[ARM] nommu: abort handler fixup for !CPU_CP15_MMU cores.

There is no FSR/FAR register on no-CP15 or MPU cores. This patch adds a
dummy abort handler which returns zero for the base restored Data Abort
model !CPU_CP15_MMU cores. The abort-lv4t.S is still used with the fix-up
for the base updated Data Abort model cores.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

7 files changed, 35 insertions, 7 deletions

diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index ae427de27ce0..6c1bd424ea61 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -97,7 +97,7 @@ config CPU_ARM9TDMI
         bool "Support ARM9TDMI processor"
         depends on !MMU
         select CPU_32v4T
-        select CPU_ABRT_EV4T
+        select CPU_ABRT_NOMMU
         select CPU_CACHE_V4
         help
           A 32-bit RISC microprocessor based on the ARM9 processor core
@@ -192,7 +192,7 @@ config CPU_ARM940T
         bool "Support ARM940T processor" if ARCH_INTEGRATOR
         depends on !MMU
         select CPU_32v4T
-        select CPU_ABRT_EV4T
+        select CPU_ABRT_NOMMU
         select CPU_CACHE_VIVT
         select CPU_CP15_MPU
         help
@@ -209,7 +209,7 @@ config CPU_ARM946E
         bool "Support ARM946E-S processor" if ARCH_INTEGRATOR
         depends on !MMU
         select CPU_32v5
-        select CPU_ABRT_EV5T
+        select CPU_ABRT_NOMMU
         select CPU_CACHE_VIVT
         select CPU_CP15_MPU
         help
@@ -392,6 +392,9 @@ config CPU_32v6
         bool
 
 # The abort model
+config CPU_ABRT_NOMMU
+        bool
+
 config CPU_ABRT_EV4
         bool
 
diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index ed81b9ef10cb..d2f5672ecf62 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_MODULES)		+= proc-syms.o
 obj-$(CONFIG_ALIGNMENT_TRAP)    += alignment.o
 obj-$(CONFIG_DISCONTIGMEM)      += discontig.o
 
+obj-$(CONFIG_CPU_ABRT_NOMMU)    += abort-nommu.o
 obj-$(CONFIG_CPU_ABRT_EV4)      += abort-ev4.o
 obj-$(CONFIG_CPU_ABRT_EV4T)     += abort-ev4t.o
 obj-$(CONFIG_CPU_ABRT_LV4T)     += abort-lv4t.o
diff --git a/arch/arm/mm/abort-lv4t.S b/arch/arm/mm/abort-lv4t.S
index db743e510214..9fb7b0e25ea1 100644
--- a/arch/arm/mm/abort-lv4t.S
+++ b/arch/arm/mm/abort-lv4t.S
@@ -19,11 +19,16 @@
  */
 ENTRY(v4t_late_abort)
         tst     r3, #PSR_T_BIT                  @ check for thumb mode
+#ifdef CONFIG_CPU_CP15_MMU
         mrc     p15, 0, r1, c5, c0, 0           @ get FSR
         mrc     p15, 0, r0, c6, c0, 0           @ get FAR
+        bic     r1, r1, #1 << 11 | 1 << 10      @ clear bits 11 and 10 of FSR
+#else
+        mov     r0, #0                          @ clear r0, r1 (no FSR/FAR)
+        mov     r1, #0
+#endif
         bne     .data_thumb_abort
         ldr     r8, [r2]                        @ read arm instruction
-        bic     r1, r1, #1 << 11 | 1 << 10      @ clear bits 11 and 10 of FSR
         tst     r8, #1 << 20                    @ L = 1 -> write?
         orreq   r1, r1, #1 << 11                @ yes.
         and     r7, r8, #15 << 24
diff --git a/arch/arm/mm/abort-nommu.S b/arch/arm/mm/abort-nommu.S
new file mode 100644
index 000000000000..a7cc7f9ee45d
--- /dev/null
+++ b/arch/arm/mm/abort-nommu.S
@@ -0,0 +1,19 @@
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+/*
+ * Function: nommu_early_abort
+ *
+ * Params  : r2 = address of aborted instruction
+ *         : r3 = saved SPSR
+ *
+ * Returns : r0 = 0 (abort address)
+ *         : r1 = 0 (FSR)
+ *
+ * Note: There is no FSR/FAR on !CPU_CP15_MMU cores.
+ *       Just fill zero into the registers.
+ */
+        .align  5
+ENTRY(nommu_early_abort)
+        mov     r0, #0                          @ clear r0, r1 (no FSR/FAR)
+        mov     r1, #0
+        mov     pc, lr
diff --git a/arch/arm/mm/proc-arm940.S b/arch/arm/mm/proc-arm940.S
index 14846ac2d0e6..2397f4b6e151 100644
--- a/arch/arm/mm/proc-arm940.S
+++ b/arch/arm/mm/proc-arm940.S
@@ -320,7 +320,7 @@ __arm940_setup:
  */
         .type   arm940_processor_functions, #object
 ENTRY(arm940_processor_functions)
-        .word   v4t_early_abort
+        .word   nommu_early_abort
         .word   cpu_arm940_proc_init
         .word   cpu_arm940_proc_fin
         .word   cpu_arm940_reset
diff --git a/arch/arm/mm/proc-arm946.S b/arch/arm/mm/proc-arm946.S
index 6dc7942c4cfe..e18617564421 100644
--- a/arch/arm/mm/proc-arm946.S
+++ b/arch/arm/mm/proc-arm946.S
@@ -375,7 +375,7 @@ __arm946_setup:
  */
         .type   arm946_processor_functions, #object
 ENTRY(arm946_processor_functions)
-        .word   v5t_early_abort
+        .word   nommu_early_abort
         .word   cpu_arm946_proc_init
         .word   cpu_arm946_proc_fin
         .word   cpu_arm946_reset
diff --git a/arch/arm/mm/proc-arm9tdmi.S b/arch/arm/mm/proc-arm9tdmi.S
index 95c90f13caa8..918ebf65d4f6 100644
--- a/arch/arm/mm/proc-arm9tdmi.S
+++ b/arch/arm/mm/proc-arm9tdmi.S
@@ -63,7 +63,7 @@ __arm9tdmi_setup:
  */
                 .type   arm9tdmi_processor_functions, #object
 ENTRY(arm9tdmi_processor_functions)
-                .word   v4t_early_abort
+                .word   nommu_early_abort
                 .word   cpu_arm9tdmi_proc_init
                 .word   cpu_arm9tdmi_proc_fin
                 .word   cpu_arm9tdmi_reset