machine_kexec.c

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/*
 * Code to handle transition of Linux booting another kernel.
 *
 * Copyright (C) 2002-2003 Eric Biederman  <[email protected]>
 * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
 * Copyright (C) 2005 IBM Corporation.
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */

#include <linux/kexec.h>
#include <linux/reboot.h>
#include <linux/threads.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/irq.h>
#include <linux/ftrace.h>

#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/sections.h>

void machine_kexec_mask_interrupts(void) {
    unsigned int i;
    struct irq_desc *desc;

    for_each_irq_desc(i, desc) {
        struct irq_chip *chip;

        chip = irq_desc_get_chip(desc);
        if (!chip)
            continue;

        if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
            chip->irq_eoi(&desc->irq_data);

        if (chip->irq_mask)
            chip->irq_mask(&desc->irq_data);

        if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
            chip->irq_disable(&desc->irq_data);
    }
}

void machine_crash_shutdown(struct pt_regs *regs)
{
    default_machine_crash_shutdown(regs);
}

/*
 * Do what every setup is needed on image and the
 * reboot code buffer to allow us to avoid allocations
 * later.
 */
int machine_kexec_prepare(struct kimage *image)
{
    if (ppc_md.machine_kexec_prepare)
        return ppc_md.machine_kexec_prepare(image);
    else
        return default_machine_kexec_prepare(image);
}

void machine_kexec_cleanup(struct kimage *image)
{
}

void arch_crash_save_vmcoreinfo(void)
{

#ifdef CONFIG_NEED_MULTIPLE_NODES
    VMCOREINFO_SYMBOL(node_data);
    VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
#endif
#ifndef CONFIG_NEED_MULTIPLE_NODES
    VMCOREINFO_SYMBOL(contig_page_data);
#endif
}

/*
 * 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)
{
    int save_ftrace_enabled;

    save_ftrace_enabled = __ftrace_enabled_save();

    if (ppc_md.machine_kexec)
        ppc_md.machine_kexec(image);
    else
        default_machine_kexec(image);

    __ftrace_enabled_restore(save_ftrace_enabled);

    /* Fall back to normal restart if we're still alive. */
    machine_restart(NULL);
    for(;;);
}

void __init reserve_crashkernel(void)
{
    unsigned long long crash_size, crash_base;
    int ret;

    /* use common parsing */
    ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
            &crash_size, &crash_base);
    if (ret == 0 && crash_size > 0) {
        crashk_res.start = crash_base;
        crashk_res.end = crash_base + crash_size - 1;
    }

    if (crashk_res.end == crashk_res.start) {
        crashk_res.start = crashk_res.end = 0;
        return;
    }

    /* We might have got these values via the command line or the
     * device tree, either way sanitise them now. */

    crash_size = resource_size(&crashk_res);

#ifndef CONFIG_NONSTATIC_KERNEL
    if (crashk_res.start != KDUMP_KERNELBASE)
        printk("Crash kernel location must be 0x%x\n",
                KDUMP_KERNELBASE);

    crashk_res.start = KDUMP_KERNELBASE;
#else
    if (!crashk_res.start) {
#ifdef CONFIG_PPC64
        /*
         * On 64bit we split the RMO in half but cap it at half of
         * a small SLB (128MB) since the crash kernel needs to place
         * itself and some stacks to be in the first segment.
         */
        crashk_res.start = min(0x80000000ULL, (ppc64_rma_size / 2));
#else
        crashk_res.start = KDUMP_KERNELBASE;
#endif
    }

    crash_base = PAGE_ALIGN(crashk_res.start);
    if (crash_base != crashk_res.start) {
        printk("Crash kernel base must be aligned to 0x%lx\n",
                PAGE_SIZE);
        crashk_res.start = crash_base;
    }

#endif
    crash_size = PAGE_ALIGN(crash_size);
    crashk_res.end = crashk_res.start + crash_size - 1;

    /* The crash region must not overlap the current kernel */
    if (overlaps_crashkernel(__pa(_stext), _end - _stext)) {
        printk(KERN_WARNING
            "Crash kernel can not overlap current kernel\n");
        crashk_res.start = crashk_res.end = 0;
        return;
    }

    /* Crash kernel trumps memory limit */
    if (memory_limit && memory_limit <= crashk_res.end) {
        memory_limit = crashk_res.end + 1;
        printk("Adjusted memory limit for crashkernel, now 0x%llx\n",
               memory_limit);
    }

    printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
            "for crashkernel (System RAM: %ldMB)\n",
            (unsigned long)(crash_size >> 20),
            (unsigned long)(crashk_res.start >> 20),
            (unsigned long)(memblock_phys_mem_size() >> 20));

    memblock_reserve(crashk_res.start, crash_size);
}

int overlaps_crashkernel(unsigned long start, unsigned long size)
{
    return (start + size) > crashk_res.start && start <= crashk_res.end;
}

/* Values we need to export to the second kernel via the device tree. */
static phys_addr_t kernel_end;
static phys_addr_t crashk_size;

static struct property kernel_end_prop = {
    .name = "linux,kernel-end",
    .length = sizeof(phys_addr_t),
    .value = &kernel_end,
};

static struct property crashk_base_prop = {
    .name = "linux,crashkernel-base",
    .length = sizeof(phys_addr_t),
    .value = &crashk_res.start,
};

static struct property crashk_size_prop = {
    .name = "linux,crashkernel-size",
    .length = sizeof(phys_addr_t),
    .value = &crashk_size,
};

static struct property memory_limit_prop = {
    .name = "linux,memory-limit",
    .length = sizeof(unsigned long long),
    .value = &memory_limit,
};

static void __init export_crashk_values(struct device_node *node)
{
    struct property *prop;

    /* There might be existing crash kernel properties, but we can't
     * be sure what's in them, so remove them. */
    prop = of_find_property(node, "linux,crashkernel-base", NULL);
    if (prop)
        prom_remove_property(node, prop);

    prop = of_find_property(node, "linux,crashkernel-size", NULL);
    if (prop)
        prom_remove_property(node, prop);

    if (crashk_res.start != 0) {
        prom_add_property(node, &crashk_base_prop);
        crashk_size = resource_size(&crashk_res);
        prom_add_property(node, &crashk_size_prop);
    }

    /*
     * memory_limit is required by the kexec-tools to limit the
     * crash regions to the actual memory used.
     */
    prom_update_property(node, &memory_limit_prop);
}

static int __init kexec_setup(void)
{
    struct device_node *node;
    struct property *prop;

    node = of_find_node_by_path("/chosen");
    if (!node)
        return -ENOENT;

    /* remove any stale properties so ours can be found */
    prop = of_find_property(node, kernel_end_prop.name, NULL);
    if (prop)
        prom_remove_property(node, prop);

    /* information needed by userspace when using default_machine_kexec */
    kernel_end = __pa(_end);
    prom_add_property(node, &kernel_end_prop);

    export_crashk_values(node);

    of_node_put(node);
    return 0;
}
late_initcall(kexec_setup);