On 19/03/15 20:35, Geoff Levand wrote: > Add three new files, kexec.h, machine_kexec.c and relocate_kernel.S to the > arm64 architecture that add support for the kexec re-boot mechanism > (CONFIG_KEXEC) on arm64 platforms. > > With the addition of arm64 kexec support shutdown code paths through the kernel > are executed that previously were not. To avoid system instability do to > problems in the current arm64 KVM kernel implementation add a Kconfig dependency > on !KEXEC to the arm64 KVM menu item. > > Signed-off-by: Geoff Levand <geoff at infradead.org> > --- > arch/arm64/Kconfig | 9 +++ > arch/arm64/include/asm/kexec.h | 48 ++++++++++++ > arch/arm64/kernel/Makefile | 1 + > arch/arm64/kernel/machine_kexec.c | 125 ++++++++++++++++++++++++++++++ > arch/arm64/kernel/relocate_kernel.S | 149 ++++++++++++++++++++++++++++++++++++ > arch/arm64/kvm/Kconfig | 1 + > include/uapi/linux/kexec.h | 1 + > 7 files changed, 334 insertions(+) > create mode 100644 arch/arm64/include/asm/kexec.h > create mode 100644 arch/arm64/kernel/machine_kexec.c > create mode 100644 arch/arm64/kernel/relocate_kernel.S > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 1b8e973..5a606d1 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -528,6 +528,15 @@ config SECCOMP > and the task is only allowed to execute a few safe syscalls > defined by each seccomp mode. > > +config KEXEC > + depends on (!SMP || PM_SLEEP_SMP) > + bool "kexec system call" > + ---help--- > + kexec is a system call that implements the ability to shutdown your > + current kernel, and to start another kernel. It is like a reboot > + but it is independent of the system firmware. And like a reboot > + you can start any kernel with it, not just Linux. > + > config XEN_DOM0 > def_bool y > depends on XEN > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h > new file mode 100644 > index 0000000..3530ff5 > --- /dev/null > +++ b/arch/arm64/include/asm/kexec.h > @@ -0,0 +1,48 @@ > +/* > + * kexec for arm64 > + * > + * Copyright (C) Linaro. > + * Copyright (C) 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. > + */ > + > +#if !defined(_ARM64_KEXEC_H) > +#define _ARM64_KEXEC_H > + > +/* Maximum physical address we can use pages from */ > + > +#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL) > + > +/* Maximum address we can reach in physical address mode */ > + > +#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL) > + > +/* Maximum address we can use for the control code buffer */ > + > +#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL) > + > +#define KEXEC_CONTROL_PAGE_SIZE 4096 > + > +#define KEXEC_ARCH KEXEC_ARCH_ARM64 > + > +#if !defined(__ASSEMBLY__) > + > +/** > + * crash_setup_regs() - save registers for the panic kernel > + * > + * @newregs: registers are saved here > + * @oldregs: registers to be saved (may be %NULL) > + */ > + > +static inline void crash_setup_regs(struct pt_regs *newregs, > + struct pt_regs *oldregs) > +{ > + /* Empty routine needed to avoid build errors. */ > +} > + > +#endif /* !defined(__ASSEMBLY__) */ > + > +#endif > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile > index 5ee07ee..da9a7ee 100644 > --- a/arch/arm64/kernel/Makefile > +++ b/arch/arm64/kernel/Makefile > @@ -35,6 +35,7 @@ arm64-obj-$(CONFIG_KGDB) += kgdb.o > arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o > arm64-obj-$(CONFIG_PCI) += pci.o > arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o > +arm64-obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o > > obj-y += $(arm64-obj-y) vdso/ > obj-m += $(arm64-obj-m) > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > new file mode 100644 > index 0000000..f1387d0 > --- /dev/null > +++ b/arch/arm64/kernel/machine_kexec.c > @@ -0,0 +1,125 @@ > +/* > + * kexec for arm64 > + * > + * Copyright (C) Linaro. > + * Copyright (C) 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/kexec.h> > +#include <linux/of_fdt.h> > +#include <linux/slab.h> > +#include <linux/uaccess.h> > + > +#include <asm/cacheflush.h> > +#include <asm/system_misc.h> > + > +/* Global variables for the relocate_kernel routine. */ > +extern const unsigned char relocate_new_kernel[]; > +extern const unsigned long relocate_new_kernel_size; > +extern unsigned long arm64_kexec_dtb_addr; > +extern unsigned long arm64_kexec_kimage_head; > +extern unsigned long arm64_kexec_kimage_start; > + > +void machine_kexec_cleanup(struct kimage *image) > +{ > + /* Empty routine needed to avoid build errors. */ > +} > + > +/** > + * machine_kexec_prepare - Prepare for a kexec reboot. > + * > + * Called from the core kexec code when a kernel image is loaded. > + */ > +int machine_kexec_prepare(struct kimage *image) > +{ > + arm64_kexec_kimage_start = image->start; > + return 0; > +} > + > +/** > + * kexec_list_flush - Helper to flush the kimage list to PoC. > + */ > +static void kexec_list_flush(unsigned long kimage_head) > +{ > + void *dest; What is the use of dest ? > + unsigned long *entry; > + > + for (entry = &kimage_head, dest = NULL; ; entry++) { > + unsigned int flag = *entry & > + (IND_DESTINATION | IND_INDIRECTION | IND_DONE | > + IND_SOURCE); You could instead do : flag = *entry & IND_FLAGS; > + void *addr = phys_to_virt(*entry & PAGE_MASK); > + > + switch (flag) { > + case IND_INDIRECTION: > + entry = (unsigned long *)addr - 1; > + __flush_dcache_area(addr, PAGE_SIZE); > + break; > + case IND_DESTINATION: > + dest = addr; > + break; > + case IND_SOURCE: > + __flush_dcache_area(addr, PAGE_SIZE); > + dest += PAGE_SIZE; > + break; > + case IND_DONE: > + return; > + default: > + BUG(); > + } > + } > +} Thanks Suzuki