![Suzuki Poulose](/assets/img/avatar_default.png)
The powerpc kernel doesn't export the memory limit enforced by 'mem=' kernel parameter. This is required for building the ELF header in kexec-tools to limit the vmcore to capture only the used memory. On powerpc the kexec-tools depends on the device-tree for memory related information, unlike /proc/iomem on the x86. Without this information, the kexec-tools assumes the entire System RAM and vmcore creates an unnecessarily larger dump. This patch exports the memory limit, if present, via chosen/linux,memory-limit property, so that the vmcore can be limited to the memory limit. The prom_init seems to export this value in the same node. But doesn't really appear there. Also the memory_limit gets adjusted with the processing of crashkernel= parameter. This patch makes sure we get the actual limit. The kexec-tools will use the value to limit the 'end' of the memory regions. Tested this patch on ppc64 and ppc32(ppc440) with a kexec-tools patch by Mahesh. Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com> Tested-by: Mahesh J. Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
264 lines
6.5 KiB
C
264 lines
6.5 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/memblock.h>
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#include <linux/of.h>
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#include <linux/irq.h>
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#include <linux/ftrace.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_kexec_mask_interrupts(void) {
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unsigned int i;
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struct irq_desc *desc;
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for_each_irq_desc(i, desc) {
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struct irq_chip *chip;
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chip = irq_desc_get_chip(desc);
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if (!chip)
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continue;
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if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
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chip->irq_eoi(&desc->irq_data);
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if (chip->irq_mask)
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chip->irq_mask(&desc->irq_data);
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if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
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chip->irq_disable(&desc->irq_data);
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}
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}
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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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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}
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void arch_crash_save_vmcoreinfo(void)
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{
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#ifdef CONFIG_NEED_MULTIPLE_NODES
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VMCOREINFO_SYMBOL(node_data);
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VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
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#endif
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#ifndef CONFIG_NEED_MULTIPLE_NODES
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VMCOREINFO_SYMBOL(contig_page_data);
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#endif
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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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int save_ftrace_enabled;
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save_ftrace_enabled = __ftrace_enabled_save();
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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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__ftrace_enabled_restore(save_ftrace_enabled);
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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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/* use common parsing */
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ret = parse_crashkernel(boot_command_line, memblock_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 = resource_size(&crashk_res);
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#ifndef CONFIG_NONSTATIC_KERNEL
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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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#ifdef CONFIG_PPC64
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/*
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* On 64bit we split the RMO in half but cap it at half of
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* a small SLB (128MB) since the crash kernel needs to place
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* itself and some stacks to be in the first segment.
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*/
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crashk_res.start = min(0x80000000ULL, (ppc64_rma_size / 2));
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#else
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crashk_res.start = KDUMP_KERNELBASE;
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#endif
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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%llx\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)(memblock_phys_mem_size() >> 20));
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memblock_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 phys_addr_t kernel_end;
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static phys_addr_t 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(phys_addr_t),
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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(phys_addr_t),
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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(phys_addr_t),
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.value = &crashk_size,
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};
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static struct property memory_limit_prop = {
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.name = "linux,memory-limit",
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.length = sizeof(unsigned long long),
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.value = &memory_limit,
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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 = resource_size(&crashk_res);
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prom_add_property(node, &crashk_size_prop);
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}
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/*
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* memory_limit is required by the kexec-tools to limit the
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* crash regions to the actual memory used.
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*/
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prom_update_property(node, &memory_limit_prop);
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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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