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Subjectkexec for 2.5.42
From
Date

O.k. My first pass at getting up to date with the current kernel is available at:
http://www.xmission.com/~ebiederm/files/kexec/linux-2.5.42.kexec.x86.diff
http://www.xmission.com/~ebiederm/files/kexec/kexec-tools-1.0.tar.gz

The big changes are:
1) I have rebundled my tools so it is a little easier to get at:
2) I have included a test case kexec_test that tests the stranger
cases, so when the kernel doesn't boot, we can rule out the kexec code.
3) I have added a call to device_shutdown so device drivers get a chance
to shut up.
4) I have moved kexec into its one system call instead of treating
sys_reboot like an ioctl. The big reason is that while there is a
lot of generic code some very architecture specific code must be
written for each architecture, and having to register a system call
means the code won't become active by accident.

I will probably split this up before sending to Linus but anyway, here
is the patch so you can pick it apart and tell me what you don't like.

Eric

MAINTAINERS | 7
arch/i386/Config.help | 14
arch/i386/config.in | 3
arch/i386/kernel/Makefile | 1
arch/i386/kernel/apic.c | 71 ++++
arch/i386/kernel/dmi_scan.c | 27 -
arch/i386/kernel/entry.S | 3
arch/i386/kernel/io_apic.c | 2
arch/i386/kernel/machine_kexec.c | 141 ++++++++
arch/i386/kernel/reboot.c | 32 -
arch/i386/kernel/relocate_kernel.S | 84 ++++
arch/i386/kernel/smp.c | 24 +
include/asm-i386/apicdef.h | 1
include/asm-i386/kexec.h | 25 +
include/linux/kexec.h | 49 ++
kernel/Makefile | 3
kernel/kexec.c | 630 +++++++++++++++++++++++++++++++++++++
kernel/sys.c | 59 +++
18 files changed, 1116 insertions, 60 deletions

diff -uNrX linux-ignore-files linux-2.5.42.eb1/MAINTAINERS linux-2.5.42.kexec.x86/MAINTAINERS
--- linux-2.5.42.eb1/MAINTAINERS Fri Oct 11 22:22:09 2002
+++ linux-2.5.42.kexec.x86/MAINTAINERS Mon Oct 14 12:16:50 2002
@@ -934,6 +934,13 @@
W: http://www.cse.unsw.edu.au/~neilb/patches/linux-devel/
S: Maintained

+KEXEC
+P: Eric Biederman
+M: ebiederm@xmission.com
+M: ebiederman@lnxi.com
+L: linux-kernel@vger.kernel.org
+S: Maintained
+
LANMEDIA WAN CARD DRIVER
P: Andrew Stanley-Jones
M: asj@lanmedia.com
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/Config.help linux-2.5.42.kexec.x86/arch/i386/Config.help
--- linux-2.5.42.eb1/arch/i386/Config.help Fri Oct 11 22:21:31 2002
+++ linux-2.5.42.kexec.x86/arch/i386/Config.help Sun Oct 13 18:54:37 2002
@@ -411,6 +411,20 @@
you have use for it; the module is called binfmt_misc.o. If you
don't know what to answer at this point, say Y.

+CONFIG_KEXEC
+ kexec is a system call that implements kernel level exec support.
+ Or the ability to boot linux from linux. The kexec system call
+ allows you to replace your current kernel with another kernel,
+ not necessarily linux.
+
+ A known caveat is that for this to be fully useful all of the
+ devices must be shutdown. One way to impelment this is to build
+ all devices as modules and remove them before rebooting.
+
+ You will probably want to dig up the elfboottools package as this
+ has the first implementation of a user client that uses this kernel
+ interface.
+
CONFIG_M386
This is the processor type of your CPU. This information is used for
optimizing purposes. In order to compile a kernel that can run on
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/config.in linux-2.5.42.kexec.x86/arch/i386/config.in
--- linux-2.5.42.eb1/arch/i386/config.in Fri Oct 11 22:21:38 2002
+++ linux-2.5.42.kexec.x86/arch/i386/config.in Mon Oct 14 11:22:16 2002
@@ -242,6 +242,9 @@
fi
fi

+if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
+ bool 'Kernel execing kernel support' CONFIG_KEXEC
+fi
endmenu

mainmenu_option next_comment
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/Makefile linux-2.5.42.kexec.x86/arch/i386/kernel/Makefile
--- linux-2.5.42.eb1/arch/i386/kernel/Makefile Fri Oct 11 22:21:34 2002
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/Makefile Mon Oct 14 10:19:32 2002
@@ -25,6 +25,7 @@
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-$(CONFIG_SOFTWARE_SUSPEND) += suspend.o
obj-$(CONFIG_X86_NUMAQ) += numaq.o

diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/apic.c linux-2.5.42.kexec.x86/arch/i386/kernel/apic.c
--- linux-2.5.42.eb1/arch/i386/kernel/apic.c Fri Oct 11 22:22:46 2002
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/apic.c Mon Oct 14 11:06:39 2002
@@ -23,6 +23,7 @@
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/kernel_stat.h>
+#include <linux/reboot.h>

#include <asm/atomic.h>
#include <asm/smp.h>
@@ -52,6 +53,14 @@
int prof_old_multiplier[NR_CPUS] = { 1, };
int prof_counter[NR_CPUS] = { 1, };

+static int apic_reboot_event(struct notifier_block *,unsigned long,void *);
+static struct notifier_block apic_reboot_notifier = {
+ apic_reboot_event,
+ NULL,
+ -1000, /* This should be the very last reboot notifier to run */
+ /* FIXME how do I move this into the device tree? */
+};
+
int get_maxlvt(void)
{
unsigned int v, ver, maxlvt;
@@ -138,6 +147,8 @@
outb(0x70, 0x22);
outb(0x01, 0x23);
}
+
+ register_reboot_notifier(&apic_reboot_notifier);
}

void disconnect_bsp_APIC(void)
@@ -153,6 +164,36 @@
outb(0x70, 0x22);
outb(0x00, 0x23);
}
+ else {
+ /* Go back to Virtual Wire compatibility mode */
+ unsigned long value;
+
+ /* For the spurious interrupt use vector F, and enable it */
+ value = apic_read(APIC_SPIV);
+ value &= ~APIC_VECTOR_MASK;
+ value |= APIC_SPIV_APIC_ENABLED;
+ value |= 0xf;
+ apic_write_around(APIC_SPIV, value);
+
+ /* For LVT0 make it edge triggered, active high, external and enabled */
+ value = apic_read(APIC_LVT0);
+ value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
+ APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
+ APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
+ value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
+ value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXINT);
+ apic_write_around(APIC_LVT0, value);
+
+ /* For LVT1 make it edge triggered, active high, nmi and enabled */
+ value = apic_read(APIC_LVT1);
+ value &= ~(
+ APIC_MODE_MASK | APIC_SEND_PENDING |
+ APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
+ APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
+ value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
+ value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
+ apic_write_around(APIC_LVT1, value);
+ }
}

void disable_local_APIC(void)
@@ -686,6 +727,7 @@
void __init init_apic_mappings(void)
{
unsigned long apic_phys;
+ unsigned long value;

/*
* If no local APIC can be found then set up a fake all
@@ -1137,6 +1179,35 @@
printk (KERN_INFO "APIC error on CPU%d: %02lx(%02lx)\n",
smp_processor_id(), v , v1);
irq_exit();
+}
+
+static int apic_reboot_event(struct notifier_block *n,
+ unsigned long code, void *p)
+{
+ if ((code != SYS_RESTART) && (code != SYS_HALT) &&
+ (code != SYS_POWER_OFF)) {
+ return NOTIFY_DONE;
+ }
+
+ /* By resetting the APIC's we disable the nmi watchdog */
+
+#if CONFIG_SMP
+ /*
+ * Stop all CPUs and turn off local APICs, so
+ * other OSs see a clean IRQ state.
+ */
+ smp_send_stop();
+#else
+ disable_local_APIC();
+#endif
+#if defined(CONFIG_X86_IO_APIC)
+ if (smp_found_config) {
+ disable_IO_APIC();
+ }
+#endif
+ disconnect_bsp_APIC();
+
+ return NOTIFY_DONE;
}

/*
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/dmi_scan.c linux-2.5.42.kexec.x86/arch/i386/kernel/dmi_scan.c
--- linux-2.5.42.eb1/arch/i386/kernel/dmi_scan.c Fri Oct 11 22:21:40 2002
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/dmi_scan.c Sun Oct 13 18:54:37 2002
@@ -204,31 +204,6 @@
return 0;
}

-/*
- * Some machines require the "reboot=s" commandline option, this quirk makes that automatic.
- */
-static __init int set_smp_reboot(struct dmi_blacklist *d)
-{
-#ifdef CONFIG_SMP
- extern int reboot_smp;
- if (reboot_smp == 0)
- {
- reboot_smp = 1;
- printk(KERN_INFO "%s series board detected. Selecting SMP-method for reboots.\n", d->ident);
- }
-#endif
- return 0;
-}
-
-/*
- * Some machines require the "reboot=b,s" commandline option, this quirk makes that automatic.
- */
-static __init int set_smp_bios_reboot(struct dmi_blacklist *d)
-{
- set_smp_reboot(d);
- set_bios_reboot(d);
- return 0;
-}

/*
* Some bioses have a broken protected mode poweroff and need to use realmode
@@ -519,7 +494,7 @@
MATCH(DMI_BIOS_VERSION, "4.60 PGMA"),
MATCH(DMI_BIOS_DATE, "134526184"), NO_MATCH
} },
- { set_smp_bios_reboot, "Dell PowerEdge 1300", { /* Handle problems with rebooting on Dell 1300's */
+ { set_bios_reboot, "Dell PowerEdge 1300", { /* Handle problems with rebooting on Dell 1300's */
MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
NO_MATCH, NO_MATCH
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/entry.S linux-2.5.42.kexec.x86/arch/i386/kernel/entry.S
--- linux-2.5.42.eb1/arch/i386/kernel/entry.S Fri Oct 11 22:21:36 2002
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/entry.S Thu Oct 17 01:49:12 2002
@@ -736,7 +736,8 @@
.long sys_alloc_hugepages /* 250 */
.long sys_free_hugepages
.long sys_exit_group
-
+ .long sys_kexec
+
.rept NR_syscalls-(.-sys_call_table)/4
.long sys_ni_syscall
.endr
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/io_apic.c linux-2.5.42.kexec.x86/arch/i386/kernel/io_apic.c
--- linux-2.5.42.eb1/arch/i386/kernel/io_apic.c Fri Oct 11 22:21:38 2002
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/io_apic.c Sun Oct 13 18:54:37 2002
@@ -1112,8 +1112,6 @@
* Clear the IO-APIC before rebooting:
*/
clear_IO_APIC();
-
- disconnect_bsp_APIC();
}

/*
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/machine_kexec.c linux-2.5.42.kexec.x86/arch/i386/kernel/machine_kexec.c
--- linux-2.5.42.eb1/arch/i386/kernel/machine_kexec.c Wed Dec 31 17:00:00 1969
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/machine_kexec.c Mon Oct 14 11:26:21 2002
@@ -0,0 +1,141 @@
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/io.h>
+
+
+/*
+ * machine_kexec
+ * =======================
+ */
+
+
+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 unaliged 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
+}
+
+static void identity_map_page(unsigned long address)
+{
+ /* This code is x86 specific...
+ * general purpose code must be more carful
+ * of caches and tlbs...
+ */
+ pgd_t *pgd;
+ pmd_t *pmd;
+ struct mm_struct *mm = current->mm;
+ spin_lock(&mm->page_table_lock);
+
+ pgd = pgd_offset(mm, address);
+ pmd = pmd_alloc(mm, pgd, address);
+
+ if (pmd) {
+ pte_t *pte = pte_alloc_map(mm, pmd, address);
+ if (pte) {
+ set_pte(pte,
+ mk_pte(virt_to_page(phys_to_virt(address)),
+ PAGE_SHARED));
+ __flush_tlb_one(address);
+ }
+ }
+ spin_unlock(&mm->page_table_lock);
+}
+
+
+typedef void (*relocate_new_kernel_t)(
+ unsigned long indirection_page, unsigned long reboot_code_buffer,
+ unsigned long start_address);
+
+const extern unsigned char relocate_new_kernel[];
+extern void relocate_new_kernel_end(void);
+const extern unsigned int relocate_new_kernel_size;
+
+void machine_kexec(struct kimage *image)
+{
+ unsigned long *indirection_page;
+ void *reboot_code_buffer;
+ relocate_new_kernel_t rnk;
+
+ /* Interrupts aren't acceptable while we reboot */
+ local_irq_disable();
+ reboot_code_buffer = image->reboot_code_buffer;
+ indirection_page = phys_to_virt(image->head & PAGE_MASK);
+
+ identity_map_page(virt_to_phys(reboot_code_buffer));
+
+ /* copy it out */
+ memcpy(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) virt_to_phys(reboot_code_buffer);
+ (*rnk)(virt_to_phys(indirection_page), virt_to_phys(reboot_code_buffer),
+ image->start);
+}
+
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/reboot.c linux-2.5.42.kexec.x86/arch/i386/kernel/reboot.c
--- linux-2.5.42.eb1/arch/i386/kernel/reboot.c Fri Oct 11 22:21:36 2002
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/reboot.c Mon Oct 14 11:03:35 2002
@@ -19,8 +19,7 @@
int reboot_thru_bios;

#ifdef CONFIG_SMP
-int reboot_smp = 0;
-static int reboot_cpu = -1;
+int reboot_cpu = -1; /* specifies the internal linux cpu id, not the apicid */
/* shamelessly grabbed from lib/vsprintf.c for readability */
#define is_digit(c) ((c) >= '0' && (c) <= '9')
#endif
@@ -42,7 +41,6 @@
break;
#ifdef CONFIG_SMP
case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
- reboot_smp = 1;
if (is_digit(*(str+1))) {
reboot_cpu = (int) (*(str+1) - '0');
if (is_digit(*(str+2)))
@@ -224,34 +222,6 @@
void machine_restart(char * __unused)
{
#if CONFIG_SMP
- int cpuid;
-
- cpuid = GET_APIC_ID(apic_read(APIC_ID));
-
- if (reboot_smp) {
-
- /* check to see if reboot_cpu is valid
- if its not, default to the BSP */
- if ((reboot_cpu == -1) ||
- (reboot_cpu > (NR_CPUS -1)) ||
- !(phys_cpu_present_map & (1<<cpuid)))
- reboot_cpu = boot_cpu_physical_apicid;
-
- reboot_smp = 0; /* use this as a flag to only go through this once*/
- /* re-run this function on the other CPUs
- it will fall though this section since we have
- cleared reboot_smp, and do the reboot if it is the
- correct CPU, otherwise it halts. */
- if (reboot_cpu != cpuid)
- smp_call_function((void *)machine_restart , NULL, 1, 0);
- }
-
- /* if reboot_cpu is still -1, then we want a tradional reboot,
- and if we are not running on the reboot_cpu,, halt */
- if ((reboot_cpu != -1) && (cpuid != reboot_cpu)) {
- for (;;)
- __asm__ __volatile__ ("hlt");
- }
/*
* Stop all CPUs and turn off local APICs and the IO-APIC, so
* other OSs see a clean IRQ state.
diff -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/relocate_kernel.S linux-2.5.42.kexec.x86/arch/i386/kernel/relocate_kernel.S
--- linux-2.5.42.eb1/arch/i386/kernel/relocate_kernel.S Wed Dec 31 17:00:00 1969
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/relocate_kernel.S Mon Oct 14 11:39:05 2002
@@ -0,0 +1,84 @@
+#include <linux/config.h>
+#include <linux/linkage.h>
+
+ /* 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 */
+
+ /* zero out flags */
+ pushl $0
+ popfl
+ cli
+
+ /* 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 */
+
+ /* Turn off paging, leave protection turned on */
+ movl %cr0, %eax /* Turn off paging (bit 31 in CR0) */
+ andl $0x7FFFFFFF, %eax
+ movl %eax, %cr0
+ 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:
+ /* 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 -uNrX linux-ignore-files linux-2.5.42.eb1/arch/i386/kernel/smp.c linux-2.5.42.kexec.x86/arch/i386/kernel/smp.c
--- linux-2.5.42.eb1/arch/i386/kernel/smp.c Fri Oct 11 22:21:31 2002
+++ linux-2.5.42.kexec.x86/arch/i386/kernel/smp.c Mon Oct 14 09:33:45 2002
@@ -611,6 +611,30 @@

void smp_send_stop(void)
{
+ extern int reboot_cpu;
+ int reboot_cpu_id;
+
+ /* The boot cpu is always logical cpu 0 */
+ reboot_cpu_id = 0;
+
+ /* See if there has been give a command line override .
+ */
+ if ((reboot_cpu != -1) && !(reboot_cpu >= NR_CPUS) &&
+ test_bit(reboot_cpu, &cpu_online_map)) {
+ reboot_cpu_id = reboot_cpu;
+ }
+
+ /* Make certain the the cpu I'm rebooting on is online */
+ if (!test_bit(reboot_cpu_id, &cpu_online_map)) {
+ reboot_cpu_id = smp_processor_id();
+ }
+
+ /* Make certain I only run on the appropriate processor */
+ set_cpus_allowed(current, 1 << reboot_cpu_id);
+
+ /* O.k. Now that I'm on the appropriate processor stop
+ * all of the others.
+ */
smp_call_function(stop_this_cpu, NULL, 1, 0);

local_irq_disable();
diff -uNrX linux-ignore-files linux-2.5.42.eb1/include/asm-i386/apicdef.h linux-2.5.42.kexec.x86/include/asm-i386/apicdef.h
--- linux-2.5.42.eb1/include/asm-i386/apicdef.h Fri Oct 11 22:22:09 2002
+++ linux-2.5.42.kexec.x86/include/asm-i386/apicdef.h Sun Oct 13 18:54:37 2002
@@ -86,6 +86,7 @@
#define APIC_LVT_REMOTE_IRR (1<<14)
#define APIC_INPUT_POLARITY (1<<13)
#define APIC_SEND_PENDING (1<<12)
+#define APIC_MODE_MASK 0x700
#define GET_APIC_DELIVERY_MODE(x) (((x)>>8)&0x7)
#define SET_APIC_DELIVERY_MODE(x,y) (((x)&~0x700)|((y)<<8))
#define APIC_MODE_FIXED 0x0
diff -uNrX linux-ignore-files linux-2.5.42.eb1/include/asm-i386/kexec.h linux-2.5.42.kexec.x86/include/asm-i386/kexec.h
--- linux-2.5.42.eb1/include/asm-i386/kexec.h Wed Dec 31 17:00:00 1969
+++ linux-2.5.42.kexec.x86/include/asm-i386/kexec.h Sun Oct 13 18:54:37 2002
@@ -0,0 +1,25 @@
+#ifndef _I386_KEXEC_H
+#define _I386_KEXEC_H
+
+#include <asm/fixmap.h>
+
+/*
+ * 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 (FIXADDR_START - PAGE_OFFSET)
+/* Maximum address we can reach in physical address mode */
+#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
+
+#define KEXEC_REBOOT_CODE_SIZE 4096
+#define KEXEC_REBOOT_CODE_ALIGN 0
+
+
+#endif /* _I386_KEXEC_H */
diff -uNrX linux-ignore-files linux-2.5.42.eb1/include/linux/kexec.h linux-2.5.42.kexec.x86/include/linux/kexec.h
--- linux-2.5.42.eb1/include/linux/kexec.h Wed Dec 31 17:00:00 1969
+++ linux-2.5.42.kexec.x86/include/linux/kexec.h Mon Oct 14 11:33:56 2002
@@ -0,0 +1,49 @@
+#ifndef LINUX_KEXEC_H
+#define LINUX_KEXEC_H
+
+#if CONFIG_KEXEC
+#include <linux/types.h>
+#include <asm/kexec.h>
+
+/*
+ * This structure is used to hold the arguments that are used when loading
+ * kernel binaries.
+ */
+
+typedef unsigned long kimage_entry_t;
+#define IND_DESTINATION 0x1
+#define IND_INDIRECTION 0x2
+#define IND_DONE 0x4
+#define IND_SOURCE 0x8
+
+struct kimage {
+ kimage_entry_t head;
+ kimage_entry_t *entry;
+ kimage_entry_t *last_entry;
+
+ unsigned long destination;
+ unsigned long offset;
+
+ unsigned long start;
+ void *reboot_code_buffer;
+};
+
+/* kexec helper functions */
+void kimage_init(struct kimage *image);
+void kimage_free(struct kimage *image);
+
+struct kexec_segment {
+ void *buf;
+ size_t bufsz;
+ void *mem;
+ size_t memsz;
+};
+
+/* kexec interface functions */
+extern void machine_kexec(struct kimage *image);
+extern int do_kexec(unsigned long entry, long nr_segments,
+ struct kexec_segment *segments, struct kimage *image);
+extern int load_elf_kernel(struct kimage *image, struct file *file);
+#endif
+#endif /* LINUX_KEXEC_H */
+
diff -uNrX linux-ignore-files linux-2.5.42.eb1/kernel/Makefile linux-2.5.42.kexec.x86/kernel/Makefile
--- linux-2.5.42.eb1/kernel/Makefile Fri Oct 11 22:21:34 2002
+++ linux-2.5.42.kexec.x86/kernel/Makefile Sun Oct 13 18:54:49 2002
@@ -19,6 +19,7 @@
obj-$(CONFIG_CPU_FREQ) += cpufreq.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += suspend.o
+obj-$(CONFIG_KEXEC) += kexec.o

ifneq ($(CONFIG_IA64),y)
# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
@@ -28,5 +29,7 @@
# to get a correct value for the wait-channel (WCHAN in ps). --davidm
CFLAGS_sched.o := $(PROFILING) -fno-omit-frame-pointer
endif
+
+obj-$(CONFIG_KEXEC) += kexec.o

include $(TOPDIR)/Rules.make
diff -uNrX linux-ignore-files linux-2.5.42.eb1/kernel/kexec.c linux-2.5.42.kexec.x86/kernel/kexec.c
--- linux-2.5.42.eb1/kernel/kexec.c Wed Dec 31 17:00:00 1969
+++ linux-2.5.42.kexec.x86/kernel/kexec.c Mon Oct 14 11:35:26 2002
@@ -0,0 +1,630 @@
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/version.h>
+#include <linux/compile.h>
+#include <linux/kexec.h>
+#include <net/checksum.h>
+#include <asm/page.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#define DEBUG 0
+
+/* As designed kexec can only use the memory that you don't
+ * need to use kmap to access. Memory that you can use virt_to_phys()
+ * on an call get_free_page to allocate.
+ *
+ * In the best case you need one page for the transition from
+ * virtual to physical memory. And this page must be identity
+ * mapped. Which pretty much leaves you with pages < PAGE_OFFSET
+ * as you can only mess with user pages.
+ *
+ * As the only subset of memory that it is easy to restrict allocation
+ * to is the physical memory mapped into the kernel, I do that
+ * with get_free_page and hope it is enough.
+ *
+ * I don't know of a good way to do this calcuate which pages get_free_page
+ * will return independent of architecture so I depend on
+ * <asm/kexec.h> to properly set
+ * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DESTINATION_MEMORY_LIMIT
+ *
+ */
+
+void kimage_init(struct kimage *image)
+{
+ memset(image, 0, sizeof(*image));
+ image->head = 0;
+ image->entry = &image->head;
+ image->last_entry = &image->head;
+}
+static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
+{
+ if (image->offset != 0) {
+ image->entry++;
+ }
+ if (image->entry == image->last_entry) {
+ kimage_entry_t *ind_page;
+ ind_page = (void *)__get_free_page(GFP_KERNEL);
+ if (!ind_page) {
+ return -ENOMEM;
+ }
+ *image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
+ image->entry = ind_page;
+ image->last_entry =
+ ind_page + ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
+ }
+ *image->entry = entry;
+ image->entry++;
+ image->offset = 0;
+ return 0;
+}
+
+static int kimage_verify_destination(unsigned long destination)
+{
+ int result;
+
+ /* Assume the page is bad unless we pass the checks */
+ result = -EADDRNOTAVAIL;
+
+ if (destination >= KEXEC_DESTINATION_MEMORY_LIMIT) {
+ goto out;
+ }
+
+ /* FIXME:
+ * add checking to ensure the new image doesn't go into
+ * invalid or reserved areas of RAM.
+ */
+ result = 0;
+out:
+ return result;
+}
+
+static int kimage_set_destination(
+ struct kimage *image, unsigned long destination)
+{
+ int result;
+ destination &= PAGE_MASK;
+ result = kimage_verify_destination(destination);
+ if (result) {
+ return result;
+ }
+ result = kimage_add_entry(image, destination | IND_DESTINATION);
+ if (result == 0) {
+ image->destination = destination;
+ }
+ return result;
+}
+
+
+static int kimage_add_page(struct kimage *image, unsigned long page)
+{
+ int result;
+ page &= PAGE_MASK;
+ result = kimage_verify_destination(image->destination);
+ if (result) {
+ return result;
+ }
+ result = kimage_add_entry(image, page | IND_SOURCE);
+ if (result == 0) {
+ image->destination += PAGE_SIZE;
+ }
+ return result;
+}
+
+
+static int kimage_terminate(struct kimage *image)
+{
+ int result;
+ result = kimage_add_entry(image, IND_DONE);
+ if (result == 0) {
+ /* Point at the terminating element */
+ image->entry--;
+ }
+ return result;
+}
+
+#define for_each_kimage_entry(image, ptr, entry) \
+ for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
+ ptr = (entry & IND_INDIRECTION)? \
+ phys_to_virt((entry & PAGE_MASK)): ptr +1)
+
+void kimage_free(struct kimage *image)
+{
+ kimage_entry_t *ptr, entry;
+ kimage_entry_t ind = 0;
+ for_each_kimage_entry(image, ptr, entry) {
+ if (entry & IND_INDIRECTION) {
+ /* Free the previous indirection page */
+ if (ind & IND_INDIRECTION) {
+ free_page((unsigned long)phys_to_virt(ind & PAGE_MASK));
+ }
+ /* Save this indirection page until we are
+ * done with it.
+ */
+ ind = entry;
+ }
+ else if (entry & IND_SOURCE) {
+ free_page((unsigned long)phys_to_virt(entry & PAGE_MASK));
+ }
+ }
+}
+
+#if DEBUG
+static void kimage_print_image(struct kimage *image)
+{
+ kimage_entry_t *ptr, entry;
+ int i;
+ printk(KERN_EMERG "kimage_print_image\n");
+ i = 0;
+ for_each_kimage_entry(image, ptr, entry) {
+ if (entry & IND_DESTINATION) {
+ printk(KERN_EMERG "%5d DEST\n", i);
+ }
+ else if (entry & IND_INDIRECTION) {
+ printk(KERN_EMERG "%5d IND\n", i);
+ }
+ else if (entry & IND_SOURCE) {
+ printk(KERN_EMERG "%5d SOURCE\n", i);
+ }
+ else if (entry & IND_DONE) {
+ printk(KERN_EMERG "%5d DONE\n", i);
+ }
+ else {
+ printk(KERN_EMERG "%5d ?\n", i);
+ }
+ i++;
+ }
+ printk(KERN_EMERG "kimage_print_image: %5d\n", i);
+}
+#endif
+static int kimage_is_destination_page(
+ struct kimage *image, unsigned long page)
+{
+ kimage_entry_t *ptr, entry;
+ unsigned long destination;
+ destination = 0;
+ page &= PAGE_MASK;
+ for_each_kimage_entry(image, ptr, entry) {
+ if (entry & IND_DESTINATION) {
+ destination = entry & PAGE_MASK;
+ }
+ else if (entry & IND_SOURCE) {
+ if (page == destination) {
+ return 1;
+ }
+ destination += PAGE_SIZE;
+ }
+ }
+ return 0;
+}
+
+static int kimage_get_unused_area(
+ struct kimage *image, unsigned long size, unsigned long align,
+ unsigned long *area)
+{
+ /* Walk through mem_map and find the first chunk of
+ * ununsed memory that is at least size bytes long.
+ */
+ /* Since the kernel plays with Page_Reseved mem_map is less
+ * than ideal for this purpose, but it will give us a correct
+ * conservative estimate of what we need to do.
+ */
+ /* For now we take advantage of the fact that all kernel pages
+ * are marked with PG_resereved to allocate a large
+ * contiguous area for the reboot code buffer.
+ */
+ unsigned long addr;
+ unsigned long start, end;
+ unsigned long mask;
+ mask = ((1 << align) -1);
+ start = end = PAGE_SIZE;
+ for(addr = PAGE_SIZE; addr < KEXEC_SOURCE_MEMORY_LIMIT; addr += PAGE_SIZE) {
+ struct page *page;
+ unsigned long aligned_start;
+ page = virt_to_page(phys_to_virt(addr));
+ if (PageReserved(page) ||
+ kimage_is_destination_page(image, addr)) {
+ /* The current page is reserved so the start &
+ * end of the next area must be atleast at the
+ * next page.
+ */
+ start = end = addr + PAGE_SIZE;
+ }
+ else {
+ /* O.k. The current page isn't reserved
+ * so push up the end of the area.
+ */
+ end = addr;
+ }
+ aligned_start = (start + mask) & ~mask;
+ if (aligned_start > start) {
+ continue;
+ }
+ if (aligned_start > end) {
+ continue;
+ }
+ if (end - aligned_start >= size) {
+ *area = aligned_start;
+ return 0;
+ }
+ }
+ *area = 0;
+ return -ENOSPC;
+}
+
+static kimage_entry_t *kimage_dst_conflict(
+ struct kimage *image, unsigned long page, kimage_entry_t *limit)
+{
+ kimage_entry_t *ptr, entry;
+ unsigned long destination = 0;
+ for_each_kimage_entry(image, ptr, entry) {
+ if (ptr == limit) {
+ return 0;
+ }
+ else if (entry & IND_DESTINATION) {
+ destination = entry & PAGE_MASK;
+ }
+ else if (entry & IND_SOURCE) {
+ if (page == destination) {
+ return ptr;
+ }
+ destination += PAGE_SIZE;
+ }
+ }
+ return 0;
+}
+
+static kimage_entry_t *kimage_src_conflict(
+ struct kimage *image, unsigned long destination, kimage_entry_t *limit)
+{
+ kimage_entry_t *ptr, entry;
+ for_each_kimage_entry(image, ptr, entry) {
+ unsigned long page;
+ if (ptr == limit) {
+ return 0;
+ }
+ else if (entry & IND_DESTINATION) {
+ /* nop */
+ }
+ else if (entry & IND_DONE) {
+ /* nop */
+ }
+ else {
+ /* SOURCE & INDIRECTION */
+ page = entry & PAGE_MASK;
+ if (page == destination) {
+ return ptr;
+ }
+ }
+ }
+ return 0;
+}
+
+static int kimage_get_off_destination_pages(struct kimage *image)
+{
+ kimage_entry_t *ptr, *cptr, entry;
+ unsigned long buffer, page;
+ unsigned long destination = 0;
+
+ /* Here we implement safe guards to insure that
+ * a source page is not copied to it's destination
+ * page before the data on the destination page is
+ * no longer useful.
+ *
+ * To make it work we actually wind up with a
+ * stronger condition. For every page considered
+ * it is either it's own destination page or it is
+ * not a destination page of any page considered.
+ *
+ * Invariants
+ * 1. buffer is not a destination of a previous page.
+ * 2. page is not a destination of a previous page.
+ * 3. destination is not a previous source page.
+ *
+ * Result: Either a source page and a destination page
+ * are the same or the page is not a destination page.
+ *
+ * These checks could be done when we allocate the pages,
+ * but doing it as a final pass allows us more freedom
+ * on how we allocate pages.
+ *
+ * Also while the checks are necessary, in practice nothing
+ * happens. The destination kernel wants to sit in the
+ * same physical addresses as the current kernel so we never
+ * actually allocate a destination page.
+ *
+ * BUGS: This is a O(N^2) algorithm.
+ */
+
+
+ buffer = __get_free_page(GFP_KERNEL);
+ if (!buffer) {
+ return -ENOMEM;
+ }
+ buffer = virt_to_phys((void *)buffer);
+ for_each_kimage_entry(image, ptr, entry) {
+ /* Here we check to see if an allocated page */
+ kimage_entry_t *limit;
+ if (entry & IND_DESTINATION) {
+ destination = entry & PAGE_MASK;
+ }
+ else if (entry & IND_INDIRECTION) {
+ /* Indirection pages must include all of their
+ * contents in limit checking.
+ */
+ limit = phys_to_virt(page + PAGE_SIZE - sizeof(*limit));
+ }
+ if (!((entry & IND_SOURCE) | (entry & IND_INDIRECTION))) {
+ continue;
+ }
+ page = entry & PAGE_MASK;
+ limit = ptr;
+
+ /* See if a previous page has the current page as it's
+ * destination.
+ * i.e. invariant 2
+ */
+ cptr = kimage_dst_conflict(image, page, limit);
+ if (cptr) {
+ unsigned long cpage;
+ kimage_entry_t centry;
+ centry = *cptr;
+ cpage = centry & PAGE_MASK;
+ memcpy(phys_to_virt(buffer), phys_to_virt(page), PAGE_SIZE);
+ memcpy(phys_to_virt(page), phys_to_virt(cpage), PAGE_SIZE);
+ *cptr = page | (centry & ~PAGE_MASK);
+ *ptr = buffer | (entry & ~PAGE_MASK);
+ buffer = cpage;
+ }
+ if (!(entry & IND_SOURCE)) {
+ continue;
+ }
+
+ /* See if a previous page is our destination page.
+ * If so claim it now.
+ * i.e. invariant 3
+ */
+ cptr = kimage_src_conflict(image, destination, limit);
+ if (cptr) {
+ unsigned long cpage;
+ kimage_entry_t centry;
+ centry = *cptr;
+ cpage = centry & PAGE_MASK;
+ memcpy(phys_to_virt(buffer), phys_to_virt(cpage), PAGE_SIZE);
+ memcpy(phys_to_virt(cpage), phys_to_virt(page), PAGE_SIZE);
+ *cptr = buffer | (centry & ~PAGE_MASK);
+ *ptr = cpage | ( entry & ~PAGE_MASK);
+ buffer = page;
+ }
+ /* If the buffer is my destination page do the copy now
+ * i.e. invariant 3 & 1
+ */
+ if (buffer == destination) {
+ memcpy(phys_to_virt(buffer), phys_to_virt(page), PAGE_SIZE);
+ *ptr = buffer | (entry & ~PAGE_MASK);
+ buffer = page;
+ }
+ }
+ free_page((unsigned long)phys_to_virt(buffer));
+ return 0;
+}
+
+static int kimage_add_empty_pages(struct kimage *image,
+ unsigned long len)
+{
+ unsigned long pos;
+ int result;
+ for(pos = 0; pos < len; pos += PAGE_SIZE) {
+ char *page;
+ result = -ENOMEM;
+ page = (void *)__get_free_page(GFP_KERNEL);
+ if (!page) {
+ goto out;
+ }
+ result = kimage_add_page(image, virt_to_phys(page));
+ if (result) {
+ goto out;
+ }
+ }
+ result = 0;
+ out:
+ return result;
+}
+
+
+static int kimage_load_segment(struct kimage *image,
+ struct kexec_segment *segment)
+{
+ unsigned long buf_start, buf_end;
+ unsigned long mstart;
+ int result;
+ unsigned long offset;
+ unsigned long offset_end;
+ unsigned char *buf;
+
+ result = 0;
+ buf = segment->buf;
+ mstart = (unsigned long)segment->mem;
+
+ offset_end = segment->memsz;
+
+ result = kimage_set_destination(image, mstart);
+ if (result < 0) {
+ goto out;
+ }
+ for(offset = 0; offset < segment->memsz; offset += PAGE_SIZE) {
+ char *page;
+ size_t size, leader;
+ page = (char *)__get_free_page(GFP_KERNEL);
+ if (page == 0) {
+ result = -ENOMEM;
+ goto out;
+ }
+ result = kimage_add_page(image, virt_to_phys(page));
+ if (result < 0) {
+ goto out;
+ }
+ if (segment->bufsz < offset) {
+ /* We are past the end zero the whole page */
+ memset(page, 0, PAGE_SIZE);
+ continue;
+ }
+ size = PAGE_SIZE;
+ leader = 0;
+ if ((offset == 0)) {
+ leader = mstart & ~PAGE_MASK;
+ }
+ if (leader) {
+ /* We are on the first page zero the unused portion */
+ memset(page, 0, leader);
+ size -= leader;
+ page += leader;
+ }
+ if (size > (segment->bufsz - offset)) {
+ size = segment->bufsz - offset;
+ }
+ result = copy_from_user(page, buf + offset, size);
+ if (result) {
+ result = (result < 0)?result : -EIO;
+ goto out;
+ }
+ if (size < (PAGE_SIZE - leader)) {
+ /* zero the trailing part of the page */
+ memset(page + size, 0, (PAGE_SIZE - leader) - size);
+ }
+ }
+ out:
+ return result;
+}
+
+
+/* do_kexec executes a new kernel
+ */
+int do_kexec(unsigned long start, long nr_segments,
+ struct kexec_segment *arg_segments, struct kimage *image)
+{
+ struct kexec_segment *segments;
+ size_t segment_bytes;
+ int i;
+
+ int result;
+ unsigned long reboot_code_buffer;
+ kimage_entry_t *end;
+
+ /* Initialize variables */
+ segments = 0;
+
+ /* We only trust the superuser with rebooting the system. */
+ if (!capable(CAP_SYS_BOOT)) {
+ result = -EPERM;
+ goto out;
+ }
+
+ if (nr_segments <= 0) {
+ result = -EINVAL;
+ goto out;
+ }
+ segment_bytes = nr_segments * sizeof(*segments);
+ segments = kmalloc(GFP_KERNEL, segment_bytes);
+ if (segments == 0) {
+ result = -ENOMEM;
+ goto out;
+ }
+ result = copy_from_user(segments, arg_segments, segment_bytes);
+ if (result) {
+ goto out;
+ }
+#if DEBUG
+ for(i = 0; i < nr_segments; i++) {
+ printk(KERN_EMERG "k_segment[%d].buf = %p\n", i, segments[i].buf);
+ printk(KERN_EMERG "k_segment[%d].bufsz = 0x%x\n", i, segments[i].bufsz);
+ printk(KERN_EMERG "k_segment[%d].mem = %p\n", i, segments[i].mem);
+ printk(KERN_EMERG "k_segment[%d].memsz = 0x%x\n", i, segments[i].memsz);
+ }
+ printk(KERN_EMERG "k_entry = 0x%08lx\n", start);
+ printk(KERN_EMERG "k_nr_segments = %d\n", nr_segments);
+ printk(KERN_EMERG "k_segments = %p\n", segments);
+#endif
+
+ /* Read in the data from user space */
+ image->start = start;
+ for(i = 0; i < nr_segments; i++) {
+ result = kimage_load_segment(image, &segments[i]);
+ if (result) {
+ goto out;
+ }
+ }
+
+ /* Terminate early so I can get a place holder. */
+ result = kimage_terminate(image);
+ if (result)
+ goto out;
+ end = image->entry;
+
+ /* Usage of the reboot code buffer is subtle. We first
+ * find a continguous area of ram, that is not one
+ * of our destination pages. We do not allocate the ram.
+ *
+ * The algorithm to make certain we do not have address
+ * conflicts requires each destination region to have some
+ * backing store so we allocate abitrary source pages.
+ *
+ * Later in machine_kexec when we copy data to the
+ * reboot_code_buffer it still may be allocated for other
+ * purposes, but we do know there are no source or destination
+ * pages in that area. And since the rest of the kernel
+ * is already shutdown those pages are free for use,
+ * regardless of their page->count values.
+ */
+ result = kimage_get_unused_area(
+ image, KEXEC_REBOOT_CODE_SIZE, KEXEC_REBOOT_CODE_ALIGN,
+ &reboot_code_buffer);
+ if (result)
+ goto out;
+
+ /* Allocating pages we should never need is silly but the
+ * code won't work correctly unless we have dummy pages to
+ * work with.
+ */
+ result = kimage_set_destination(image, reboot_code_buffer);
+ if (result)
+ goto out;
+ result = kimage_add_empty_pages(image, KEXEC_REBOOT_CODE_SIZE);
+ if (result)
+ goto out;
+ image->reboot_code_buffer = phys_to_virt(reboot_code_buffer);
+
+ result = kimage_terminate(image);
+ if (result)
+ goto out;
+
+ result = kimage_get_off_destination_pages(image);
+ if (result)
+ goto out;
+
+#if DEBUG
+ kimage_print_image(image);
+#endif
+
+ /* Now hide the extra source pages for the reboot code buffer
+ * What is the logic with the reboot code buffer, should it
+ * be mapped 1-1 by this point FIXME verify this?
+ */
+ image->entry = end;
+ result = kimage_terminate(image);
+ if (result)
+ goto out;
+
+#if DEBUG
+ kimage_print_image(image);
+#endif
+
+ result = 0;
+ out:
+ /* cleanup and exit */
+ if (segments) kfree(segments);
+ return result;
+}
+
diff -uNrX linux-ignore-files linux-2.5.42.eb1/kernel/sys.c linux-2.5.42.kexec.x86/kernel/sys.c
--- linux-2.5.42.eb1/kernel/sys.c Fri Oct 11 22:21:31 2002
+++ linux-2.5.42.kexec.x86/kernel/sys.c Thu Oct 17 02:26:18 2002
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/fs.h>
+#include <linux/kexec.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/times.h>
@@ -428,6 +429,64 @@
unlock_kernel();
return 0;
}
+
+#ifdef CONFIG_KEXEC
+/*
+ * Exec Kernel system call: for obvious reasons only root may call it.
+ *
+ * This call breaks up into three pieces.
+ * - A generic part which loads the new kernel from the current
+ * address space, and very carefully places the data in the
+ * allocated pages.
+ *
+ * - A generic part that interacts with the kernel and tells all of
+ * the devices to shut down. Preventing on-going dmas, and placing
+ * the devices in a consistent state so a later kernel can
+ * reinitialize them.
+ *
+ * - A machine specific part that includes the syscall number
+ * and the copies the image to it's final destination. And
+ * jumps into the image at entry.
+ *
+ * kexec does not sync, or unmount filesystems so if you need
+ * that to happen you need to do that yourself.
+ */
+asmlinkage long sys_kexec(unsigned long entry, long nr_segments,
+ struct kexec_segment *segments)
+{
+ /* Am I using to much stack space here? */
+ struct kimage image;
+ int result;
+
+ /* We only trust the superuser with rebooting the system. */
+ if (!capable(CAP_SYS_BOOT))
+ return -EPERM;
+
+ lock_kernel();
+ kimage_init(&image);
+ result = do_kexec(entry, nr_segments, segments, &image);
+ if (result) {
+ kimage_free(&image);
+ unlock_kernel();
+ return result;
+ }
+
+ /* The point of no return is here... */
+ notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
+ system_running = 0;
+ device_shutdown();
+ machine_kexec(&image);
+ /* We never get here but... */
+ kimage_free(&image);
+ unlock_kernel();
+}
+#else
+asmlinkage long sys_kexec(unsigned long entry, long nr_segments,
+ struct kexec_segment *segments)
+{
+ return -ENOSYS;
+}
+#endif /* CONFIG_KEXEC */

static void deferred_cad(void *dummy)
{
-
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