MIPS: mm: c-r4k: Panic if IL or DL fields have a reserved value

According to MIPS32 and MIPS64 PRA documents,
a value of 7 in IL and DL fields is marked as "Reserved"
so panic if the core uses this value in the config1 register.
Also simplify the code a little bit.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5861/

1 files changed, 16 insertions, 8 deletions

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 62ffd20ea869..a4e1a692e45a 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1013,10 +1013,14 @@ static void probe_pcache(void)
                  */
                 config1 = read_c0_config1();
 
-                if ((lsize = ((config1 >> 19) & 7)))
-                        c->icache.linesz = 2 << lsize;
-                else
-                        c->icache.linesz = lsize;
+                lsize = (config1 >> 19) & 7;
+
+                /* IL == 7 is reserved */
+                if (lsize == 7)
+                        panic("Invalid icache line size");
+
+                c->icache.linesz = lsize ? 2 << lsize : 0;
+
                 c->icache.sets = 32 << (((config1 >> 22) + 1) & 7);
                 c->icache.ways = 1 + ((config1 >> 16) & 7);
 
@@ -1033,10 +1037,14 @@ static void probe_pcache(void)
                  */
                 c->dcache.flags = 0;
 
-                if ((lsize = ((config1 >> 10) & 7)))
-                        c->dcache.linesz = 2 << lsize;
-                else
-                        c->dcache.linesz= lsize;
+                lsize = (config1 >> 10) & 7;
+
+                /* DL == 7 is reserved */
+                if (lsize == 7)
+                        panic("Invalid dcache line size");
+
+                c->dcache.linesz = lsize ? 2 << lsize : 0;
+
                 c->dcache.sets = 32 << (((config1 >> 13) + 1) & 7);
                 c->dcache.ways = 1 + ((config1 >> 7) & 7);