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linuxdebug/arch/powerpc/kernel/head_8xx.S

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null pointer error
2024-07-16 15:50:57 +02:00
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
* Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
* Low-level exception handlers and MMU support
* rewritten by Paul Mackerras.
* Copyright (C) 1996 Paul Mackerras.
* MPC8xx modifications by Dan Malek
* Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
*
* This file contains low-level support and setup for PowerPC 8xx
* embedded processors, including trap and interrupt dispatch.
*/
#include <linux/init.h>
#include <linux/magic.h>
#include <linux/pgtable.h>
#include <linux/sizes.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/cache.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/export.h>
#include <asm/code-patching-asm.h>
#include <asm/interrupt.h>
/*
* Value for the bits that have fixed value in RPN entries.
* Also used for tagging DAR for DTLBerror.
*/
#define RPN_PATTERN 0x00f0
#include "head_32.h"
.macro compare_to_kernel_boundary scratch, addr
#if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000
/* By simply checking Address >= 0x80000000, we know if its a kernel address */
not. \scratch, \addr
#else
rlwinm \scratch, \addr, 16, 0xfff8
cmpli cr0, \scratch, PAGE_OFFSET@h
#endif
.endm
#define PAGE_SHIFT_512K 19
#define PAGE_SHIFT_8M 23
__HEAD
_GLOBAL(_stext);
_GLOBAL(_start);
/* MPC8xx
* This port was done on an MBX board with an 860. Right now I only
* support an ELF compressed (zImage) boot from EPPC-Bug because the
* code there loads up some registers before calling us:
* r3: ptr to board info data
* r4: initrd_start or if no initrd then 0
* r5: initrd_end - unused if r4 is 0
* r6: Start of command line string
* r7: End of command line string
*
* I decided to use conditional compilation instead of checking PVR and
* adding more processor specific branches around code I don't need.
* Since this is an embedded processor, I also appreciate any memory
* savings I can get.
*
* The MPC8xx does not have any BATs, but it supports large page sizes.
* We first initialize the MMU to support 8M byte pages, then load one
* entry into each of the instruction and data TLBs to map the first
* 8M 1:1. I also mapped an additional I/O space 1:1 so we can get to
* the "internal" processor registers before MMU_init is called.
*
* -- Dan
*/
.globl __start
__start:
mr r31,r3 /* save device tree ptr */
/* We have to turn on the MMU right away so we get cache modes
* set correctly.
*/
bl initial_mmu
/* We now have the lower 8 Meg mapped into TLB entries, and the caches
* ready to work.
*/
turn_on_mmu:
mfmsr r0
ori r0,r0,MSR_DR|MSR_IR
mtspr SPRN_SRR1,r0
lis r0,start_here@h
ori r0,r0,start_here@l
mtspr SPRN_SRR0,r0
rfi /* enables MMU */
#ifdef CONFIG_PERF_EVENTS
.align 4
.globl itlb_miss_counter
itlb_miss_counter:
.space 4
.globl dtlb_miss_counter
dtlb_miss_counter:
.space 4
.globl instruction_counter
instruction_counter:
.space 4
#endif
/* System reset */
EXCEPTION(INTERRUPT_SYSTEM_RESET, Reset, system_reset_exception)
/* Machine check */
START_EXCEPTION(INTERRUPT_MACHINE_CHECK, MachineCheck)
EXCEPTION_PROLOG INTERRUPT_MACHINE_CHECK MachineCheck handle_dar_dsisr=1
prepare_transfer_to_handler
bl machine_check_exception
b interrupt_return
/* External interrupt */
EXCEPTION(INTERRUPT_EXTERNAL, HardwareInterrupt, do_IRQ)
/* Alignment exception */
START_EXCEPTION(INTERRUPT_ALIGNMENT, Alignment)
EXCEPTION_PROLOG INTERRUPT_ALIGNMENT Alignment handle_dar_dsisr=1
prepare_transfer_to_handler
bl alignment_exception
REST_NVGPRS(r1)
b interrupt_return
/* Program check exception */
START_EXCEPTION(INTERRUPT_PROGRAM, ProgramCheck)
EXCEPTION_PROLOG INTERRUPT_PROGRAM ProgramCheck
prepare_transfer_to_handler
bl program_check_exception
REST_NVGPRS(r1)
b interrupt_return
/* Decrementer */
EXCEPTION(INTERRUPT_DECREMENTER, Decrementer, timer_interrupt)
/* System call */
START_EXCEPTION(INTERRUPT_SYSCALL, SystemCall)
SYSCALL_ENTRY INTERRUPT_SYSCALL
/* Single step - not used on 601 */
EXCEPTION(INTERRUPT_TRACE, SingleStep, single_step_exception)
/* On the MPC8xx, this is a software emulation interrupt. It occurs
* for all unimplemented and illegal instructions.
*/
START_EXCEPTION(INTERRUPT_SOFT_EMU_8xx, SoftEmu)
EXCEPTION_PROLOG INTERRUPT_SOFT_EMU_8xx SoftEmu
prepare_transfer_to_handler
bl emulation_assist_interrupt
REST_NVGPRS(r1)
b interrupt_return
/*
* For the MPC8xx, this is a software tablewalk to load the instruction
* TLB. The task switch loads the M_TWB register with the pointer to the first
* level table.
* If we discover there is no second level table (value is zero) or if there
* is an invalid pte, we load that into the TLB, which causes another fault
* into the TLB Error interrupt where we can handle such problems.
* We have to use the MD_xxx registers for the tablewalk because the
* equivalent MI_xxx registers only perform the attribute functions.
*/
#ifdef CONFIG_8xx_CPU15
#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp) \
addi tmp, addr, PAGE_SIZE; \
tlbie tmp; \
addi tmp, addr, -PAGE_SIZE; \
tlbie tmp
#else
#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp)
#endif
START_EXCEPTION(INTERRUPT_INST_TLB_MISS_8xx, InstructionTLBMiss)
mtspr SPRN_SPRG_SCRATCH2, r10
mtspr SPRN_M_TW, r11
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
mfspr r10, SPRN_SRR0 /* Get effective address of fault */
INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11)
mtspr SPRN_MD_EPN, r10
#ifdef CONFIG_MODULES
mfcr r11
compare_to_kernel_boundary r10, r10
#endif
mfspr r10, SPRN_M_TWB /* Get level 1 table */
#ifdef CONFIG_MODULES
blt+ 3f
rlwinm r10, r10, 0, 20, 31
oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha
3:
mtcr r11
#endif
lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */
mtspr SPRN_MD_TWC, r11
mfspr r10, SPRN_MD_TWC
lwz r10, 0(r10) /* Get the pte */
rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED
rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K
mtspr SPRN_MI_TWC, r11
/* The Linux PTE won't go exactly into the MMU TLB.
* Software indicator bits 20 and 23 must be clear.
* Software indicator bits 22, 24, 25, 26, and 27 must be
* set. All other Linux PTE bits control the behavior
* of the MMU.
*/
rlwinm r10, r10, 0, ~0x0f00 /* Clear bits 20-23 */
rlwimi r10, r10, 4, 0x0400 /* Copy _PAGE_EXEC into bit 21 */
ori r10, r10, RPN_PATTERN | 0x200 /* Set 22 and 24-27 */
mtspr SPRN_MI_RPN, r10 /* Update TLB entry */
/* Restore registers */
0: mfspr r10, SPRN_SPRG_SCRATCH2
mfspr r11, SPRN_M_TW
rfi
patch_site 0b, patch__itlbmiss_exit_1
#ifdef CONFIG_PERF_EVENTS
patch_site 0f, patch__itlbmiss_perf
0: lwz r10, (itlb_miss_counter - PAGE_OFFSET)@l(0)
addi r10, r10, 1
stw r10, (itlb_miss_counter - PAGE_OFFSET)@l(0)
mfspr r10, SPRN_SPRG_SCRATCH2
mfspr r11, SPRN_M_TW
rfi
#endif
START_EXCEPTION(INTERRUPT_DATA_TLB_MISS_8xx, DataStoreTLBMiss)
mtspr SPRN_SPRG_SCRATCH2, r10
mtspr SPRN_M_TW, r11
mfcr r11
/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
mfspr r10, SPRN_MD_EPN
compare_to_kernel_boundary r10, r10
mfspr r10, SPRN_M_TWB /* Get level 1 table */
blt+ 3f
rlwinm r10, r10, 0, 20, 31
oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha
3:
mtcr r11
lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */
mtspr SPRN_MD_TWC, r11
mfspr r10, SPRN_MD_TWC
lwz r10, 0(r10) /* Get the pte */
/* Insert Guarded and Accessed flags into the TWC from the Linux PTE.
* It is bit 27 of both the Linux PTE and the TWC (at least
* I got that right :-). It will be better when we can put
* this into the Linux pgd/pmd and load it in the operation
* above.
*/
rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED
rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K
mtspr SPRN_MD_TWC, r11
/* The Linux PTE won't go exactly into the MMU TLB.
* Software indicator bits 24, 25, 26, and 27 must be
* set. All other Linux PTE bits control the behavior
* of the MMU.
*/
li r11, RPN_PATTERN
rlwimi r10, r11, 0, 24, 27 /* Set 24-27 */
mtspr SPRN_MD_RPN, r10 /* Update TLB entry */
mtspr SPRN_DAR, r11 /* Tag DAR */
/* Restore registers */
0: mfspr r10, SPRN_SPRG_SCRATCH2
mfspr r11, SPRN_M_TW
rfi
patch_site 0b, patch__dtlbmiss_exit_1
#ifdef CONFIG_PERF_EVENTS
patch_site 0f, patch__dtlbmiss_perf
0: lwz r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0)
addi r10, r10, 1
stw r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0)
mfspr r10, SPRN_SPRG_SCRATCH2
mfspr r11, SPRN_M_TW
rfi
#endif
/* This is an instruction TLB error on the MPC8xx. This could be due
* to many reasons, such as executing guarded memory or illegal instruction
* addresses. There is nothing to do but handle a big time error fault.
*/
START_EXCEPTION(INTERRUPT_INST_TLB_ERROR_8xx, InstructionTLBError)
/* 0x400 is InstructionAccess exception, needed by bad_page_fault() */
EXCEPTION_PROLOG INTERRUPT_INST_STORAGE InstructionTLBError
andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */
andis. r10,r9,SRR1_ISI_NOPT@h
beq+ .Litlbie
tlbie r12
.Litlbie:
stw r12, _DAR(r11)
stw r5, _DSISR(r11)
prepare_transfer_to_handler
bl do_page_fault
b interrupt_return
/* This is the data TLB error on the MPC8xx. This could be due to
* many reasons, including a dirty update to a pte. We bail out to
* a higher level function that can handle it.
*/
START_EXCEPTION(INTERRUPT_DATA_TLB_ERROR_8xx, DataTLBError)
EXCEPTION_PROLOG_0 handle_dar_dsisr=1
mfspr r11, SPRN_DAR
cmpwi cr1, r11, RPN_PATTERN
beq- cr1, FixupDAR /* must be a buggy dcbX, icbi insn. */
DARFixed:/* Return from dcbx instruction bug workaround */
EXCEPTION_PROLOG_1
/* 0x300 is DataAccess exception, needed by bad_page_fault() */
EXCEPTION_PROLOG_2 INTERRUPT_DATA_STORAGE DataTLBError handle_dar_dsisr=1
lwz r4, _DAR(r11)
lwz r5, _DSISR(r11)
andis. r10,r5,DSISR_NOHPTE@h
beq+ .Ldtlbie
tlbie r4
.Ldtlbie:
prepare_transfer_to_handler
bl do_page_fault
b interrupt_return
#ifdef CONFIG_VMAP_STACK
vmap_stack_overflow_exception
#endif
/* On the MPC8xx, these next four traps are used for development
* support of breakpoints and such. Someday I will get around to
* using them.
*/
START_EXCEPTION(INTERRUPT_DATA_BREAKPOINT_8xx, DataBreakpoint)
EXCEPTION_PROLOG_0 handle_dar_dsisr=1
mfspr r11, SPRN_SRR0
cmplwi cr1, r11, (.Ldtlbie - PAGE_OFFSET)@l
cmplwi cr7, r11, (.Litlbie - PAGE_OFFSET)@l
cror 4*cr1+eq, 4*cr1+eq, 4*cr7+eq
bne cr1, 1f
mtcr r10
mfspr r10, SPRN_SPRG_SCRATCH0
mfspr r11, SPRN_SPRG_SCRATCH1
rfi
1: EXCEPTION_PROLOG_1
EXCEPTION_PROLOG_2 INTERRUPT_DATA_BREAKPOINT_8xx DataBreakpoint handle_dar_dsisr=1
mfspr r4,SPRN_BAR
stw r4,_DAR(r11)
prepare_transfer_to_handler
bl do_break
REST_NVGPRS(r1)
b interrupt_return
#ifdef CONFIG_PERF_EVENTS
START_EXCEPTION(INTERRUPT_INST_BREAKPOINT_8xx, InstructionBreakpoint)
mtspr SPRN_SPRG_SCRATCH0, r10
lwz r10, (instruction_counter - PAGE_OFFSET)@l(0)
addi r10, r10, -1
stw r10, (instruction_counter - PAGE_OFFSET)@l(0)
lis r10, 0xffff
ori r10, r10, 0x01
mtspr SPRN_COUNTA, r10
mfspr r10, SPRN_SPRG_SCRATCH0
rfi
#else
EXCEPTION(INTERRUPT_INST_BREAKPOINT_8xx, Trap_1d, unknown_exception)
#endif
EXCEPTION(0x1e00, Trap_1e, unknown_exception)
EXCEPTION(0x1f00, Trap_1f, unknown_exception)
__HEAD
. = 0x2000
/* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions
* by decoding the registers used by the dcbx instruction and adding them.
* DAR is set to the calculated address.
*/
FixupDAR:/* Entry point for dcbx workaround. */
mtspr SPRN_M_TW, r10
/* fetch instruction from memory. */
mfspr r10, SPRN_SRR0
mtspr SPRN_MD_EPN, r10
rlwinm r11, r10, 16, 0xfff8
cmpli cr1, r11, PAGE_OFFSET@h
mfspr r11, SPRN_M_TWB /* Get level 1 table */
blt+ cr1, 3f
/* create physical page address from effective address */
tophys(r11, r10)
mfspr r11, SPRN_M_TWB /* Get level 1 table */
rlwinm r11, r11, 0, 20, 31
oris r11, r11, (swapper_pg_dir - PAGE_OFFSET)@ha
3:
lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */
mtspr SPRN_MD_TWC, r11
mtcrf 0x01, r11
mfspr r11, SPRN_MD_TWC
lwz r11, 0(r11) /* Get the pte */
bt 28,200f /* bit 28 = Large page (8M) */
/* concat physical page address(r11) and page offset(r10) */
rlwimi r11, r10, 0, 32 - PAGE_SHIFT, 31
201: lwz r11,0(r11)
/* Check if it really is a dcbx instruction. */
/* dcbt and dcbtst does not generate DTLB Misses/Errors,
* no need to include them here */
xoris r10, r11, 0x7c00 /* check if major OP code is 31 */
rlwinm r10, r10, 0, 21, 5
cmpwi cr1, r10, 2028 /* Is dcbz? */
beq+ cr1, 142f
cmpwi cr1, r10, 940 /* Is dcbi? */
beq+ cr1, 142f
cmpwi cr1, r10, 108 /* Is dcbst? */
beq+ cr1, 144f /* Fix up store bit! */
cmpwi cr1, r10, 172 /* Is dcbf? */
beq+ cr1, 142f
cmpwi cr1, r10, 1964 /* Is icbi? */
beq+ cr1, 142f
141: mfspr r10,SPRN_M_TW
b DARFixed /* Nope, go back to normal TLB processing */
200:
/* concat physical page address(r11) and page offset(r10) */
rlwimi r11, r10, 0, 32 - PAGE_SHIFT_8M, 31
b 201b
144: mfspr r10, SPRN_DSISR
rlwinm r10, r10,0,7,5 /* Clear store bit for buggy dcbst insn */
mtspr SPRN_DSISR, r10
142: /* continue, it was a dcbx, dcbi instruction. */
mfctr r10
mtdar r10 /* save ctr reg in DAR */
rlwinm r10, r11, 24, 24, 28 /* offset into jump table for reg RB */
addi r10, r10, 150f@l /* add start of table */
mtctr r10 /* load ctr with jump address */
xor r10, r10, r10 /* sum starts at zero */
bctr /* jump into table */
150:
add r10, r10, r0 ;b 151f
add r10, r10, r1 ;b 151f
add r10, r10, r2 ;b 151f
add r10, r10, r3 ;b 151f
add r10, r10, r4 ;b 151f
add r10, r10, r5 ;b 151f
add r10, r10, r6 ;b 151f
add r10, r10, r7 ;b 151f
add r10, r10, r8 ;b 151f
add r10, r10, r9 ;b 151f
mtctr r11 ;b 154f /* r10 needs special handling */
mtctr r11 ;b 153f /* r11 needs special handling */
add r10, r10, r12 ;b 151f
add r10, r10, r13 ;b 151f
add r10, r10, r14 ;b 151f
add r10, r10, r15 ;b 151f
add r10, r10, r16 ;b 151f
add r10, r10, r17 ;b 151f
add r10, r10, r18 ;b 151f
add r10, r10, r19 ;b 151f
add r10, r10, r20 ;b 151f
add r10, r10, r21 ;b 151f
add r10, r10, r22 ;b 151f
add r10, r10, r23 ;b 151f
add r10, r10, r24 ;b 151f
add r10, r10, r25 ;b 151f
add r10, r10, r26 ;b 151f
add r10, r10, r27 ;b 151f
add r10, r10, r28 ;b 151f
add r10, r10, r29 ;b 151f
add r10, r10, r30 ;b 151f
add r10, r10, r31
151:
rlwinm r11,r11,19,24,28 /* offset into jump table for reg RA */
cmpwi cr1, r11, 0
beq cr1, 152f /* if reg RA is zero, don't add it */
addi r11, r11, 150b@l /* add start of table */
mtctr r11 /* load ctr with jump address */
rlwinm r11,r11,0,16,10 /* make sure we don't execute this more than once */
bctr /* jump into table */
152:
mfdar r11
mtctr r11 /* restore ctr reg from DAR */
mfspr r11, SPRN_SPRG_THREAD
stw r10, DAR(r11)
mfspr r10, SPRN_DSISR
stw r10, DSISR(r11)
mfspr r10,SPRN_M_TW
b DARFixed /* Go back to normal TLB handling */
/* special handling for r10,r11 since these are modified already */
153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */
add r10, r10, r11 /* add it */
mfctr r11 /* restore r11 */
b 151b
154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */
add r10, r10, r11 /* add it */
mfctr r11 /* restore r11 */
b 151b
/*
* This is where the main kernel code starts.
*/
start_here:
/* ptr to current */
lis r2,init_task@h
ori r2,r2,init_task@l
/* ptr to phys current thread */
tophys(r4,r2)
addi r4,r4,THREAD /* init task's THREAD */
mtspr SPRN_SPRG_THREAD,r4
/* stack */
lis r1,init_thread_union@ha
addi r1,r1,init_thread_union@l
lis r0, STACK_END_MAGIC@h
ori r0, r0, STACK_END_MAGIC@l
stw r0, 0(r1)
li r0,0
stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
lis r6, swapper_pg_dir@ha
tophys(r6,r6)
mtspr SPRN_M_TWB, r6
bl early_init /* We have to do this with MMU on */
/*
* Decide what sort of machine this is and initialize the MMU.
*/
#ifdef CONFIG_KASAN
bl kasan_early_init
#endif
li r3,0
mr r4,r31
bl machine_init
bl MMU_init
/*
* Go back to running unmapped so we can load up new values
* and change to using our exception vectors.
* On the 8xx, all we have to do is invalidate the TLB to clear
* the old 8M byte TLB mappings and load the page table base register.
*/
/* The right way to do this would be to track it down through
* init's THREAD like the context switch code does, but this is
* easier......until someone changes init's static structures.
*/
lis r4,2f@h
ori r4,r4,2f@l
tophys(r4,r4)
li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
mtspr SPRN_SRR0,r4
mtspr SPRN_SRR1,r3
rfi
/* Load up the kernel context */
2:
#ifdef CONFIG_PIN_TLB_IMMR
lis r0, MD_TWAM@h
oris r0, r0, 0x1f00
mtspr SPRN_MD_CTR, r0
LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID)
tlbie r0
mtspr SPRN_MD_EPN, r0
LOAD_REG_IMMEDIATE(r0, MD_SVALID | MD_PS512K | MD_GUARDED)
mtspr SPRN_MD_TWC, r0
mfspr r0, SPRN_IMMR
rlwinm r0, r0, 0, 0xfff80000
ori r0, r0, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \
_PAGE_NO_CACHE | _PAGE_PRESENT
mtspr SPRN_MD_RPN, r0
lis r0, (MD_TWAM | MD_RSV4I)@h
mtspr SPRN_MD_CTR, r0
#endif
#if !defined(CONFIG_PIN_TLB_DATA) && !defined(CONFIG_PIN_TLB_IMMR)
lis r0, MD_TWAM@h
mtspr SPRN_MD_CTR, r0
#endif
tlbia /* Clear all TLB entries */
sync /* wait for tlbia/tlbie to finish */
/* set up the PTE pointers for the Abatron bdiGDB.
*/
lis r5, abatron_pteptrs@h
ori r5, r5, abatron_pteptrs@l
stw r5, 0xf0(0) /* Must match your Abatron config file */
tophys(r5,r5)
lis r6, swapper_pg_dir@h
ori r6, r6, swapper_pg_dir@l
stw r6, 0(r5)
/* Now turn on the MMU for real! */
li r4,MSR_KERNEL
lis r3,start_kernel@h
ori r3,r3,start_kernel@l
mtspr SPRN_SRR0,r3
mtspr SPRN_SRR1,r4
rfi /* enable MMU and jump to start_kernel */
/* Set up the initial MMU state so we can do the first level of
* kernel initialization. This maps the first 8 MBytes of memory 1:1
* virtual to physical. Also, set the cache mode since that is defined
* by TLB entries and perform any additional mapping (like of the IMMR).
* If configured to pin some TLBs, we pin the first 8 Mbytes of kernel,
* 24 Mbytes of data, and the 512k IMMR space. Anything not covered by
* these mappings is mapped by page tables.
*/
initial_mmu:
li r8, 0
mtspr SPRN_MI_CTR, r8 /* remove PINNED ITLB entries */
lis r10, MD_TWAM@h
mtspr SPRN_MD_CTR, r10 /* remove PINNED DTLB entries */
tlbia /* Invalidate all TLB entries */
lis r8, MI_APG_INIT@h /* Set protection modes */
ori r8, r8, MI_APG_INIT@l
mtspr SPRN_MI_AP, r8
lis r8, MD_APG_INIT@h
ori r8, r8, MD_APG_INIT@l
mtspr SPRN_MD_AP, r8
/* Map the lower RAM (up to 32 Mbytes) into the ITLB and DTLB */
lis r8, MI_RSV4I@h
ori r8, r8, 0x1c00
oris r12, r10, MD_RSV4I@h
ori r12, r12, 0x1c00
li r9, 4 /* up to 4 pages of 8M */
mtctr r9
lis r9, KERNELBASE@h /* Create vaddr for TLB */
li r10, MI_PS8MEG | _PMD_ACCESSED | MI_SVALID
li r11, MI_BOOTINIT /* Create RPN for address 0 */
1:
mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */
addi r8, r8, 0x100
ori r0, r9, MI_EVALID /* Mark it valid */
mtspr SPRN_MI_EPN, r0
mtspr SPRN_MI_TWC, r10
mtspr SPRN_MI_RPN, r11 /* Store TLB entry */
mtspr SPRN_MD_CTR, r12
addi r12, r12, 0x100
mtspr SPRN_MD_EPN, r0
mtspr SPRN_MD_TWC, r10
mtspr SPRN_MD_RPN, r11
addis r9, r9, 0x80
addis r11, r11, 0x80
bdnz 1b
/* Since the cache is enabled according to the information we
* just loaded into the TLB, invalidate and enable the caches here.
* We should probably check/set other modes....later.
*/
lis r8, IDC_INVALL@h
mtspr SPRN_IC_CST, r8
mtspr SPRN_DC_CST, r8
lis r8, IDC_ENABLE@h
mtspr SPRN_IC_CST, r8
mtspr SPRN_DC_CST, r8
/* Disable debug mode entry on breakpoints */
mfspr r8, SPRN_DER
#ifdef CONFIG_PERF_EVENTS
rlwinm r8, r8, 0, ~0xc
#else
rlwinm r8, r8, 0, ~0x8
#endif
mtspr SPRN_DER, r8
blr
_GLOBAL(mmu_pin_tlb)
lis r9, (1f - PAGE_OFFSET)@h
ori r9, r9, (1f - PAGE_OFFSET)@l
mfmsr r10
mflr r11
li r12, MSR_KERNEL & ~(MSR_IR | MSR_DR | MSR_RI)
rlwinm r0, r10, 0, ~MSR_RI
rlwinm r0, r0, 0, ~MSR_EE
mtmsr r0
isync
.align 4
mtspr SPRN_SRR0, r9
mtspr SPRN_SRR1, r12
rfi
1:
li r5, 0
lis r6, MD_TWAM@h
mtspr SPRN_MI_CTR, r5
mtspr SPRN_MD_CTR, r6
tlbia
LOAD_REG_IMMEDIATE(r5, 28 << 8)
LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED)
LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT)
LOAD_REG_ADDR(r9, _sinittext)
li r0, 4
mtctr r0
2: ori r0, r6, MI_EVALID
mtspr SPRN_MI_CTR, r5
mtspr SPRN_MI_EPN, r0
mtspr SPRN_MI_TWC, r7
mtspr SPRN_MI_RPN, r8
addi r5, r5, 0x100
addis r6, r6, SZ_8M@h
addis r8, r8, SZ_8M@h
cmplw r6, r9
bdnzt lt, 2b
lis r0, MI_RSV4I@h
mtspr SPRN_MI_CTR, r0
LOAD_REG_IMMEDIATE(r5, 28 << 8 | MD_TWAM)
#ifdef CONFIG_PIN_TLB_DATA
LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED)
li r8, 0
#ifdef CONFIG_PIN_TLB_IMMR
li r0, 3
#else
li r0, 4
#endif
mtctr r0
cmpwi r4, 0
beq 4f
LOAD_REG_ADDR(r9, _sinittext)
2: ori r0, r6, MD_EVALID
ori r12, r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT
mtspr SPRN_MD_CTR, r5
mtspr SPRN_MD_EPN, r0
mtspr SPRN_MD_TWC, r7
mtspr SPRN_MD_RPN, r12
addi r5, r5, 0x100
addis r6, r6, SZ_8M@h
addis r8, r8, SZ_8M@h
cmplw r6, r9
bdnzt lt, 2b
4:
2: ori r0, r6, MD_EVALID
ori r12, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT
mtspr SPRN_MD_CTR, r5
mtspr SPRN_MD_EPN, r0
mtspr SPRN_MD_TWC, r7
mtspr SPRN_MD_RPN, r12
addi r5, r5, 0x100
addis r6, r6, SZ_8M@h
addis r8, r8, SZ_8M@h
cmplw r6, r3
bdnzt lt, 2b
#endif
#ifdef CONFIG_PIN_TLB_IMMR
LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID)
LOAD_REG_IMMEDIATE(r7, MD_SVALID | MD_PS512K | MD_GUARDED | _PMD_ACCESSED)
mfspr r8, SPRN_IMMR
rlwinm r8, r8, 0, 0xfff80000
ori r8, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \
_PAGE_NO_CACHE | _PAGE_PRESENT
mtspr SPRN_MD_CTR, r5
mtspr SPRN_MD_EPN, r0
mtspr SPRN_MD_TWC, r7
mtspr SPRN_MD_RPN, r8
#endif
#if defined(CONFIG_PIN_TLB_IMMR) || defined(CONFIG_PIN_TLB_DATA)
lis r0, (MD_RSV4I | MD_TWAM)@h
mtspr SPRN_MD_CTR, r0
#endif
mtspr SPRN_SRR1, r10
mtspr SPRN_SRR0, r11
rfi