MN10300: AM34 erratum requires MMUCTR read and write on exception entry

An AM34 erratum requires MMUCTR read and write on entry to certain exceptions,
prior to EPSW.NMID being cleared to allow NMIs to happen.

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 26 insertions, 6 deletions

diff --git a/arch/mn10300/mm/tlb-mn10300.S b/arch/mn10300/mm/tlb-mn10300.S
index 7095147dcb8..ccf622999a5 100644
--- a/arch/mn10300/mm/tlb-mn10300.S
+++ b/arch/mn10300/mm/tlb-mn10300.S
@@ -27,7 +27,6 @@
 ###############################################################################
         .type   itlb_miss,@function
 ENTRY(itlb_miss)
-        and     ~EPSW_NMID,epsw
 #ifdef CONFIG_GDBSTUB
         movm    [d2,d3,a2],(sp)
 #else
@@ -38,6 +37,12 @@ ENTRY(itlb_miss)
         nop
 #endif
 
+#if defined(CONFIG_ERRATUM_NEED_TO_RELOAD_MMUCTR)
+        mov     (MMUCTR),d2
+        mov     d2,(MMUCTR)
+#endif
+
+        and     ~EPSW_NMID,epsw
         mov     (IPTEU),d3
         mov     (PTBR),a2
         mov     d3,d2
@@ -79,7 +84,6 @@ itlb_miss_fault:
 ###############################################################################
         .type   dtlb_miss,@function
 ENTRY(dtlb_miss)
-        and     ~EPSW_NMID,epsw
 #ifdef CONFIG_GDBSTUB
         movm    [d2,d3,a2],(sp)
 #else
@@ -90,6 +94,12 @@ ENTRY(dtlb_miss)
         nop
 #endif
 
+#if defined(CONFIG_ERRATUM_NEED_TO_RELOAD_MMUCTR)
+        mov     (MMUCTR),d2
+        mov     d2,(MMUCTR)
+#endif
+
+        and     ~EPSW_NMID,epsw
         mov     (DPTEU),d3
         mov     (PTBR),a2
         mov     d3,d2
@@ -130,9 +140,15 @@ dtlb_miss_fault:
 ###############################################################################
         .type   itlb_aerror,@function
 ENTRY(itlb_aerror)
-        and     ~EPSW_NMID,epsw
         add     -4,sp
         SAVE_ALL
+
+#if defined(CONFIG_ERRATUM_NEED_TO_RELOAD_MMUCTR)
+        mov     (MMUCTR),d1
+        mov     d1,(MMUCTR)
+#endif
+
+        and     ~EPSW_NMID,epsw
         add     -4,sp                           # need to pass three params
 
         # calculate the fault code
@@ -148,7 +164,6 @@ ENTRY(itlb_aerror)
         clr     d0
         mov     d0,(IPTEL)
 
-        and     ~EPSW_NMID,epsw
         or      EPSW_IE,epsw
         mov     fp,d0
         call    do_page_fault[],0               # do_page_fault(regs,code,addr
@@ -163,10 +178,16 @@ ENTRY(itlb_aerror)
 ###############################################################################
         .type   dtlb_aerror,@function
 ENTRY(dtlb_aerror)
-        and     ~EPSW_NMID,epsw
         add     -4,sp
         SAVE_ALL
+
+#if defined(CONFIG_ERRATUM_NEED_TO_RELOAD_MMUCTR)
+        mov     (MMUCTR),d1
+        mov     d1,(MMUCTR)
+#endif
+
         add     -4,sp                           # need to pass three params
+        and     ~EPSW_NMID,epsw
 
         # calculate the fault code
         movhu   (MMUFCR_DFC),d1
@@ -180,7 +201,6 @@ ENTRY(dtlb_aerror)
         clr     d0
         mov     d0,(DPTEL)
 
-        and     ~EPSW_NMID,epsw
         or      EPSW_IE,epsw
         mov     fp,d0
         call    do_page_fault[],0               # do_page_fault(regs,code,addr