patch-2.3.30 linux/arch/ppc/kernel/head_4xx.S

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diff -u --recursive --new-file v2.3.29/linux/arch/ppc/kernel/head_4xx.S linux/arch/ppc/kernel/head_4xx.S
@@ -0,0 +1,600 @@
+/*
+ *    Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org>
+ *      Initial PowerPC version.
+ *    Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu>
+ *      Rewritten for PReP
+ *    Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
+ *      Low-level exception handers, MMU support, and rewrite.
+ *    Copyright (c) 1997 Dan Malek <dmalek@jlc.net>
+ *      PowerPC 8xx modifications.
+ *    Copyright (c) 1998-1999 TiVo, Inc.
+ *      PowerPC 403GCX modifications.
+ *    Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
+ *      PowerPC 403GCX/405GP modifications.
+ *
+ *    Module name: head_4xx.S
+ *
+ *    Description:
+ *      Kernel execution entry point code.
+ *
+ *    This program is free software; you can redistribute it and/or
+ *    modify it under the terms of the GNU General Public License
+ *    as published by the Free Software Foundation; either version
+ *    2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/config.h>
+
+#include <asm/processor.h>
+#include <asm/4xx.h>
+#include <asm/403gcx.h>
+#include <asm/405gp.h>
+#include <asm/page.h>
+#include <asm/mmu.h>
+
+#include "ppc_asm.h"
+
+
+/* Preprocessor Defines */
+
+#define	STND_EXC	0
+#define	CRIT_EXC	1
+
+###
+### Check to make sure the right processor has been defined.
+###
+
+#if !defined(CONFIG_4xx)
+#error "This file is only appropriate for kernels supporting the PPC4xx."
+#endif
+
+###
+### Execution entry point.
+###
+
+###
+### As with the other PowerPC ports, it is expected that when code
+### execution begins here, the following registers contain valid, yet
+### optional, information:
+###
+###   r3 - ???
+###   r4 - Starting address of the init RAM disk
+###   r5 - Ending address of the init RAM disk
+###   r6 - Start of kernel command line string (e.g. "mem=96m")
+###   r7 - End of kernel command line string
+### 
+	
+	.text
+_GLOBAL(_stext)
+_GLOBAL(_start)
+	## Save residual data, init RAM disk, and command line parameters
+	
+	mr	r31,r3
+	mr	r30,r4
+	mr	r29,r5
+	mr	r28,r6
+	mr	r27,r7
+
+	## Set the ID for this CPU
+
+	li	r24,0
+
+	## Establish exception vector base
+	
+	lis	r0,KERNELBASE@h
+	mtspr	SPRN_EVPR,r0
+
+	## Jump to the main PowerPC kernel start-up code
+	
+1:	lis	r7,start_here@ha
+	addi	r7,r7,start_here@l
+	mtlr	r7
+	blr
+
+###
+### Exception vector entry code. This code runs with address translation
+### turned off (i.e. using physical addresses). We assume SPRG3 has the
+### physical address of the current task thread_struct.
+### 
+
+	## Common exception code for all exception types.
+
+#define COMMON_PROLOG							     \
+0:	mtspr	SPRN_SPRG0,r20;		/* We need r20, move it to SPRG0   */\
+	mtspr	SPRN_SPRG1,r21;		/* We need r21, move it to SPRG1   */\
+	mfcr	r20;			/* We need the CR, move it to r20  */\
+	mfspr	r21,SPRN_SPRG2;		/* Exception stack to use	   */\
+	cmpwi	cr0,r21,0;		/* From user mode or RTAS?	   */\
+	bne	1f;			/* Not RTAS, branch		   */\
+	tophys(r21, r1);		/* Convert vka in r1 to pka in r21 */\
+	subi	r21,r21,INT_FRAME_SIZE;	/* Allocate an exception frame	   */\
+1:	stw	r20,_CCR(r21);		/* Save CR on the stack		   */\
+	stw	r22,GPR22(r21);		/* Save r22 on the stack	   */\
+	stw	r23,GPR23(r21);		/* r23 Save on the stack	   */\
+	mfspr	r20,SPRN_SPRG0;		/* Get r20 back out of SPRG0	   */\
+	stw	r20,GPR20(r21);		/* Save r20 on the stack	   */\
+	mfspr	r22,SPRN_SPRG1;		/* Get r21 back out of SPRG0	   */\
+	stw	r22,GPR21(r21);		/* Save r21 on the stack	   */\
+	mflr	r20;							     \
+	stw	r20,_LINK(r21);		/* Save LR on the stack		   */\
+	mfctr	r22;							     \
+	stw	r22,_CTR(r21);		/* Save CTR on the stack	   */\
+	mfspr	r20,XER;						     \
+	stw	r20,_XER(r21);		/* Save XER on the stack	   */
+
+#define	COMMON_EPILOG							     \
+	stw	r0,GPR0(r21);		/* Save r0 on the stack		   */\
+	stw	r1,GPR1(r21);		/* Save r1 on the stack		   */\
+	stw	r2,GPR2(r21);		/* Save r2 on the stack		   */\
+	stw	r1,0(r21);						     \
+	tovirt(r1,r21);			/* Set-up new kernel stack pointer */\
+	SAVE_4GPRS(3, r21);		/* Save r3 through r6 on the stack */
+
+	## Common exception code for standard (non-critical) exceptions.
+
+#define	STND_EXCEPTION_PROLOG						     \
+	COMMON_PROLOG;							     \
+	mfspr	r22,SPRN_SRR0;		/* Faulting instruction address	   */\
+	mfspr	r23,SPRN_SRR1;		/* MSR at the time of fault	   */\
+	COMMON_EPILOG;
+
+	## Common exception code for critical exceptions.
+	
+#define	CRIT_EXCEPTION_PROLOG						     \
+	COMMON_PROLOG;							     \
+	mfspr	r22,SPRN_SRR2;		/* Faulting instruction address	   */\
+	mfspr	r23,SPRN_SRR3;		/* MSR at the time of fault	   */\
+	COMMON_EPILOG;
+
+###
+### Macros for specific exception types
+### 
+
+#define	START_EXCEPTION(n, label)					     \
+	. = n;								     \
+label:
+
+
+#define FINISH_EXCEPTION(func)						     \
+	bl	transfer_to_handler;					     \
+	.long	func;							     \
+	.long	ret_from_except
+	
+		
+#define STND_EXCEPTION(n, label, func)					     \
+	START_EXCEPTION(n, label);					     \
+	STND_EXCEPTION_PROLOG;						     \
+	addi	r3,r1,STACK_FRAME_OVERHEAD;				     \
+	li	r0,STND_EXC;						     \
+	li	r20,MSR_KERNEL;						     \
+	FINISH_EXCEPTION(func)
+
+	
+#define	CRIT_EXCEPTION(n, label, func)					     \
+	START_EXCEPTION(n, label);					     \
+	CRIT_EXCEPTION_PROLOG;						     \
+	addi	r3,r1,STACK_FRAME_OVERHEAD;				     \
+	li	r0,CRIT_EXC;						     \
+	li	r20,MSR_KERNEL;						     \
+	FINISH_EXCEPTION(func)
+
+
+#define	INTR_EXCEPTION(n, label, func)					     \
+	START_EXCEPTION(n, label);					     \
+	STND_EXCEPTION_PROLOG;						     \
+	addi	r3,r1,STACK_FRAME_OVERHEAD;				     \
+	li	r0,STND_EXC;						     \
+	li	r20,MSR_KERNEL;						     \
+	li	r4,0;							     \
+	bl	transfer_to_handler;					     \
+_GLOBAL(do_IRQ_intercept);						     \
+	.long	func;							     \
+	.long	ret_from_except
+
+	
+###
+### Exception vectors.
+### 
+	
+### 0x0100 - Critical Interrupt Exception
+
+	CRIT_EXCEPTION(0x0100,	CriticalInterrupt,	UnknownException)
+
+### 0x0200 - Machine Check Exception
+	
+	CRIT_EXCEPTION(0x0200,	MachineCheck,		MachineCheckException)
+
+### 0x0300 - Data Storage Exception
+
+	START_EXCEPTION(0x0300,	DataAccess)
+	STND_EXCEPTION_PROLOG
+	mfspr	r5,SPRN_ESR		# Grab the ESR, save it, pass as arg3
+	stw	r5,_ESR(r21)
+	mfspr	r4,SPRN_DEAR		# Grab the DEAR, save it, pass as arg2
+	stw	r4,_DEAR(r21)
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	li	r0,STND_EXC		# This is a standard exception
+	li	r20,MSR_KERNEL
+	rlwimi	r20,r23,0,16,16		# Copy EE bit from the saved MSR
+	FINISH_EXCEPTION(do_page_fault)	# do_page_fault(regs, ESR, DEAR)
+	
+### 0x0400 - Instruction Storage Exception
+
+	START_EXCEPTION(0x0400, InstructionAccess)
+	STND_EXCEPTION_PROLOG
+	mr	r4,r22			# Pass SRR0 as arg2
+	mr	r5,r23			# Pass SRR1 as arg3
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	li	r0,STND_EXC		# This is a standard exception
+	li	r20,MSR_KERNEL
+	rlwimi	r20,r23,0,16,16		# Copy EE bit from the saved MSR
+	FINISH_EXCEPTION(do_page_fault)	# do_page_fault(regs, SRR0, SRR1)
+	
+### 0x0500 - External Interrupt Exception
+
+	INTR_EXCEPTION(0x0500,	HardwareInterrupt,	do_IRQ)
+	
+### 0x0600 - Alignment Exception
+	
+	START_EXCEPTION(0x0600, Alignment)
+	STND_EXCEPTION_PROLOG
+	mfspr	r4,SPRN_DEAR		# Grab the DEAR and save it
+	stw	r4,_DEAR(r21)
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	li	r0,STND_EXC		# This is a standard exception
+	li	r20,MSR_KERNEL
+	rlwimi	r20,r23,0,16,16		# Copy EE bit from the saved MSR
+	FINISH_EXCEPTION(AlignmentException)
+
+### 0x0700 - Program Exception
+
+	START_EXCEPTION(0x0700,	ProgramCheck)
+	STND_EXCEPTION_PROLOG
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	li	r0,STND_EXC		# This is a standard exception
+	li	r20,MSR_KERNEL
+	rlwimi	r20,r23,0,16,16		# Copy EE bit from the saved MSR
+	FINISH_EXCEPTION(ProgramCheckException)
+	
+	STND_EXCEPTION(0x0800,	Trap_08,		UnknownException)
+	STND_EXCEPTION(0x0900,	Trap_09,		UnknownException)
+	STND_EXCEPTION(0x0A00,	Trap_0A,		UnknownException)
+	STND_EXCEPTION(0x0B00,	Trap_0B,		UnknownException)		
+### 0x0C00 - System Call Exception
+
+	START_EXCEPTION(0x0C00,	SystemCall)
+	STND_EXCEPTION_PROLOG
+	stw	r3,ORIG_GPR3(r21)
+	li	r0,STND_EXC		# This is a standard exception
+	li	r20,MSR_KERNEL
+	rlwimi	r20,r23,0,16,16		# Copy EE bit from the saved MSR
+	FINISH_EXCEPTION(DoSyscall)
+
+	STND_EXCEPTION(0x0D00,	Trap_0D,		UnknownException)
+	STND_EXCEPTION(0x0E00,	Trap_0E,		UnknownException)
+	STND_EXCEPTION(0x0F00,	Trap_0F,		UnknownException)
+
+#if 0
+### 0x1000 - Programmable Interval Timer (PIT) Exception
+
+	STND_EXCEPTION(0x1000,	PITException,		UnknownException)
+
+### 0x1010 - Fixed Interval Timer (FIT) Exception
+	
+	STND_EXCEPTION(0x1010,	FITException,		UnknownException)
+
+### 0x1020 - Watchdog Timer (WDT) Exception
+
+	CRIT_EXCEPTION(0x1020,	WDTException,		UnknownException)
+#endif
+
+### 0x1100 - Data TLB Miss Exception
+	
+	START_EXCEPTION(0x1100,	DTLBMiss)
+	STND_EXCEPTION_PROLOG
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	li	r0,STND_EXC
+	li	r20,MSR_KERNEL
+	FINISH_EXCEPTION(UnknownException)
+
+### 0x1200 - Instruction TLB Miss Exception
+	
+	START_EXCEPTION(0x1200,	ITLBMiss)
+	STND_EXCEPTION_PROLOG
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	li	r0,STND_EXC
+	li	r20,MSR_KERNEL
+	FINISH_EXCEPTION(UnknownException)	
+
+	STND_EXCEPTION(0x1300,	Trap_13,		UnknownException)
+	STND_EXCEPTION(0x1400,	Trap_14,		UnknownException)
+	STND_EXCEPTION(0x1500,	Trap_15,		UnknownException)
+	STND_EXCEPTION(0x1600,	Trap_16,		UnknownException)
+	STND_EXCEPTION(0x1700,	Trap_17,		UnknownException)
+	STND_EXCEPTION(0x1800,	Trap_18,		UnknownException)
+	STND_EXCEPTION(0x1900,	Trap_19,		UnknownException)
+	STND_EXCEPTION(0x1A00,	Trap_1A,		UnknownException)
+	STND_EXCEPTION(0x1B00,	Trap_1B,		UnknownException)
+	STND_EXCEPTION(0x1C00,	Trap_1C,		UnknownException)
+	STND_EXCEPTION(0x1D00,	Trap_1D,		UnknownException)
+	STND_EXCEPTION(0x1E00,	Trap_1E,		UnknownException)
+	STND_EXCEPTION(0x1F00,	Trap_1F,		UnknownException)
+	
+### 0x2000 - Debug Exception
+
+	CRIT_EXCEPTION(0x2000,	DebugTrap,		UnknownException)
+
+###
+### Other PowerPC processors, namely those derived from the 6xx-series
+### have vectors from 0x2100 through 0x2F00 defined, but marked as reserved.
+### However, for the 4xx-series processors these are neither defined nor
+### reserved.
+### 
+
+### 
+### This code finishes saving the registers to the exception frame
+### and jumps to the appropriate handler for the exception, turning
+### on address translation.
+###
+
+_GLOBAL(transfer_to_handler)
+	stw	r22,_NIP(r21)		# Save the faulting IP on the stack
+	stw	r23,_MSR(r21)		# Save the exception MSR on the stack
+	SAVE_GPR(7, r21)		# Save r7 on the stack
+	SAVE_4GPRS(8, r21)		# Save r8 through r11 on the stack
+	SAVE_8GPRS(12, r21)		# Save r12 through r19 on the stack
+	SAVE_8GPRS(24, r21)		# Save r24 through r31 on the stack
+	andi.	r23,r23,MSR_PR		# Is this from user space?
+	mfspr	r23,SPRN_SPRG3		# If from user, fix up THREAD.regs
+	beq	2f			# No, it is from the kernel; branch.
+	addi	r24,r1,STACK_FRAME_OVERHEAD
+	stw	r24,PT_REGS(r23)	# 
+2:	addi	r2,r23,-THREAD		# Set r2 to current thread
+	tovirt(r2,r2)
+	mflr	r23
+	andi.	r24,r23,0x3f00		# Get vector offset
+	stw	r24,TRAP(r21)
+	li	r22,RESULT
+	stwcx.	r22,r22,r21		# Clear the reservation
+	li	r22,0
+	stw	r22,RESULT(r21)
+	mtspr	SPRN_SPRG2,r22		# r1 is now the kernel stack pointer
+	addi	r24,r2,TASK_STRUCT_SIZE	# Check for kernel stack overflow
+	cmplw	cr0,r1,r2
+	cmplw	cr1,r1,r24
+	crand	cr1,cr1,cr4
+	bgt-	stack_ovf		# If r2 < r1 < r2 + TASK_STRUCT_SIZE
+	lwz	r24,0(r23)		# Virtual address of the handler
+	lwz	r23,4(r23)		# Handler return pointer
+	cmpwi	cr0,r0,STND_EXC		# What type of exception is this?
+	bne	3f			# It is a critical exception...
+
+	## Standard exception jump path
+	
+	mtspr	SPRN_SRR0,r24		# Set up the instruction pointer
+	mtspr	SPRN_SRR1,r20		# Set up the machine state register
+	mtlr	r23			# Set up the return pointer
+	SYNC
+	rfi				# Enable the MMU, jump to the handler
+
+	## Critical exception jump path
+
+3:	mtspr	SPRN_SRR2,r24		# Set up the instruction pointer
+	mtspr	SPRN_SRR3,r20		# Set up the machine state register
+	mtlr	r23			# Set up the return pointer
+	SYNC
+	rfci				# Enable the MMU, jump to the handler
+
+###
+### On kernel stack overlow, load up an initial stack pointer and call
+### StackOverflow(regs), which should NOT return.
+### 
+
+stack_ovf:
+	addi	r3,r1,STACK_FRAME_OVERHEAD
+	lis	r1,init_task_union@ha
+	addi	r1,r1,init_task_union@l
+	addi	r1,r1,TASK_UNION_SIZE - STACK_FRAME_OVERHEAD
+	lis	r24,StackOverflow@ha
+	addi	r24,r24,StackOverflow@l
+	li	r20,MSR_KERNEL
+	mtspr	SPRN_SRR0,r24		# Set up the instruction pointer
+	mtspr	SPRN_SRR1,r20		# Set up the machine state register
+	SYNC
+	rfi				# Enable the MMU, jump to StackOverflow
+
+###
+### extern void giveup_altivec(struct task_struct *prev)
+###
+### The PowerPC 4xx family of processors do not have AltiVec capabilities, so
+### this just returns.
+###
+
+_GLOBAL(giveup_altivec)
+	blr
+	
+###
+### extern void giveup_fpu(struct task_struct *prev)
+###
+### The PowerPC 4xx family of processors do not have an FPU, so this just
+### returns.
+###
+
+_GLOBAL(giveup_fpu)
+	blr
+
+###
+### extern void abort(void)
+###
+### At present, this routine just applies a system reset.
+### 
+	
+_GLOBAL(abort)
+	mfspr	r13,SPRN_DBCR
+	ori	r13,r13,DBCR_RST(SYSTEM)@h
+	mtspr	SPRN_DBCR,r13
+
+	
+###
+### This code is jumped-to from the startup code. It copies the kernel
+### image from wherever it happens to be currently running at in physical
+### address space to physical address 0.
+###
+### In general, for a running Linux/PPC system:
+###   Kernel Physical Address (KPA) = 0x00000000
+###   Kernel Virtual Address (KVA)  = 0xC0000000
+###
+ 
+#if 0
+relocate_kernel:
+	lis	r9,0x426f		/* if booted from BootX, don't */
+	addi	r9,r9,0x6f58		/* translate source addr */
+	cmpw	r31,r9			/* (we have to on chrp) */
+	beq	7f
+	rlwinm	r4,r4,0,8,31		/* translate source address */
+	add	r4,r4,r3		/* to region mapped with BATs */
+7:	addis	r9,r26,klimit@ha	/* fetch klimit */
+	lwz	r25,klimit@l(r9)
+	addis	r25,r25,-KERNELBASE@h
+	li	r6,0			/* Destination offset */
+	li	r5,0x4000		/* # bytes of memory to copy */
+	bl	copy_and_flush		/* copy the first 0x4000 bytes */
+	addi	r0,r3,4f@l		/* jump to the address of 4f */
+	mtctr	r0			/* in copy and do the rest. */
+	bctr				/* jump to the copy */
+4:	mr	r5,r25
+	bl	copy_and_flush		/* copy the rest */
+	b	turn_on_mmu
+
+/*
+ * Copy routine used to copy the kernel to start at physical address 0
+ * and flush and invalidate the caches as needed.
+ * r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset
+ * on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5.
+ */
+copy_and_flush:
+	addi	r5,r5,-4
+	addi	r6,r6,-4
+4:	li	r0,8
+	mtctr	r0
+3:	addi	r6,r6,4			/* copy a cache line */
+	lwzx	r0,r6,r4
+	stwx	r0,r6,r3
+	bdnz	3b
+	dcbst	r6,r3			/* write it to memory */
+	sync
+	icbi	r6,r3			/* flush the icache line */
+	cmplw	0,r6,r5
+	blt	4b
+	isync
+	addi	r5,r5,4
+	addi	r6,r6,4
+	blr
+#endif
+	
+### 
+### This is where the main kernel code starts.
+### 
+
+start_here:
+	## Establish a pointer to the current task
+	
+	lis	r2,init_task_union@h
+	ori	r2,r2,init_task_union@l
+	
+	## Clear out the BSS as per ANSI C requirements
+
+	lis	r7,_end@ha
+	addi	r7,r7,_end@l
+	lis	r8,__bss_start@ha
+	addi	r8,r8,__bss_start@l
+	subf	r7,r8,r7
+	addi	r7,r7,3
+	srwi.	r7,r7,2
+	beq	2f
+	addi	r8,r8,-4
+	mtctr	r7
+	li	r0,0
+3:	stwu	r0,4(r8)
+	bdnz	3b
+
+	## Stack
+	
+2:	addi	r1,r2,TASK_UNION_SIZE
+	li	r0,0
+	stwu	r0,-STACK_FRAME_OVERHEAD(r1)
+
+	## Determine what type of platform this is.
+
+	mr	r3,r31
+	mr	r4,r30
+	mr	r5,r29
+	mr	r6,r28
+	mr	r7,r27
+	bl	identify_machine
+	
+	## Initialize the memory management unit.
+
+	bl	MMU_init
+
+	## Go back to running unmapped so that we can change to our
+	## exception vectors.
+
+	lis	r4,2f@h
+	ori	r4,r4,2f@l
+	tophys(r4,r4)
+	li	r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
+	mtspr	SPRN_SRR0,r4		# Set up the instruction pointer
+	mtspr	SPRN_SRR1,r3		# Set up the machine state register
+	rfi
+
+	## Load up the kernel context
+
+2:	SYNC				# Force all PTE updates to finish
+#	tlbia				# Clear all TLB entries
+#	sync				# Wait for tlbia to finish...
+
+	## Set up for using our exception vectors
+	
+	tophys(r4,r2)			# Pointer to physical current thread
+	addi	r4,r4,THREAD		# The init task thread
+	mtspr	SPRN_SPRG3,r4		# Save it for exceptions later
+	li	r3,0			# 
+	mtspr	SPRN_SPRG2,r3		# 0 implies r1 has kernel stack pointer
+	
+	## Really turn on the MMU and jump into the kernel
+
+        lis     r4,MSR_KERNEL@h
+        ori     r4,r4,MSR_KERNEL@l
+        lis     r3,start_kernel@h
+        ori     r3,r3,start_kernel@l
+        mtspr   SPRN_SRR0,r3		# Set up the instruction pointer
+        mtspr   SPRN_SRR1,r4		# Set up the machine state register
+        rfi				# Enable the MMU, jump to the kernel
+
+_GLOBAL(set_context)
+	mtspr	SPRN_PID,r3
+	tlbia
+	SYNC
+	blr
+
+###
+### We put a few things here that have to be page-aligned. This stuff
+### goes at the beginning of the data segment, which is page-aligned.
+###
+
+	.data
+_GLOBAL(sdata)
+_GLOBAL(empty_zero_page)
+	.space	4096
+_GLOBAL(swapper_pg_dir)
+	.space	4096	
+
+###
+### This space gets a copy of optional info passed to us by the bootstrap
+### which is used to pass parameters into the kernel like root=/dev/sda1, etc.
+###
+
+_GLOBAL(cmd_line)
+	.space	512
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)