exceptions-64e.S

/*
 *  Boot code and exception vectors for Book3E processors
 *
 *  Copyright (C) 2007 Ben. Herrenschmidt (benh@kernel.crashing.org), IBM Corp.
 *
 *  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/threads.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
#include <asm/setup.h>
#include <asm/thread_info.h>
#include <asm/reg.h>
#include <asm/exception-64e.h>
#include <asm/bug.h>
#include <asm/irqflags.h>
#include <asm/ptrace.h>
#include <asm/ppc-opcode.h>
#include <asm/mmu.h>

/* XXX This will ultimately add space for a special exception save
 *     structure used to save things like SRR0/SRR1, SPRGs, MAS, etc...
 *     when taking special interrupts. For now we don't support that,
 *     special interrupts from within a non-standard level will probably
 *     blow you up
 */
#define	SPECIAL_EXC_FRAME_SIZE	INT_FRAME_SIZE

/* Exception prolog code for all exceptions */
#define EXCEPTION_PROLOG(n, type, addition)				    \
	mtspr	SPRN_SPRG_##type##_SCRATCH,r13;	/* get spare registers */   \
	mfspr	r13,SPRN_SPRG_PACA;	/* get PACA */			    \
	std	r10,PACA_EX##type+EX_R10(r13);				    \
	std	r11,PACA_EX##type+EX_R11(r13);				    \
	mfcr	r10;			/* save CR */			    \
	addition;			/* additional code for that exc. */ \
	std	r1,PACA_EX##type+EX_R1(r13); /* save old r1 in the PACA */  \
	stw	r10,PACA_EX##type+EX_CR(r13); /* save old CR in the PACA */ \
	mfspr	r11,SPRN_##type##_SRR1;/* what are we coming from */	    \
	type##_SET_KSTACK;		/* get special stack if necessary */\
	andi.	r10,r11,MSR_PR;		/* save stack pointer */	    \
	beq	1f;			/* branch around if supervisor */   \
	ld	r1,PACAKSAVE(r13);	/* get kernel stack coming from usr */\
1:	cmpdi	cr1,r1,0;		/* check if SP makes sense */	    \
	bge-	cr1,exc_##n##_bad_stack;/* bad stack (TODO: out of line) */ \
	mfspr	r10,SPRN_##type##_SRR0;	/* read SRR0 before touching stack */

/* Exception type-specific macros */
#define	GEN_SET_KSTACK							    \
	subi	r1,r1,INT_FRAME_SIZE;	/* alloc frame on kernel stack */
#define SPRN_GEN_SRR0	SPRN_SRR0
#define SPRN_GEN_SRR1	SPRN_SRR1

#define CRIT_SET_KSTACK						            \
	ld	r1,PACA_CRIT_STACK(r13);				    \
	subi	r1,r1,SPECIAL_EXC_FRAME_SIZE;
#define SPRN_CRIT_SRR0	SPRN_CSRR0
#define SPRN_CRIT_SRR1	SPRN_CSRR1

#define DBG_SET_KSTACK						            \
	ld	r1,PACA_DBG_STACK(r13);					    \
	subi	r1,r1,SPECIAL_EXC_FRAME_SIZE;
#define SPRN_DBG_SRR0	SPRN_DSRR0
#define SPRN_DBG_SRR1	SPRN_DSRR1

#define MC_SET_KSTACK						            \
	ld	r1,PACA_MC_STACK(r13);					    \
	subi	r1,r1,SPECIAL_EXC_FRAME_SIZE;
#define SPRN_MC_SRR0	SPRN_MCSRR0
#define SPRN_MC_SRR1	SPRN_MCSRR1

#define NORMAL_EXCEPTION_PROLOG(n, addition)				    \
	EXCEPTION_PROLOG(n, GEN, addition##_GEN)

#define CRIT_EXCEPTION_PROLOG(n, addition)				    \
	EXCEPTION_PROLOG(n, CRIT, addition##_CRIT)

#define DBG_EXCEPTION_PROLOG(n, addition)				    \
	EXCEPTION_PROLOG(n, DBG, addition##_DBG)

#define MC_EXCEPTION_PROLOG(n, addition)				    \
	EXCEPTION_PROLOG(n, MC, addition##_MC)


/* Variants of the "addition" argument for the prolog
 */
#define PROLOG_ADDITION_NONE_GEN
#define PROLOG_ADDITION_NONE_CRIT
#define PROLOG_ADDITION_NONE_DBG
#define PROLOG_ADDITION_NONE_MC

#define PROLOG_ADDITION_MASKABLE_GEN					    \
	lbz	r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */	    \
	cmpwi	cr0,r11,0;		/* yes -> go out of line */	    \
	beq	masked_interrupt_book3e;

#define PROLOG_ADDITION_2REGS_GEN					    \
	std	r14,PACA_EXGEN+EX_R14(r13);				    \
	std	r15,PACA_EXGEN+EX_R15(r13)

#define PROLOG_ADDITION_1REG_GEN					    \
	std	r14,PACA_EXGEN+EX_R14(r13);

#define PROLOG_ADDITION_2REGS_CRIT					    \
	std	r14,PACA_EXCRIT+EX_R14(r13);				    \
	std	r15,PACA_EXCRIT+EX_R15(r13)

#define PROLOG_ADDITION_2REGS_DBG					    \
	std	r14,PACA_EXDBG+EX_R14(r13);				    \
	std	r15,PACA_EXDBG+EX_R15(r13)

#define PROLOG_ADDITION_2REGS_MC					    \
	std	r14,PACA_EXMC+EX_R14(r13);				    \
	std	r15,PACA_EXMC+EX_R15(r13)

/* Core exception code for all exceptions except TLB misses.
 * XXX: Needs to make SPRN_SPRG_GEN depend on exception type
 */
#define EXCEPTION_COMMON(n, excf, ints)					    \
	std	r0,GPR0(r1);		/* save r0 in stackframe */	    \
	std	r2,GPR2(r1);		/* save r2 in stackframe */	    \
	SAVE_4GPRS(3, r1);		/* save r3 - r6 in stackframe */    \
	SAVE_2GPRS(7, r1);		/* save r7, r8 in stackframe */	    \
	std	r9,GPR9(r1);		/* save r9 in stackframe */	    \
	std	r10,_NIP(r1);		/* save SRR0 to stackframe */	    \
	std	r11,_MSR(r1);		/* save SRR1 to stackframe */	    \
	ACCOUNT_CPU_USER_ENTRY(r10,r11);/* accounting (uses cr0+eq) */	    \
	ld	r3,excf+EX_R10(r13);	/* get back r10 */		    \
	ld	r4,excf+EX_R11(r13);	/* get back r11 */		    \
	mfspr	r5,SPRN_SPRG_GEN_SCRATCH;/* get back r13 */		    \
	std	r12,GPR12(r1);		/* save r12 in stackframe */	    \
	ld	r2,PACATOC(r13);	/* get kernel TOC into r2 */	    \
	mflr	r6;			/* save LR in stackframe */	    \
	mfctr	r7;			/* save CTR in stackframe */	    \
	mfspr	r8,SPRN_XER;		/* save XER in stackframe */	    \
	ld	r9,excf+EX_R1(r13);	/* load orig r1 back from PACA */   \
	lwz	r10,excf+EX_CR(r13);	/* load orig CR back from PACA	*/  \
	lbz	r11,PACASOFTIRQEN(r13);	/* get current IRQ softe */	    \
	ld	r12,exception_marker@toc(r2);				    \
	li	r0,0;							    \
	std	r3,GPR10(r1);		/* save r10 to stackframe */	    \
	std	r4,GPR11(r1);		/* save r11 to stackframe */	    \
	std	r5,GPR13(r1);		/* save it to stackframe */	    \
	std	r6,_LINK(r1);						    \
	std	r7,_CTR(r1);						    \
	std	r8,_XER(r1);						    \
	li	r3,(n)+1;		/* indicate partial regs in trap */ \
	std	r9,0(r1);		/* store stack frame back link */   \
	std	r10,_CCR(r1);		/* store orig CR in stackframe */   \
	std	r9,GPR1(r1);		/* store stack frame back link */   \
	std	r11,SOFTE(r1);		/* and save it to stackframe */     \
	std	r12,STACK_FRAME_OVERHEAD-16(r1); /* mark the frame */	    \
	std	r3,_TRAP(r1);		/* set trap number		*/  \
	std	r0,RESULT(r1);		/* clear regs->result */	    \
	ints;

/* Variants for the "ints" argument */
#define INTS_KEEP
#define INTS_DISABLE_SOFT						    \
	stb	r0,PACASOFTIRQEN(r13);	/* mark interrupts soft-disabled */ \
	TRACE_DISABLE_INTS;
#define INTS_DISABLE_HARD						    \
	stb	r0,PACAHARDIRQEN(r13); /* and hard disabled */
#define INTS_DISABLE_ALL						    \
	INTS_DISABLE_SOFT						    \
	INTS_DISABLE_HARD

/* This is called by exceptions that used INTS_KEEP (that is did not clear
 * neither soft nor hard IRQ indicators in the PACA. This will restore MSR:EE
 * to it's previous value
 *
 * XXX In the long run, we may want to open-code it in order to separate the
 *     load from the wrtee, thus limiting the latency caused by the dependency
 *     but at this point, I'll favor code clarity until we have a near to final
 *     implementation
 */
#define INTS_RESTORE_HARD						    \
	ld	r11,_MSR(r1);						    \
	wrtee	r11;

/* XXX FIXME: Restore r14/r15 when necessary */
#define BAD_STACK_TRAMPOLINE(n)						    \
exc_##n##_bad_stack:							    \
	li	r1,(n);			/* get exception number */	    \
	sth	r1,PACA_TRAP_SAVE(r13);	/* store trap */		    \
	b	bad_stack_book3e;	/* bad stack error */

#define	EXCEPTION_STUB(loc, label)					\
	. = interrupt_base_book3e + loc;				\
	nop;	/* To make debug interrupts happy */			\
	b	exc_##label##_book3e;

#define ACK_NONE(r)
#define ACK_DEC(r)							\
	lis	r,TSR_DIS@h;						\
	mtspr	SPRN_TSR,r
#define ACK_FIT(r)							\
	lis	r,TSR_FIS@h;						\
	mtspr	SPRN_TSR,r

#define MASKABLE_EXCEPTION(trapnum, label, hdlr, ack)			\
	START_EXCEPTION(label);						\
	NORMAL_EXCEPTION_PROLOG(trapnum, PROLOG_ADDITION_MASKABLE)	\
	EXCEPTION_COMMON(trapnum, PACA_EXGEN, INTS_DISABLE_ALL)		\
	ack(r8);							\
	addi	r3,r1,STACK_FRAME_OVERHEAD;				\
	bl	hdlr;							\
	b	.ret_from_except_lite;

/* This value is used to mark exception frames on the stack. */
	.section	".toc","aw"
exception_marker:
	.tc	ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER


/*
 * And here we have the exception vectors !
 */

	.text
	.balign	0x1000
	.globl interrupt_base_book3e
interrupt_base_book3e:					/* fake trap */
	/* Note: If real debug exceptions are supported by the HW, the vector
	 * below will have to be patched up to point to an appropriate handler
	 */
	EXCEPTION_STUB(0x000, machine_check)		/* 0x0200 */
	EXCEPTION_STUB(0x020, critical_input)		/* 0x0580 */
	EXCEPTION_STUB(0x040, debug_crit)		/* 0x0d00 */
	EXCEPTION_STUB(0x060, data_storage)		/* 0x0300 */
	EXCEPTION_STUB(0x080, instruction_storage)	/* 0x0400 */
	EXCEPTION_STUB(0x0a0, external_input)		/* 0x0500 */
	EXCEPTION_STUB(0x0c0, alignment)		/* 0x0600 */
	EXCEPTION_STUB(0x0e0, program)			/* 0x0700 */
	EXCEPTION_STUB(0x100, fp_unavailable)		/* 0x0800 */
	EXCEPTION_STUB(0x120, system_call)		/* 0x0c00 */
	EXCEPTION_STUB(0x140, ap_unavailable)		/* 0x0f20 */
	EXCEPTION_STUB(0x160, decrementer)		/* 0x0900 */
	EXCEPTION_STUB(0x180, fixed_interval)		/* 0x0980 */
	EXCEPTION_STUB(0x1a0, watchdog)			/* 0x09f0 */
	EXCEPTION_STUB(0x1c0, data_tlb_miss)
	EXCEPTION_STUB(0x1e0, instruction_tlb_miss)

#if 0
	EXCEPTION_STUB(0x280, processor_doorbell)
	EXCEPTION_STUB(0x220, processor_doorbell_crit)
#endif
	.globl interrupt_end_book3e
interrupt_end_book3e:

/* Critical Input Interrupt */
	START_EXCEPTION(critical_input);
	CRIT_EXCEPTION_PROLOG(0x100, PROLOG_ADDITION_NONE)
//	EXCEPTION_COMMON(0x100, PACA_EXCRIT, INTS_DISABLE_ALL)
//	bl	special_reg_save_crit
//	addi	r3,r1,STACK_FRAME_OVERHEAD
//	bl	.critical_exception
//	b	ret_from_crit_except
	b	.

/* Machine Check Interrupt */
	START_EXCEPTION(machine_check);
	CRIT_EXCEPTION_PROLOG(0x200, PROLOG_ADDITION_NONE)
//	EXCEPTION_COMMON(0x200, PACA_EXMC, INTS_DISABLE_ALL)
//	bl	special_reg_save_mc
//	addi	r3,r1,STACK_FRAME_OVERHEAD
//	bl	.machine_check_exception
//	b	ret_from_mc_except
	b	.

/* Data Storage Interrupt */
	START_EXCEPTION(data_storage)
	NORMAL_EXCEPTION_PROLOG(0x300, PROLOG_ADDITION_2REGS)
	mfspr	r14,SPRN_DEAR
	mfspr	r15,SPRN_ESR
	EXCEPTION_COMMON(0x300, PACA_EXGEN, INTS_KEEP)
	b	storage_fault_common

/* Instruction Storage Interrupt */
	START_EXCEPTION(instruction_storage);
	NORMAL_EXCEPTION_PROLOG(0x400, PROLOG_ADDITION_2REGS)
	li	r15,0
	mr	r14,r10
	EXCEPTION_COMMON(0x400, PACA_EXGEN, INTS_KEEP)
	b	storage_fault_common

/* External Input Interrupt */
	MASKABLE_EXCEPTION(0x500, external_input, .do_IRQ, ACK_NONE)

/* Alignment */
	START_EXCEPTION(alignment);
	NORMAL_EXCEPTION_PROLOG(0x600, PROLOG_ADDITION_2REGS)
	mfspr	r14,SPRN_DEAR
	mfspr	r15,SPRN_ESR
	EXCEPTION_COMMON(0x600, PACA_EXGEN, INTS_KEEP)
	b	alignment_more	/* no room, go out of line */

/* Program Interrupt */
	START_EXCEPTION(program);
	NORMAL_EXCEPTION_PROLOG(0x700, PROLOG_ADDITION_1REG)
	mfspr	r14,SPRN_ESR
	EXCEPTION_COMMON(0x700, PACA_EXGEN, INTS_DISABLE_SOFT)
	std	r14,_DSISR(r1)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ld	r14,PACA_EXGEN+EX_R14(r13)
	bl	.save_nvgprs
	INTS_RESTORE_HARD
	bl	.program_check_exception
	b	.ret_from_except

/* Floating Point Unavailable Interrupt */
	START_EXCEPTION(fp_unavailable);
	NORMAL_EXCEPTION_PROLOG(0x800, PROLOG_ADDITION_NONE)
	/* we can probably do a shorter exception entry for that one... */
	EXCEPTION_COMMON(0x800, PACA_EXGEN, INTS_KEEP)
	bne	1f			/* if from user, just load it up */
	bl	.save_nvgprs
	addi	r3,r1,STACK_FRAME_OVERHEAD
	INTS_RESTORE_HARD
	bl	.kernel_fp_unavailable_exception
	BUG_OPCODE
1:	ld	r12,_MSR(r1)
	bl	.load_up_fpu
	b	fast_exception_return

/* Decrementer Interrupt */
	MASKABLE_EXCEPTION(0x900, decrementer, .timer_interrupt, ACK_DEC)

/* Fixed Interval Timer Interrupt */
	MASKABLE_EXCEPTION(0x980, fixed_interval, .unknown_exception, ACK_FIT)

/* Watchdog Timer Interrupt */
	START_EXCEPTION(watchdog);
	CRIT_EXCEPTION_PROLOG(0x9f0, PROLOG_ADDITION_NONE)
//	EXCEPTION_COMMON(0x9f0, PACA_EXCRIT, INTS_DISABLE_ALL)
//	bl	special_reg_save_crit
//	addi	r3,r1,STACK_FRAME_OVERHEAD
//	bl	.unknown_exception
//	b	ret_from_crit_except
	b	.

/* System Call Interrupt */
	START_EXCEPTION(system_call)
	mr	r9,r13			/* keep a copy of userland r13 */
	mfspr	r11,SPRN_SRR0		/* get return address */
	mfspr	r12,SPRN_SRR1		/* get previous MSR */
	mfspr	r13,SPRN_SPRG_PACA	/* get our PACA */
	b	system_call_common

/* Auxillary Processor Unavailable Interrupt */
	START_EXCEPTION(ap_unavailable);
	NORMAL_EXCEPTION_PROLOG(0xf20, PROLOG_ADDITION_NONE)
	EXCEPTION_COMMON(0xf20, PACA_EXGEN, INTS_KEEP)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	bl	.save_nvgprs
	INTS_RESTORE_HARD
	bl	.unknown_exception
	b	.ret_from_except

/* Debug exception as a critical interrupt*/
	START_EXCEPTION(debug_crit);
	CRIT_EXCEPTION_PROLOG(0xd00, PROLOG_ADDITION_2REGS)

	/*
	 * If there is a single step or branch-taken exception in an
	 * exception entry sequence, it was probably meant to apply to
	 * the code where the exception occurred (since exception entry
	 * doesn't turn off DE automatically).  We simulate the effect
	 * of turning off DE on entry to an exception handler by turning
	 * off DE in the CSRR1 value and clearing the debug status.
	 */

	mfspr	r14,SPRN_DBSR		/* check single-step/branch taken */
	andis.	r15,r14,DBSR_IC@h
	beq+	1f

	LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e)
	LOAD_REG_IMMEDIATE(r15,interrupt_end_book3e)
	cmpld	cr0,r10,r14
	cmpld	cr1,r10,r15
	blt+	cr0,1f
	bge+	cr1,1f

	/* here it looks like we got an inappropriate debug exception. */
	lis	r14,DBSR_IC@h		/* clear the IC event */
	rlwinm	r11,r11,0,~MSR_DE	/* clear DE in the CSRR1 value */
	mtspr	SPRN_DBSR,r14
	mtspr	SPRN_CSRR1,r11
	lwz	r10,PACA_EXCRIT+EX_CR(r13)	/* restore registers */
	ld	r1,PACA_EXCRIT+EX_R1(r13)
	ld	r14,PACA_EXCRIT+EX_R14(r13)
	ld	r15,PACA_EXCRIT+EX_R15(r13)
	mtcr	r10
	ld	r10,PACA_EXCRIT+EX_R10(r13)	/* restore registers */
	ld	r11,PACA_EXCRIT+EX_R11(r13)
	mfspr	r13,SPRN_SPRG_CRIT_SCRATCH
	rfci

	/* Normal debug exception */
	/* XXX We only handle coming from userspace for now since we can't
	 *     quite save properly an interrupted kernel state yet
	 */
1:	andi.	r14,r11,MSR_PR;		/* check for userspace again */
	beq	kernel_dbg_exc;		/* if from kernel mode */

	/* Now we mash up things to make it look like we are coming on a
	 * normal exception
	 */
	mfspr	r15,SPRN_SPRG_CRIT_SCRATCH
	mtspr	SPRN_SPRG_GEN_SCRATCH,r15
	mfspr	r14,SPRN_DBSR
	EXCEPTION_COMMON(0xd00, PACA_EXCRIT, INTS_DISABLE_ALL)
	std	r14,_DSISR(r1)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	mr	r4,r14
	ld	r14,PACA_EXCRIT+EX_R14(r13)
	ld	r15,PACA_EXCRIT+EX_R15(r13)
	bl	.save_nvgprs
	bl	.DebugException
	b	.ret_from_except

kernel_dbg_exc:
	b	.	/* NYI */


/*
 * An interrupt came in while soft-disabled; clear EE in SRR1,
 * clear paca->hard_enabled and return.
 */
masked_interrupt_book3e:
	mtcr	r10
	stb	r11,PACAHARDIRQEN(r13)
	mfspr	r10,SPRN_SRR1
	rldicl	r11,r10,48,1		/* clear MSR_EE */
	rotldi	r10,r11,16
	mtspr	SPRN_SRR1,r10
	ld	r10,PACA_EXGEN+EX_R10(r13);	/* restore registers */
	ld	r11,PACA_EXGEN+EX_R11(r13);
	mfspr	r13,SPRN_SPRG_GEN_SCRATCH;
	rfi
	b	.

/*
 * This is called from 0x300 and 0x400 handlers after the prologs with
 * r14 and r15 containing the fault address and error code, with the
 * original values stashed away in the PACA
 */
storage_fault_common:
	std	r14,_DAR(r1)
	std	r15,_DSISR(r1)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	mr	r4,r14
	mr	r5,r15
	ld	r14,PACA_EXGEN+EX_R14(r13)
	ld	r15,PACA_EXGEN+EX_R15(r13)
	INTS_RESTORE_HARD
	bl	.do_page_fault
	cmpdi	r3,0
	bne-	1f
	b	.ret_from_except_lite
1:	bl	.save_nvgprs
	mr	r5,r3
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ld	r4,_DAR(r1)
	bl	.bad_page_fault
	b	.ret_from_except

/*
 * Alignment exception doesn't fit entirely in the 0x100 bytes so it
 * continues here.
 */
alignment_more:
	std	r14,_DAR(r1)
	std	r15,_DSISR(r1)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ld	r14,PACA_EXGEN+EX_R14(r13)
	ld	r15,PACA_EXGEN+EX_R15(r13)
	bl	.save_nvgprs
	INTS_RESTORE_HARD
	bl	.alignment_exception
	b	.ret_from_except

/*
 * We branch here from entry_64.S for the last stage of the exception
 * return code path. MSR:EE is expected to be off at that point
 */
_GLOBAL(exception_return_book3e)
	b	1f

/* This is the return from load_up_fpu fast path which could do with
 * less GPR restores in fact, but for now we have a single return path
 */
	.globl fast_exception_return
fast_exception_return:
	wrteei	0
1:	mr	r0,r13
	ld	r10,_MSR(r1)
	REST_4GPRS(2, r1)
	andi.	r6,r10,MSR_PR
	REST_2GPRS(6, r1)
	beq	1f
	ACCOUNT_CPU_USER_EXIT(r10, r11)
	ld	r0,GPR13(r1)

1:	stdcx.	r0,0,r1		/* to clear the reservation */

	ld	r8,_CCR(r1)
	ld	r9,_LINK(r1)
	ld	r10,_CTR(r1)
	ld	r11,_XER(r1)
	mtcr	r8
	mtlr	r9
	mtctr	r10
	mtxer	r11
	REST_2GPRS(8, r1)
	ld	r10,GPR10(r1)
	ld	r11,GPR11(r1)
	ld	r12,GPR12(r1)
	mtspr	SPRN_SPRG_GEN_SCRATCH,r0

	std	r10,PACA_EXGEN+EX_R10(r13);
	std	r11,PACA_EXGEN+EX_R11(r13);
	ld	r10,_NIP(r1)
	ld	r11,_MSR(r1)
	ld	r0,GPR0(r1)
	ld	r1,GPR1(r1)
	mtspr	SPRN_SRR0,r10
	mtspr	SPRN_SRR1,r11
	ld	r10,PACA_EXGEN+EX_R10(r13)
	ld	r11,PACA_EXGEN+EX_R11(r13)
	mfspr	r13,SPRN_SPRG_GEN_SCRATCH
	rfi

/*
 * Trampolines used when spotting a bad kernel stack pointer in
 * the exception entry code.
 *
 * TODO: move some bits like SRR0 read to trampoline, pass PACA
 * index around, etc... to handle crit & mcheck
 */
BAD_STACK_TRAMPOLINE(0x000)
BAD_STACK_TRAMPOLINE(0x100)
BAD_STACK_TRAMPOLINE(0x200)
BAD_STACK_TRAMPOLINE(0x300)
BAD_STACK_TRAMPOLINE(0x400)
BAD_STACK_TRAMPOLINE(0x500)
BAD_STACK_TRAMPOLINE(0x600)
BAD_STACK_TRAMPOLINE(0x700)
BAD_STACK_TRAMPOLINE(0x800)
BAD_STACK_TRAMPOLINE(0x900)
BAD_STACK_TRAMPOLINE(0x980)
BAD_STACK_TRAMPOLINE(0x9f0)
BAD_STACK_TRAMPOLINE(0xa00)
BAD_STACK_TRAMPOLINE(0xb00)
BAD_STACK_TRAMPOLINE(0xc00)
BAD_STACK_TRAMPOLINE(0xd00)
BAD_STACK_TRAMPOLINE(0xe00)
BAD_STACK_TRAMPOLINE(0xf00)
BAD_STACK_TRAMPOLINE(0xf20)

	.globl	bad_stack_book3e
bad_stack_book3e:
	/* XXX: Needs to make SPRN_SPRG_GEN depend on exception type */
	mfspr	r10,SPRN_SRR0;		  /* read SRR0 before touching stack */
	ld	r1,PACAEMERGSP(r13)
	subi	r1,r1,64+INT_FRAME_SIZE
	std	r10,_NIP(r1)
	std	r11,_MSR(r1)
	ld	r10,PACA_EXGEN+EX_R1(r13) /* FIXME for crit & mcheck */
	lwz	r11,PACA_EXGEN+EX_CR(r13) /* FIXME for crit & mcheck */
	std	r10,GPR1(r1)
	std	r11,_CCR(r1)
	mfspr	r10,SPRN_DEAR
	mfspr	r11,SPRN_ESR
	std	r10,_DAR(r1)
	std	r11,_DSISR(r1)
	std	r0,GPR0(r1);		/* save r0 in stackframe */	    \
	std	r2,GPR2(r1);		/* save r2 in stackframe */	    \
	SAVE_4GPRS(3, r1);		/* save r3 - r6 in stackframe */    \
	SAVE_2GPRS(7, r1);		/* save r7, r8 in stackframe */	    \
	std	r9,GPR9(r1);		/* save r9 in stackframe */	    \
	ld	r3,PACA_EXGEN+EX_R10(r13);/* get back r10 */		    \
	ld	r4,PACA_EXGEN+EX_R11(r13);/* get back r11 */		    \
	mfspr	r5,SPRN_SPRG_GEN_SCRATCH;/* get back r13 XXX can be wrong */ \
	std	r3,GPR10(r1);		/* save r10 to stackframe */	    \
	std	r4,GPR11(r1);		/* save r11 to stackframe */	    \
	std	r12,GPR12(r1);		/* save r12 in stackframe */	    \
	std	r5,GPR13(r1);		/* save it to stackframe */	    \
	mflr	r10
	mfctr	r11
	mfxer	r12
	std	r10,_LINK(r1)
	std	r11,_CTR(r1)
	std	r12,_XER(r1)
	SAVE_10GPRS(14,r1)
	SAVE_8GPRS(24,r1)
	lhz	r12,PACA_TRAP_SAVE(r13)
	std	r12,_TRAP(r1)
	addi	r11,r1,INT_FRAME_SIZE
	std	r11,0(r1)
	li	r12,0
	std	r12,0(r11)
	ld	r2,PACATOC(r13)
1:	addi	r3,r1,STACK_FRAME_OVERHEAD
	bl	.kernel_bad_stack
	b	1b

/*
 * Setup the initial TLB for a core. This current implementation
 * assume that whatever we are running off will not conflict with
 * the new mapping at PAGE_OFFSET.
 * We also make various assumptions about the processor we run on,
 * this might have to be made more flexible based on the content
 * of MMUCFG and friends.
 */
_GLOBAL(initial_tlb_book3e)

	/* Setup MAS 0,1,2,3 and 7 for tlbwe of a 1G entry that maps the
	 * kernel linear mapping. We also set MAS8 once for all here though
	 * that will have to be made dependent on whether we are running under
	 * a hypervisor I suppose.
	 */
	li	r3,MAS0_HES | MAS0_WQ_ALLWAYS
	mtspr	SPRN_MAS0,r3
	lis	r3,(MAS1_VALID | MAS1_IPROT)@h
	ori	r3,r3,BOOK3E_PAGESZ_1GB << MAS1_TSIZE_SHIFT
	mtspr	SPRN_MAS1,r3
	LOAD_REG_IMMEDIATE(r3, PAGE_OFFSET | MAS2_M)
	mtspr	SPRN_MAS2,r3
	li	r3,MAS3_SR | MAS3_SW | MAS3_SX
	mtspr	SPRN_MAS7_MAS3,r3
	li	r3,0
	mtspr	SPRN_MAS8,r3

	/* Write the TLB entry */
	tlbwe

	/* Now we branch the new virtual address mapped by this entry */
	LOAD_REG_IMMEDIATE(r3,1f)
	mtctr	r3
	bctr

1:	/* We are now running at PAGE_OFFSET, clean the TLB of everything
	 * else (XXX we should scan for bolted crap from the firmware too)
	 */
	PPC_TLBILX(0,0,0)
	sync
	isync

	/* We translate LR and return */
	mflr	r3
	tovirt(r3,r3)
	mtlr	r3
	blr

/*
 * Main entry (boot CPU, thread 0)
 *
 * We enter here from head_64.S, possibly after the prom_init trampoline
 * with r3 and r4 already saved to r31 and 30 respectively and in 64 bits
 * mode. Anything else is as it was left by the bootloader
 *
 * Initial requirements of this port:
 *
 * - Kernel loaded at 0 physical
 * - A good lump of memory mapped 0:0 by UTLB entry 0
 * - MSR:IS & MSR:DS set to 0
 *
 * Note that some of the above requirements will be relaxed in the future
 * as the kernel becomes smarter at dealing with different initial conditions
 * but for now you have to be careful
 */
_GLOBAL(start_initialization_book3e)
	mflr	r28

	/* First, we need to setup some initial TLBs to map the kernel
	 * text, data and bss at PAGE_OFFSET. We don't have a real mode
	 * and always use AS 0, so we just set it up to match our link
	 * address and never use 0 based addresses.
	 */
	bl	.initial_tlb_book3e

	/* Init global core bits */
	bl	.init_core_book3e

	/* Init per-thread bits */
	bl	.init_thread_book3e

	/* Return to common init code */
	tovirt(r28,r28)
	mtlr	r28
	blr


/*
 * Secondary core/processor entry
 *
 * This is entered for thread 0 of a secondary core, all other threads
 * are expected to be stopped. It's similar to start_initialization_book3e
 * except that it's generally entered from the holding loop in head_64.S
 * after CPUs have been gathered by Open Firmware.
 *
 * We assume we are in 32 bits mode running with whatever TLB entry was
 * set for us by the firmware or POR engine.
 */
_GLOBAL(book3e_secondary_core_init_tlb_set)
	li	r4,1
	b	.generic_secondary_smp_init

_GLOBAL(book3e_secondary_core_init)
	mflr	r28

	/* Do we need to setup initial TLB entry ? */
	cmplwi	r4,0
	bne	2f

	/* Setup TLB for this core */
	bl	.initial_tlb_book3e

	/* We can return from the above running at a different
	 * address, so recalculate r2 (TOC)
	 */
	bl	.relative_toc

	/* Init global core bits */
2:	bl	.init_core_book3e

	/* Init per-thread bits */
3:	bl	.init_thread_book3e

	/* Return to common init code at proper virtual address.
	 *
	 * Due to various previous assumptions, we know we entered this
	 * function at either the final PAGE_OFFSET mapping or using a
	 * 1:1 mapping at 0, so we don't bother doing a complicated check
	 * here, we just ensure the return address has the right top bits.
	 *
	 * Note that if we ever want to be smarter about where we can be
	 * started from, we have to be careful that by the time we reach
	 * the code below we may already be running at a different location
	 * than the one we were called from since initial_tlb_book3e can
	 * have moved us already.
	 */
	cmpdi	cr0,r28,0
	blt	1f
	lis	r3,PAGE_OFFSET@highest
	sldi	r3,r3,32
	or	r28,r28,r3
1:	mtlr	r28
	blr

_GLOBAL(book3e_secondary_thread_init)
	mflr	r28
	b	3b

_STATIC(init_core_book3e)
	/* Establish the interrupt vector base */
	LOAD_REG_IMMEDIATE(r3, interrupt_base_book3e)
	mtspr	SPRN_IVPR,r3
	sync
	blr

_STATIC(init_thread_book3e)
	lis	r3,(SPRN_EPCR_ICM | SPRN_EPCR_GICM)@h
	mtspr	SPRN_EPCR,r3

	/* Make sure interrupts are off */
	wrteei	0

	/* disable watchdog and FIT and enable DEC interrupts */
	lis	r3,TCR_DIE@h
	mtspr	SPRN_TCR,r3

	blr