arm64: Add back cpu reset routines
Commit 68234df4ea
("arm64: kill flush_cache_all()") removed the global
arm64 routines cpu_reset() and cpu_soft_restart() needed by the arm64
kexec and kdump support. Add back a simplified version of
cpu_soft_restart() with some changes needed for kexec in the new files
cpu_reset.S, and cpu_reset.h.
When a CPU is reset it needs to be put into the exception level it had when
it entered the kernel. Update cpu_soft_restart() to accept an argument
which signals if the reset address should be entered at EL1 or EL2, and
add a new hypercall HVC_SOFT_RESTART which is used for the EL2 switch.
Signed-off-by: Geoff Levand <geoff@infradead.org>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
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@ -34,6 +34,11 @@
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*/
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#define HVC_SET_VECTORS 1
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/*
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* HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
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*/
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#define HVC_SOFT_RESTART 2
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#define BOOT_CPU_MODE_EL1 (0xe11)
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#define BOOT_CPU_MODE_EL2 (0xe12)
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54
arch/arm64/kernel/cpu-reset.S
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54
arch/arm64/kernel/cpu-reset.S
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@ -0,0 +1,54 @@
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/*
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* CPU reset routines
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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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* Copyright (C) 2015 Huawei Futurewei Technologies.
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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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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/sysreg.h>
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#include <asm/virt.h>
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.text
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.pushsection .idmap.text, "ax"
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/*
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* __cpu_soft_restart(el2_switch, entry, arg0, arg1, arg2) - Helper for
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* cpu_soft_restart.
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*
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* @el2_switch: Flag to indicate a swich to EL2 is needed.
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* @entry: Location to jump to for soft reset.
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* arg0: First argument passed to @entry.
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* arg1: Second argument passed to @entry.
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* arg2: Third argument passed to @entry.
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*
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* Put the CPU into the same state as it would be if it had been reset, and
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* branch to what would be the reset vector. It must be executed with the
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* flat identity mapping.
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*/
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ENTRY(__cpu_soft_restart)
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/* Clear sctlr_el1 flags. */
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mrs x12, sctlr_el1
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ldr x13, =SCTLR_ELx_FLAGS
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bic x12, x12, x13
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msr sctlr_el1, x12
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isb
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cbz x0, 1f // el2_switch?
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mov x0, #HVC_SOFT_RESTART
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hvc #0 // no return
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1: mov x18, x1 // entry
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mov x0, x2 // arg0
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mov x1, x3 // arg1
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mov x2, x4 // arg2
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br x18
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ENDPROC(__cpu_soft_restart)
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.popsection
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34
arch/arm64/kernel/cpu-reset.h
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34
arch/arm64/kernel/cpu-reset.h
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@ -0,0 +1,34 @@
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/*
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* CPU reset routines
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*
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* Copyright (C) 2015 Huawei Futurewei Technologies.
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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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#ifndef _ARM64_CPU_RESET_H
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#define _ARM64_CPU_RESET_H
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#include <asm/virt.h>
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void __cpu_soft_restart(unsigned long el2_switch, unsigned long entry,
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unsigned long arg0, unsigned long arg1, unsigned long arg2);
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static inline void __noreturn cpu_soft_restart(unsigned long el2_switch,
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unsigned long entry, unsigned long arg0, unsigned long arg1,
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unsigned long arg2)
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{
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typeof(__cpu_soft_restart) *restart;
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el2_switch = el2_switch && !is_kernel_in_hyp_mode() &&
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is_hyp_mode_available();
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restart = (void *)virt_to_phys(__cpu_soft_restart);
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cpu_install_idmap();
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restart(el2_switch, entry, arg0, arg1, arg2);
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unreachable();
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}
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#endif
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@ -71,8 +71,16 @@ el1_sync:
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msr vbar_el2, x1
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b 9f
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2: cmp x0, #HVC_SOFT_RESTART
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b.ne 3f
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mov x0, x2
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mov x2, x4
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mov x4, x1
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mov x1, x3
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br x4 // no return
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/* Someone called kvm_call_hyp() against the hyp-stub... */
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2: mov x0, #ARM_EXCEPTION_HYP_GONE
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3: mov x0, #ARM_EXCEPTION_HYP_GONE
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9: eret
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ENDPROC(el1_sync)
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