diff -uNr linux-2.6.8-rc1-flush-init-mm/arch/i386/Kconfig linux-2.6.8-rc1-i386-kexec/arch/i386/Kconfig --- linux-2.6.8-rc1-flush-init-mm/arch/i386/Kconfig Tue Jul 13 19:06:12 2004 +++ linux-2.6.8-rc1-i386-kexec/arch/i386/Kconfig Wed Jul 14 17:56:04 2004 @@ -1310,6 +1310,25 @@ endmenu +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. + + The name comes from the similiarity to the exec system call. + + 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. As of this writing the exact hardware interface is + strongly in flux, so no good recommendation can be made. + +endmenu + source "security/Kconfig" source "crypto/Kconfig" diff -uNr linux-2.6.8-rc1-flush-init-mm/arch/i386/defconfig linux-2.6.8-rc1-i386-kexec/arch/i386/defconfig --- linux-2.6.8-rc1-flush-init-mm/arch/i386/defconfig Tue Jul 13 19:06:12 2004 +++ linux-2.6.8-rc1-i386-kexec/arch/i386/defconfig Wed Jul 14 17:55:18 2004 @@ -94,6 +94,7 @@ CONFIG_NR_CPUS=8 CONFIG_SCHED_SMT=y CONFIG_PREEMPT=y +CONFIG_KEXEC=y CONFIG_X86_LOCAL_APIC=y CONFIG_X86_IO_APIC=y CONFIG_X86_TSC=y diff -uNr linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/Makefile linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/Makefile --- linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/Makefile Tue Jul 13 19:06:12 2004 +++ linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/Makefile Wed Jul 14 17:58:26 2004 @@ -23,6 +23,7 @@ obj-$(CONFIG_X86_MPPARSE) += mpparse.o obj-$(CONFIG_X86_LOCAL_APIC) += apic.o nmi.o obj-$(CONFIG_X86_IO_APIC) += io_apic.o +obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o obj-$(CONFIG_X86_NUMAQ) += numaq.o obj-$(CONFIG_X86_SUMMIT_NUMA) += summit.o obj-$(CONFIG_MODULES) += module.o diff -uNr linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/entry.S linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/entry.S --- linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/entry.S Tue Jun 15 23:19:02 2004 +++ linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/entry.S Wed Jul 14 17:56:47 2004 @@ -885,6 +885,6 @@ .long sys_mq_timedreceive /* 280 */ .long sys_mq_notify .long sys_mq_getsetattr - .long sys_ni_syscall /* reserved for kexec */ + .long sys_kexec_load syscall_table_size=(.-sys_call_table) diff -uNr linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/machine_kexec.c linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/machine_kexec.c --- linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/machine_kexec.c Wed Dec 31 17:00:00 1969 +++ linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/machine_kexec.c Wed Jul 14 17:57:40 2004 @@ -0,0 +1,122 @@ +/* + * machine_kexec.c - handle transition of Linux booting another kernel + * Copyright (C) 2002-2004 Eric Biederman + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +static void set_idt(void *newidt, __u16 limit) +{ + unsigned char curidt[6]; + + /* ia32 supports unaliged loads & stores */ + (*(__u16 *)(curidt)) = limit; + (*(__u32 *)(curidt +2)) = (unsigned long)(newidt); + + __asm__ __volatile__ ( + "lidt %0\n" + : "=m" (curidt) + ); +}; + + +static void set_gdt(void *newgdt, __u16 limit) +{ + unsigned char curgdt[6]; + + /* ia32 supports unaligned loads & stores */ + (*(__u16 *)(curgdt)) = limit; + (*(__u32 *)(curgdt +2)) = (unsigned long)(newgdt); + + __asm__ __volatile__ ( + "lgdt %0\n" + : "=m" (curgdt) + ); +}; + +static void load_segments(void) +{ +#define __STR(X) #X +#define STR(X) __STR(X) + + __asm__ __volatile__ ( + "\tljmp $"STR(__KERNEL_CS)",$1f\n" + "\t1:\n" + "\tmovl $"STR(__KERNEL_DS)",%eax\n" + "\tmovl %eax,%ds\n" + "\tmovl %eax,%es\n" + "\tmovl %eax,%fs\n" + "\tmovl %eax,%gs\n" + "\tmovl %eax,%ss\n" + ); +#undef STR +#undef __STR +} + +typedef void (*relocate_new_kernel_t)( + unsigned long indirection_page, unsigned long reboot_code_buffer, + unsigned long start_address, unsigned int has_pae); + +const extern unsigned char relocate_new_kernel[]; +extern void relocate_new_kernel_end(void); +const extern unsigned int relocate_new_kernel_size; +extern void use_mm(struct mm_struct *mm); + +/* + * Do not allocate memory (or fail in any way) in machine_kexec(). + * We are past the point of no return, committed to rebooting now. + */ +void machine_kexec(struct kimage *image) +{ + unsigned long indirection_page; + unsigned long reboot_code_buffer; + relocate_new_kernel_t rnk; + + /* switch to an mm where the reboot_code_buffer is identity mapped */ + use_mm(&init_mm); + stop_apics(); + + /* Interrupts aren't acceptable while we reboot */ + local_irq_disable(); + reboot_code_buffer = page_to_pfn(image->reboot_code_pages) << PAGE_SHIFT; + indirection_page = image->head & PAGE_MASK; + + /* copy it out */ + memcpy((void *)reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size); + + /* The segment registers are funny things, they are + * automatically loaded from a table, in memory wherever you + * set them to a specific selector, but this table is never + * accessed again you set the segment to a different selector. + * + * The more common model is are caches where the behide + * the scenes work is done, but is also dropped at arbitrary + * times. + * + * I take advantage of this here by force loading the + * segments, before I zap the gdt with an invalid value. + */ + load_segments(); + /* The gdt & idt are now invalid. + * If you want to load them you must set up your own idt & gdt. + */ + set_gdt(phys_to_virt(0),0); + set_idt(phys_to_virt(0),0); + + /* now call it */ + rnk = (relocate_new_kernel_t) reboot_code_buffer; + (*rnk)(indirection_page, reboot_code_buffer, image->start, cpu_has_pae); +} diff -uNr linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/relocate_kernel.S linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/relocate_kernel.S --- linux-2.6.8-rc1-flush-init-mm/arch/i386/kernel/relocate_kernel.S Wed Dec 31 17:00:00 1969 +++ linux-2.6.8-rc1-i386-kexec/arch/i386/kernel/relocate_kernel.S Wed Jul 14 17:59:06 2004 @@ -0,0 +1,118 @@ +/* + * relocate_kernel.S - put the kernel image in place to boot + * Copyright (C) 2002-2004 Eric Biederman + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#include + + /* + * Must be relocatable PIC code callable as a C function, that once + * it starts can not use the previous processes stack. + */ + .globl relocate_new_kernel +relocate_new_kernel: + /* read the arguments and say goodbye to the stack */ + movl 4(%esp), %ebx /* indirection_page */ + movl 8(%esp), %ebp /* reboot_code_buffer */ + movl 12(%esp), %edx /* start address */ + movl 16(%esp), %ecx /* cpu_has_pae */ + + /* zero out flags, and disable interrupts */ + pushl $0 + popfl + + /* set a new stack at the bottom of our page... */ + lea 4096(%ebp), %esp + + /* store the parameters back on the stack */ + pushl %edx /* store the start address */ + + /* Set cr0 to a known state: + * 31 0 == Paging disabled + * 18 0 == Alignment check disabled + * 16 0 == Write protect disabled + * 3 0 == No task switch + * 2 0 == Don't do FP software emulation. + * 0 1 == Proctected mode enabled + */ + movl %cr0, %eax + andl $~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax + orl $(1<<0), %eax + movl %eax, %cr0 + + /* clear cr4 if applicable */ + testl %ecx, %ecx + jz 1f + /* Set cr4 to a known state: + * Setting everything to zero seems safe. + */ + movl %cr4, %eax + andl $0, %eax + movl %eax, %cr4 + + jmp 1f +1: + + /* Flush the TLB (needed?) */ + xorl %eax, %eax + movl %eax, %cr3 + + /* Do the copies */ + cld +0: /* top, read another word for the indirection page */ + movl %ebx, %ecx + movl (%ebx), %ecx + addl $4, %ebx + testl $0x1, %ecx /* is it a destination page */ + jz 1f + movl %ecx, %edi + andl $0xfffff000, %edi + jmp 0b +1: + testl $0x2, %ecx /* is it an indirection page */ + jz 1f + movl %ecx, %ebx + andl $0xfffff000, %ebx + jmp 0b +1: + testl $0x4, %ecx /* is it the done indicator */ + jz 1f + jmp 2f +1: + testl $0x8, %ecx /* is it the source indicator */ + jz 0b /* Ignore it otherwise */ + movl %ecx, %esi /* For every source page do a copy */ + andl $0xfffff000, %esi + + movl $1024, %ecx + rep ; movsl + jmp 0b + +2: + + /* To be certain of avoiding problems with self-modifying code + * I need to execute a serializing instruction here. + * So I flush the TLB, it's handy, and not processor dependent. + */ + xorl %eax, %eax + movl %eax, %cr3 + + /* set all of the registers to known values */ + /* leave %esp alone */ + + xorl %eax, %eax + xorl %ebx, %ebx + xorl %ecx, %ecx + xorl %edx, %edx + xorl %esi, %esi + xorl %edi, %edi + xorl %ebp, %ebp + ret +relocate_new_kernel_end: + + .globl relocate_new_kernel_size +relocate_new_kernel_size: + .long relocate_new_kernel_end - relocate_new_kernel diff -uNr linux-2.6.8-rc1-flush-init-mm/include/asm-i386/kexec.h linux-2.6.8-rc1-i386-kexec/include/asm-i386/kexec.h --- linux-2.6.8-rc1-flush-init-mm/include/asm-i386/kexec.h Wed Dec 31 17:00:00 1969 +++ linux-2.6.8-rc1-i386-kexec/include/asm-i386/kexec.h Wed Jul 14 17:59:50 2004 @@ -0,0 +1,23 @@ +#ifndef _I386_KEXEC_H +#define _I386_KEXEC_H + +#include + +/* + * KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return. + * I.e. Maximum page that is mapped directly into kernel memory, + * and kmap is not required. + * + * Someone correct me if FIXADDR_START - PAGEOFFSET is not the correct + * calculation for the amount of memory directly mappable into the + * kernel memory space. + */ + +/* 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) + +#define KEXEC_REBOOT_CODE_SIZE 4096 + +#endif /* _I386_KEXEC_H */