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9c413e25d9
During boot, we take the debug OS lock before interrupts are enabled. This is required to prevent clearing of PSTATE.D on the interrupt entry path, which could result in spurious debug exceptions before we've got round to resetting things like the hardware breakpoints registers to a sane state. A problem with this approach is that taking the OS lock prevents an external JTAG debugger from debugging the system, which is especially irritating during boot, where JTAG debugging can be most useful. This patch clears mdscr_el1 rather than taking the lock, clearing the MDE and KDE bits and preventing self-hosted hardware debug exceptions from occurring. Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: stable@vger.kernel.org
175 lines
4.1 KiB
ArmAsm
175 lines
4.1 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-hwdef.h>
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#include <asm/pgtable.h>
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#include "proc-macros.S"
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#ifndef CONFIG_SMP
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/* PTWs cacheable, inner/outer WBWA not shareable */
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#define TCR_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA
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#else
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/* PTWs cacheable, inner/outer WBWA shareable */
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#define TCR_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA | TCR_SHARED
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#endif
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#define MAIR(attr, mt) ((attr) << ((mt) * 8))
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/*
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* cpu_cache_off()
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*
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* Turn the CPU D-cache off.
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*/
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ENTRY(cpu_cache_off)
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mrs x0, sctlr_el1
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bic x0, x0, #1 << 2 // clear SCTLR.C
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msr sctlr_el1, x0
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isb
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ret
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ENDPROC(cpu_cache_off)
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/*
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* cpu_reset(loc)
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*
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* Perform a soft reset of the system. Put the CPU into the same state
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* as it would be if it had been reset, and branch to what would be the
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* reset vector. It must be executed with the flat identity mapping.
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*
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* - loc - location to jump to for soft reset
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*/
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.align 5
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ENTRY(cpu_reset)
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mrs x1, sctlr_el1
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bic x1, x1, #1
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msr sctlr_el1, x1 // disable the MMU
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isb
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ret x0
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ENDPROC(cpu_reset)
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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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/*
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* cpu_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 w1, 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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ret
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ENDPROC(cpu_do_switch_mm)
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cpu_name:
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.ascii "AArch64 Processor"
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.align
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.section ".text.init", #alloc, #execinstr
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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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/*
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* Preserve the link register across the function call.
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*/
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mov x28, lr
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bl __flush_dcache_all
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mov lr, x28
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ic iallu // I+BTB cache invalidate
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dsb sy
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mov x0, #3 << 20
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msr cpacr_el1, x0 // Enable FP/ASIMD
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msr mdscr_el1, xzr // Reset mdscr_el1
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tlbi vmalle1is // invalidate I + D TLBs
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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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*/
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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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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_FLAGS | TCR_IPS_40BIT | \
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TCR_ASID16 | (1 << 31)
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#ifdef CONFIG_ARM64_64K_PAGES
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orr x10, x10, TCR_TG0_64K
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orr x10, x10, TCR_TG1_64K
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#endif
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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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* 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.. .... .... < hardware reserved
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* .... .100 .... 01.1 11.1 ..01 0001 1101 < software settings
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*/
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.type crval, #object
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crval:
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.word 0x030802e2 // clear
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.word 0x0405d11d // set
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