Commit f9076ecf authored by Geoff Levand's avatar Geoff Levand Committed by Catalin Marinas

arm64: Add back cpu reset routines

Commit 68234df4 ("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: default avatarGeoff Levand <geoff@infradead.org>
Reviewed-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent b69e0dc1
......@@ -34,6 +34,11 @@
*/
#define HVC_SET_VECTORS 1
/*
* HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
*/
#define HVC_SOFT_RESTART 2
#define BOOT_CPU_MODE_EL1 (0xe11)
#define BOOT_CPU_MODE_EL2 (0xe12)
......
/*
* CPU reset routines
*
* Copyright (C) 2001 Deep Blue Solutions Ltd.
* Copyright (C) 2012 ARM Ltd.
* Copyright (C) 2015 Huawei Futurewei Technologies.
*
* 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.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/sysreg.h>
#include <asm/virt.h>
.text
.pushsection .idmap.text, "ax"
/*
* __cpu_soft_restart(el2_switch, entry, arg0, arg1, arg2) - Helper for
* cpu_soft_restart.
*
* @el2_switch: Flag to indicate a swich to EL2 is needed.
* @entry: Location to jump to for soft reset.
* arg0: First argument passed to @entry.
* arg1: Second argument passed to @entry.
* arg2: Third argument passed to @entry.
*
* 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. It must be executed with the
* flat identity mapping.
*/
ENTRY(__cpu_soft_restart)
/* Clear sctlr_el1 flags. */
mrs x12, sctlr_el1
ldr x13, =SCTLR_ELx_FLAGS
bic x12, x12, x13
msr sctlr_el1, x12
isb
cbz x0, 1f // el2_switch?
mov x0, #HVC_SOFT_RESTART
hvc #0 // no return
1: mov x18, x1 // entry
mov x0, x2 // arg0
mov x1, x3 // arg1
mov x2, x4 // arg2
br x18
ENDPROC(__cpu_soft_restart)
.popsection
/*
* CPU reset routines
*
* Copyright (C) 2015 Huawei Futurewei Technologies.
*
* 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.
*/
#ifndef _ARM64_CPU_RESET_H
#define _ARM64_CPU_RESET_H
#include <asm/virt.h>
void __cpu_soft_restart(unsigned long el2_switch, unsigned long entry,
unsigned long arg0, unsigned long arg1, unsigned long arg2);
static inline void __noreturn cpu_soft_restart(unsigned long el2_switch,
unsigned long entry, unsigned long arg0, unsigned long arg1,
unsigned long arg2)
{
typeof(__cpu_soft_restart) *restart;
el2_switch = el2_switch && !is_kernel_in_hyp_mode() &&
is_hyp_mode_available();
restart = (void *)virt_to_phys(__cpu_soft_restart);
cpu_install_idmap();
restart(el2_switch, entry, arg0, arg1, arg2);
unreachable();
}
#endif
......@@ -71,8 +71,16 @@ el1_sync:
msr vbar_el2, x1
b 9f
2: cmp x0, #HVC_SOFT_RESTART
b.ne 3f
mov x0, x2
mov x2, x4
mov x4, x1
mov x1, x3
br x4 // no return
/* Someone called kvm_call_hyp() against the hyp-stub... */
2: mov x0, #ARM_EXCEPTION_HYP_GONE
3: mov x0, #ARM_EXCEPTION_HYP_GONE
9: eret
ENDPROC(el1_sync)
......
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