5 files changed, 168 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 6783c2e5512d..a8298949d166 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -738,6 +738,20 @@ config XIP_PHYS_ADDR
           be linked for and stored to.  This address is dependent on your
           own flash usage.
 
+config KEXEC
+        bool "Kexec system call (EXPERIMENTAL)"
+        depends on EXPERIMENTAL
+        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 indepedent of the system firmware.   And like a reboot
+          you can start any kernel with it, not just Linux.
+
+          It is an ongoing process to be certain the hardware in a machine
+          is properly shutdown, so do not be surprised if this code does not
+          initially work for you.  It may help to enable device hotplugging
+          support.
+
 endmenu
 
 if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP || ARCH_IMX )
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index ab06a86e85d5..d5002889773e 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_ARTHUR)		+= arthur.o
 obj-$(CONFIG_ISA_DMA)           += dma-isa.o
 obj-$(CONFIG_PCI)               += bios32.o isa.o
 obj-$(CONFIG_SMP)               += smp.o
+obj-$(CONFIG_KEXEC)             += machine_kexec.o relocate_kernel.o
 obj-$(CONFIG_OABI_COMPAT)       += sys_oabi-compat.o
 
 obj-$(CONFIG_CRUNCH)            += crunch.o crunch-bits.o
diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
index f7598cbc7ec5..ae89cdd82b16 100644
--- a/arch/arm/kernel/calls.S
+++ b/arch/arm/kernel/calls.S
@@ -356,6 +356,7 @@
                 CALL(sys_move_pages)
 /* 345 */       CALL(sys_getcpu)
                 CALL(sys_ni_syscall)            /* eventually epoll_pwait */
+                CALL(sys_kexec_load)
 #ifndef syscalls_counted
 .equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls
 #define syscalls_counted
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
new file mode 100644
index 000000000000..863c66454f2b
--- /dev/null
+++ b/arch/arm/kernel/machine_kexec.c
@@ -0,0 +1,78 @@
+/*
+ * machine_kexec.c - handle transition of Linux booting another kernel
+ */
+
+#include <linux/mm.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/mmu_context.h>
+#include <asm/io.h>
+#include <asm/cacheflush.h>
+#include <asm/mach-types.h>
+
+const extern unsigned char relocate_new_kernel[];
+const extern unsigned int relocate_new_kernel_size;
+
+extern void setup_mm_for_reboot(char mode);
+
+extern unsigned long kexec_start_address;
+extern unsigned long kexec_indirection_page;
+extern unsigned long kexec_mach_type;
+
+/*
+ * Provide a dummy crash_notes definition while crash dump arrives to arm.
+ * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
+ */
+
+int machine_kexec_prepare(struct kimage *image)
+{
+        return 0;
+}
+
+void machine_kexec_cleanup(struct kimage *image)
+{
+}
+
+void machine_shutdown(void)
+{
+}
+
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+}
+
+void machine_kexec(struct kimage *image)
+{
+        unsigned long page_list;
+        unsigned long reboot_code_buffer_phys;
+        void *reboot_code_buffer;
+
+
+        page_list = image->head & PAGE_MASK;
+
+        /* we need both effective and real address here */
+        reboot_code_buffer_phys =
+            page_to_pfn(image->control_code_page) << PAGE_SHIFT;
+        reboot_code_buffer = page_address(image->control_code_page);
+
+        /* Prepare parameters for reboot_code_buffer*/
+        kexec_start_address = image->start;
+        kexec_indirection_page = page_list;
+        kexec_mach_type = machine_arch_type;
+
+        /* copy our kernel relocation code to the control code page */
+        memcpy(reboot_code_buffer,
+               relocate_new_kernel, relocate_new_kernel_size);
+
+
+        flush_icache_range((unsigned long) reboot_code_buffer,
+                           (unsigned long) reboot_code_buffer + KEXEC_CONTROL_CODE_SIZE);
+        printk(KERN_INFO "Bye!\n");
+
+        cpu_proc_fin();
+        setup_mm_for_reboot(0); /* mode is not used, so just pass 0*/
+        cpu_reset(reboot_code_buffer_phys);
+}
diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
new file mode 100644
index 000000000000..7baadae7cb27
--- /dev/null
+++ b/arch/arm/kernel/relocate_kernel.S
@@ -0,0 +1,74 @@
+/*
+ * relocate_kernel.S - put the kernel image in place to boot
+ */
+
+#include <asm/kexec.h>
+
+        .globl relocate_new_kernel
+relocate_new_kernel:
+
+        ldr     r0,kexec_indirection_page
+        ldr     r1,kexec_start_address
+
+
+0:      /* top, read another word for the indirection page */
+        ldr     r3, [r0],#4
+
+        /* Is it a destination page. Put destination address to r4 */
+        tst     r3,#1,0
+        beq     1f
+        bic     r4,r3,#1
+        b       0b
+1:
+        /* Is it an indirection page */
+        tst     r3,#2,0
+        beq     1f
+        bic     r0,r3,#2
+        b       0b
+1:
+
+        /* are we done ? */
+        tst     r3,#4,0
+        beq     1f
+        b       2f
+
+1:
+        /* is it source ? */
+        tst     r3,#8,0
+        beq     0b
+        bic r3,r3,#8
+        mov r6,#1024
+9:
+        ldr r5,[r3],#4
+        str r5,[r4],#4
+        subs r6,r6,#1
+        bne 9b
+        b 0b
+
+2:
+        /* Jump to relocated kernel */
+        mov lr,r1
+        mov r0,#0
+        ldr r1,kexec_mach_type
+        mov r2,#0
+        mov pc,lr
+
+        .globl kexec_start_address
+kexec_start_address:
+        .long   0x0
+
+        .globl kexec_indirection_page
+kexec_indirection_page:
+        .long   0x0
+
+        .globl kexec_mach_type
+kexec_mach_type:
+        .long   0x0
+
+relocate_new_kernel_end:
+
+        .globl relocate_new_kernel_size
+relocate_new_kernel_size:
+        .long relocate_new_kernel_end - relocate_new_kernel
+
+