/*
* arch/ppc/kernel/head_44x.S
*
* Kernel execution entry point code.
*
* 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.
* Copyright 2000 MontaVista Software Inc.
* PPC405 modifications
* PowerPC 403GCX/405GP modifications.
* Author: MontaVista Software, Inc.
* frank_rowand@mvista.com or source@mvista.com
* debbie_chu@mvista.com
* Copyright 2002-2004 MontaVista Software, Inc.
* PowerPC 44x support, Matt Porter <mporter@kernel.crashing.org>
*
* 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/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/ibm4xx.h>
#include <asm/ibm44x.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/offsets.h>
/*
* Macros
*/
#define SET_IVOR(vector_number, vector_label) \
li r26,vector_label@l; \
mtspr SPRN_IVOR##vector_number,r26; \
sync
/* As with the other PowerPC ports, it is expected that when code
* execution begins here, the following registers contain valid, yet
* optional, information:
*
* r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.)
* 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=128")
* r7 - End of kernel command line string
*
*/
.text
_GLOBAL(_stext)
_GLOBAL(_start)
/*
* Reserve a word at a fixed location to store the address
* of abatron_pteptrs
*/
nop
/*
* Save parameters we are passed
*/
mr r31,r3
mr r30,r4
mr r29,r5
mr r28,r6
mr r27,r7
li r24,0 /* CPU number */
/*
* Set up the initial MMU state
*
* We are still executing code at the virtual address
* mappings set by the firmware for the base of RAM.
*
* We first invalidate all TLB entries but the one
* we are running from. We then load the KERNELBASE
* mappings so we can begin to use kernel addresses
* natively and so the interrupt vector locations are
* permanently pinned (necessary since Book E
* implementations always have translation enabled).
*
* TODO: Use the known TLB entry we are running from to
* determine which physical region we are located
* in. This can be used to determine where in RAM
* (on a shared CPU system) or PCI memory space
* (on a DRAMless system) we are located.
* For now, we assume a perfect world which means
* we are located at the base of DRAM (physical 0).
*/
/*
* Search TLB for entry that we are currently using.
* Invalidate all entries but the one we are using.
*/
/* Load our current PID->MMUCR TID and MSR IS->MMUCR STS */
mfspr r3,SPRN_PID /* Get PID */
mfmsr r4 /* Get MSR */
andi. r4,r4,MSR_IS@l /* TS=1? */
beq wmmucr /* If not, leave STS=0 */
oris r3,r3,PPC44x_MMUCR_STS@h /* Set STS=1 */
wmmucr: mtspr SPRN_MMUCR,r3 /* Put MMUCR */
sync
bl invstr /* Find our address */
invstr: mflr r5 /* Make it accessible */
tlbsx r23,0,r5 /* Find entry we are in */
li r4,0 /* Start at TLB entry 0 */
li r3,0 /* Set PAGEID inval value */
1: cmpw r23,r4 /* Is this our entry? */
beq skpinv /* If so, skip the inval */
tlbwe r3,r4,PPC44x_TLB_PAGEID /* If not, inval the entry */
skpinv: addi r4,r4,1 /* Increment */
cmpwi r4,64 /* Are we done? */
bne 1b /* If not, repeat */
isync /* If so, context change */
/*
* Configure and load pinned entry into TLB slot 63.
*/
lis r3,KERNELBASE@h /* Load the kernel virtual address */
ori r3,r3,KERNELBASE@l
/* Kernel is at the base of RAM */
li r4, 0 /* Load the kernel physical address */
/* Load the kernel PID = 0 */
li r0,0
mtspr SPRN_PID,r0
sync
/* Initialize MMUCR */
li r5,0
mtspr SPRN_MMUCR,r5
sync
/* pageid fields */
clrrwi r3,r3,10 /* Mask off the effective page number */
ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M
/* xlat fields */
clrrwi r4,r4,10 /* Mask off the real page number */
/* ERPN is 0 for first 4GB page */
/* attrib fields */
/* Added guarded bit to protect against speculative loads/stores */
li r5,0
ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G)
li r0,63 /* TLB slot 63 */
tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */
tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
/* Force context change */
mfmsr r0
mtspr SRR1, r0
lis r0,3f@h
ori r0,r0,3f@l
mtspr SRR0,r0
sync
rfi
/* If necessary, invalidate original entry we used */
3: cmpwi r23,63
beq 4f
li r6,0
tlbwe r6,r23,PPC44x_TLB_PAGEID
isync
4:
#ifdef CONFIG_SERIAL_TEXT_DEBUG
/*
* Add temporary UART mapping for early debug. This
* mapping must be identical to that used by the early
* bootloader code since the same asm/serial.h parameters
* are used for polled operation.
*/
/* pageid fields */
lis r3,0xe000
ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_256M
/* xlat fields */
lis r4,0x4000 /* RPN is 0x40000000 */
ori r4,r4,0x0001 /* ERPN is 1 for second 4GB page */
/* attrib fields */
li r5,0
ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_I | PPC44x_TLB_G)
li r0,1 /* TLB slot 1 */
tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */
tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */
tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */
/* Force context change */
isync
#endif /* CONFIG_SERIAL_TEXT_DEBUG */
/* Establish the interrupt vector offsets */
SET_IVOR(0, CriticalInput);
SET_IVOR(1, MachineCheck);
SET_IVOR(2, DataStorage);
SET_IVOR(3, InstructionStorage);
SET_IVOR(4, ExternalInput);
SET_IVOR(5, Alignment);
SET_IVOR(6, Program);
SET_IVOR(7, FloatingPointUnavailable);
SET_IVOR(8, SystemCall);
SET_IVOR(9, AuxillaryProcessorUnavailable);
SET_IVOR(10, Decrementer);
SET_IVOR(11, FixedIntervalTimer);
SET_IVOR(12, WatchdogTimer);
SET_IVOR(13, DataTLBError);
SET_IVOR(14, InstructionTLBError);
SET_IVOR(15, Debug);
/* Establish the interrupt vector base */
lis r4,interrupt_base@h /* IVPR only uses the high 16-bits */
mtspr SPRN_IVPR,r4
/*
* This is where the main kernel code starts.
*/
/* ptr to current */
lis r2,init_task@h
ori r2,r2,init_task@l
/* ptr to current thread */
addi r4,r2,THREAD /* init task's THREAD */
mtspr SPRG3,r4
/* stack */
lis r1,init_thread_union@h
ori r1,r1,init_thread_union@l
li r0,0
stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
bl early_init
/*
* Decide what sort of machine this is and initialize the MMU.
*/
mr r3,r31
mr r4,r30
mr r5,r29
mr r6,r28
mr r7,r27
bl machine_init
bl MMU_init
/* Setup PTE pointers for the Abatron bdiGDB */
lis r6, swapper_pg_dir@h
ori r6, r6, swapper_pg_dir@l
lis r5, abatron_pteptrs@h
ori r5, r5, abatron_pteptrs@l
lis r4, KERNELBASE@h
ori r4, r4, KERNELBASE@l
stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */
stw r6, 0(r5)
/* Let's move on */
lis r4,start_kernel@h
ori r4,r4,start_kernel@l
lis r3,MSR_KERNEL@h
ori r3,r3,MSR_KERNEL@l
mtspr SRR0,r4
mtspr SRR1,r3
rfi /* change context and jump to start_kernel */
/*
* Interrupt vector entry code
*
* The Book E MMUs are always on so we don't need to handle
* interrupts in real mode as with previous PPC processors. In
* this case we handle interrupts in the kernel virtual address
* space.
*
* Interrupt vectors are dynamically placed relative to the
* interrupt prefix as determined by the address of interrupt_base.
* The interrupt vectors offsets are programmed using the labels
* for each interrupt vector entry.
*
* Interrupt vectors must be aligned on a 16 byte boundary.
* We align on a 32 byte cache line boundary for good measure.
*/
#define NORMAL_EXCEPTION_PROLOG \
mtspr SPRN_SPRG0,r10; /* save two registers to work with */\
mtspr SPRN_SPRG1,r11; \
mtspr SPRN_SPRG4W,r1; \
mfcr r10; /* save CR in r10 for now */\
mfspr r11,SPRN_SRR1; /* check whether user or kernel */\
andi. r11,r11,MSR_PR; \
beq 1f; \
mfspr r1,SPRG3; /* if from user, start at top of */\
lwz r1,THREAD_INFO-THREAD(r1); /* this thread's kernel stack */\
addi r1,r1,THREAD_SIZE; \
1: subi r1,r1,INT_FRAME_SIZE; /* Allocate an exception frame */\
tophys(r11,r1); \
stw r10,_CCR(r11); /* save various registers */\
stw r12,GPR12(r11); \
stw r9,GPR9(r11); \
mfspr r10,SPRG0; \
stw r10,GPR10(r11); \
mfspr r12,SPRG1; \
stw r12,GPR11(r11); \
mflr r10; \
stw r10,_LINK(r11); \
mfspr r10,SPRG4R; \
mfspr r12,SRR0; \
stw r10,GPR1(r11); \
mfspr r9,SRR1; \
stw r10,0(r11); \
rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
stw r0,GPR0(r11); \
SAVE_4GPRS(3, r11); \
SAVE_2GPRS(7, r11)
/*
* Exception prolog for critical exceptions. This is a little different
* from the normal exception prolog above since a critical exception
* can potentially occur at any point during normal exception processing.
* Thus we cannot use the same SPRG registers as the normal prolog above.
* Instead we use a couple of words of memory at low physical addresses.
* This is OK since we don't support SMP on these processors. For Book E
* processors, we also have a reserved register (SPRG2) that is only used
* in critical exceptions so we can free up a GPR to use as the base for
* indirect access to the critical exception save area. This is necessary
* since the MMU is always on and the save area is offset from KERNELBASE.
*/
#define CRITICAL_EXCEPTION_PROLOG \
mtspr SPRG2,r8; /* SPRG2 only used in criticals */ \
lis r8,crit_save@ha; \
stw r10,crit_r10@l(r8); \
stw r11,crit_r11@l(r8); \
mfspr r10,SPRG0; \
stw r10,crit_sprg0@l(r8); \
mfspr r10,SPRG1; \
stw r10,crit_sprg1@l(r8); \
mfspr r10,SPRG4R; \
stw r10,crit_sprg4@l(r8); \
mfspr r10,SPRG5R; \
stw r10,crit_sprg5@l(r8); \
mfspr r10,SPRG7R; \
stw r10,crit_sprg7@l(r8); \
mfspr r10,SPRN_PID; \
stw r10,crit_pid@l(r8); \
mfspr r10,SRR0; \
stw r10,crit_srr0@l(r8); \
mfspr r10,SRR1; \
stw r10,crit_srr1@l(r8); \
mfspr r8,SPRG2; /* SPRG2 only used in criticals */ \
mfcr r10; /* save CR in r10 for now */\
mfspr r11,SPRN_CSRR1; /* check whether user or kernel */\
andi. r11,r11,MSR_PR; \
lis r11,critical_stack_top@h; \
ori r11,r11,critical_stack_top@l; \
beq 1f; \
/* COMING FROM USER MODE */ \
mfspr r11,SPRG3; /* if from user, start at top of */\
lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
addi r11,r11,THREAD_SIZE; \
1: subi r11,r11,INT_FRAME_SIZE; /* Allocate an exception frame */\
stw r10,_CCR(r11); /* save various registers */\
stw r12,GPR12(r11); \
stw r9,GPR9(r11); \
mflr r10; \
stw r10,_LINK(r11); \
mfspr r12,SPRN_DEAR; /* save DEAR and ESR in the frame */\
stw r12,_DEAR(r11); /* since they may have had stuff */\
mfspr r9,SPRN_ESR; /* in them at the point where the */\
stw r9,_ESR(r11); /* exception was taken */\
mfspr r12,CSRR0; \
stw r1,GPR1(r11); \
mfspr r9,CSRR1; \
stw r1,0(r11); \
tovirt(r1,r11); \
rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
stw r0,GPR0(r11); \
SAVE_4GPRS(3, r11); \
SAVE_2GPRS(7, r11)
/*
* Exception prolog for machine check exceptions. This is similar to
* the critical exception prolog, except that machine check exceptions
* have their own save area. For Book E processors, we also have a
* reserved register (SPRG6) that is only used in machine check exceptions
* so we can free up a GPR to use as the base for indirect access to the
* machine check exception save area. This is necessary since the MMU
* is always on and the save area is offset from KERNELBASE.
*/
#define MCHECK_EXCEPTION_PROLOG \
mtspr SPRG6W,r8; /* SPRG6 used in machine checks */ \
lis r8,mcheck_save@ha; \
stw r10,mcheck_r10@l(r8); \
stw r11,mcheck_r11@l(r8); \
mfspr r10,SPRG0; \
stw r10,mcheck_sprg0@l(r8); \
mfspr r10,SPRG1; \
stw r10,mcheck_sprg1@l(r8); \
mfspr r10,SPRG4R; \
stw r10,mcheck_sprg4@l(r8); \
mfspr r10,SPRG5R; \
stw r10,mcheck_sprg5@l(r8); \
mfspr r10,SPRG7R; \
stw r10,mcheck_sprg7@l(r8); \
mfspr r10,SPRN_PID; \
stw r10,mcheck_pid@l(r8); \
mfspr r10,SRR0; \
stw r10,mcheck_srr0@l(r8); \
mfspr r10,SRR1; \
stw r10,mcheck_srr1@l(r8); \
mfspr r10,CSRR0; \
stw r10,mcheck_csrr0@l(r8); \
mfspr r10,CSRR1; \
stw r10,mcheck_csrr1@l(r8); \
mfspr r8,SPRG6R; /* SPRG6 used in machine checks */ \
mfcr r10; /* save CR in r10 for now */\
mfspr r11,SPRN_MCSRR1; /* check whether user or kernel */\
andi. r11,r11,MSR_PR; \
lis r11,mcheck_stack_top@h; \
ori r11,r11,mcheck_stack_top@l; \
beq 1f; \
/* COMING FROM USER MODE */ \
mfspr r11,SPRG3; /* if from user, start at top of */\
lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
addi r11,r11,THREAD_SIZE; \
1: subi r11,r11,INT_FRAME_SIZE; /* Allocate an exception frame */\
stw r10,_CCR(r11); /* save various registers */\
stw r12,GPR12(r11); \
stw r9,GPR9(r11); \
mflr r10; \
stw r10,_LINK(r11); \
mfspr r12,SPRN_DEAR; /* save DEAR and ESR in the frame */\
stw r12,_DEAR(r11); /* since they may have had stuff */\
mfspr r9,SPRN_ESR; /* in them at the point where the */\
stw r9,_ESR(r11); /* exception was taken */\
mfspr r12,MCSRR0; \
stw r1,GPR1(r11); \
mfspr r9,MCSRR1; \
stw r1,0(r11); \
tovirt(r1,r11); \
rlwinm r9,r9,0,14,12; /* clear MSR_WE (necessary?) */\
stw r0,GPR0(r11); \
SAVE_4GPRS(3, r11); \
SAVE_2GPRS(7, r11)
/*
* Exception vectors.
*/
#define START_EXCEPTION(label) \
.align 5; \
label:
#define FINISH_EXCEPTION(func) \
bl transfer_to_handler_full; \
.long func; \
.long ret_from_except_full
#define EXCEPTION(n, label, hdlr, xfer) \
START_EXCEPTION(label); \
NORMAL_EXCEPTION_PROLOG; \
addi r3,r1,STACK_FRAME_OVERHEAD; \
xfer(n, hdlr)
#define CRITICAL_EXCEPTION(n, label, hdlr) \
START_EXCEPTION(label); \
CRITICAL_EXCEPTION_PROLOG; \
addi r3,r1,STACK_FRAME_OVERHEAD; \
EXC_XFER_TEMPLATE(hdlr, n+2, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
NOCOPY, transfer_to_handler_full, \
ret_from_except_full)
#define MCHECK_EXCEPTION(n, label, hdlr) \
START_EXCEPTION(label); \
MCHECK_EXCEPTION_PROLOG; \
lis r4,MCSR_MCS@h; \
mtspr SPRN_MCSR,r4; \
mfspr r5,SPRN_ESR; \
stw r5,_ESR(r11); \
addi r3,r1,STACK_FRAME_OVERHEAD; \
EXC_XFER_TEMPLATE(hdlr, n+2, (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
NOCOPY, mcheck_transfer_to_handler, \
ret_from_mcheck_exc)
#define EXC_XFER_TEMPLATE(hdlr, trap, msr, copyee, tfer, ret) \
li r10,trap; \
stw r10,TRAP(r11); \
lis r10,msr@h; \
ori r10,r10,msr@l; \
copyee(r10, r9); \
bl tfer; \
.long hdlr; \
.long ret
#define COPY_EE(d, s) rlwimi d,s,0,16,16
#define NOCOPY(d, s)
#define EXC_XFER_STD(n, hdlr) \
EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, NOCOPY, transfer_to_handler_full, \
ret_from_except_full)
#define EXC_XFER_LITE(n, hdlr) \
EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, NOCOPY, transfer_to_handler, \
ret_from_except)
#define EXC_XFER_EE(n, hdlr) \
EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, COPY_EE, transfer_to_handler_full, \
ret_from_except_full)
#define EXC_XFER_EE_LITE(n, hdlr) \
EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, COPY_EE, transfer_to_handler, \
ret_from_except)
interrupt_base:
/* Critical Input Interrupt */
CRITICAL_EXCEPTION(0x0100, CriticalInput, UnknownException)
/* Machine Check Interrupt */
#ifdef CONFIG_440A
MCHECK_EXCEPTION(0x0200, MachineCheck, MachineCheckException)
#else
CRITICAL_EXCEPTION(0x0200, MachineCheck, MachineCheckException)
#endif
/* Data Storage Interrupt */
START_EXCEPTION(DataStorage)
mtspr SPRG0, r10 /* Save some working registers */
mtspr SPRG1, r11
mtspr SPRG4W, r12
mtspr SPRG5W, r13
mfcr r11
mtspr SPRG7W, r11
/*
* Check if it was a store fault, if not then bail
* because a user tried to access a kernel or
* read-protected page. Otherwise, get the
* offending address and handle it.
*/
mfspr r10, SPRN_ESR
andis. r10, r10, ESR_ST@h
beq 2f
mfspr r10, SPRN_DEAR /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
andis. r11, r10, 0x8000
beq 3f
lis r11, swapper_pg_dir@h
ori r11, r11, swapper_pg_dir@l
mfspr r12,SPRN_MMUCR
rlwinm r12,r12,0,0,23 /* Clear TID */
b 4f
/* Get the PGD for the current thread */
3:
mfspr r11,SPRG3
lwz r11,PGDIR(r11)
/* Load PID into MMUCR TID */
mfspr r12,SPRN_MMUCR /* Get MMUCR */
mfspr r13,SPRN_PID /* Get PID */
rlwimi r12,r13,0,24,31 /* Set TID */
4:
mtspr SPRN_MMUCR,r12
rlwinm r12, r10, 13, 19, 29 /* Compute pgdir/pmd offset */
lwzx r11, r12, r11 /* Get pgd/pmd entry */
rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
beq 2f /* Bail if no table */
rlwimi r12, r10, 23, 20, 28 /* Compute pte address */
lwz r11, 4(r12) /* Get pte entry */
andi. r13, r11, _PAGE_RW /* Is it writeable? */
beq 2f /* Bail if not */
/* Update 'changed'.
*/
ori r11, r11, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE
stw r11, 4(r12) /* Update Linux page table */
li r13, PPC44x_TLB_SR@l /* Set SR */
rlwimi r13, r11, 29, 29, 29 /* SX = _PAGE_HWEXEC */
rlwimi r13, r11, 0, 30, 30 /* SW = _PAGE_RW */
rlwimi r13, r11, 29, 28, 28 /* UR = _PAGE_USER */
rlwimi r12, r11, 31, 26, 26 /* (_PAGE_USER>>1)->r12 */
rlwimi r12, r11, 29, 30, 30 /* (_PAGE_USER>>3)->r12 */
and r12, r12, r11 /* HWEXEC/RW & USER */
rlwimi r13, r12, 0, 26, 26 /* UX = HWEXEC & USER */
rlwimi r13, r12, 3, 27, 27 /* UW = RW & USER */
rlwimi r11,r13,0,26,31 /* Insert static perms */
rlwinm r11,r11,0,20,15 /* Clear U0-U3 */
/* find the TLB index that caused the fault. It has to be here. */
tlbsx r10, 0, r10
tlbwe r11, r10, PPC44x_TLB_ATTRIB /* Write ATTRIB */
/* Done...restore registers and get out of here.
*/
mfspr r11, SPRG7R
mtcr r11
mfspr r13, SPRG5R
mfspr r12, SPRG4R
mfspr r11, SPRG1
mfspr r10, SPRG0
rfi /* Force context change */
2:
/*
* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
mfspr r11, SPRG7R
mtcr r11
mfspr r13, SPRG5R
mfspr r12, SPRG4R
mfspr r11, SPRG1
mfspr r10, SPRG0
b data_access
/* Instruction Storage Interrupt */
START_EXCEPTION(InstructionStorage)
NORMAL_EXCEPTION_PROLOG
mr r4,r12 /* Pass SRR0 as arg2 */
li r5,0 /* Pass zero as arg3 */
EXC_XFER_EE_LITE(0x0400, handle_page_fault)
/* External Input Interrupt */
EXCEPTION(0x0500, ExternalInput, do_IRQ, EXC_XFER_LITE)
/* Alignment Interrupt */
START_EXCEPTION(Alignment)
NORMAL_EXCEPTION_PROLOG
mfspr r4,SPRN_DEAR /* Grab the DEAR and save it */
stw r4,_DEAR(r11)
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_EE(0x0600, AlignmentException)
/* Program Interrupt */
START_EXCEPTION(Program)
NORMAL_EXCEPTION_PROLOG
mfspr r4,SPRN_ESR /* Grab the ESR and save it */
stw r4,_ESR(r11)
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0x700, ProgramCheckException)
/* Floating Point Unavailable Interrupt */
EXCEPTION(0x2010, FloatingPointUnavailable, UnknownException, EXC_XFER_EE)
/* System Call Interrupt */
START_EXCEPTION(SystemCall)
NORMAL_EXCEPTION_PROLOG
EXC_XFER_EE_LITE(0x0c00, DoSyscall)
/* Auxillary Processor Unavailable Interrupt */
EXCEPTION(0x2020, AuxillaryProcessorUnavailable, UnknownException, EXC_XFER_EE)
/* Decrementer Interrupt */
START_EXCEPTION(Decrementer)
NORMAL_EXCEPTION_PROLOG
lis r0,TSR_DIS@h /* Setup the DEC interrupt mask */
mtspr SPRN_TSR,r0 /* Clear the DEC interrupt */
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_LITE(0x1000, timer_interrupt)
/* Fixed Internal Timer Interrupt */
/* TODO: Add FIT support */
EXCEPTION(0x1010, FixedIntervalTimer, UnknownException, EXC_XFER_EE)
/* Watchdog Timer Interrupt */
/* TODO: Add watchdog support */
CRITICAL_EXCEPTION(0x1020, WatchdogTimer, UnknownException)
/* Data TLB Error Interrupt */
START_EXCEPTION(DataTLBError)
mtspr SPRG0, r10 /* Save some working registers */
mtspr SPRG1, r11
mtspr SPRG4W, r12
mtspr SPRG5W, r13
mfcr r11
mtspr SPRG7W, r11
mfspr r10, SPRN_DEAR /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
andis. r11, r10, 0x8000
beq 3f
lis r11, swapper_pg_dir@h
ori r11, r11, swapper_pg_dir@l
mfspr r12,SPRN_MMUCR
rlwinm r12,r12,0,0,23 /* Clear TID */
b 4f
/* Get the PGD for the current thread */
3:
mfspr r11,SPRG3
lwz r11,PGDIR(r11)
/* Load PID into MMUCR TID */
mfspr r12,SPRN_MMUCR
mfspr r13,SPRN_PID /* Get PID */
rlwimi r12,r13,0,24,31 /* Set TID */
4:
mtspr SPRN_MMUCR,r12
rlwinm r12, r10, 13, 19, 29 /* Compute pgdir/pmd offset */
lwzx r11, r12, r11 /* Get pgd/pmd entry */
rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
beq 2f /* Bail if no table */
rlwimi r12, r10, 23, 20, 28 /* Compute pte address */
lwz r11, 4(r12) /* Get pte entry */
andi. r13, r11, _PAGE_PRESENT /* Is the page present? */
beq 2f /* Bail if not present */
ori r11, r11, _PAGE_ACCESSED
stw r11, 4(r12)
/* Jump to common tlb load */
b finish_tlb_load
2:
/* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
mfspr r11, SPRG7R
mtcr r11
mfspr r13, SPRG5R
mfspr r12, SPRG4R
mfspr r11, SPRG1
mfspr r10, SPRG0
b data_access
/* Instruction TLB Error Interrupt */
/*
* Nearly the same as above, except we get our
* information from different registers and bailout
* to a different point.
*/
START_EXCEPTION(InstructionTLBError)
mtspr SPRG0, r10 /* Save some working registers */
mtspr SPRG1, r11
mtspr SPRG4W, r12
mtspr SPRG5W, r13
mfcr r11
mtspr SPRG7W, r11
mfspr r10, SRR0 /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
andis. r11, r10, 0x8000
beq 3f
lis r11, swapper_pg_dir@h
ori r11, r11, swapper_pg_dir@l
mfspr r12,SPRN_MMUCR
rlwinm r12,r12,0,0,23 /* Clear TID */
b 4f
/* Get the PGD for the current thread */
3:
mfspr r11,SPRG3
lwz r11,PGDIR(r11)
/* Load PID into MMUCR TID */
mfspr r12,SPRN_MMUCR
mfspr r13,SPRN_PID /* Get PID */
rlwimi r12,r13,0,24,31 /* Set TID */
4:
mtspr SPRN_MMUCR,r12
rlwinm r12, r10, 13, 19, 29 /* Compute pgdir/pmd offset */
lwzx r11, r12, r11 /* Get pgd/pmd entry */
rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
beq 2f /* Bail if no table */
rlwimi r12, r10, 23, 20, 28 /* Compute pte address */
lwz r11, 4(r12) /* Get pte entry */
andi. r13, r11, _PAGE_PRESENT /* Is the page present? */
beq 2f /* Bail if not present */
ori r11, r11, _PAGE_ACCESSED
stw r11, 4(r12)
/* Jump to common TLB load point */
b finish_tlb_load
2:
/* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
mfspr r11, SPRG7R
mtcr r11
mfspr r13, SPRG5R
mfspr r12, SPRG4R
mfspr r11, SPRG1
mfspr r10, SPRG0
b InstructionStorage
/* Check for a single step debug exception while in an exception
* handler before state has been saved. This is to catch the case
* where an instruction that we are trying to single step causes
* an exception (eg ITLB/DTLB miss) and thus the first instruction of
* the exception handler generates a single step debug exception.
*
* If we get a debug trap on the first instruction of an exception handler,
* we reset the MSR_DE in the _exception handler's_ MSR (the debug trap is
* a critical exception, so we are using SPRN_CSRR1 to manipulate the MSR).
* The exception handler was handling a non-critical interrupt, so it will
* save (and later restore) the MSR via SPRN_SRR1, which will still have
* the MSR_DE bit set.
*/
/* Debug Interrupt */
START_EXCEPTION(Debug)
CRITICAL_EXCEPTION_PROLOG
/*
* If this 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 r10,SPRN_DBSR /* check single-step/branch taken */
andis. r10,r10,(DBSR_IC|DBSR_BT)@h
beq+ 1f
andi. r0,r9,MSR_PR /* check supervisor */
beq 2f /* branch if we need to fix it up... */
/* continue normal handling for a critical exception... */
1: mfspr r4,SPRN_DBSR
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_TEMPLATE(DebugException, 0x2002, \
(MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
/* here it looks like we got an inappropriate debug exception. */
2: rlwinm r9,r9,0,~MSR_DE /* clear DE in the CSRR1 value */
mtspr SPRN_DBSR,r10 /* clear the IC/BT debug intr status */
/* restore state and get out */
lwz r10,_CCR(r11)
lwz r0,GPR0(r11)
lwz r1,GPR1(r11)
mtcrf 0x80,r10
mtspr CSRR0,r12
mtspr CSRR1,r9
lwz r9,GPR9(r11)
mtspr SPRG2,r8; /* SPRG2 only used in criticals */
lis r8,crit_save@ha;
lwz r10,crit_r10@l(r8)
lwz r11,crit_r11@l(r8)
mfspr r8,SPRG2
rfci
b .
/*
* Local functions
*/
/*
* Data TLB exceptions will bail out to this point
* if they can't resolve the lightweight TLB fault.
*/
data_access:
NORMAL_EXCEPTION_PROLOG
mfspr r5,SPRN_ESR /* Grab the ESR, save it, pass arg3 */
stw r5,_ESR(r11)
mfspr r4,SPRN_DEAR /* Grab the DEAR, save it, pass arg2 */
EXC_XFER_EE_LITE(0x0300, handle_page_fault)
/*
* Both the instruction and data TLB miss get to this
* point to load the TLB.
* r10 - EA of fault
* r11 - available to use
* r12 - Pointer to the 64-bit PTE
* r13 - available to use
* MMUCR - loaded with proper value when we get here
* Upon exit, we reload everything and RFI.
*/
finish_tlb_load:
/*
* We set execute, because we don't have the granularity to
* properly set this at the page level (Linux problem).
* If shared is set, we cause a zero PID->TID load.
* Many of these bits are software only. Bits we don't set
* here we (properly should) assume have the appropriate value.
*/
/* Load the next available TLB index */
lis r13, tlb_44x_index@ha
lwz r13, tlb_44x_index@l(r13)
/* Load the TLB high watermark */
lis r11, tlb_44x_hwater@ha
lwz r11, tlb_44x_hwater@l(r11)
/* Increment, rollover, and store TLB index */
addi r13, r13, 1
cmpw 0, r13, r11 /* reserve entries */
ble 7f
li r13, 0
7:
/* Store the next available TLB index */
lis r11, tlb_44x_index@ha
stw r13, tlb_44x_index@l(r11)
lwz r11, 0(r12) /* Get MS word of PTE */
lwz r12, 4(r12) /* Get LS word of PTE */
rlwimi r11, r12, 0, 0 , 19 /* Insert RPN */
tlbwe r11, r13, PPC44x_TLB_XLAT /* Write XLAT */
/*
* Create PAGEID. This is the faulting address,
* page size, and valid flag.
*/
li r11, PPC44x_TLB_VALID | PPC44x_TLB_4K
rlwimi r10, r11, 0, 20, 31 /* Insert valid and page size */
tlbwe r10, r13, PPC44x_TLB_PAGEID /* Write PAGEID */
li r10, PPC44x_TLB_SR@l /* Set SR */
rlwimi r10, r12, 0, 30, 30 /* Set SW = _PAGE_RW */
rlwimi r10, r12, 29, 29, 29 /* SX = _PAGE_HWEXEC */
rlwimi r10, r12, 29, 28, 28 /* UR = _PAGE_USER */
rlwimi r11, r12, 31, 26, 26 /* (_PAGE_USER>>1)->r12 */
and r11, r12, r11 /* HWEXEC & USER */
rlwimi r10, r11, 0, 26, 26 /* UX = HWEXEC & USER */
rlwimi r12, r10, 0, 26, 31 /* Insert static perms */
rlwinm r12, r12, 0, 20, 15 /* Clear U0-U3 */
tlbwe r12, r13, PPC44x_TLB_ATTRIB /* Write ATTRIB */
/* Done...restore registers and get out of here.
*/
mfspr r11, SPRG7R
mtcr r11
mfspr r13, SPRG5R
mfspr r12, SPRG4R
mfspr r11, SPRG1
mfspr r10, SPRG0
rfi /* Force context change */
/*
* Global functions
*/
/*
* extern void giveup_altivec(struct task_struct *prev)
*
* The 44x core does not have an AltiVec unit.
*/
_GLOBAL(giveup_altivec)
blr
/*
* extern void giveup_fpu(struct task_struct *prev)
*
* The 44x core does not have an FPU.
*/
_GLOBAL(giveup_fpu)
blr
/*
* extern void abort(void)
*
* At present, this routine just applies a system reset.
*/
_GLOBAL(abort)
mfspr r13,SPRN_DBCR0
oris r13,r13,DBCR0_RST_SYSTEM@h
mtspr SPRN_DBCR0,r13
_GLOBAL(set_context)
#ifdef CONFIG_BDI_SWITCH
/* Context switch the PTE pointer for the Abatron BDI2000.
* The PGDIR is the second parameter.
*/
lis r5, abatron_pteptrs@h
ori r5, r5, abatron_pteptrs@l
stw r4, 0x4(r5)
#endif
mtspr SPRN_PID,r3
isync /* Force context change */
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
/*
* To support >32-bit physical addresses, we use an 8KB pgdir.
*/
_GLOBAL(swapper_pg_dir)
.space 8192
.section .bss
/* Stack for handling critical exceptions from kernel mode */
critical_stack_bottom:
.space 4096
critical_stack_top:
.previous
/* Stack for handling machine check exceptions from kernel mode */
mcheck_stack_bottom:
.space 4096
mcheck_stack_top:
.previous
/*
* This area is used for temporarily saving registers during the
* critical and machine check exception prologs. It must always
* follow the page aligned allocations, so it starts on a page
* boundary, ensuring that all crit_save areas are in a single
* page.
*/
/* crit_save */
_GLOBAL(crit_save)
.space 4
_GLOBAL(crit_r10)
.space 4
_GLOBAL(crit_r11)
.space 4
_GLOBAL(crit_sprg0)
.space 4
_GLOBAL(crit_sprg1)
.space 4
_GLOBAL(crit_sprg4)
.space 4
_GLOBAL(crit_sprg5)
.space 4
_GLOBAL(crit_sprg7)
.space 4
_GLOBAL(crit_pid)
.space 4
_GLOBAL(crit_srr0)
.space 4
_GLOBAL(crit_srr1)
.space 4
/* mcheck_save */
_GLOBAL(mcheck_save)
.space 4
_GLOBAL(mcheck_r10)
.space 4
_GLOBAL(mcheck_r11)
.space 4
_GLOBAL(mcheck_sprg0)
.space 4
_GLOBAL(mcheck_sprg1)
.space 4
_GLOBAL(mcheck_sprg4)
.space 4
_GLOBAL(mcheck_sprg5)
.space 4
_GLOBAL(mcheck_sprg7)
.space 4
_GLOBAL(mcheck_pid)
.space 4
_GLOBAL(mcheck_srr0)
.space 4
_GLOBAL(mcheck_srr1)
.space 4
_GLOBAL(mcheck_csrr0)
.space 4
_GLOBAL(mcheck_csrr1)
.space 4
/*
* 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
/*
* Room for two PTE pointers, usually the kernel and current user pointers
* to their respective root page table.
*/
abatron_pteptrs:
.space 8
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