/*
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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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mrs x11, tpidr_el1
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mrs x12, sp_el0
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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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stp x11, x12, [x0, #80]
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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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.pushsection ".idmap.text", "awx"
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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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ldp x13, x14, [x0, #80]
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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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msr tpidr_el1, x13
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msr sp_el0, x14
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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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.popsection
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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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mrs x2, ttbr1_el1
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mmid x1, x1 // get mm->context.id
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#ifdef CONFIG_ARM64_SW_TTBR0_PAN
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bfi x0, x1, #48, #16 // set the ASID field in TTBR0
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#endif
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bfi x2, x1, #48, #16 // set the ASID
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msr ttbr1_el1, x2 // in TTBR1 (since TCR.A1 is set)
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isb
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msr ttbr0_el1, x0 // now update TTBR0
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isb
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b post_ttbr_update_workaround // Back to C code...
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ENDPROC(cpu_do_switch_mm)
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.pushsection ".idmap.text", "awx"
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.macro __idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
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adrp \tmp1, empty_zero_page
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msr ttbr1_el1, \tmp1
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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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.endm
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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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__idmap_cpu_set_reserved_ttbr1 x1, x3
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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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#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
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.pushsection ".idmap.text", "awx"
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.macro __idmap_kpti_get_pgtable_ent, type
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dc cvac, cur_\()\type\()p // Ensure any existing dirty
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dmb sy // lines are written back before
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ldr \type, [cur_\()\type\()p] // loading the entry
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tbz \type, #0, next_\()\type // Skip invalid entries
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.endm
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.macro __idmap_kpti_put_pgtable_ent_ng, type
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orr \type, \type, #PTE_NG // Same bit for blocks and pages
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str \type, [cur_\()\type\()p] // Update the entry and ensure
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dmb sy // that it is visible to all
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dc civac, cur_\()\type\()p // CPUs.
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.endm
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/*
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* void __kpti_install_ng_mappings(int cpu, int num_cpus, phys_addr_t swapper)
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*
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* Called exactly once from stop_machine context by each CPU found during boot.
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*/
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__idmap_kpti_flag:
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.long 1
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ENTRY(idmap_kpti_install_ng_mappings)
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cpu .req w0
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num_cpus .req w1
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swapper_pa .req x2
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swapper_ttb .req x3
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flag_ptr .req x4
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cur_pgdp .req x5
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end_pgdp .req x6
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pgd .req x7
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cur_pudp .req x8
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end_pudp .req x9
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pud .req x10
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cur_pmdp .req x11
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end_pmdp .req x12
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pmd .req x13
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cur_ptep .req x14
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end_ptep .req x15
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pte .req x16
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mrs swapper_ttb, ttbr1_el1
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adr flag_ptr, __idmap_kpti_flag
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cbnz cpu, __idmap_kpti_secondary
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/* We're the boot CPU. Wait for the others to catch up */
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sevl
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1: wfe
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ldaxr w18, [flag_ptr]
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eor w18, w18, num_cpus
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cbnz w18, 1b
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/* We need to walk swapper, so turn off the MMU. */
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mrs x18, sctlr_el1
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bic x18, x18, #SCTLR_ELx_M
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msr sctlr_el1, x18
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isb
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/* Everybody is enjoying the idmap, so we can rewrite swapper. */
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/* PGD */
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mov cur_pgdp, swapper_pa
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add end_pgdp, cur_pgdp, #(PTRS_PER_PGD * 8)
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do_pgd: __idmap_kpti_get_pgtable_ent pgd
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tbnz pgd, #1, walk_puds
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__idmap_kpti_put_pgtable_ent_ng pgd
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next_pgd:
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add cur_pgdp, cur_pgdp, #8
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cmp cur_pgdp, end_pgdp
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b.ne do_pgd
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/* Publish the updated tables and nuke all the TLBs */
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dsb sy
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tlbi vmalle1is
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dsb ish
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isb
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/* We're done: fire up the MMU again */
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mrs x18, sctlr_el1
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orr x18, x18, #SCTLR_ELx_M
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msr sctlr_el1, x18
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isb
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/* Set the flag to zero to indicate that we're all done */
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str wzr, [flag_ptr]
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ret
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/* PUD */
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walk_puds:
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.if CONFIG_PGTABLE_LEVELS > 3
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pte_to_phys cur_pudp, pgd
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add end_pudp, cur_pudp, #(PTRS_PER_PUD * 8)
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do_pud: __idmap_kpti_get_pgtable_ent pud
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tbnz pud, #1, walk_pmds
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__idmap_kpti_put_pgtable_ent_ng pud
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next_pud:
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add cur_pudp, cur_pudp, 8
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cmp cur_pudp, end_pudp
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b.ne do_pud
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b next_pgd
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.else /* CONFIG_PGTABLE_LEVELS <= 3 */
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mov pud, pgd
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b walk_pmds
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next_pud:
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b next_pgd
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.endif
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/* PMD */
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walk_pmds:
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.if CONFIG_PGTABLE_LEVELS > 2
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pte_to_phys cur_pmdp, pud
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add end_pmdp, cur_pmdp, #(PTRS_PER_PMD * 8)
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do_pmd: __idmap_kpti_get_pgtable_ent pmd
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tbnz pmd, #1, walk_ptes
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__idmap_kpti_put_pgtable_ent_ng pmd
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next_pmd:
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add cur_pmdp, cur_pmdp, #8
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cmp cur_pmdp, end_pmdp
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b.ne do_pmd
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b next_pud
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.else /* CONFIG_PGTABLE_LEVELS <= 2 */
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mov pmd, pud
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b walk_ptes
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next_pmd:
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b next_pud
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.endif
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/* PTE */
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walk_ptes:
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pte_to_phys cur_ptep, pmd
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add end_ptep, cur_ptep, #(PTRS_PER_PTE * 8)
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do_pte: __idmap_kpti_get_pgtable_ent pte
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__idmap_kpti_put_pgtable_ent_ng pte
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next_pte:
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add cur_ptep, cur_ptep, #8
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cmp cur_ptep, end_ptep
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b.ne do_pte
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b next_pmd
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/* Secondary CPUs end up here */
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__idmap_kpti_secondary:
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/* Uninstall swapper before surgery begins */
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__idmap_cpu_set_reserved_ttbr1 x18, x17
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/* Increment the flag to let the boot CPU we're ready */
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1: ldxr w18, [flag_ptr]
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add w18, w18, #1
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stxr w17, w18, [flag_ptr]
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cbnz w17, 1b
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/* Wait for the boot CPU to finish messing around with swapper */
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sevl
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1: wfe
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ldxr w18, [flag_ptr]
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cbnz w18, 1b
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/* All done, act like nothing happened */
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msr ttbr1_el1, swapper_ttb
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isb
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ret
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.unreq cpu
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.unreq num_cpus
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.unreq swapper_pa
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.unreq swapper_ttb
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.unreq flag_ptr
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.unreq cur_pgdp
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.unreq end_pgdp
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.unreq pgd
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.unreq cur_pudp
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.unreq end_pudp
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.unreq pud
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.unreq cur_pmdp
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.unreq end_pmdp
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.unreq pmd
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.unreq cur_ptep
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.unreq end_ptep
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.unreq pte
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ENDPROC(idmap_kpti_install_ng_mappings)
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.popsection
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#endif
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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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.pushsection ".idmap.text", "awx"
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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 | TCR_A1
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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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#ifdef CONFIG_ARM64_ERRATUM_1024718
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/* Disable hardware DBM on Cortex-A55 r0p0, r0p1 & r1p0 */
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cpu_midr_match MIDR_CORTEX_A55, MIDR_CPU_VAR_REV(0, 0), MIDR_CPU_VAR_REV(1, 0), x1, x2, x3, x4
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cbnz x1, 1f
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#endif
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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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.popsection
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