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 <[email protected]>
---
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
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