From f9076ecfb1216a478312b1c078d04792df6d4477 Mon Sep 17 00:00:00 2001 From: Geoff Levand Date: Thu, 23 Jun 2016 17:54:48 +0000 Subject: arm64: Add back cpu reset routines Commit 68234df4ea79 ("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 Reviewed-by: James Morse Signed-off-by: Catalin Marinas --- arch/arm64/kernel/cpu-reset.S | 54 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 arch/arm64/kernel/cpu-reset.S (limited to 'arch/arm64/kernel/cpu-reset.S') diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S new file mode 100644 index 000000000000..65f42d257414 --- /dev/null +++ b/arch/arm64/kernel/cpu-reset.S @@ -0,0 +1,54 @@ +/* + * 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 +#include +#include +#include + +.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 -- cgit v1.2.1