arc: move low-level interrupt and exception handlers in a separate file

This separation makes maintenance of code easier because those low-level
interrupt- or exception handling routines are pretty static and usually
require not much care while start-up code is a subject of modifications
and enhancements.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

1 files changed, 151 insertions, 0 deletions

diff --git a/arch/arc/lib/ints_low.S b/arch/arc/lib/ints_low.S
new file mode 100644
index 00000000000..161cf37dc48
--- /dev/null
+++ b/arch/arc/lib/ints_low.S
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2013-2015 Synopsys, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <linux/linkage.h>
+
+/*
+ * Note on the LD/ST addressing modes with address register write-back
+ *
+ * LD.a same as LD.aw
+ *
+ * LD.a    reg1, [reg2, x]  => Pre Incr
+ *      Eff Addr for load = [reg2 + x]
+ *
+ * LD.ab   reg1, [reg2, x]  => Post Incr
+ *      Eff Addr for load = [reg2]
+ */
+
+.macro PUSH reg
+	st.a	\reg, [%sp, -4]
+.endm
+
+.macro PUSHAX aux
+	lr	%r9, [\aux]
+	PUSH	%r9
+.endm
+
+.macro  SAVE_R1_TO_R24
+	PUSH	%r1
+	PUSH	%r2
+	PUSH	%r3
+	PUSH	%r4
+	PUSH	%r5
+	PUSH	%r6
+	PUSH	%r7
+	PUSH	%r8
+	PUSH	%r9
+	PUSH	%r10
+	PUSH	%r11
+	PUSH	%r12
+	PUSH	%r13
+	PUSH	%r14
+	PUSH	%r15
+	PUSH	%r16
+	PUSH	%r17
+	PUSH	%r18
+	PUSH	%r19
+	PUSH	%r20
+	PUSH	%r21
+	PUSH	%r22
+	PUSH	%r23
+	PUSH	%r24
+.endm
+
+.macro SAVE_ALL_SYS
+	/* saving %r0 to reg->r0 in advance since we read %ecr into it */
+	st	%r0, [%sp, -8]
+	lr	%r0, [%ecr]	/* all stack addressing is manual so far */
+	st	%r0, [%sp]
+	st	%sp, [%sp, -4]
+	/* now move %sp to reg->r0 position so we can do "push" automatically */
+	sub	%sp, %sp, 8
+
+	SAVE_R1_TO_R24
+	PUSH	%r25
+	PUSH	%gp
+	PUSH	%fp
+	PUSH	%blink
+	PUSHAX	%eret
+	PUSHAX	%erstatus
+	PUSH	%lp_count
+	PUSHAX	%lp_end
+	PUSHAX	%lp_start
+	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
+
+ENTRY(memory_error)
+	SAVE_ALL_SYS
+	SAVE_EXCEPTION_SOURCE
+	mov	%r1, %sp
+	j	do_memory_error
+ENDPROC(memory_error)
+
+ENTRY(instruction_error)
+	SAVE_ALL_SYS
+	SAVE_EXCEPTION_SOURCE
+	mov	%r1, %sp
+	j	do_instruction_error
+ENDPROC(instruction_error)
+
+ENTRY(interrupt_handler)
+	/* Todo - save and restore CPU context when interrupts will be in use */
+	bl	do_interrupt_handler
+	rtie
+ENDPROC(interrupt_handler)
+
+ENTRY(EV_MachineCheck)
+	SAVE_ALL_SYS
+	SAVE_EXCEPTION_SOURCE
+	mov	%r1, %sp
+	j	do_machine_check_fault
+ENDPROC(EV_MachineCheck)
+
+ENTRY(EV_TLBMissI)
+	SAVE_ALL_SYS
+	mov	%r0, %sp
+	j	do_itlb_miss
+ENDPROC(EV_TLBMissI)
+
+ENTRY(EV_TLBMissD)
+	SAVE_ALL_SYS
+	mov	%r0, %sp
+	j	do_dtlb_miss
+ENDPROC(EV_TLBMissD)
+
+ENTRY(EV_TLBProtV)
+	SAVE_ALL_SYS
+	SAVE_EXCEPTION_SOURCE
+	mov	%r1, %sp
+	j	do_tlb_prot_violation
+ENDPROC(EV_TLBProtV)
+
+ENTRY(EV_PrivilegeV)
+	SAVE_ALL_SYS
+	mov	%r0, %sp
+	j	do_privilege_violation
+ENDPROC(EV_PrivilegeV)
+
+ENTRY(EV_Trap)
+	SAVE_ALL_SYS
+	mov	%r0, %sp
+	j	do_trap
+ENDPROC(EV_Trap)
+
+ENTRY(EV_Extension)
+	SAVE_ALL_SYS
+	mov	%r0, %sp
+	j	do_extension
+ENDPROC(EV_Extension)