![Milton Miller](/assets/img/avatar_default.png)
Enforce that the crash kernel region never overlaps the current kernel, as it will be written directly on kexec load. Also, default to the previous KDUMP_KERNELBASE if the start is 0. Other architectures (x86, ia64) state that specifying the start address 0 (or omitting it) will result in the kernel allocating it. Before the relocatable patch in 2.6.28, powerpc would adjust any other start value to the hardcoded KDUMP_KERNELBASE of 32M. Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
213 lines
5.5 KiB
C
213 lines
5.5 KiB
C
/*
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* Code to handle transition of Linux booting another kernel.
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*
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* Copyright (C) 2002-2003 Eric Biederman <ebiederm@xmission.com>
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* GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
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* Copyright (C) 2005 IBM Corporation.
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/kexec.h>
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#include <linux/reboot.h>
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#include <linux/threads.h>
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#include <linux/lmb.h>
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#include <linux/of.h>
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#include <asm/machdep.h>
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#include <asm/prom.h>
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#include <asm/sections.h>
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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if (ppc_md.machine_crash_shutdown)
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ppc_md.machine_crash_shutdown(regs);
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else
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default_machine_crash_shutdown(regs);
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}
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/*
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* Do what every setup is needed on image and the
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* reboot code buffer to allow us to avoid allocations
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* later.
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*/
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int machine_kexec_prepare(struct kimage *image)
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{
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if (ppc_md.machine_kexec_prepare)
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return ppc_md.machine_kexec_prepare(image);
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else
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return default_machine_kexec_prepare(image);
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}
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void machine_kexec_cleanup(struct kimage *image)
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{
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if (ppc_md.machine_kexec_cleanup)
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ppc_md.machine_kexec_cleanup(image);
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}
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/*
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* Do not allocate memory (or fail in any way) in machine_kexec().
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* We are past the point of no return, committed to rebooting now.
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*/
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void machine_kexec(struct kimage *image)
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{
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if (ppc_md.machine_kexec)
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ppc_md.machine_kexec(image);
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else
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default_machine_kexec(image);
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/* Fall back to normal restart if we're still alive. */
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machine_restart(NULL);
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for(;;);
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}
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void __init reserve_crashkernel(void)
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{
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unsigned long long crash_size, crash_base;
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int ret;
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/* this is necessary because of lmb_phys_mem_size() */
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lmb_analyze();
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/* use common parsing */
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ret = parse_crashkernel(boot_command_line, lmb_phys_mem_size(),
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&crash_size, &crash_base);
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if (ret == 0 && crash_size > 0) {
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crashk_res.start = crash_base;
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crashk_res.end = crash_base + crash_size - 1;
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}
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if (crashk_res.end == crashk_res.start) {
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crashk_res.start = crashk_res.end = 0;
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return;
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}
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/* We might have got these values via the command line or the
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* device tree, either way sanitise them now. */
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crash_size = crashk_res.end - crashk_res.start + 1;
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#ifndef CONFIG_RELOCATABLE
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if (crashk_res.start != KDUMP_KERNELBASE)
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printk("Crash kernel location must be 0x%x\n",
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KDUMP_KERNELBASE);
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crashk_res.start = KDUMP_KERNELBASE;
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#else
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if (!crashk_res.start) {
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/*
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* unspecified address, choose a region of specified size
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* can overlap with initrd (ignoring corruption when retained)
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* ppc64 requires kernel and some stacks to be in first segemnt
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*/
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crashk_res.start = KDUMP_KERNELBASE;
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}
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crash_base = PAGE_ALIGN(crashk_res.start);
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if (crash_base != crashk_res.start) {
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printk("Crash kernel base must be aligned to 0x%lx\n",
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PAGE_SIZE);
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crashk_res.start = crash_base;
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}
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#endif
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crash_size = PAGE_ALIGN(crash_size);
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crashk_res.end = crashk_res.start + crash_size - 1;
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/* The crash region must not overlap the current kernel */
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if (overlaps_crashkernel(__pa(_stext), _end - _stext)) {
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printk(KERN_WARNING
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"Crash kernel can not overlap current kernel\n");
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crashk_res.start = crashk_res.end = 0;
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return;
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}
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/* Crash kernel trumps memory limit */
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if (memory_limit && memory_limit <= crashk_res.end) {
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memory_limit = crashk_res.end + 1;
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printk("Adjusted memory limit for crashkernel, now 0x%lx\n",
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memory_limit);
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}
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printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
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"for crashkernel (System RAM: %ldMB)\n",
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(unsigned long)(crash_size >> 20),
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(unsigned long)(crashk_res.start >> 20),
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(unsigned long)(lmb_phys_mem_size() >> 20));
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lmb_reserve(crashk_res.start, crash_size);
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}
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int overlaps_crashkernel(unsigned long start, unsigned long size)
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{
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return (start + size) > crashk_res.start && start <= crashk_res.end;
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}
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/* Values we need to export to the second kernel via the device tree. */
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static unsigned long kernel_end;
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static unsigned long crashk_size;
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static struct property kernel_end_prop = {
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.name = "linux,kernel-end",
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.length = sizeof(unsigned long),
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.value = &kernel_end,
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};
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static struct property crashk_base_prop = {
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.name = "linux,crashkernel-base",
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.length = sizeof(unsigned long),
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.value = &crashk_res.start,
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};
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static struct property crashk_size_prop = {
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.name = "linux,crashkernel-size",
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.length = sizeof(unsigned long),
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.value = &crashk_size,
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};
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static void __init export_crashk_values(struct device_node *node)
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{
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struct property *prop;
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/* There might be existing crash kernel properties, but we can't
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* be sure what's in them, so remove them. */
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prop = of_find_property(node, "linux,crashkernel-base", NULL);
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if (prop)
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prom_remove_property(node, prop);
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prop = of_find_property(node, "linux,crashkernel-size", NULL);
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if (prop)
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prom_remove_property(node, prop);
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if (crashk_res.start != 0) {
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prom_add_property(node, &crashk_base_prop);
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crashk_size = crashk_res.end - crashk_res.start + 1;
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prom_add_property(node, &crashk_size_prop);
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}
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}
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static int __init kexec_setup(void)
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{
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struct device_node *node;
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struct property *prop;
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node = of_find_node_by_path("/chosen");
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if (!node)
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return -ENOENT;
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/* remove any stale properties so ours can be found */
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prop = of_find_property(node, kernel_end_prop.name, NULL);
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if (prop)
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prom_remove_property(node, prop);
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/* information needed by userspace when using default_machine_kexec */
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kernel_end = __pa(_end);
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prom_add_property(node, &kernel_end_prop);
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export_crashk_values(node);
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of_node_put(node);
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return 0;
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}
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late_initcall(kexec_setup);
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