Depending on MMU presence in CPU there're differences in HW behavior. For example address of instruction that caused exception is put in ECR register if MMU exists and in ERET register otherwise.
Signed-off-by: Alexey Brodkin abrodkin@synopsys.com Signed-off-by: Igor Guryanov guryanov@synopsys.com --- arch/arc/config.mk | 4 ++++ arch/arc/cpu/arc700/start.S | 18 ++++++++++++++---- 2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/arch/arc/config.mk b/arch/arc/config.mk index e408800..5321987 100644 --- a/arch/arc/config.mk +++ b/arch/arc/config.mk @@ -21,6 +21,10 @@ ifeq ($(CROSS_COMPILE),) CROSS_COMPILE := $(ARC_CROSS_COMPILE) endif
+ifdef CONFIG_ARC_MMU_VER +CONFIG_MMU = 1 +endif + PLATFORM_CPPFLAGS += -ffixed-r25 -D__ARC__ -gdwarf-2
# Needed for relocation diff --git a/arch/arc/cpu/arc700/start.S b/arch/arc/cpu/arc700/start.S index 4d505bf..2318282 100644 --- a/arch/arc/cpu/arc700/start.S +++ b/arch/arc/cpu/arc700/start.S @@ -78,6 +78,16 @@ PUSHAX %erbta .endm
+.macro SAVE_EXCEPTION_SOURCE +#ifdef CONFIG_MMU + /* If MMU exists exception faulting address is loaded in EFA reg */ + lr %r0, [%efa] +#else + /* Otherwise in ERET (exception return) reg */ + lr %r0, [%eret] +#endif +.endm + .align 4 .globl _start _start: @@ -102,13 +112,13 @@ _start:
memory_error: SAVE_ALL_SYS - lr %r0, [%efa] + SAVE_EXCEPTION_SOURCE mov %r1, %sp j do_memory_error
instruction_error: SAVE_ALL_SYS - lr %r0, [%efa] + SAVE_EXCEPTION_SOURCE mov %r1, %sp j do_instruction_error
@@ -119,7 +129,7 @@ interrupt_handler:
EV_MachineCheck: SAVE_ALL_SYS - lr %r0, [%efa] + SAVE_EXCEPTION_SOURCE mov %r1, %sp j do_machine_check_fault
@@ -135,7 +145,7 @@ EV_TLBMissD:
EV_TLBProtV: SAVE_ALL_SYS - lr %r0, [%efa] + SAVE_EXCEPTION_SOURCE mov %r1, %sp j do_tlb_prot_violation