ARC: mm: arc700: Don't assume 2 colours for aliasing VIPT dcache

commit 08fe007968b2b45e831daf74899f79a54d73f773 upstream.

An ARC700 customer reported linux boot crashes when upgrading to bigger
L1 dcache (64K from 32K). Turns out they had an aliasing VIPT config and
current code only assumed 2 colours, while theirs had 4. So default to 4
colours and complain if there are fewer. Ideally this needs to be a
Kconfig option, but heck that's too much of hassle for a single user.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arc/include/asm/cacheflush.h b/arch/arc/include/asm/cacheflush.h
index fbe3587c4f36f1add284667fd8a04edbe90ea2ef..56aeb5efe6042329bd6d27cf54faaa6cb9f16334 100644 (file)
--- a/arch/arc/include/asm/cacheflush.h
+++ b/arch/arc/include/asm/cacheflush.h
@@ -85,6 +85,10 @@ void flush_anon_page(struct vm_area_struct *vma,
  */
 #define PG_dc_clean    PG_arch_1
 
+#define CACHE_COLORS_NUM       4
+#define CACHE_COLORS_MSK       (CACHE_COLORS_NUM - 1)
+#define CACHE_COLOR(addr)      (((unsigned long)(addr) >> (PAGE_SHIFT)) & CACHE_COLORS_MSK)
+
 /*
  * Simple wrapper over config option
  * Bootup code ensures that hardware matches kernel configuration
@@ -94,8 +98,6 @@ static inline int cache_is_vipt_aliasing(void)
        return IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING);
 }
 
-#define CACHE_COLOR(addr)      (((unsigned long)(addr) >> (PAGE_SHIFT)) & 1)
-
 /*
  * checks if two addresses (after page aligning) index into same cache set
  */

diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index aaf1e2d1d9003c01b7040a611488dcb9d24d3d3e..d81b6d7e11e79d64b34de28acc798ceaf6a2d1b5 100644 (file)
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -960,11 +960,16 @@ void arc_cache_init(void)
                /* check for D-Cache aliasing on ARCompact: ARCv2 has PIPT */
                if (is_isa_arcompact()) {
                        int handled = IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING);
-
-                       if (dc->alias && !handled)
-                               panic("Enable CONFIG_ARC_CACHE_VIPT_ALIASING\n");
-                       else if (!dc->alias && handled)
+                       int num_colors = dc->sz_k/dc->assoc/TO_KB(PAGE_SIZE);
+
+                       if (dc->alias) {
+                               if (!handled)
+                                       panic("Enable CONFIG_ARC_CACHE_VIPT_ALIASING\n");
+                               if (CACHE_COLORS_NUM != num_colors)
+                                       panic("CACHE_COLORS_NUM not optimized for config\n");
+                       } else if (!dc->alias && handled) {
                                panic("Disable CONFIG_ARC_CACHE_VIPT_ALIASING\n");
+                       }
                }
        }