ARC: entry.S: split into ARCompact ISA specific, common bits

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 3 insertions, 297 deletions

diff --git a/arch/arc/include/asm/entry.h b/arch/arc/include/asm/entry.h
index 408a71378b5e..f61032c53d51 100644
--- a/arch/arc/include/asm/entry.h
+++ b/arch/arc/include/asm/entry.h
@@ -1,45 +1,23 @@
 /*
+ * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
- *
- * Vineetg: March 2009 (Supporting 2 levels of Interrupts)
- *  Stack switching code can no longer reliably rely on the fact that
- *  if we are NOT in user mode, stack is switched to kernel mode.
- *  e.g. L2 IRQ interrupted a L1 ISR which had not yet completed
- *  it's prologue including stack switching from user mode
- *
- * Vineetg: Aug 28th 2008: Bug #94984
- *  -Zero Overhead Loop Context shd be cleared when entering IRQ/EXcp/Trap
- *   Normally CPU does this automatically, however when doing FAKE rtie,
- *   we also need to explicitly do this. The problem in macros
- *   FAKE_RET_FROM_EXCPN and FAKE_RET_FROM_EXCPN_LOCK_IRQ was that this bit
- *   was being "CLEARED" rather then "SET". Actually "SET" clears ZOL context
- *
- * Vineetg: May 5th 2008
- *  -Modified CALLEE_REG save/restore macros to handle the fact that
- *      r25 contains the kernel current task ptr
- *  - Defined Stack Switching Macro to be reused in all intr/excp hdlrs
- *  - Shaved off 11 instructions from RESTORE_ALL_INT1 by using the
- *      address Write back load ld.ab instead of seperate ld/add instn
- *
- * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
  */
 
 #ifndef __ASM_ARC_ENTRY_H
 #define __ASM_ARC_ENTRY_H
 
-#ifdef __ASSEMBLY__
 #include <asm/unistd.h>		/* For NR_syscalls defination */
-#include <asm/asm-offsets.h>
 #include <asm/arcregs.h>
 #include <asm/ptrace.h>
 #include <asm/processor.h>	/* For VMALLOC_START */
-#include <asm/thread_info.h>	/* For THREAD_SIZE */
 #include <asm/mmu.h>
 
+#include <asm/entry-compact.h>	/* ISA specific bits */
+
 /* Note on the LD/ST addr modes with addr reg wback
  *
  * LD.a same as LD.aw
@@ -240,117 +218,6 @@
 
 .endm
 
-/*--------------------------------------------------------------
- * Switch to Kernel Mode stack if SP points to User Mode stack
- *
- * Entry   : r9 contains pre-IRQ/exception/trap status32
- * Exit    : SP is set to kernel mode stack pointer
- *           If CURR_IN_REG, r25 set to "current" task pointer
- * Clobbers: r9
- *-------------------------------------------------------------*/
-
-.macro SWITCH_TO_KERNEL_STK
-
-	/* User Mode when this happened ? Yes: Proceed to switch stack */
-	bbit1   r9, STATUS_U_BIT, 88f
-
-	/* OK we were already in kernel mode when this event happened, thus can
-	 * assume SP is kernel mode SP. _NO_ need to do any stack switching
-	 */
-
-#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
-	/* However....
-	 * If Level 2 Interrupts enabled, we may end up with a corner case:
-	 * 1. User Task executing
-	 * 2. L1 IRQ taken, ISR starts (CPU auto-switched to KERNEL mode)
-	 * 3. But before it could switch SP from USER to KERNEL stack
-	 *      a L2 IRQ "Interrupts" L1
-	 * Thay way although L2 IRQ happened in Kernel mode, stack is still
-	 * not switched.
-	 * To handle this, we may need to switch stack even if in kernel mode
-	 * provided SP has values in range of USER mode stack ( < 0x7000_0000 )
-	 */
-	brlo sp, VMALLOC_START, 88f
-
-	/* TODO: vineetg:
-	 * We need to be a bit more cautious here. What if a kernel bug in
-	 * L1 ISR, caused SP to go whaco (some small value which looks like
-	 * USER stk) and then we take L2 ISR.
-	 * Above brlo alone would treat it as a valid L1-L2 sceanrio
-	 * instead of shouting alound
-	 * The only feasible way is to make sure this L2 happened in
-	 * L1 prelogue ONLY i.e. ilink2 is less than a pre-set marker in
-	 * L1 ISR before it switches stack
-	 */
-
-#endif
-
-	/* Save Pre Intr/Exception KERNEL MODE SP on kernel stack
-	 * safe-keeping not really needed, but it keeps the epilogue code
-	 * (SP restore) simpler/uniform.
-	 */
-	b.d	66f
-	mov	r9, sp
-
-88: /*------Intr/Ecxp happened in user mode, "switch" stack ------ */
-
-	GET_CURR_TASK_ON_CPU   r9
-
-	/* With current tsk in r9, get it's kernel mode stack base */
-	GET_TSK_STACK_BASE  r9, r9
-
-66:
-#ifdef CONFIG_ARC_CURR_IN_REG
-	/*
-	 * Treat r25 as scratch reg, save it on stack first
-	 * Load it with current task pointer
-	 */
-	st	r25, [r9, -4]
-	GET_CURR_TASK_ON_CPU   r25
-#endif
-
-	/* Save Pre Intr/Exception User SP on kernel stack */
-	st.a    sp, [r9, -16]	; Make room for orig_r0, ECR, user_r25
-
-	/* CAUTION:
-	 * SP should be set at the very end when we are done with everything
-	 * In case of 2 levels of interrupt we depend on value of SP to assume
-	 * that everything else is done (loading r25 etc)
-	 */
-
-	/* set SP to point to kernel mode stack */
-	mov sp, r9
-
-	/* ----- Stack Switched to kernel Mode, Now save REG FILE ----- */
-
-.endm
-
-/*------------------------------------------------------------
- * "FAKE" a rtie to return from CPU Exception context
- * This is to re-enable Exceptions within exception
- * Look at EV_ProtV to see how this is actually used
- *-------------------------------------------------------------*/
-
-.macro FAKE_RET_FROM_EXCPN
-
-	ld  r9, [sp, PT_status32]
-	bic  r9, r9, (STATUS_U_MASK|STATUS_DE_MASK)
-	bset r9, r9, STATUS_L_BIT
-	sr  r9, [erstatus]
-	mov r9, 55f
-	sr  r9, [eret]
-
-	rtie
-55:
-.endm
-
-/*
- * @reg [OUT] &thread_info of "current"
- */
-.macro GET_CURR_THR_INFO_FROM_SP  reg
-	bic \reg, sp, (THREAD_SIZE - 1)
-.endm
-
 /*
  * @reg [OUT] thread_info->flags of "current"
  */
@@ -359,165 +226,6 @@
 	ld  \reg, [\reg, THREAD_INFO_FLAGS]
 .endm
 
-/*--------------------------------------------------------------
- * For early Exception/ISR Prologue, a core reg is temporarily needed to
- * code the rest of prolog (stack switching). This is done by stashing
- * it to memory (non-SMP case) or SCRATCH0 Aux Reg (SMP).
- *
- * Before saving the full regfile - this reg is restored back, only
- * to be saved again on kernel mode stack, as part of pt_regs.
- *-------------------------------------------------------------*/
-.macro PROLOG_FREEUP_REG	reg, mem
-#ifdef CONFIG_SMP
-	sr  \reg, [ARC_REG_SCRATCH_DATA0]
-#else
-	st  \reg, [\mem]
-#endif
-.endm
-
-.macro PROLOG_RESTORE_REG	reg, mem
-#ifdef CONFIG_SMP
-	lr  \reg, [ARC_REG_SCRATCH_DATA0]
-#else
-	ld  \reg, [\mem]
-#endif
-.endm
-
-/*--------------------------------------------------------------
- * Exception Entry prologue
- * -Switches stack to K mode (if not already)
- * -Saves the register file
- *
- * After this it is safe to call the "C" handlers
- *-------------------------------------------------------------*/
-.macro EXCEPTION_PROLOGUE
-
-	/* Need at least 1 reg to code the early exception prologue */
-	PROLOG_FREEUP_REG r9, @ex_saved_reg1
-
-	/* U/K mode at time of exception (stack not switched if already K) */
-	lr  r9, [erstatus]
-
-	/* ARC700 doesn't provide auto-stack switching */
-	SWITCH_TO_KERNEL_STK
-
-	lr	r9, [ecr]
-	st      r9, [sp, 8]    /* ECR */
-	st      r0, [sp, 4]    /* orig_r0, needed only for sys calls */
-
-	/* Restore r9 used to code the early prologue */
-	PROLOG_RESTORE_REG  r9, @ex_saved_reg1
-
-	SAVE_R0_TO_R12
-	PUSH	gp
-	PUSH	fp
-	PUSH	blink
-	PUSHAX	eret
-	PUSHAX	erstatus
-	PUSH	lp_count
-	PUSHAX	lp_end
-	PUSHAX	lp_start
-	PUSHAX	erbta
-.endm
-
-/*--------------------------------------------------------------
- * Restore all registers used by system call or Exceptions
- * SP should always be pointing to the next free stack element
- * when entering this macro.
- *
- * NOTE:
- *
- * It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg
- * for memory load operations. If used in that way interrupts are deffered
- * by hardware and that is not good.
- *-------------------------------------------------------------*/
-.macro EXCEPTION_EPILOGUE
-	POPAX	erbta
-	POPAX	lp_start
-	POPAX	lp_end
-
-	POP	r9
-	mov	lp_count, r9	;LD to lp_count is not allowed
-
-	POPAX	erstatus
-	POPAX	eret
-	POP	blink
-	POP	fp
-	POP	gp
-	RESTORE_R12_TO_R0
-
-	ld  sp, [sp] /* restore original sp */
-	/* orig_r0, ECR, user_r25 skipped automatically */
-.endm
-
-/* Dummy ECR values for Interrupts */
-#define event_IRQ1		0x0031abcd
-#define event_IRQ2		0x0032abcd
-
-.macro INTERRUPT_PROLOGUE  LVL
-
-	/* free up r9 as scratchpad */
-	PROLOG_FREEUP_REG r9, @int\LVL\()_saved_reg
-
-	/* Which mode (user/kernel) was the system in when intr occurred */
-	lr  r9, [status32_l\LVL\()]
-
-	SWITCH_TO_KERNEL_STK
-
-	/* restore original r9 */
-	PROLOG_RESTORE_REG  r9, @int\LVL\()_saved_reg
-
-	/* now we are ready to save the remaining context */
-	st      0x003\LVL\()abcd, [sp, 8]    /* Dummy ECR */
-	st      0, [sp, 4]    /* orig_r0 , N/A for IRQ */
-
-	SAVE_R0_TO_R12
-	PUSH	gp
-	PUSH	fp
-	PUSH	blink
-	PUSH	ilink\LVL\()
-	PUSHAX	status32_l\LVL\()
-	PUSH	lp_count
-	PUSHAX	lp_end
-	PUSHAX	lp_start
-	PUSHAX	bta_l\LVL\()
-.endm
-
-/*--------------------------------------------------------------
- * Restore all registers used by interrupt handlers.
- *
- * NOTE:
- *
- * It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg
- * for memory load operations. If used in that way interrupts are deffered
- * by hardware and that is not good.
- *-------------------------------------------------------------*/
-.macro INTERRUPT_EPILOGUE  LVL
-	POPAX	bta_l\LVL\()
-	POPAX	lp_start
-	POPAX	lp_end
-
-	POP	r9
-	mov	lp_count, r9	;LD to lp_count is not allowed
-
-	POPAX	status32_l\LVL\()
-	POP	ilink\LVL\()
-	POP	blink
-	POP	fp
-	POP	gp
-	RESTORE_R12_TO_R0
-
-	ld  sp, [sp] /* restore original sp */
-	/* orig_r0, ECR, user_r25 skipped automatically */
-.endm
-
-/* Get CPU-ID of this core */
-.macro  GET_CPU_ID  reg
-	lr  \reg, [identity]
-	lsr \reg, \reg, 8
-	bmsk \reg, \reg, 7
-.endm
-
 #ifdef CONFIG_SMP
 
 /*-------------------------------------------------
@@ -586,6 +294,4 @@
 
 #endif	/* CONFIG_ARC_CURR_IN_REG */
 
-#endif  /* __ASSEMBLY__ */
-
 #endif  /* __ASM_ARC_ENTRY_H */