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744c6c37cc
Changes to make the resume from cpu_suspend() code behave more like
secondary boot caused debug exceptions to be unmasked early by
__cpu_setup(). We then go on to restore mdscr_el1 in cpu_do_resume(),
potentially taking break or watch points based on uninitialised registers.
Mask debug exceptions in cpu_do_resume(), which is specific to resume
from cpu_suspend(). Debug exceptions will be restored to their original
state by local_dbg_restore() in cpu_suspend(), which runs after
hw_breakpoint_restore() has re-initialised the other registers.
Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Fixes: cabe1c81ea ("arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va")
Cc: <stable@vger.kernel.org> # 4.7+
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
269 lines
6.3 KiB
ArmAsm
269 lines
6.3 KiB
ArmAsm
/*
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* Based on arch/arm/mm/proc.S
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*
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* Copyright (C) 2001 Deep Blue Solutions Ltd.
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* Copyright (C) 2012 ARM Ltd.
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* Author: Catalin Marinas <catalin.marinas@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/init.h>
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/asm-offsets.h>
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#include <asm/hwcap.h>
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#include <asm/pgtable.h>
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#include <asm/pgtable-hwdef.h>
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#include <asm/cpufeature.h>
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#include <asm/alternative.h>
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#ifdef CONFIG_ARM64_64K_PAGES
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#define TCR_TG_FLAGS TCR_TG0_64K | TCR_TG1_64K
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#elif defined(CONFIG_ARM64_16K_PAGES)
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#define TCR_TG_FLAGS TCR_TG0_16K | TCR_TG1_16K
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#else /* CONFIG_ARM64_4K_PAGES */
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#define TCR_TG_FLAGS TCR_TG0_4K | TCR_TG1_4K
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#endif
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#define TCR_SMP_FLAGS TCR_SHARED
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/* PTWs cacheable, inner/outer WBWA */
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#define TCR_CACHE_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA
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#define MAIR(attr, mt) ((attr) << ((mt) * 8))
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/*
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* cpu_do_idle()
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*
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* Idle the processor (wait for interrupt).
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*/
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ENTRY(cpu_do_idle)
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dsb sy // WFI may enter a low-power mode
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wfi
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ret
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ENDPROC(cpu_do_idle)
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#ifdef CONFIG_CPU_PM
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/**
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* cpu_do_suspend - save CPU registers context
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*
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* x0: virtual address of context pointer
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*/
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ENTRY(cpu_do_suspend)
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mrs x2, tpidr_el0
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mrs x3, tpidrro_el0
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mrs x4, contextidr_el1
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mrs x5, cpacr_el1
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mrs x6, tcr_el1
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mrs x7, vbar_el1
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mrs x8, mdscr_el1
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mrs x9, oslsr_el1
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mrs x10, sctlr_el1
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stp x2, x3, [x0]
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stp x4, xzr, [x0, #16]
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stp x5, x6, [x0, #32]
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stp x7, x8, [x0, #48]
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stp x9, x10, [x0, #64]
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ret
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ENDPROC(cpu_do_suspend)
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/**
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* cpu_do_resume - restore CPU register context
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*
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* x0: Address of context pointer
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*/
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ENTRY(cpu_do_resume)
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ldp x2, x3, [x0]
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ldp x4, x5, [x0, #16]
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ldp x6, x8, [x0, #32]
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ldp x9, x10, [x0, #48]
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ldp x11, x12, [x0, #64]
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msr tpidr_el0, x2
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msr tpidrro_el0, x3
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msr contextidr_el1, x4
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msr cpacr_el1, x6
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/* Don't change t0sz here, mask those bits when restoring */
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mrs x5, tcr_el1
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bfi x8, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
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msr tcr_el1, x8
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msr vbar_el1, x9
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/*
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* __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
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* debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
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* exception. Mask them until local_dbg_restore() in cpu_suspend()
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* resets them.
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*/
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disable_dbg
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msr mdscr_el1, x10
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msr sctlr_el1, x12
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/*
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* Restore oslsr_el1 by writing oslar_el1
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*/
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ubfx x11, x11, #1, #1
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msr oslar_el1, x11
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reset_pmuserenr_el0 x0 // Disable PMU access from EL0
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isb
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ret
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ENDPROC(cpu_do_resume)
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#endif
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/*
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* cpu_do_switch_mm(pgd_phys, tsk)
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*
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* Set the translation table base pointer to be pgd_phys.
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*
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* - pgd_phys - physical address of new TTB
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*/
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ENTRY(cpu_do_switch_mm)
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mmid x1, x1 // get mm->context.id
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bfi x0, x1, #48, #16 // set the ASID
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msr ttbr0_el1, x0 // set TTBR0
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isb
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alternative_if_not ARM64_WORKAROUND_CAVIUM_27456
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ret
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nop
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nop
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nop
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alternative_else
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ic iallu
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dsb nsh
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isb
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ret
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alternative_endif
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ENDPROC(cpu_do_switch_mm)
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.pushsection ".idmap.text", "ax"
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/*
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* void idmap_cpu_replace_ttbr1(phys_addr_t new_pgd)
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*
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* This is the low-level counterpart to cpu_replace_ttbr1, and should not be
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* called by anything else. It can only be executed from a TTBR0 mapping.
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*/
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ENTRY(idmap_cpu_replace_ttbr1)
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mrs x2, daif
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msr daifset, #0xf
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adrp x1, empty_zero_page
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msr ttbr1_el1, x1
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isb
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tlbi vmalle1
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dsb nsh
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isb
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msr ttbr1_el1, x0
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isb
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msr daif, x2
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ret
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ENDPROC(idmap_cpu_replace_ttbr1)
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.popsection
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/*
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* __cpu_setup
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*
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* Initialise the processor for turning the MMU on. Return in x0 the
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* value of the SCTLR_EL1 register.
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*/
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ENTRY(__cpu_setup)
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tlbi vmalle1 // Invalidate local TLB
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dsb nsh
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mov x0, #3 << 20
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msr cpacr_el1, x0 // Enable FP/ASIMD
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mov x0, #1 << 12 // Reset mdscr_el1 and disable
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msr mdscr_el1, x0 // access to the DCC from EL0
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isb // Unmask debug exceptions now,
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enable_dbg // since this is per-cpu
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reset_pmuserenr_el0 x0 // Disable PMU access from EL0
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/*
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* Memory region attributes for LPAE:
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*
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* n = AttrIndx[2:0]
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* n MAIR
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* DEVICE_nGnRnE 000 00000000
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* DEVICE_nGnRE 001 00000100
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* DEVICE_GRE 010 00001100
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* NORMAL_NC 011 01000100
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* NORMAL 100 11111111
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* NORMAL_WT 101 10111011
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*/
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ldr x5, =MAIR(0x00, MT_DEVICE_nGnRnE) | \
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MAIR(0x04, MT_DEVICE_nGnRE) | \
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MAIR(0x0c, MT_DEVICE_GRE) | \
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MAIR(0x44, MT_NORMAL_NC) | \
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MAIR(0xff, MT_NORMAL) | \
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MAIR(0xbb, MT_NORMAL_WT)
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msr mair_el1, x5
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/*
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* Prepare SCTLR
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*/
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adr x5, crval
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ldp w5, w6, [x5]
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mrs x0, sctlr_el1
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bic x0, x0, x5 // clear bits
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orr x0, x0, x6 // set bits
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/*
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* Set/prepare TCR and TTBR. We use 512GB (39-bit) address range for
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* both user and kernel.
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*/
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ldr x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
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TCR_TG_FLAGS | TCR_ASID16 | TCR_TBI0
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tcr_set_idmap_t0sz x10, x9
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/*
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* Read the PARange bits from ID_AA64MMFR0_EL1 and set the IPS bits in
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* TCR_EL1.
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*/
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mrs x9, ID_AA64MMFR0_EL1
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bfi x10, x9, #32, #3
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#ifdef CONFIG_ARM64_HW_AFDBM
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/*
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* Hardware update of the Access and Dirty bits.
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*/
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mrs x9, ID_AA64MMFR1_EL1
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and x9, x9, #0xf
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cbz x9, 2f
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cmp x9, #2
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b.lt 1f
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orr x10, x10, #TCR_HD // hardware Dirty flag update
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1: orr x10, x10, #TCR_HA // hardware Access flag update
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2:
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#endif /* CONFIG_ARM64_HW_AFDBM */
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msr tcr_el1, x10
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ret // return to head.S
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ENDPROC(__cpu_setup)
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/*
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* We set the desired value explicitly, including those of the
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* reserved bits. The values of bits EE & E0E were set early in
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* el2_setup, which are left untouched below.
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*
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* n n T
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* U E WT T UD US IHBS
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* CE0 XWHW CZ ME TEEA S
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* .... .IEE .... NEAI TE.I ..AD DEN0 ACAM
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* 0011 0... 1101 ..0. ..0. 10.. .0.. .... < hardware reserved
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* .... .1.. .... 01.1 11.1 ..01 0.01 1101 < software settings
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*/
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.type crval, #object
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crval:
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.word 0xfcffffff // clear
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.word 0x34d5d91d // set
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