_kernel_vmap_range;
+
 	build_clear_page();
 	build_copy_page();
 }

arch/mips/mm/c-r3k.c

@@ -299,6 +299,11 @@ static void r3k_flush_cache_sigtramp(unsigned long addr)
 	write_c0_status(flags);
 }
 
+static void r3k_flush_kernel_vmap_range(unsigned long vaddr, int size)
+{
+	BUG();
+}
+
 static void r3k_dma_cache_wback_inv(unsigned long start, unsigned long size)
 {
 	/* Catch bad driver code */
@@ -323,6 +328,8 @@ void __cpuinit r3k_cache_init(void)
 	flush_icache_range = r3k_flush_icache_range;
 	local_flush_icache_range = r3k_flush_icache_range;
 
+	__flush_kernel_vmap_range = r3k_flush_kernel_vmap_range;
+
 	flush_cache_sigtramp = r3k_flush_cache_sigtramp;
 	local_flush_data_cache_page = local_r3k_flush_data_cache_page;
 	flush_data_cache_page = r3k_flush_data_cache_page;

arch/mips/mm/c-r4k.c

@@ -722,6 +722,39 @@ static void r4k_flush_icache_all(void)
 		r4k_blast_icache();
 }
 
+struct flush_kernel_vmap_range_args {
+	unsigned long	vaddr;
+	int		size;
+};
+
+static inline void local_r4k_flush_kernel_vmap_range(void *args)
+{
+	struct flush_kernel_vmap_range_args *vmra = args;
+	unsigned long vaddr = vmra->vaddr;
+	int size = vmra->size;
+
+	/*
+	 * Aliases only affect the primary caches so don't bother with
+	 * S-caches or T-caches.
+	 */
+	if (cpu_has_safe_index_cacheops && size >= dcache_size)
+		r4k_blast_dcache();
+	else {
+		R4600_HIT_CACHEOP_WAR_IMPL;
+		blast_dcache_range(vaddr, vaddr + size);
+	}
+}
+
+static void r4k_flush_kernel_vmap_range(unsigned long vaddr, int size)
+{
+	struct flush_kernel_vmap_range_args args;
+
+	args.vaddr = (unsigned long) vaddr;
+	args.size = size;
+
+	r4k_on_each_cpu(local_r4k_flush_kernel_vmap_range, &args);
+}
+
 static inline void rm7k_erratum31(void)
 {
 	const unsigned long ic_lsize = 32;
@@ -1403,6 +1436,8 @@ void __cpuinit r4k_cache_init(void)
 	flush_cache_page	= r4k_flush_cache_page;
 	flush_cache_range	= r4k_flush_cache_range;
 
+	__flush_kernel_vmap_range = r4k_flush_kernel_vmap_range;
+
 	flush_cache_sigtramp	= r4k_flush_cache_sigtramp;
 	flush_icache_all	= r4k_flush_icache_all;
 	local_flush_data_cache_page	= local_r4k_flush_data_cache_page;

arch/mips/mm/c-tx39.c

@@ -253,6 +253,11 @@ static void tx39_flush_icache_range(unsigned long start, unsigned long end)
 	}
 }
 
+static void tx39_flush_kernel_vmap_range(unsigned long vaddr, int size)
+{
+	BUG();
+}
+
 static void tx39_dma_cache_wback_inv(unsigned long addr, unsigned long size)
 {
 	unsigned long end;
@@ -394,6 +399,8 @@ void __cpuinit tx39_cache_init(void)
 		flush_icache_range = tx39_flush_icache_range;
 		local_flush_icache_range = tx39_flush_icache_range;
 
+		__flush_kernel_vmap_range = tx39_flush_kernel_vmap_range;
+
 		flush_cache_sigtramp = tx39_flush_cache_sigtramp;
 		local_flush_data_cache_page = local_tx39_flush_data_cache_page;
 		flush_data_cache_page = tx39_flush_data_cache_page;

arch/mips/mm/cache.c

@@ -35,6 +35,11 @@ void (*local_flush_icache_range)(unsigned long start, unsigned long end);
 void (*__flush_cache_vmap)(void);
 void (*__flush_cache_vunmap)(void);
 
+void (*__flush_kernel_vmap_range)(unsigned long vaddr, int size);
+void (*__invalidate_kernel_vmap_range)(unsigned long vaddr, int size);
+
+EXPORT_SYMBOL_GPL(__flush_kernel_vmap_range);
+
 /* MIPS specific cache operations */
 void (*flush_cache_sigtramp)(unsigned long addr);
 void (*local_flush_data_cache_page)(void * addr);