Blackfin arch: fix bug cplbmgr.S does not exit properly on error condition

https://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=1685

Ensure that cache/protection is turned back on when we get a
fault, and ensure that the initial population of the CPLB tables are
correct - that kernel is locked in CPLB tables

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

3 files changed, 22 insertions, 11 deletions

diff --git a/arch/blackfin/kernel/cplbinit.c b/arch/blackfin/kernel/cplbinit.c
index f2db6a5e2b5b..7392ac2d2c29 100644
--- a/arch/blackfin/kernel/cplbinit.c
+++ b/arch/blackfin/kernel/cplbinit.c
@@ -163,8 +163,8 @@ static struct cplb_desc cplb_data[] = {
 
 static u16 __init lock_kernel_check(u32 start, u32 end)
 {
-        if ((start <= (u32) _stext && end >= (u32) _end)
-            || (start >= (u32) _stext && end <= (u32) _end))
+        if ((end   <= (u32) _end && end   >= (u32)_stext) ||
+            (start <= (u32) _end && start >= (u32)_stext))
                 return IN_KERNEL;
         return 0;
 }
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index ce9981b5339b..fbdf999bd2b5 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -670,8 +670,8 @@ void dump_bfin_regs(struct pt_regs *fp, void *retaddr)
                 printk("\n");
         } else
                 printk("\n" KERN_NOTICE
-                        "Cannot look at the [PC] for it is"
-                        " in unreadable memory - sorry\n");
+                        "Cannot look at the [PC] <%p> for it is"
+                        " in unreadable memory - sorry\n", retaddr);
 
         printk(KERN_NOTICE "\n" KERN_NOTICE "SEQUENCER STATUS:\n");
         printk(KERN_NOTICE " SEQSTAT: %08lx  IPEND: %04lx  SYSCFG: %04lx\n",
diff --git a/arch/blackfin/mach-common/cplbmgr.S b/arch/blackfin/mach-common/cplbmgr.S
index 946703ef48ff..6f909cbfac7b 100644
--- a/arch/blackfin/mach-common/cplbmgr.S
+++ b/arch/blackfin/mach-common/cplbmgr.S
@@ -73,7 +73,7 @@ ENTRY(_cplb_mgr)
         /* ICPLB Miss Exception. We need to choose one of the
         * currently-installed CPLBs, and replace it with one
         * from the configuration table.
-        */
+        */
 
         P4.L = LO(ICPLB_FAULT_ADDR);
         P4.H = HI(ICPLB_FAULT_ADDR);
@@ -222,7 +222,7 @@ ENTRY(_cplb_mgr)
 
         /* See if failed address > start address */
         CC = R4 <= R0(IU);
-        IF !CC JUMP .Linext;
+        IF !CC JUMP .Linext;
 
         /* extract page size (17:16)*/
         R3 = EXTRACT(R2, R1.L) (Z);
@@ -271,16 +271,27 @@ ENTRY(_cplb_mgr)
 
 /* FAILED CASES*/
 .Lno_page_in_table:
-        ( R7:4,P5:3 ) = [SP++];
         R0 = CPLB_NO_ADDR_MATCH;
-        RTS;
+        JUMP .Lfail_ret;
+
 .Lall_locked:
-        ( R7:4,P5:3 ) = [SP++];
         R0 = CPLB_NO_UNLOCKED;
-        RTS;
+        JUMP .Lfail_ret;
+
 .Lprot_violation:
-        ( R7:4,P5:3 ) = [SP++];
         R0 = CPLB_PROT_VIOL;
+
+.Lfail_ret:
+        /* Make sure we turn protection/cache back on, even in the failing case */
+        BITSET(R5,ENICPLB_P);
+        CLI R2;
+        SSYNC;          /* SSYNC required before writing to IMEM_CONTROL. */
+        .align 8;
+        [P4] = R5;
+        SSYNC;
+        STI R2;
+
+        ( R7:4,P5:3 ) = [SP++];
         RTS;
 
 .Ldcplb_write: