powerpc/mpc85xx: Don't relocate exception vectors

Booke does not require exception vectors to be located at address zero.
U-Boot was doing so anyway, simply because that's how it had been done
on other PPC.  The downside of this is that once the OS is loaded to
address zero, the exception vectors have been overwritten -- which
makes it difficult to diagnose a crash that happens after that point.

The IVOR setup and trap entry code is simplified somewhat as a result.

Also, there is no longer a need to align individual exceptions on 0x100
byte boundaries.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>

1 files changed, 57 insertions, 121 deletions

diff --git a/arch/powerpc/cpu/mpc85xx/start.S b/arch/powerpc/cpu/mpc85xx/start.S
index d8c9fb6..61883cb 100644
--- a/arch/powerpc/cpu/mpc85xx/start.S
+++ b/arch/powerpc/cpu/mpc85xx/start.S
@@ -252,39 +252,36 @@ l2_disabled:
 	lis	r1,CONFIG_SYS_MONITOR_BASE@h
 	mtspr	IVPR,r1
 
-	lis	r3,(CONFIG_SYS_MONITOR_BASE & 0xffff)@h
-	ori	r3,r3,(CONFIG_SYS_MONITOR_BASE & 0xffff)@l
-
-	addi	r4,r3,CriticalInput - _start + _START_OFFSET
+	li	r4,CriticalInput@l
 	mtspr	IVOR0,r4	/* 0: Critical input */
-	addi	r4,r3,MachineCheck - _start + _START_OFFSET
+	li	r4,MachineCheck@l
 	mtspr	IVOR1,r4	/* 1: Machine check */
-	addi	r4,r3,DataStorage - _start + _START_OFFSET
+	li	r4,DataStorage@l
 	mtspr	IVOR2,r4	/* 2: Data storage */
-	addi	r4,r3,InstStorage - _start + _START_OFFSET
+	li	r4,InstStorage@l
 	mtspr	IVOR3,r4	/* 3: Instruction storage */
-	addi	r4,r3,ExtInterrupt - _start + _START_OFFSET
+	li	r4,ExtInterrupt@l
 	mtspr	IVOR4,r4	/* 4: External interrupt */
-	addi	r4,r3,Alignment - _start + _START_OFFSET
+	li	r4,Alignment@l
 	mtspr	IVOR5,r4	/* 5: Alignment */
-	addi	r4,r3,ProgramCheck - _start + _START_OFFSET
+	li	r4,ProgramCheck@l
 	mtspr	IVOR6,r4	/* 6: Program check */
-	addi	r4,r3,FPUnavailable - _start + _START_OFFSET
+	li	r4,FPUnavailable@l
 	mtspr	IVOR7,r4	/* 7: floating point unavailable */
-	addi	r4,r3,SystemCall - _start + _START_OFFSET
+	li	r4,SystemCall@l
 	mtspr	IVOR8,r4	/* 8: System call */
 	/* 9: Auxiliary processor unavailable(unsupported) */
-	addi	r4,r3,Decrementer - _start + _START_OFFSET
+	li	r4,Decrementer@l
 	mtspr	IVOR10,r4	/* 10: Decrementer */
-	addi	r4,r3,IntervalTimer - _start + _START_OFFSET
+	li	r4,IntervalTimer@l
 	mtspr	IVOR11,r4	/* 11: Interval timer */
-	addi	r4,r3,WatchdogTimer - _start + _START_OFFSET
+	li	r4,WatchdogTimer@l
 	mtspr	IVOR12,r4	/* 12: Watchdog timer */
-	addi	r4,r3,DataTLBError - _start + _START_OFFSET
+	li	r4,DataTLBError@l
 	mtspr	IVOR13,r4	/* 13: Data TLB error */
-	addi	r4,r3,InstructionTLBError - _start + _START_OFFSET
+	li	r4,InstructionTLBError@l
 	mtspr	IVOR14,r4	/* 14: Instruction TLB error */
-	addi	r4,r3,DebugBreakpoint - _start + _START_OFFSET
+	li	r4,DebugBreakpoint@l
 	mtspr	IVOR15,r4	/* 15: Debug */
 #endif
 
@@ -1121,7 +1118,7 @@ switch_as:
 	/*--------------------------------------------------------------*/
 	lis	r3,CONFIG_SYS_MONITOR_BASE@h
 	ori	r3,r3,CONFIG_SYS_MONITOR_BASE@l
-	addi	r3,r3,_start_cont - _start + _START_OFFSET
+	addi	r3,r3,_start_cont - _start
 	mtlr	r3
 	blr
 #endif
@@ -1165,7 +1162,6 @@ _start_cont:
 	/* NOTREACHED - board_init_f() does not return */
 
 #ifndef MINIMAL_SPL
-	. = EXC_OFF_SYS_RESET
 	.globl	_start_of_vectors
 _start_of_vectors:
 
@@ -1185,7 +1181,6 @@ _start_of_vectors:
 	STD_EXCEPTION(0x0500, ExtInterrupt, ExtIntException)
 
 /* Alignment exception. */
-	. = 0x0600
 Alignment:
 	EXCEPTION_PROLOG(SRR0, SRR1)
 	mfspr	r4,DAR
@@ -1193,21 +1188,20 @@ Alignment:
 	mfspr	r5,DSISR
 	stw	r5,_DSISR(r21)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	EXC_XFER_TEMPLATE(Alignment, AlignmentException, MSR_KERNEL, COPY_EE)
+	EXC_XFER_TEMPLATE(0x600, Alignment, AlignmentException,
+		MSR_KERNEL, COPY_EE)
 
 /* Program check exception */
-	. = 0x0700
 ProgramCheck:
 	EXCEPTION_PROLOG(SRR0, SRR1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	EXC_XFER_TEMPLATE(ProgramCheck, ProgramCheckException,
+	EXC_XFER_TEMPLATE(0x700, ProgramCheck, ProgramCheckException,
 		MSR_KERNEL, COPY_EE)
 
 	/* No FPU on MPC85xx.  This exception is not supposed to happen.
 	*/
 	STD_EXCEPTION(0x0800, FPUnavailable, UnknownException)
 
-	. = 0x0900
 /*
  * r0 - SYSCALL number
  * r3-... arguments
@@ -1293,32 +1287,22 @@ _end_of_vectors:
  * This code finishes saving the registers to the exception frame
  * and jumps to the appropriate handler for the exception.
  * Register r21 is pointer into trap frame, r1 has new stack pointer.
+ * r23 is the address of the handler.
  */
 	.globl	transfer_to_handler
 transfer_to_handler:
-	stw	r22,_NIP(r21)
-	lis	r22,MSR_POW@h
-	andc	r23,r23,r22
-	stw	r23,_MSR(r21)
 	SAVE_GPR(7, r21)
 	SAVE_4GPRS(8, r21)
 	SAVE_8GPRS(12, r21)
 	SAVE_8GPRS(24, r21)
 
-	mflr	r23
-	andi.	r24,r23,0x3f00		/* get vector offset */
-	stw	r24,TRAP(r21)
 	li	r22,0
 	stw	r22,RESULT(r21)
 	mtspr	SPRG2,r22		/* r1 is now kernel sp */
 
-	lwz	r24,0(r23)		/* virtual address of handler */
-	lwz	r23,4(r23)		/* where to go when done */
-	mtspr	SRR0,r24
-	mtspr	SRR1,r20
-	mtlr	r23
-	SYNC
-	rfi				/* jump to handler, enable MMU */
+	mtctr	r23			/* virtual address of handler */
+	mtmsr	r20
+	bctrl
 
 int_return:
 	mfmsr	r28		/* Disable interrupts */
@@ -1728,7 +1712,7 @@ relocate_code:
  * initialization, now running from RAM.
  */
 
-	addi	r0,r10,in_ram - _start + _START_OFFSET
+	addi	r0,r10,in_ram - _start
 
 	/*
 	 * As IVPR is going to point RAM address,
@@ -1816,89 +1800,41 @@ clear_bss:
 	 */
 	.globl	trap_init
 trap_init:
-	mflr	r4			/* save link register		*/
-	GET_GOT
-	lwz	r7,GOT(_start_of_vectors)
-	lwz	r8,GOT(_end_of_vectors)
-
-	li	r9,0x100		/* reset vector always at 0x100 */
-
-	cmplw	0,r7,r8
-	bgelr				/* return if r7>=r8 - just in case */
-1:
-	lwz	r0,0(r7)
-	stw	r0,0(r9)
-	addi	r7,r7,4
-	addi	r9,r9,4
-	cmplw	0,r7,r8
-	bne	1b
+	/* Update IVORs as per relocation */
+	mtspr	IVPR,r3
 
-	/*
-	 * relocate `hdlr' and `int_return' entries
-	 */
-	li	r7,.L_CriticalInput - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_MachineCheck - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_DataStorage - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_InstStorage - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_ExtInterrupt - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_Alignment - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_ProgramCheck - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_FPUnavailable - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_Decrementer - _start + _START_OFFSET
-	bl	trap_reloc
-	li	r7,.L_IntervalTimer - _start + _START_OFFSET
-	li	r8,_end_of_vectors - _start + _START_OFFSET
-2:
-	bl	trap_reloc
-	addi	r7,r7,0x100		/* next exception vector	*/
-	cmplw	0,r7,r8
-	blt	2b
-
-	/* Update IVORs as per relocated vector table address */
-	li	r7,0x0100
-	mtspr	IVOR0,r7	/* 0: Critical input */
-	li	r7,0x0200
-	mtspr	IVOR1,r7	/* 1: Machine check */
-	li	r7,0x0300
-	mtspr	IVOR2,r7	/* 2: Data storage */
-	li	r7,0x0400
-	mtspr	IVOR3,r7	/* 3: Instruction storage */
-	li	r7,0x0500
-	mtspr	IVOR4,r7	/* 4: External interrupt */
-	li	r7,0x0600
-	mtspr	IVOR5,r7	/* 5: Alignment */
-	li	r7,0x0700
-	mtspr	IVOR6,r7	/* 6: Program check */
-	li	r7,0x0800
-	mtspr	IVOR7,r7	/* 7: floating point unavailable */
-	li	r7,0x0900
-	mtspr	IVOR8,r7	/* 8: System call */
+	li	r4,CriticalInput@l
+	mtspr	IVOR0,r4	/* 0: Critical input */
+	li	r4,MachineCheck@l
+	mtspr	IVOR1,r4	/* 1: Machine check */
+	li	r4,DataStorage@l
+	mtspr	IVOR2,r4	/* 2: Data storage */
+	li	r4,InstStorage@l
+	mtspr	IVOR3,r4	/* 3: Instruction storage */
+	li	r4,ExtInterrupt@l
+	mtspr	IVOR4,r4	/* 4: External interrupt */
+	li	r4,Alignment@l
+	mtspr	IVOR5,r4	/* 5: Alignment */
+	li	r4,ProgramCheck@l
+	mtspr	IVOR6,r4	/* 6: Program check */
+	li	r4,FPUnavailable@l
+	mtspr	IVOR7,r4	/* 7: floating point unavailable */
+	li	r4,SystemCall@l
+	mtspr	IVOR8,r4	/* 8: System call */
 	/* 9: Auxiliary processor unavailable(unsupported) */
-	li	r7,0x0a00
-	mtspr	IVOR10,r7	/* 10: Decrementer */
-	li	r7,0x0b00
-	mtspr	IVOR11,r7	/* 11: Interval timer */
-	li	r7,0x0c00
-	mtspr	IVOR12,r7	/* 12: Watchdog timer */
-	li	r7,0x0d00
-	mtspr	IVOR13,r7	/* 13: Data TLB error */
-	li	r7,0x0e00
-	mtspr	IVOR14,r7	/* 14: Instruction TLB error */
-	li	r7,0x0f00
-	mtspr	IVOR15,r7	/* 15: Debug */
-
-	lis	r7,0x0
-	mtspr	IVPR,r7
-
-	mtlr	r4			/* restore link register	*/
+	li	r4,Decrementer@l
+	mtspr	IVOR10,r4	/* 10: Decrementer */
+	li	r4,IntervalTimer@l
+	mtspr	IVOR11,r4	/* 11: Interval timer */
+	li	r4,WatchdogTimer@l
+	mtspr	IVOR12,r4	/* 12: Watchdog timer */
+	li	r4,DataTLBError@l
+	mtspr	IVOR13,r4	/* 13: Data TLB error */
+	li	r4,InstructionTLBError@l
+	mtspr	IVOR14,r4	/* 14: Instruction TLB error */
+	li	r4,DebugBreakpoint@l
+	mtspr	IVOR15,r4	/* 15: Debug */
+
 	blr
 
 .globl unlock_ram_in_cache