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kernel-fxtec-pro1x/arch/powerpc/kernel/head_44x.S
Suzuki Poulose 26ecb6c44b powerpc/44x: Enable CONFIG_RELOCATABLE for PPC44x 
The following patch adds relocatable kernel support - based on processing
of dynamic relocations - for PPC44x kernel.

We find the runtime address of _stext and relocate ourselves based
on the following calculation.

	virtual_base = ALIGN(KERNELBASE,256M) +
			MODULO(_stext.run,256M)

relocate() is called with the Effective Virtual Base Address (as
shown below)

            | Phys. Addr| Virt. Addr |
Page (256M) |------------------------|
Boundary    |           |            |
            |           |            |
            |           |            |
Kernel Load |___________|_ __ _ _ _ _|<- Effective
Addr(_stext)|           |      ^     |Virt. Base Addr
            |           |      |     |
            |           |      |     |
            |           |reloc_offset|
            |           |      |     |
            |           |      |     |
            |           |______v_____|<-(KERNELBASE)%256M
            |           |            |
            |           |            |
            |           |            |
Page(256M)  |-----------|------------|
Boundary    |           |            |

The virt_phys_offset is updated accordingly, i.e,

	virt_phys_offset = effective. kernel virt base - kernstart_addr

I have tested the patches on 440x platforms only. However this should
work fine for PPC_47x also, as we only depend on the runtime address
and the current TLB XLAT entry for the startup code, which is available
in r25. I don't have access to a 47x board yet. So, it would be great if
somebody could test this on 47x.

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Tony Breeds <tony@bakeyournoodle.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2011-12-20 10:21:57 -05:00

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/*
* 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 2002-2005 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/init.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ptrace.h>
#include <asm/synch.h>
#include "head_booke.h"
/* 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
*
*/
__HEAD
_ENTRY(_stext);
_ENTRY(_start);
/*
* Reserve a word at a fixed location to store the address
* of abatron_pteptrs
*/
nop
mr r31,r3 /* save device tree ptr */
li r24,0 /* CPU number */
#ifdef CONFIG_RELOCATABLE
/*
* Relocate ourselves to the current runtime address.
* This is called only by the Boot CPU.
* "relocate" is called with our current runtime virutal
* address.
* r21 will be loaded with the physical runtime address of _stext
*/
bl 0f /* Get our runtime address */
0: mflr r21 /* Make it accessible */
addis r21,r21,(_stext - 0b)@ha
addi r21,r21,(_stext - 0b)@l /* Get our current runtime base */
/*
* We have the runtime (virutal) address of our base.
* We calculate our shift of offset from a 256M page.
* We could map the 256M page we belong to at PAGE_OFFSET and
* get going from there.
*/
lis r4,KERNELBASE@h
ori r4,r4,KERNELBASE@l
rlwinm r6,r21,0,4,31 /* r6 = PHYS_START % 256M */
rlwinm r5,r4,0,4,31 /* r5 = KERNELBASE % 256M */
subf r3,r5,r6 /* r3 = r6 - r5 */
add r3,r4,r3 /* Required Virutal Address */
bl relocate
#endif
bl init_cpu_state
/*
* 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 SPRN_SPRG_THREAD,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
#ifdef CONFIG_RELOCATABLE
/*
* Relocatable kernel support based on processing of dynamic
* relocation entries.
*
* r25 will contain RPN/ERPN for the start address of memory
* r21 will contain the current offset of _stext
*/
lis r3,kernstart_addr@ha
la r3,kernstart_addr@l(r3)
/*
* Compute the kernstart_addr.
* kernstart_addr => (r6,r8)
* kernstart_addr & ~0xfffffff => (r6,r7)
*/
rlwinm r6,r25,0,28,31 /* ERPN. Bits 32-35 of Address */
rlwinm r7,r25,0,0,3 /* RPN - assuming 256 MB page size */
rlwinm r8,r21,0,4,31 /* r8 = (_stext & 0xfffffff) */
or r8,r7,r8 /* Compute the lower 32bit of kernstart_addr */
/* Store kernstart_addr */
stw r6,0(r3) /* higher 32bit */
stw r8,4(r3) /* lower 32bit */
/*
* Compute the virt_phys_offset :
* virt_phys_offset = stext.run - kernstart_addr
*
* stext.run = (KERNELBASE & ~0xfffffff) + (kernstart_addr & 0xfffffff)
* When we relocate, we have :
*
* (kernstart_addr & 0xfffffff) = (stext.run & 0xfffffff)
*
* hence:
* virt_phys_offset = (KERNELBASE & ~0xfffffff) - (kernstart_addr & ~0xfffffff)
*
*/
/* KERNELBASE&~0xfffffff => (r4,r5) */
li r4, 0 /* higer 32bit */
lis r5,KERNELBASE@h
rlwinm r5,r5,0,0,3 /* Align to 256M, lower 32bit */
/*
* 64bit subtraction.
*/
subfc r5,r7,r5
subfe r4,r6,r4
/* Store virt_phys_offset */
lis r3,virt_phys_offset@ha
la r3,virt_phys_offset@l(r3)
stw r4,0(r3)
stw r5,4(r3)
#elif defined(CONFIG_DYNAMIC_MEMSTART)
/*
* Mapping based, page aligned dynamic kernel loading.
*
* r25 will contain RPN/ERPN for the start address of memory
*
* Add the difference between KERNELBASE and PAGE_OFFSET to the
* start of physical memory to get kernstart_addr.
*/
lis r3,kernstart_addr@ha
la r3,kernstart_addr@l(r3)
lis r4,KERNELBASE@h
ori r4,r4,KERNELBASE@l
lis r5,PAGE_OFFSET@h
ori r5,r5,PAGE_OFFSET@l
subf r4,r5,r4
rlwinm r6,r25,0,28,31 /* ERPN */
rlwinm r7,r25,0,0,3 /* RPN - assuming 256 MB page size */
add r7,r7,r4
stw r6,0(r3)
stw r7,4(r3)
#endif
/*
* Decide what sort of machine this is and initialize the MMU.
*/
li r3,0
mr r4,r31
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)
/* Clear the Machine Check Syndrome Register */
li r0,0
mtspr SPRN_MCSR,r0
/* 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 SPRN_SRR0,r4
mtspr SPRN_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.
*/
interrupt_base:
/* Critical Input Interrupt */
CRITICAL_EXCEPTION(0x0100, CriticalInput, unknown_exception)
/* Machine Check Interrupt */
CRITICAL_EXCEPTION(0x0200, MachineCheck, machine_check_exception)
MCHECK_EXCEPTION(0x0210, MachineCheckA, machine_check_exception)
/* Data Storage Interrupt */
DATA_STORAGE_EXCEPTION
/* Instruction Storage Interrupt */
INSTRUCTION_STORAGE_EXCEPTION
/* External Input Interrupt */
EXCEPTION(0x0500, ExternalInput, do_IRQ, EXC_XFER_LITE)
/* Alignment Interrupt */
ALIGNMENT_EXCEPTION
/* Program Interrupt */
PROGRAM_EXCEPTION
/* Floating Point Unavailable Interrupt */
#ifdef CONFIG_PPC_FPU
FP_UNAVAILABLE_EXCEPTION
#else
EXCEPTION(0x2010, FloatingPointUnavailable, unknown_exception, EXC_XFER_EE)
#endif
/* System Call Interrupt */
START_EXCEPTION(SystemCall)
NORMAL_EXCEPTION_PROLOG
EXC_XFER_EE_LITE(0x0c00, DoSyscall)
/* Auxiliary Processor Unavailable Interrupt */
EXCEPTION(0x2020, AuxillaryProcessorUnavailable, unknown_exception, EXC_XFER_EE)
/* Decrementer Interrupt */
DECREMENTER_EXCEPTION
/* Fixed Internal Timer Interrupt */
/* TODO: Add FIT support */
EXCEPTION(0x1010, FixedIntervalTimer, unknown_exception, EXC_XFER_EE)
/* Watchdog Timer Interrupt */
/* TODO: Add watchdog support */
#ifdef CONFIG_BOOKE_WDT
CRITICAL_EXCEPTION(0x1020, WatchdogTimer, WatchdogException)
#else
CRITICAL_EXCEPTION(0x1020, WatchdogTimer, unknown_exception)
#endif
/* Data TLB Error Interrupt */
START_EXCEPTION(DataTLBError44x)
mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
mtspr SPRN_SPRG_WSCRATCH1, r11
mtspr SPRN_SPRG_WSCRATCH2, r12
mtspr SPRN_SPRG_WSCRATCH3, r13
mfcr r11
mtspr SPRN_SPRG_WSCRATCH4, r11
mfspr r10, SPRN_DEAR /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
lis r11, PAGE_OFFSET@h
cmplw r10, r11
blt+ 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,SPRN_SPRG_THREAD
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
/* Mask of required permission bits. Note that while we
* do copy ESR:ST to _PAGE_RW position as trying to write
* to an RO page is pretty common, we don't do it with
* _PAGE_DIRTY. We could do it, but it's a fairly rare
* event so I'd rather take the overhead when it happens
* rather than adding an instruction here. We should measure
* whether the whole thing is worth it in the first place
* as we could avoid loading SPRN_ESR completely in the first
* place...
*
* TODO: Is it worth doing that mfspr & rlwimi in the first
* place or can we save a couple of instructions here ?
*/
mfspr r12,SPRN_ESR
li r13,_PAGE_PRESENT|_PAGE_ACCESSED
rlwimi r13,r12,10,30,30
/* Load the PTE */
/* Compute pgdir/pmd offset */
rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
lwzx r11, r12, r11 /* Get pgd/pmd entry */
rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
beq 2f /* Bail if no table */
/* Compute pte address */
rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
lwz r11, 0(r12) /* Get high word of pte entry */
lwz r12, 4(r12) /* Get low word of pte entry */
lis r10,tlb_44x_index@ha
andc. r13,r13,r12 /* Check permission */
/* Load the next available TLB index */
lwz r13,tlb_44x_index@l(r10)
bne 2f /* Bail if permission mismach */
/* Increment, rollover, and store TLB index */
addi r13,r13,1
/* Compare with watermark (instruction gets patched) */
.globl tlb_44x_patch_hwater_D
tlb_44x_patch_hwater_D:
cmpwi 0,r13,1 /* reserve entries */
ble 5f
li r13,0
5:
/* Store the next available TLB index */
stw r13,tlb_44x_index@l(r10)
/* Re-load the faulting address */
mfspr r10,SPRN_DEAR
/* Jump to common tlb load */
b finish_tlb_load_44x
2:
/* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
mfspr r11, SPRN_SPRG_RSCRATCH4
mtcr r11
mfspr r13, SPRN_SPRG_RSCRATCH3
mfspr r12, SPRN_SPRG_RSCRATCH2
mfspr r11, SPRN_SPRG_RSCRATCH1
mfspr r10, SPRN_SPRG_RSCRATCH0
b DataStorage
/* 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(InstructionTLBError44x)
mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
mtspr SPRN_SPRG_WSCRATCH1, r11
mtspr SPRN_SPRG_WSCRATCH2, r12
mtspr SPRN_SPRG_WSCRATCH3, r13
mfcr r11
mtspr SPRN_SPRG_WSCRATCH4, r11
mfspr r10, SPRN_SRR0 /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
lis r11, PAGE_OFFSET@h
cmplw r10, r11
blt+ 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,SPRN_SPRG_THREAD
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
/* Make up the required permissions */
li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
/* Compute pgdir/pmd offset */
rlwinm r12, r10, PPC44x_PGD_OFF_SHIFT, PPC44x_PGD_OFF_MASK_BIT, 29
lwzx r11, r12, r11 /* Get pgd/pmd entry */
rlwinm. r12, r11, 0, 0, 20 /* Extract pt base address */
beq 2f /* Bail if no table */
/* Compute pte address */
rlwimi r12, r10, PPC44x_PTE_ADD_SHIFT, PPC44x_PTE_ADD_MASK_BIT, 28
lwz r11, 0(r12) /* Get high word of pte entry */
lwz r12, 4(r12) /* Get low word of pte entry */
lis r10,tlb_44x_index@ha
andc. r13,r13,r12 /* Check permission */
/* Load the next available TLB index */
lwz r13,tlb_44x_index@l(r10)
bne 2f /* Bail if permission mismach */
/* Increment, rollover, and store TLB index */
addi r13,r13,1
/* Compare with watermark (instruction gets patched) */
.globl tlb_44x_patch_hwater_I
tlb_44x_patch_hwater_I:
cmpwi 0,r13,1 /* reserve entries */
ble 5f
li r13,0
5:
/* Store the next available TLB index */
stw r13,tlb_44x_index@l(r10)
/* Re-load the faulting address */
mfspr r10,SPRN_SRR0
/* Jump to common TLB load point */
b finish_tlb_load_44x
2:
/* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
mfspr r11, SPRN_SPRG_RSCRATCH4
mtcr r11
mfspr r13, SPRN_SPRG_RSCRATCH3
mfspr r12, SPRN_SPRG_RSCRATCH2
mfspr r11, SPRN_SPRG_RSCRATCH1
mfspr r10, SPRN_SPRG_RSCRATCH0
b InstructionStorage
/*
* Both the instruction and data TLB miss get to this
* point to load the TLB.
* r10 - EA of fault
* r11 - PTE high word value
* r12 - PTE low word value
* r13 - TLB index
* MMUCR - loaded with proper value when we get here
* Upon exit, we reload everything and RFI.
*/
finish_tlb_load_44x:
/* Combine RPN & ERPN an write WS 0 */
rlwimi r11,r12,0,0,31-PAGE_SHIFT
tlbwe r11,r13,PPC44x_TLB_XLAT
/*
* Create WS1. This is the faulting address (EPN),
* page size, and valid flag.
*/
li r11,PPC44x_TLB_VALID | PPC44x_TLBE_SIZE
/* Insert valid and page size */
rlwimi r10,r11,0,PPC44x_PTE_ADD_MASK_BIT,31
tlbwe r10,r13,PPC44x_TLB_PAGEID /* Write PAGEID */
/* And WS 2 */
li r10,0xf85 /* Mask to apply from PTE */
rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */
and r11,r12,r10 /* Mask PTE bits to keep */
andi. r10,r12,_PAGE_USER /* User page ? */
beq 1f /* nope, leave U bits empty */
rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */
1: tlbwe r11,r13,PPC44x_TLB_ATTRIB /* Write ATTRIB */
/* Done...restore registers and get out of here.
*/
mfspr r11, SPRN_SPRG_RSCRATCH4
mtcr r11
mfspr r13, SPRN_SPRG_RSCRATCH3
mfspr r12, SPRN_SPRG_RSCRATCH2
mfspr r11, SPRN_SPRG_RSCRATCH1
mfspr r10, SPRN_SPRG_RSCRATCH0
rfi /* Force context change */
/* TLB error interrupts for 476
*/
#ifdef CONFIG_PPC_47x
START_EXCEPTION(DataTLBError47x)
mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */
mtspr SPRN_SPRG_WSCRATCH1,r11
mtspr SPRN_SPRG_WSCRATCH2,r12
mtspr SPRN_SPRG_WSCRATCH3,r13
mfcr r11
mtspr SPRN_SPRG_WSCRATCH4,r11
mfspr r10,SPRN_DEAR /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
lis r11,PAGE_OFFSET@h
cmplw cr0,r10,r11
blt+ 3f
lis r11,swapper_pg_dir@h
ori r11,r11, swapper_pg_dir@l
li r12,0 /* MMUCR = 0 */
b 4f
/* Get the PGD for the current thread and setup MMUCR */
3: mfspr r11,SPRN_SPRG3
lwz r11,PGDIR(r11)
mfspr r12,SPRN_PID /* Get PID */
4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */
/* Mask of required permission bits. Note that while we
* do copy ESR:ST to _PAGE_RW position as trying to write
* to an RO page is pretty common, we don't do it with
* _PAGE_DIRTY. We could do it, but it's a fairly rare
* event so I'd rather take the overhead when it happens
* rather than adding an instruction here. We should measure
* whether the whole thing is worth it in the first place
* as we could avoid loading SPRN_ESR completely in the first
* place...
*
* TODO: Is it worth doing that mfspr & rlwimi in the first
* place or can we save a couple of instructions here ?
*/
mfspr r12,SPRN_ESR
li r13,_PAGE_PRESENT|_PAGE_ACCESSED
rlwimi r13,r12,10,30,30
/* Load the PTE */
/* Compute pgdir/pmd offset */
rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
lwzx r11,r12,r11 /* Get pgd/pmd entry */
/* Word 0 is EPN,V,TS,DSIZ */
li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/
li r12,0
tlbwe r10,r12,0
/* XXX can we do better ? Need to make sure tlbwe has established
* latch V bit in MMUCR0 before the PTE is loaded further down */
#ifdef CONFIG_SMP
isync
#endif
rlwinm. r12,r11,0,0,20 /* Extract pt base address */
/* Compute pte address */
rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
beq 2f /* Bail if no table */
lwz r11,0(r12) /* Get high word of pte entry */
/* XXX can we do better ? maybe insert a known 0 bit from r11 into the
* bottom of r12 to create a data dependency... We can also use r10
* as destination nowadays
*/
#ifdef CONFIG_SMP
lwsync
#endif
lwz r12,4(r12) /* Get low word of pte entry */
andc. r13,r13,r12 /* Check permission */
/* Jump to common tlb load */
beq finish_tlb_load_47x
2: /* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
mfspr r11,SPRN_SPRG_RSCRATCH4
mtcr r11
mfspr r13,SPRN_SPRG_RSCRATCH3
mfspr r12,SPRN_SPRG_RSCRATCH2
mfspr r11,SPRN_SPRG_RSCRATCH1
mfspr r10,SPRN_SPRG_RSCRATCH0
b DataStorage
/* 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(InstructionTLBError47x)
mtspr SPRN_SPRG_WSCRATCH0,r10 /* Save some working registers */
mtspr SPRN_SPRG_WSCRATCH1,r11
mtspr SPRN_SPRG_WSCRATCH2,r12
mtspr SPRN_SPRG_WSCRATCH3,r13
mfcr r11
mtspr SPRN_SPRG_WSCRATCH4,r11
mfspr r10,SPRN_SRR0 /* Get faulting address */
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
lis r11,PAGE_OFFSET@h
cmplw cr0,r10,r11
blt+ 3f
lis r11,swapper_pg_dir@h
ori r11,r11, swapper_pg_dir@l
li r12,0 /* MMUCR = 0 */
b 4f
/* Get the PGD for the current thread and setup MMUCR */
3: mfspr r11,SPRN_SPRG_THREAD
lwz r11,PGDIR(r11)
mfspr r12,SPRN_PID /* Get PID */
4: mtspr SPRN_MMUCR,r12 /* Set MMUCR */
/* Make up the required permissions */
li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
/* Load PTE */
/* Compute pgdir/pmd offset */
rlwinm r12,r10,PPC44x_PGD_OFF_SHIFT,PPC44x_PGD_OFF_MASK_BIT,29
lwzx r11,r12,r11 /* Get pgd/pmd entry */
/* Word 0 is EPN,V,TS,DSIZ */
li r12,PPC47x_TLB0_VALID | PPC47x_TLBE_SIZE
rlwimi r10,r12,0,32-PAGE_SHIFT,31 /* Insert valid and page size*/
li r12,0
tlbwe r10,r12,0
/* XXX can we do better ? Need to make sure tlbwe has established
* latch V bit in MMUCR0 before the PTE is loaded further down */
#ifdef CONFIG_SMP
isync
#endif
rlwinm. r12,r11,0,0,20 /* Extract pt base address */
/* Compute pte address */
rlwimi r12,r10,PPC44x_PTE_ADD_SHIFT,PPC44x_PTE_ADD_MASK_BIT,28
beq 2f /* Bail if no table */
lwz r11,0(r12) /* Get high word of pte entry */
/* XXX can we do better ? maybe insert a known 0 bit from r11 into the
* bottom of r12 to create a data dependency... We can also use r10
* as destination nowadays
*/
#ifdef CONFIG_SMP
lwsync
#endif
lwz r12,4(r12) /* Get low word of pte entry */
andc. r13,r13,r12 /* Check permission */
/* Jump to common TLB load point */
beq finish_tlb_load_47x
2: /* The bailout. Restore registers to pre-exception conditions
* and call the heavyweights to help us out.
*/
mfspr r11, SPRN_SPRG_RSCRATCH4
mtcr r11
mfspr r13, SPRN_SPRG_RSCRATCH3
mfspr r12, SPRN_SPRG_RSCRATCH2
mfspr r11, SPRN_SPRG_RSCRATCH1
mfspr r10, SPRN_SPRG_RSCRATCH0
b InstructionStorage
/*
* Both the instruction and data TLB miss get to this
* point to load the TLB.
* r10 - free to use
* r11 - PTE high word value
* r12 - PTE low word value
* r13 - free to use
* MMUCR - loaded with proper value when we get here
* Upon exit, we reload everything and RFI.
*/
finish_tlb_load_47x:
/* Combine RPN & ERPN an write WS 1 */
rlwimi r11,r12,0,0,31-PAGE_SHIFT
tlbwe r11,r13,1
/* And make up word 2 */
li r10,0xf85 /* Mask to apply from PTE */
rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */
and r11,r12,r10 /* Mask PTE bits to keep */
andi. r10,r12,_PAGE_USER /* User page ? */
beq 1f /* nope, leave U bits empty */
rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */
1: tlbwe r11,r13,2
/* Done...restore registers and get out of here.
*/
mfspr r11, SPRN_SPRG_RSCRATCH4
mtcr r11
mfspr r13, SPRN_SPRG_RSCRATCH3
mfspr r12, SPRN_SPRG_RSCRATCH2
mfspr r11, SPRN_SPRG_RSCRATCH1
mfspr r10, SPRN_SPRG_RSCRATCH0
rfi
#endif /* CONFIG_PPC_47x */
/* Debug Interrupt */
/*
* This statement needs to exist at the end of the IVPR
* definition just in case you end up taking a debug
* exception within another exception.
*/
DEBUG_CRIT_EXCEPTION
/*
* Global functions
*/
/*
* Adjust the machine check IVOR on 440A cores
*/
_GLOBAL(__fixup_440A_mcheck)
li r3,MachineCheckA@l
mtspr SPRN_IVOR1,r3
sync
blr
/*
* 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.
*/
#ifndef CONFIG_PPC_FPU
_GLOBAL(giveup_fpu)
blr
#endif
_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
/*
* Init CPU state. This is called at boot time or for secondary CPUs
* to setup initial TLB entries, setup IVORs, etc...
*
*/
_GLOBAL(init_cpu_state)
mflr r22
#ifdef CONFIG_PPC_47x
/* We use the PVR to differenciate 44x cores from 476 */
mfspr r3,SPRN_PVR
srwi r3,r3,16
cmplwi cr0,r3,PVR_476FPE@h
beq head_start_47x
cmplwi cr0,r3,PVR_476@h
beq head_start_47x
cmplwi cr0,r3,PVR_476_ISS@h
beq head_start_47x
#endif /* CONFIG_PPC_47x */
/*
* In case the firmware didn't do it, we apply some workarounds
* that are good for all 440 core variants here
*/
mfspr r3,SPRN_CCR0
rlwinm r3,r3,0,0,27 /* disable icache prefetch */
isync
mtspr SPRN_CCR0,r3
isync
sync
/*
* Set up the initial MMU state for 44x
*
* 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.
*/
#ifdef CONFIG_NONSTATIC_KERNEL
/*
* In case of a NONSTATIC_KERNEL we reuse the TLB XLAT
* entries of the initial mapping set by the boot loader.
* The XLAT entry is stored in r25
*/
/* Read the XLAT entry for our current mapping */
tlbre r25,r23,PPC44x_TLB_XLAT
lis r3,KERNELBASE@h
ori r3,r3,KERNELBASE@l
/* Use our current RPN entry */
mr r4,r25
#else
lis r3,PAGE_OFFSET@h
ori r3,r3,PAGE_OFFSET@l
/* Kernel is at the base of RAM */
li r4, 0 /* Load the kernel physical address */
#endif
/* 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 SPRN_SRR1, r0
lis r0,3f@h
ori r0,r0,3f@l
mtspr SPRN_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_PPC_EARLY_DEBUG_44x
/* Add UART mapping for early debug. */
/* pageid fields */
lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
ori r3,r3,PPC44x_TLB_VALID|PPC44x_TLB_TS|PPC44x_TLB_64K
/* xlat fields */
lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
/* attrib fields */
li r5,(PPC44x_TLB_SW|PPC44x_TLB_SR|PPC44x_TLB_I|PPC44x_TLB_G)
li r0,62 /* TLB slot 0 */
tlbwe r3,r0,PPC44x_TLB_PAGEID
tlbwe r4,r0,PPC44x_TLB_XLAT
tlbwe r5,r0,PPC44x_TLB_ATTRIB
/* Force context change */
isync
#endif /* CONFIG_PPC_EARLY_DEBUG_44x */
/* 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, DataTLBError44x);
SET_IVOR(14, InstructionTLBError44x);
SET_IVOR(15, DebugCrit);
b head_start_common
#ifdef CONFIG_PPC_47x
#ifdef CONFIG_SMP
/* Entry point for secondary 47x processors */
_GLOBAL(start_secondary_47x)
mr r24,r3 /* CPU number */
bl init_cpu_state
/* Now we need to bolt the rest of kernel memory which
* is done in C code. We must be careful because our task
* struct or our stack can (and will probably) be out
* of reach of the initial 256M TLB entry, so we use a
* small temporary stack in .bss for that. This works
* because only one CPU at a time can be in this code
*/
lis r1,temp_boot_stack@h
ori r1,r1,temp_boot_stack@l
addi r1,r1,1024-STACK_FRAME_OVERHEAD
li r0,0
stw r0,0(r1)
bl mmu_init_secondary
/* Now we can get our task struct and real stack pointer */
/* Get current_thread_info and current */
lis r1,secondary_ti@ha
lwz r1,secondary_ti@l(r1)
lwz r2,TI_TASK(r1)
/* Current stack pointer */
addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
li r0,0
stw r0,0(r1)
/* Kernel stack for exception entry in SPRG3 */
addi r4,r2,THREAD /* init task's THREAD */
mtspr SPRN_SPRG3,r4
b start_secondary
#endif /* CONFIG_SMP */
/*
* Set up the initial MMU state for 44x
*
* We are still executing code at the virtual address
* mappings set by the firmware for the base of RAM.
*/
head_start_47x:
/* 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 1f /* If not, leave STS=0 */
oris r3,r3,PPC47x_MMUCR_STS@h /* Set STS=1 */
1: mtspr SPRN_MMUCR,r3 /* Put MMUCR */
sync
/* Find the entry we are running from */
bl 1f
1: mflr r23
tlbsx r23,0,r23
tlbre r24,r23,0
tlbre r25,r23,1
tlbre r26,r23,2
/*
* Cleanup time
*/
/* Initialize MMUCR */
li r5,0
mtspr SPRN_MMUCR,r5
sync
clear_all_utlb_entries:
#; Set initial values.
addis r3,0,0x8000
addi r4,0,0
addi r5,0,0
b clear_utlb_entry
#; Align the loop to speed things up.
.align 6
clear_utlb_entry:
tlbwe r4,r3,0
tlbwe r5,r3,1
tlbwe r5,r3,2
addis r3,r3,0x2000
cmpwi r3,0
bne clear_utlb_entry
addis r3,0,0x8000
addis r4,r4,0x100
cmpwi r4,0
bne clear_utlb_entry
#; Restore original entry.
oris r23,r23,0x8000 /* specify the way */
tlbwe r24,r23,0
tlbwe r25,r23,1
tlbwe r26,r23,2
/*
* Configure and load pinned entry into TLB for the kernel core
*/
lis r3,PAGE_OFFSET@h
ori r3,r3,PAGE_OFFSET@l
/* Load the kernel PID = 0 */
li r0,0
mtspr SPRN_PID,r0
sync
/* Word 0 */
clrrwi r3,r3,12 /* Mask off the effective page number */
ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_256M
/* Word 1 - use r25. RPN is the same as the original entry */
/* Word 2 */
li r5,0
ori r5,r5,PPC47x_TLB2_S_RWX
#ifdef CONFIG_SMP
ori r5,r5,PPC47x_TLB2_M
#endif
/* We write to way 0 and bolted 0 */
lis r0,0x8800
tlbwe r3,r0,0
tlbwe r25,r0,1
tlbwe r5,r0,2
/*
* Configure SSPCR, ISPCR and USPCR for now to search everything, we can fix
* them up later
*/
LOAD_REG_IMMEDIATE(r3, 0x9abcdef0)
mtspr SPRN_SSPCR,r3
mtspr SPRN_USPCR,r3
LOAD_REG_IMMEDIATE(r3, 0x12345670)
mtspr SPRN_ISPCR,r3
/* Force context change */
mfmsr r0
mtspr SPRN_SRR1, r0
lis r0,3f@h
ori r0,r0,3f@l
mtspr SPRN_SRR0,r0
sync
rfi
/* Invalidate original entry we used */
3:
rlwinm r24,r24,0,21,19 /* clear the "valid" bit */
tlbwe r24,r23,0
addi r24,0,0
tlbwe r24,r23,1
tlbwe r24,r23,2
isync /* Clear out the shadow TLB entries */
#ifdef CONFIG_PPC_EARLY_DEBUG_44x
/* Add UART mapping for early debug. */
/* Word 0 */
lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h
ori r3,r3,PPC47x_TLB0_VALID | PPC47x_TLB0_TS | PPC47x_TLB0_1M
/* Word 1 */
lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h
ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH
/* Word 2 */
li r5,(PPC47x_TLB2_S_RW | PPC47x_TLB2_IMG)
/* Bolted in way 0, bolt slot 5, we -hope- we don't hit the same
* congruence class as the kernel, we need to make sure of it at
* some point
*/
lis r0,0x8d00
tlbwe r3,r0,0
tlbwe r4,r0,1
tlbwe r5,r0,2
/* Force context change */
isync
#endif /* CONFIG_PPC_EARLY_DEBUG_44x */
/* Establish the interrupt vector offsets */
SET_IVOR(0, CriticalInput);
SET_IVOR(1, MachineCheckA);
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, DataTLBError47x);
SET_IVOR(14, InstructionTLBError47x);
SET_IVOR(15, DebugCrit);
/* We configure icbi to invalidate 128 bytes at a time since the
* current 32-bit kernel code isn't too happy with icache != dcache
* block size
*/
mfspr r3,SPRN_CCR0
oris r3,r3,0x0020
mtspr SPRN_CCR0,r3
isync
#endif /* CONFIG_PPC_47x */
/*
* Here we are back to code that is common between 44x and 47x
*
* We proceed to further kernel initialization and return to the
* main kernel entry
*/
head_start_common:
/* Establish the interrupt vector base */
lis r4,interrupt_base@h /* IVPR only uses the high 16-bits */
mtspr SPRN_IVPR,r4
/*
* If the kernel was loaded at a non-zero 256 MB page, we need to
* mask off the most significant 4 bits to get the relative address
* from the start of physical memory
*/
rlwinm r22,r22,0,4,31
addis r22,r22,PAGE_OFFSET@h
mtlr r22
isync
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
.align PAGE_SHIFT
.globl sdata
sdata:
.globl empty_zero_page
empty_zero_page:
.space PAGE_SIZE
/*
* To support >32-bit physical addresses, we use an 8KB pgdir.
*/
.globl swapper_pg_dir
swapper_pg_dir:
.space PGD_TABLE_SIZE
/*
* Room for two PTE pointers, usually the kernel and current user pointers
* to their respective root page table.
*/
abatron_pteptrs:
.space 8
#ifdef CONFIG_SMP
.align 12
temp_boot_stack:
.space 1024
#endif /* CONFIG_SMP */
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