MIPS: Fix cacheinfo overflow

The recently added MIPS cacheinfo support used a macro populate_cache()
to populate the cacheinfo structures depending on which caches are
present. However the macro contains multiple statements without
enclosing them in a do {} while (0) loop, so the L2 and L3 cache
conditionals in populate_cache_leaves() only conditionalised the first
statement in the macro.

This overflows the buffer allocated by detect_cache_attributes(),
resulting in boot failures under QEMU where neither the L2 or L2 caches
are present.

Enclose the macro statements in a do {} while (0) block to keep the
whole macro inside the conditionals.

Fixes: ef462f3b64e9 ("MIPS: Add cacheinfo support")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Justin Chen <justin.chen@broadcom.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: bcm-kernel-feedback-list@broadcom.com
Patchwork: https://patchwork.linux-mips.org/patch/15276/

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/mips/kernel/cacheinfo.c b/arch/mips/kernel/cacheinfo.c
index a92bbbae969b..97d5239ca47b 100644
--- a/arch/mips/kernel/cacheinfo.c
+++ b/arch/mips/kernel/cacheinfo.c
@@ -17,6 +17,7 @@
 
 /* Populates leaf and increments to next leaf */
 #define populate_cache(cache, leaf, c_level, c_type)            \
+do {                                                            \
         leaf->type = c_type;                                    \
         leaf->level = c_level;                                  \
         leaf->coherency_line_size = c->cache.linesz;            \
@@ -24,7 +25,8 @@
         leaf->ways_of_associativity = c->cache.ways;            \
         leaf->size = c->cache.linesz * c->cache.sets *          \
                 c->cache.ways;                                  \
-        leaf++;
+        leaf++;                                                 \
+} while (0)
 
 static int __init_cache_level(unsigned int cpu)
 {