Add PIC32 exception handling macros

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3629 42af7a65-404d-4744-a932-0658087f49c3

arch/mips/src/mips32/mips32-excptmacros.h

+/********************************************************************************************
+ * arch/mips/src/mips32/mips32-excptmacros.h
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ********************************************************************************************/
+
+#ifndef __ARCH_MIPS_SRC_MIPS32_MIPS32_EXCPTMACROS_H
+#define __ARCH_MIPS_SRC_MIPS32_MIPS32_EXCPTMACROS_H
+
+/********************************************************************************************
+ * Included Files
+ ********************************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <arch/irq.h>
+#include <arch/mips32/cp0.h>
+
+#ifdef __ASSEMBLY__
+
+/********************************************************************************************
+ * Pre-Processor Definitions
+ ********************************************************************************************/
+
+/********************************************************************************************
+ * Global Symbols
+ ********************************************************************************************/
+
+#if CONFIG_ARCH_INTERRUPTSTACK > 3
+	.global		g_stackbase
+	.global		g_nestlevel
+#endif
+
+/********************************************************************************************
+ * Assembly Language Macros
+ ********************************************************************************************/
+
+/********************************************************************************************
+ * General Usage Example:
+ *
+ * my_exception:
+ *		EXCPT_PROLOGUE t0			- Save registers on stack, enable nested interrupts
+ *		move a0, sp					- Pass register save structure as the parameter 1
+ *		USE_INTSTACK, t0, t1, t2	- Switch to the interrupt stack
+ *		jal	handler					- Handle the exception IN=old regs OUT=new regs
+ *		di							- Disable interrupts
+ *		RESTORE_STACK t0, t1		- Undo the operations of USE_STACK
+ *		EXCPT_EPILOGUE v0			- Return to the context returned by handler()
+ *
+ ********************************************************************************************/
+/********************************************************************************************
+ * Name: EXCPT_PROLOGUE
+ *
+ * Description:
+ *   Provides the "prologue" logic that should appear at the beginning of every exception
+ *   handler.
+ *
+ * On Entry:
+ *   sp - Points to the top of the stack
+ *   tmp - Is a register the can be modified for scratch usage (after it has been saved)
+ *   k0 and k1 - Since we are in an exception handler, these are available for use
+ *
+ * At completion:
+ *   Register state is saved on the stack; All registers are available for usage except sp
+ *   and k1:
+ *
+ *   - sp points the beginning of the register save area
+ *   - k1 holds the value of the STATUS register
+ *
+ *   The following registers are modified: k0, k1, sp, a0
+ *
+ ********************************************************************************************/
+
+	.macro		EXCPT_PROLOGUE, tmp
+
+	/* Get the SP from the previous shadow set */
+
+#if 0
+	rdpgpr	sp, sp
+#endif
+
+	/* "When entering the interrupt handler routine, the interrupt controller must first
+	 *  save the current priority and exception PC counter from Interrupt  Priority (IPL)
+	 *  bits (Status<15:10>) and the ErrorEPC register, respectively, on the stack. ..."
+	 */
+
+	mfc0	k0, MIPS32_CP0_CAUSE
+	mfc0 	k1, MIPS32_CP0_EPC
+
+	/* Isolate the pending interrupt level in bits 0-5 of k0 */
+
+	srl		k0, k0, CP0_CAUSE_IP_SHIFT
+
+	/* Create the register context stack frame large enough to hold the entire register save
+	 * array.
+	 */
+
+	addiu	sp, sp, -XCPTCONTEXT_SIZE
+
+	/* Save the EPC and STATUS in the register context array */
+
+	sw		k1, REG_EPC(sp)
+	mfc0	k1, MIPS32_CP0_STATUS
+	sw		k1, REG_STATUS(sp)
+
+	/* Then insert pending interrupt level as the current mask level in the CP0 status
+	 * register. Also clear bits 1-4 in new value of the status register:
+	 *
+     *   Bit 1: Exception Level
+     *   Bit 2: Error Level
+	 *   Bit 3: (not used in PIC32MX)
+	 *   Bit 4: Operating mode == USER
+	 */
+
+	ins 	k1, \tmp, CP0_STATUS_IPL_SHIFT, 6
+	ins		k1, zero, 1, 4
+
+	/* And Enable interrupts */
+
+	mtc0	k1, MIPS32_CP0_STATUS
+
+	/* Save floating point registers */
+
+	mfhi	k0
+	sw		k0, REG_MFHI(sp)
+	mflo	k0
+	sw		k0, REG_MFLO(sp)
+
+	/* Save general purpose registers */
+	/* $1: at_reg, assembler temporary */
+
+	sw		$1, REG_AT(sp)
+
+	/* $2-$3 = v0-v1: Return value registers */
+
+	sw		v0, REG_V0(sp)
+	sw		v1, REG_V1(sp)
+
+	/* $4-$7 = a0-a3: Argument registers */
+
+	sw		a0, REG_A0(sp)
+	sw		a1, REG_A1(sp)
+	sw		a2, REG_A2(sp)
+	sw		a3, REG_A3(sp)
+
+	/* $8-$15 = t0-t7: Volatile registers */
+
+	sw		t0, REG_T0(sp)
+	sw		t1, REG_T1(sp)
+	sw		t2, REG_T2(sp)
+	sw		t3, REG_T3(sp)
+	sw		t4, REG_T4(sp)
+	sw		t5, REG_T5(sp)
+	sw		t6, REG_T6(sp)
+	sw		t7, REG_T7(sp)
+
+	/* $16-$23 = s0-s7: Static registers */
+
+	sw		s0, REG_S0(sp)
+	sw		s1, REG_S1(sp)
+	sw		s2, REG_S2(sp)
+	sw		s3, REG_S3(sp)
+	sw		s4, REG_S4(sp)
+	sw		s5, REG_S5(sp)
+	sw		s6, REG_S6(sp)
+	sw		s7, REG_S7(sp)
+
+	/* $24-25 = t8-t9: More Volatile registers */
+
+	sw		t8, REG_T8(sp)
+	sw		t9, REG_T9(sp)
+
+	/* $26-$27 = ko-k1: Reserved for use in exeption handers.  These do not need to be
+	 * saved.
+	 *
+	 * $28 = gp: Only needs to be saved under conditions where there are multiple, per-
+	 * thread values for the GP.
+	 */
+
+#ifdef MIPS32_SAVE_GP
+	sw		gp, REG_GP(sp)
+#endif
+
+	/* $30 = either s8 or fp:  Depends if a frame pointer is used or not */
+
+	sw		s8, REG_S8(sp)
+
+	/* $31 = ra: Return address */
+
+	sw		ra, REG_RA(sp)
+
+	/* $29 = sp:  The value of the stack pointer on return from the exception.  a0 is
+	 * used as a temporary
+	 */
+
+	addiu	\tmp, sp, XCPTCONTEXT_SIZE
+	sw		\tmp, REG_SP(sp)
+	.endm
+
+/********************************************************************************************
+ * Name: EXCPT_EPILOGUE
+ *
+ * Description:
+ *   Provides the "epilogue" logic that should appear at the end of every exception handler.
+ *
+ * On input:
+ *   regs - points to the register save structure.  NOTE:  This *may not* be an address
+ *          lying in a stack!  It might be an address in a TCB!
+ *   Interrupts are disabled (via 'di')
+ *
+ * On completion:
+ *   All registers restored
+ *	 eret is executed to return from the exception
+ *
+ ********************************************************************************************/
+
+	.macro	EXCPT_EXIT, regs
+
+	/* Since interrupts are disabled via di can now use k0 and k1 again.  Use k1 as the
+	 * pointer to the register save array.
+	 */
+
+	move	k1, \regs
+
+	/* Restore the floating point register state */
+
+	lw		k0, REG_MTLO(k1)
+	mtlo	k0
+	lw		k0, REG_MTHI(k1)
+	mthi	k0
+
+	/* Restore general purpose registers */
+	/* $1: at_reg, assembler temporary */
+
+	lw		$1, REG_AT(k1)
+
+	/* $2-$3 = v0-v1: Return value registers */
+
+	lw		v0, REG_V0(k1)
+	lw		v1, REG_V1(k1)
+
+	/* $4-$7 = a0-a3: Argument registers */
+
+	lw		a0, REG_A0(k1)
+	lw		a1, REG_A1(k1)
+	lw		a2, REG_A2(k1)
+	lw		a3, REG_A3(k1)
+
+	/* $8-$15 = t0-t7: Volatile registers */
+
+	lw		t0, REG_T0(k1)
+	lw		t1, REG_T1(k1)
+	lw		t2, REG_T2(k1)
+	lw		t3, REG_T3(k1)
+	lw		t4, REG_T4(k1)
+	lw		t5, REG_T5(k1)
+	lw		t6, REG_T6(k1)
+	lw		t7, REG_T7(k1)
+
+	/* $16-$23 = s0-s7: Static registers */
+
+	lw		s0, REG_S0(k1)
+	lw		s1, REG_S1(k1)
+	lw		s2, REG_S2(k1)
+	lw		s3, REG_S3(k1)
+	lw		s4, REG_S4(k1)
+	lw		s5, REG_S5(k1)
+	lw		s6, REG_S6(k1)
+	lw		s7, REG_S7(k1)
+
+	/* $24-25 = t8-t9: More Volatile registers */
+
+	lw		t8, REG_T8(k1)
+	lw		t9, REG_T9(k1)
+
+	/* $26-$27 = ko-k1: Reserved for use in exeption handers.  These do not need to be
+	 * saved.
+	 *
+	 * $28 = gp: Only needs to be saved under conditions where there are multiple, per-
+	 * thread values for the GP.
+	 */
+
+#ifdef MIPS32_SAVE_GP
+	lw		gp, REG_GP(k1)
+#endif
+
+	/* $30 = either s8 or fp:  Depends if a frame pointer is used or not */
+
+	lw		s8, REG_S8(k1)
+
+	/* $31 = ra: Return address */
+
+	lw		ra, REG_RA(k1)
+
+	/* Finally, restore CP status and the EPC */
+
+	lw		k0, REG_STATUS(k1)
+	lw		k1, REG_EPC(k1)
+	mtc0	k0, MIPS32_CP0_STATUS
+	ehb
+	mtc0 	k1, MIPS32_CP0_EPC
+	eret 
+	nop
+	.endm
+
+/********************************************************************************************
+ * Name: USE_INTSTACK
+ *
+ * Description:
+ *   Switch to the interrupt stack (if enabled in the configuration).
+ *
+ * On Entry:
+ *   sp - Current value of the user stack pointer
+ *   tmp1, tmp2, and tmp3 are registers that can be used temporarily.
+ *   All interrupts should still be disabled.
+ *
+ * At completion:
+ *   If the nesting level is 0, then (1) the user stack pointer is saved at the base of the
+ *   interrupt stack and sp points to the interrupt stack.
+ *   The values of tmp1, tmp2, tmp3, and sp have been altered
+ *
+ ********************************************************************************************/
+
+	.macro	USE_INTSTACK, tmp1, tmp2, tmp3
+#if CONFIG_ARCH_INTERRUPTSTACK > 3
+
+	/* Check the nesting level.  If there are no nested interrupts, then we can
+	 * claim the interrupt stack.
+	 */
+
+	la		\tmp1, g_nestlevel
+	lw		\tmp2, (\tmp1)
+	bne		1f
+	nop
+
+	/* Use the interrupt stack, pushing the user stack pointer onto the interrupt
+	 * stack first.
+	 */
+
+	la		\tmp3, g_intstack
+	sw		sp, (\tmp3)
+	move	sp, \tmp3
+1:
+	/* Increment the interrupt nesting level */
+
+	addiu	\tmp2, \tmp2, 1
+	sw		\tmp2, 0(\tmp1)
+#endif
+	.endm
+
+/********************************************************************************************
+ * Name: RESTORE_STACK
+ *
+ * Description:
+ *   Restore the user stack.  Not really.. actually only decrements the nesting level.  We
+ *   always get the new stack pointer for the register save array.
+ *
+ * On Entry:
+ *   tmp1 and tmp2 are registers that can be used temporarily.
+ *   All interrupts must be disabled.
+ *
+ * At completion:
+ *   Current nesting level is decremented
+ *   The values of tmp1 and  tmp2 have been altered
+ *
+ ********************************************************************************************/
+
+	.macro		RESTORE_STACK, tmp1, tmp2
+#if CONFIG_ARCH_INTERRUPTSTACK > 3
+
+	/* Decrement the nesting level */
+
+	la		\tmp1, g_nestlevel
+	lw		\tmp2, (\tmp1)
+	addiu	\tmp2, \tmp2, -1
+	sw		\tmp2, 0(\tmp1)
+#endif
+	.endm
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_MIPS_SRC_MIPS32_MIPS32_EXCPTMACROS_H */

arch/mips/src/mips32/up_initialstate.c

@@ -54,6 +54,20 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+#ifdef CONFIG_SUPPRESS_INTERRUPTS
+
+  /* Enable only software interrupts */
+
+# define INITIAL_STATUS (CP0_STATUS_IE | CP0_STATUS_EXL | CP0_STATUS_IM_SWINTS)
+
+#else
+
+  /* Enable all interrupts */
+
+# define INITIAL_STATUS (CP0_STATUS_IE | CP0_STATUS_EXL | CP0_STATUS_IM_ALL)
+
+#endif
+
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -83,13 +97,16 @@
 void up_initial_state(_TCB *tcb)
 {
   struct xcptcontext *xcp = &tcb->xcp;
-  irqstate_t status;
 
   /* Initialize the initial exception register context structure */
 
   memset(xcp, 0, sizeof(struct xcptcontext));
 
-  /* Save the initial stack pointer */
+  /* Save the initial stack pointer.  Hmmm.. the stack is set to the very
+   * beginning of the stack region.  Some functions may want to store data on
+   * the caller's stack and it might be good to reserve some space.  However,
+   * only the start function would do that and we have control over that one
+   */
 
   xcp->regs[REG_SP]      = (uint32_t)tcb->adj_stack_ptr;
 
@@ -118,13 +135,6 @@ void up_initial_state(_TCB *tcb)
 
   /* Enable or disable interrupts, based on user configuration */
 
-  status = cp0_getstatus();
-# ifdef CONFIG_SUPPRESS_INTERRUPTS
-  status   &= ~CP0_STATUS_IM_MASK;  /* Disable all interrupts */
-  status   |= CP0_STATUS_IM_SWINTS; /* Make sure that S/W interrupts enabled */
-#else
-  status   |= CP0_STATUS_IM_ALL;    /* Enable all interrupts */
-# endif
-  xcp->regs[REG_STATUS] = status;
+  xcp->regs[REG_STATUS] = INITIAL_STATUS;
 }
 

arch/mips/src/pic32mx/pic32mx-irq.c

@@ -60,6 +60,11 @@
 /****************************************************************************
  * Definitions
  ****************************************************************************/
+/* Configuration ************************************************************/
+
+#ifdef CONFIG_PIC32MX_MVEC
+#  error "Multi-vectors not supported"
+#endif
 
 /****************************************************************************
  * Public Data