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android_kernel_xiaomi_sm8350/arch/arm/mm/proc-v6.S
Russell King 4b46d64165 ARM: ensure initial page tables are setup for SMP systems 
Mapping the same memory using two different attributes (memory
type, shareability, cacheability) is unpredictable.  During boot,
we encounter a situation when we're updating the kernel's page
tables which can lead to dirty cache lines existing in the cache
which are subsequently missed.  This causes stack corruption,
and therefore a crash.

Therefore, ensure that the shared and cacheability settings
matches the configuration that will be used later; this together
with the restriction in early_cachepolicy() ensures that we won't
create a mismatch during boot.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-11-02 16:59:59 +00:00

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/*
* linux/arch/arm/mm/proc-v6.S
*
* Copyright (C) 2001 Deep Blue Solutions Ltd.
* Modified by Catalin Marinas for noMMU support
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This is the "shell" of the ARMv6 processor support.
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/hwcap.h>
#include <asm/pgtable-hwdef.h>
#include <asm/pgtable.h>
#include "proc-macros.S"
#define D_CACHE_LINE_SIZE 32
#define TTB_C (1 << 0)
#define TTB_S (1 << 1)
#define TTB_IMP (1 << 2)
#define TTB_RGN_NC (0 << 3)
#define TTB_RGN_WBWA (1 << 3)
#define TTB_RGN_WT (2 << 3)
#define TTB_RGN_WB (3 << 3)
#ifndef CONFIG_SMP
#define TTB_FLAGS TTB_RGN_WBWA
#define PMD_FLAGS PMD_SECT_WB
#else
#define TTB_FLAGS TTB_RGN_WBWA|TTB_S
#define PMD_FLAGS PMD_SECT_WBWA|PMD_SECT_S
#endif
ENTRY(cpu_v6_proc_init)
mov pc, lr
ENTRY(cpu_v6_proc_fin)
stmfd sp!, {lr}
cpsid if @ disable interrupts
bl v6_flush_kern_cache_all
mrc p15, 0, r0, c1, c0, 0 @ ctrl register
bic r0, r0, #0x1000 @ ...i............
bic r0, r0, #0x0006 @ .............ca.
mcr p15, 0, r0, c1, c0, 0 @ disable caches
ldmfd sp!, {pc}
/*
* cpu_v6_reset(loc)
*
* Perform a soft reset of the system. Put the CPU into the
* same state as it would be if it had been reset, and branch
* to what would be the reset vector.
*
* - loc - location to jump to for soft reset
*
* It is assumed that:
*/
.align 5
ENTRY(cpu_v6_reset)
mov pc, r0
/*
* cpu_v6_do_idle()
*
* Idle the processor (eg, wait for interrupt).
*
* IRQs are already disabled.
*/
ENTRY(cpu_v6_do_idle)
mov r1, #0
mcr p15, 0, r1, c7, c10, 4 @ DWB - WFI may enter a low-power mode
mcr p15, 0, r1, c7, c0, 4 @ wait for interrupt
mov pc, lr
ENTRY(cpu_v6_dcache_clean_area)
#ifndef TLB_CAN_READ_FROM_L1_CACHE
1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
add r0, r0, #D_CACHE_LINE_SIZE
subs r1, r1, #D_CACHE_LINE_SIZE
bhi 1b
#endif
mov pc, lr
/*
* cpu_arm926_switch_mm(pgd_phys, tsk)
*
* Set the translation table base pointer to be pgd_phys
*
* - pgd_phys - physical address of new TTB
*
* It is assumed that:
* - we are not using split page tables
*/
ENTRY(cpu_v6_switch_mm)
#ifdef CONFIG_MMU
mov r2, #0
ldr r1, [r1, #MM_CONTEXT_ID] @ get mm->context.id
orr r0, r0, #TTB_FLAGS
mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB
mcr p15, 0, r2, c7, c10, 4 @ drain write buffer
mcr p15, 0, r0, c2, c0, 0 @ set TTB 0
mcr p15, 0, r1, c13, c0, 1 @ set context ID
#endif
mov pc, lr
/*
* cpu_v6_set_pte_ext(ptep, pte, ext)
*
* Set a level 2 translation table entry.
*
* - ptep - pointer to level 2 translation table entry
* (hardware version is stored at -1024 bytes)
* - pte - PTE value to store
* - ext - value for extended PTE bits
*/
armv6_mt_table cpu_v6
ENTRY(cpu_v6_set_pte_ext)
#ifdef CONFIG_MMU
armv6_set_pte_ext cpu_v6
#endif
mov pc, lr
cpu_v6_name:
.asciz "ARMv6-compatible processor"
.align
__INIT
/*
* __v6_setup
*
* Initialise TLB, Caches, and MMU state ready to switch the MMU
* on. Return in r0 the new CP15 C1 control register setting.
*
* We automatically detect if we have a Harvard cache, and use the
* Harvard cache control instructions insead of the unified cache
* control instructions.
*
* This should be able to cover all ARMv6 cores.
*
* It is assumed that:
* - cache type register is implemented
*/
__v6_setup:
#ifdef CONFIG_SMP
mrc p15, 0, r0, c1, c0, 1 @ Enable SMP/nAMP mode
orr r0, r0, #0x20
mcr p15, 0, r0, c1, c0, 1
#endif
mov r0, #0
mcr p15, 0, r0, c7, c14, 0 @ clean+invalidate D cache
mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
mcr p15, 0, r0, c7, c15, 0 @ clean+invalidate cache
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
#ifdef CONFIG_MMU
mcr p15, 0, r0, c8, c7, 0 @ invalidate I + D TLBs
mcr p15, 0, r0, c2, c0, 2 @ TTB control register
orr r4, r4, #TTB_FLAGS
mcr p15, 0, r4, c2, c0, 1 @ load TTB1
#endif /* CONFIG_MMU */
adr r5, v6_crval
ldmia r5, {r5, r6}
#ifdef CONFIG_CPU_ENDIAN_BE8
orr r6, r6, #1 << 25 @ big-endian page tables
#endif
mrc p15, 0, r0, c1, c0, 0 @ read control register
bic r0, r0, r5 @ clear bits them
orr r0, r0, r6 @ set them
mov pc, lr @ return to head.S:__ret
/*
* V X F I D LR
* .... ...E PUI. .T.T 4RVI ZFRS BLDP WCAM
* rrrr rrrx xxx0 0101 xxxx xxxx x111 xxxx < forced
* 0 110 0011 1.00 .111 1101 < we want
*/
.type v6_crval, #object
v6_crval:
crval clear=0x01e0fb7f, mmuset=0x00c0387d, ucset=0x00c0187c
.type v6_processor_functions, #object
ENTRY(v6_processor_functions)
.word v6_early_abort
.word v6_pabort
.word cpu_v6_proc_init
.word cpu_v6_proc_fin
.word cpu_v6_reset
.word cpu_v6_do_idle
.word cpu_v6_dcache_clean_area
.word cpu_v6_switch_mm
.word cpu_v6_set_pte_ext
.size v6_processor_functions, . - v6_processor_functions
.type cpu_arch_name, #object
cpu_arch_name:
.asciz "armv6"
.size cpu_arch_name, . - cpu_arch_name
.type cpu_elf_name, #object
cpu_elf_name:
.asciz "v6"
.size cpu_elf_name, . - cpu_elf_name
.align
.section ".proc.info.init", #alloc, #execinstr
/*
* Match any ARMv6 processor core.
*/
.type __v6_proc_info, #object
__v6_proc_info:
.long 0x0007b000
.long 0x0007f000
.long PMD_TYPE_SECT | \
PMD_SECT_AP_WRITE | \
PMD_SECT_AP_READ | \
PMD_FLAGS
.long PMD_TYPE_SECT | \
PMD_SECT_XN | \
PMD_SECT_AP_WRITE | \
PMD_SECT_AP_READ
b __v6_setup
.long cpu_arch_name
.long cpu_elf_name
.long HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP|HWCAP_JAVA
.long cpu_v6_name
.long v6_processor_functions
.long v6wbi_tlb_fns
.long v6_user_fns
.long v6_cache_fns
.size __v6_proc_info, . - __v6_proc_info
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