// SPDX-License-Identifier: GPL-2.0-only
/*
 * ppc64 code to implement the kexec_file_load syscall
 *
 * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
 * Copyright (C) 2004  IBM Corp.
 * Copyright (C) 2004,2005  Milton D Miller II, IBM Corporation
 * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
 * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
 * Copyright (C) 2020  IBM Corporation
 *
 * Based on kexec-tools' kexec-ppc64.c, kexec-elf-rel-ppc64.c, fs2dt.c.
 * Heavily modified for the kernel by
 * Hari Bathini, IBM Corporation.
 */

#include <linux/kexec.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <linux/of_device.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/setup.h>
#include <asm/drmem.h>
#include <asm/kexec_ranges.h>
#include <asm/crashdump-ppc64.h>

struct umem_info {
        u64 *buf;               /* data buffer for usable-memory property */
        u32 size;               /* size allocated for the data buffer */
        u32 max_entries;        /* maximum no. of entries */
        u32 idx;                /* index of current entry */

        /* usable memory ranges to look up */
        unsigned int nr_ranges;
        const struct crash_mem_range *ranges;
};

const struct kexec_file_ops * const kexec_file_loaders[] = {
        &kexec_elf64_ops,
        NULL
};

/**
 * get_exclude_memory_ranges - Get exclude memory ranges. This list includes
 *                             regions like opal/rtas, tce-table, initrd,
 *                             kernel, htab which should be avoided while
 *                             setting up kexec load segments.
 * @mem_ranges:                Range list to add the memory ranges to.
 *
 * Returns 0 on success, negative errno on error.
 */
static int get_exclude_memory_ranges(struct crash_mem **mem_ranges)
{
        int ret;

        ret = add_tce_mem_ranges(mem_ranges);
        if (ret)
                goto out;

        ret = add_initrd_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_htab_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_kernel_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_rtas_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_opal_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_reserved_mem_ranges(mem_ranges);
        if (ret)
                goto out;

        /* exclude memory ranges should be sorted for easy lookup */
        sort_memory_ranges(*mem_ranges, true);
out:
        if (ret)
                pr_err("Failed to setup exclude memory ranges\n");
        return ret;
}

/**
 * get_usable_memory_ranges - Get usable memory ranges. This list includes
 *                            regions like crashkernel, opal/rtas & tce-table,
 *                            that kdump kernel could use.
 * @mem_ranges:               Range list to add the memory ranges to.
 *
 * Returns 0 on success, negative errno on error.
 */
static int get_usable_memory_ranges(struct crash_mem **mem_ranges)
{
        int ret;

        /*
         * Early boot failure observed on guests when low memory (first memory
         * block?) is not added to usable memory. So, add [0, crashk_res.end]
         * instead of [crashk_res.start, crashk_res.end] to workaround it.
         * Also, crashed kernel's memory must be added to reserve map to
         * avoid kdump kernel from using it.
         */
        ret = add_mem_range(mem_ranges, 0, crashk_res.end + 1);
        if (ret)
                goto out;

        ret = add_rtas_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_opal_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_tce_mem_ranges(mem_ranges);
out:
        if (ret)
                pr_err("Failed to setup usable memory ranges\n");
        return ret;
}

/**
 * get_crash_memory_ranges - Get crash memory ranges. This list includes
 *                           first/crashing kernel's memory regions that
 *                           would be exported via an elfcore.
 * @mem_ranges:              Range list to add the memory ranges to.
 *
 * Returns 0 on success, negative errno on error.
 */
static int get_crash_memory_ranges(struct crash_mem **mem_ranges)
{
        phys_addr_t base, end;
        struct crash_mem *tmem;
        u64 i;
        int ret;

        for_each_mem_range(i, &base, &end) {
                u64 size = end - base;

                /* Skip backup memory region, which needs a separate entry */
                if (base == BACKUP_SRC_START) {
                        if (size > BACKUP_SRC_SIZE) {
                                base = BACKUP_SRC_END + 1;
                                size -= BACKUP_SRC_SIZE;
                        } else
                                continue;
                }

                ret = add_mem_range(mem_ranges, base, size);
                if (ret)
                        goto out;

                /* Try merging adjacent ranges before reallocation attempt */
                if ((*mem_ranges)->nr_ranges == (*mem_ranges)->max_nr_ranges)
                        sort_memory_ranges(*mem_ranges, true);
        }

        /* Reallocate memory ranges if there is no space to split ranges */
        tmem = *mem_ranges;
        if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
                tmem = realloc_mem_ranges(mem_ranges);
                if (!tmem)
                        goto out;
        }

        /* Exclude crashkernel region */
        ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.end);
        if (ret)
                goto out;

        /*
         * FIXME: For now, stay in parity with kexec-tools but if RTAS/OPAL
         *        regions are exported to save their context at the time of
         *        crash, they should actually be backed up just like the
         *        first 64K bytes of memory.
         */
        ret = add_rtas_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_opal_mem_range(mem_ranges);
        if (ret)
                goto out;

        /* create a separate program header for the backup region */
        ret = add_mem_range(mem_ranges, BACKUP_SRC_START, BACKUP_SRC_SIZE);
        if (ret)
                goto out;

        sort_memory_ranges(*mem_ranges, false);
out:
        if (ret)
                pr_err("Failed to setup crash memory ranges\n");
        return ret;
}

/**
 * get_reserved_memory_ranges - Get reserve memory ranges. This list includes
 *                              memory regions that should be added to the
 *                              memory reserve map to ensure the region is
 *                              protected from any mischief.
 * @mem_ranges:                 Range list to add the memory ranges to.
 *
 * Returns 0 on success, negative errno on error.
 */
static int get_reserved_memory_ranges(struct crash_mem **mem_ranges)
{
        int ret;

        ret = add_rtas_mem_range(mem_ranges);
        if (ret)
                goto out;

        ret = add_tce_mem_ranges(mem_ranges);
        if (ret)
                goto out;

        ret = add_reserved_mem_ranges(mem_ranges);
out:
        if (ret)
                pr_err("Failed to setup reserved memory ranges\n");
        return ret;
}

/**
 * __locate_mem_hole_top_down - Looks top down for a large enough memory hole
 *                              in the memory regions between buf_min & buf_max
 *                              for the buffer. If found, sets kbuf->mem.
 * @kbuf:                       Buffer contents and memory parameters.
 * @buf_min:                    Minimum address for the buffer.
 * @buf_max:                    Maximum address for the buffer.
 *
 * Returns 0 on success, negative errno on error.
 */
static int __locate_mem_hole_top_down(struct kexec_buf *kbuf,
                                      u64 buf_min, u64 buf_max)
{
        int ret = -EADDRNOTAVAIL;
        phys_addr_t start, end;
        u64 i;

        for_each_mem_range_rev(i, &start, &end) {
                /*
                 * memblock uses [start, end) convention while it is
                 * [start, end] here. Fix the off-by-one to have the
                 * same convention.
                 */
                end -= 1;

                if (start > buf_max)
                        continue;

                /* Memory hole not found */
                if (end < buf_min)
                        break;

                /* Adjust memory region based on the given range */
                if (start < buf_min)
                        start = buf_min;
                if (end > buf_max)
                        end = buf_max;

                start = ALIGN(start, kbuf->buf_align);
                if (start < end && (end - start + 1) >= kbuf->memsz) {
                        /* Suitable memory range found. Set kbuf->mem */
                        kbuf->mem = ALIGN_DOWN(end - kbuf->memsz + 1,
                                               kbuf->buf_align);
                        ret = 0;
                        break;
                }
        }

        return ret;
}

/**
 * locate_mem_hole_top_down_ppc64 - Skip special memory regions to find a
 *                                  suitable buffer with top down approach.
 * @kbuf:                           Buffer contents and memory parameters.
 * @buf_min:                        Minimum address for the buffer.
 * @buf_max:                        Maximum address for the buffer.
 * @emem:                           Exclude memory ranges.
 *
 * Returns 0 on success, negative errno on error.
 */
static int locate_mem_hole_top_down_ppc64(struct kexec_buf *kbuf,
                                          u64 buf_min, u64 buf_max,
                                          const struct crash_mem *emem)
{
        int i, ret = 0, err = -EADDRNOTAVAIL;
        u64 start, end, tmin, tmax;

        tmax = buf_max;
        for (i = (emem->nr_ranges - 1); i >= 0; i--) {
                start = emem->ranges[i].start;
                end = emem->ranges[i].end;

                if (start > tmax)
                        continue;

                if (end < tmax) {
                        tmin = (end < buf_min ? buf_min : end + 1);
                        ret = __locate_mem_hole_top_down(kbuf, tmin, tmax);
                        if (!ret)
                                return 0;
                }

                tmax = start - 1;

                if (tmax < buf_min) {
                        ret = err;
                        break;
                }
                ret = 0;
        }

        if (!ret) {
                tmin = buf_min;
                ret = __locate_mem_hole_top_down(kbuf, tmin, tmax);
        }
        return ret;
}

/**
 * __locate_mem_hole_bottom_up - Looks bottom up for a large enough memory hole
 *                               in the memory regions between buf_min & buf_max
 *                               for the buffer. If found, sets kbuf->mem.
 * @kbuf:                        Buffer contents and memory parameters.
 * @buf_min:                     Minimum address for the buffer.
 * @buf_max:                     Maximum address for the buffer.
 *
 * Returns 0 on success, negative errno on error.
 */
static int __locate_mem_hole_bottom_up(struct kexec_buf *kbuf,
                                       u64 buf_min, u64 buf_max)
{
        int ret = -EADDRNOTAVAIL;
        phys_addr_t start, end;
        u64 i;

        for_each_mem_range(i, &start, &end) {
                /*
                 * memblock uses [start, end) convention while it is
                 * [start, end] here. Fix the off-by-one to have the
                 * same convention.
                 */
                end -= 1;

                if (end < buf_min)
                        continue;

                /* Memory hole not found */
                if (start > buf_max)
                        break;

                /* Adjust memory region based on the given range */
                if (start < buf_min)
                        start = buf_min;
                if (end > buf_max)
                        end = buf_max;

                start = ALIGN(start, kbuf->buf_align);
                if (start < end && (end - start + 1) >= kbuf->memsz) {
                        /* Suitable memory range found. Set kbuf->mem */
                        kbuf->mem = start;
                        ret = 0;
                        break;
                }
        }

        return ret;
}

/**
 * locate_mem_hole_bottom_up_ppc64 - Skip special memory regions to find a
 *                                   suitable buffer with bottom up approach.
 * @kbuf:                            Buffer contents and memory parameters.
 * @buf_min:                         Minimum address for the buffer.
 * @buf_max:                         Maximum address for the buffer.
 * @emem:                            Exclude memory ranges.
 *
 * Returns 0 on success, negative errno on error.
 */
static int locate_mem_hole_bottom_up_ppc64(struct kexec_buf *kbuf,
                                           u64 buf_min, u64 buf_max,
                                           const struct crash_mem *emem)
{
        int i, ret = 0, err = -EADDRNOTAVAIL;
        u64 start, end, tmin, tmax;

        tmin = buf_min;
        for (i = 0; i < emem->nr_ranges; i++) {
                start = emem->ranges[i].start;
                end = emem->ranges[i].end;

                if (end < tmin)
                        continue;

                if (start > tmin) {
                        tmax = (start > buf_max ? buf_max : start - 1);
                        ret = __locate_mem_hole_bottom_up(kbuf, tmin, tmax);
                        if (!ret)
                                return 0;
                }

                tmin = end + 1;

                if (tmin > buf_max) {
                        ret = err;
                        break;
                }
                ret = 0;
        }

        if (!ret) {
                tmax = buf_max;
                ret = __locate_mem_hole_bottom_up(kbuf, tmin, tmax);
        }
        return ret;
}

/**
 * check_realloc_usable_mem - Reallocate buffer if it can't accommodate entries
 * @um_info:                  Usable memory buffer and ranges info.
 * @cnt:                      No. of entries to accommodate.
 *
 * Frees up the old buffer if memory reallocation fails.
 *
 * Returns buffer on success, NULL on error.
 */
static u64 *check_realloc_usable_mem(struct umem_info *um_info, int cnt)
{
        u32 new_size;
        u64 *tbuf;

        if ((um_info->idx + cnt) <= um_info->max_entries)
                return um_info->buf;

        new_size = um_info->size + MEM_RANGE_CHUNK_SZ;
        tbuf = krealloc(um_info->buf, new_size, GFP_KERNEL);
        if (tbuf) {
                um_info->buf = tbuf;
                um_info->size = new_size;
                um_info->max_entries = (um_info->size / sizeof(u64));
        }

        return tbuf;
}

/**
 * add_usable_mem - Add the usable memory ranges within the given memory range
 *                  to the buffer
 * @um_info:        Usable memory buffer and ranges info.
 * @base:           Base address of memory range to look for.
 * @end:            End address of memory range to look for.
 *
 * Returns 0 on success, negative errno on error.
 */
static int add_usable_mem(struct umem_info *um_info, u64 base, u64 end)
{
        u64 loc_base, loc_end;
        bool add;
        int i;

        for (i = 0; i < um_info->nr_ranges; i++) {
                add = false;
                loc_base = um_info->ranges[i].start;
                loc_end = um_info->ranges[i].end;
                if (loc_base >= base && loc_end <= end)
                        add = true;
                else if (base < loc_end && end > loc_base) {
                        if (loc_base < base)
                                loc_base = base;
                        if (loc_end > end)
                                loc_end = end;
                        add = true;
                }

                if (add) {
                        if (!check_realloc_usable_mem(um_info, 2))
                                return -ENOMEM;

                        um_info->buf[um_info->idx++] = cpu_to_be64(loc_base);
                        um_info->buf[um_info->idx++] =
                                        cpu_to_be64(loc_end - loc_base + 1);
                }
        }

        return 0;
}

/**
 * kdump_setup_usable_lmb - This is a callback function that gets called by
 *                          walk_drmem_lmbs for every LMB to set its
 *                          usable memory ranges.
 * @lmb:                    LMB info.
 * @usm:                    linux,drconf-usable-memory property value.
 * @data:                   Pointer to usable memory buffer and ranges info.
 *
 * Returns 0 on success, negative errno on error.
 */
static int kdump_setup_usable_lmb(struct drmem_lmb *lmb, const __be32 **usm,
                                  void *data)
{
        struct umem_info *um_info;
        int tmp_idx, ret;
        u64 base, end;

        /*
         * kdump load isn't supported on kernels already booted with
         * linux,drconf-usable-memory property.
         */
        if (*usm) {
                pr_err("linux,drconf-usable-memory property already exists!");
                return -EINVAL;
        }

        um_info = data;
        tmp_idx = um_info->idx;
        if (!check_realloc_usable_mem(um_info, 1))
                return -ENOMEM;

        um_info->idx++;
        base = lmb->base_addr;
        end = base + drmem_lmb_size() - 1;
        ret = add_usable_mem(um_info, base, end);
        if (!ret) {
                /*
                 * Update the no. of ranges added. Two entries (base & size)
                 * for every range added.
                 */
                um_info->buf[tmp_idx] =
                                cpu_to_be64((um_info->idx - tmp_idx - 1) / 2);
        }

        return ret;
}

#define NODE_PATH_LEN           256
/**
 * add_usable_mem_property - Add usable memory property for the given
 *                           memory node.
 * @fdt:                     Flattened device tree for the kdump kernel.
 * @dn:                      Memory node.
 * @um_info:                 Usable memory buffer and ranges info.
 *
 * Returns 0 on success, negative errno on error.
 */
static int add_usable_mem_property(void *fdt, struct device_node *dn,
                                   struct umem_info *um_info)
{
        int n_mem_addr_cells, n_mem_size_cells, node;
        char path[NODE_PATH_LEN];
        int i, len, ranges, ret;
        const __be32 *prop;
        u64 base, end;

        of_node_get(dn);

        if (snprintf(path, NODE_PATH_LEN, "%pOF", dn) > (NODE_PATH_LEN - 1)) {
                pr_err("Buffer (%d) too small for memory node: %pOF\n",
                       NODE_PATH_LEN, dn);
                return -EOVERFLOW;
        }
        pr_debug("Memory node path: %s\n", path);

        /* Now that we know the path, find its offset in kdump kernel's fdt */
        node = fdt_path_offset(fdt, path);
        if (node < 0) {
                pr_err("Malformed device tree: error reading %s\n", path);
                ret = -EINVAL;
                goto out;
        }

        /* Get the address & size cells */
        n_mem_addr_cells = of_n_addr_cells(dn);
        n_mem_size_cells = of_n_size_cells(dn);
        pr_debug("address cells: %d, size cells: %d\n", n_mem_addr_cells,
                 n_mem_size_cells);

        um_info->idx  = 0;
        if (!check_realloc_usable_mem(um_info, 2)) {
                ret = -ENOMEM;
                goto out;
        }

        prop = of_get_property(dn, "reg", &len);
        if (!prop || len <= 0) {
                ret = 0;
                goto out;
        }

        /*
         * "reg" property represents sequence of (addr,size) tuples
         * each representing a memory range.
         */
        ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);

        for (i = 0; i < ranges; i++) {
                base = of_read_number(prop, n_mem_addr_cells);
                prop += n_mem_addr_cells;
                end = base + of_read_number(prop, n_mem_size_cells) - 1;
                prop += n_mem_size_cells;

                ret = add_usable_mem(um_info, base, end);
                if (ret)
                        goto out;
        }

        /*
         * No kdump kernel usable memory found in this memory node.
         * Write (0,0) tuple in linux,usable-memory property for
         * this region to be ignored.
         */
        if (um_info->idx == 0) {
                um_info->buf[0] = 0;
                um_info->buf[1] = 0;
                um_info->idx = 2;
        }

        ret = fdt_setprop(fdt, node, "linux,usable-memory", um_info->buf,
                          (um_info->idx * sizeof(u64)));

out:
        of_node_put(dn);
        return ret;
}


/**
 * update_usable_mem_fdt - Updates kdump kernel's fdt with linux,usable-memory
 *                         and linux,drconf-usable-memory DT properties as
 *                         appropriate to restrict its memory usage.
 * @fdt:                   Flattened device tree for the kdump kernel.
 * @usable_mem:            Usable memory ranges for kdump kernel.
 *
 * Returns 0 on success, negative errno on error.
 */
static int update_usable_mem_fdt(void *fdt, struct crash_mem *usable_mem)
{
        struct umem_info um_info;
        struct device_node *dn;
        int node, ret = 0;

        if (!usable_mem) {
                pr_err("Usable memory ranges for kdump kernel not found\n");
                return -ENOENT;
        }

        node = fdt_path_offset(fdt, "/ibm,dynamic-reconfiguration-memory");
        if (node == -FDT_ERR_NOTFOUND)
                pr_debug("No dynamic reconfiguration memory found\n");
        else if (node < 0) {
                pr_err("Malformed device tree: error reading /ibm,dynamic-reconfiguration-memory.\n");
                return -EINVAL;
        }

        um_info.buf  = NULL;
        um_info.size = 0;
        um_info.max_entries = 0;
        um_info.idx  = 0;
        /* Memory ranges to look up */
        um_info.ranges = &(usable_mem->ranges[0]);
        um_info.nr_ranges = usable_mem->nr_ranges;

        dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
        if (dn) {
                ret = walk_drmem_lmbs(dn, &um_info, kdump_setup_usable_lmb);
                of_node_put(dn);

                if (ret) {
                        pr_err("Could not setup linux,drconf-usable-memory property for kdump\n");
                        goto out;
                }

                ret = fdt_setprop(fdt, node, "linux,drconf-usable-memory",
                                  um_info.buf, (um_info.idx * sizeof(u64)));
                if (ret) {
                        pr_err("Failed to update fdt with linux,drconf-usable-memory property");
                        goto out;
                }
        }

        /*
         * Walk through each memory node and set linux,usable-memory property
         * for the corresponding node in kdump kernel's fdt.
         */
        for_each_node_by_type(dn, "memory") {
                ret = add_usable_mem_property(fdt, dn, &um_info);
                if (ret) {
                        pr_err("Failed to set linux,usable-memory property for %s node",
                               dn->full_name);
                        goto out;
                }
        }

out:
        kfree(um_info.buf);
        return ret;
}

/**
 * load_backup_segment - Locate a memory hole to place the backup region.
 * @image:               Kexec image.
 * @kbuf:                Buffer contents and memory parameters.
 *
 * Returns 0 on success, negative errno on error.
 */
static int load_backup_segment(struct kimage *image, struct kexec_buf *kbuf)
{
        void *buf;
        int ret;

        /*
         * Setup a source buffer for backup segment.
         *
         * A source buffer has no meaning for backup region as data will
         * be copied from backup source, after crash, in the purgatory.
         * But as load segment code doesn't recognize such segments,
         * setup a dummy source buffer to keep it happy for now.
         */
        buf = vzalloc(BACKUP_SRC_SIZE);
        if (!buf)
                return -ENOMEM;

        kbuf->buffer = buf;
        kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
        kbuf->bufsz = kbuf->memsz = BACKUP_SRC_SIZE;
        kbuf->top_down = false;

        ret = kexec_add_buffer(kbuf);
        if (ret) {
                vfree(buf);
                return ret;
        }

        image->arch.backup_buf = buf;
        image->arch.backup_start = kbuf->mem;
        return 0;
}

/**
 * update_backup_region_phdr - Update backup region's offset for the core to
 *                             export the region appropriately.
 * @image:                     Kexec image.
 * @ehdr:                      ELF core header.
 *
 * Assumes an exclusive program header is setup for the backup region
 * in the ELF headers
 *
 * Returns nothing.
 */
static void update_backup_region_phdr(struct kimage *image, Elf64_Ehdr *ehdr)
{
        Elf64_Phdr *phdr;
        unsigned int i;

        phdr = (Elf64_Phdr *)(ehdr + 1);
        for (i = 0; i < ehdr->e_phnum; i++) {
                if (phdr->p_paddr == BACKUP_SRC_START) {
                        phdr->p_offset = image->arch.backup_start;
                        pr_debug("Backup region offset updated to 0x%lx\n",
                                 image->arch.backup_start);
                        return;
                }
        }
}

/**
 * load_elfcorehdr_segment - Setup crash memory ranges and initialize elfcorehdr
 *                           segment needed to load kdump kernel.
 * @image:                   Kexec image.
 * @kbuf:                    Buffer contents and memory parameters.
 *
 * Returns 0 on success, negative errno on error.
 */
static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf)
{
        struct crash_mem *cmem = NULL;
        unsigned long headers_sz;
        void *headers = NULL;
        int ret;

        ret = get_crash_memory_ranges(&cmem);
        if (ret)
                goto out;

        /* Setup elfcorehdr segment */
        ret = crash_prepare_elf64_headers(cmem, false, &headers, &headers_sz);
        if (ret) {
                pr_err("Failed to prepare elf headers for the core\n");
                goto out;
        }

        /* Fix the offset for backup region in the ELF header */
        update_backup_region_phdr(image, headers);

        kbuf->buffer = headers;
        kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
        kbuf->bufsz = kbuf->memsz = headers_sz;
        kbuf->top_down = false;

        ret = kexec_add_buffer(kbuf);
        if (ret) {
                vfree(headers);
                goto out;
        }

        image->elf_load_addr = kbuf->mem;
        image->elf_headers_sz = headers_sz;
        image->elf_headers = headers;
out:
        kfree(cmem);
        return ret;
}

/**
 * load_crashdump_segments_ppc64 - Initialize the additional segements needed
 *                                 to load kdump kernel.
 * @image:                         Kexec image.
 * @kbuf:                          Buffer contents and memory parameters.
 *
 * Returns 0 on success, negative errno on error.
 */
int load_crashdump_segments_ppc64(struct kimage *image,
                                  struct kexec_buf *kbuf)
{
        int ret;

        /* Load backup segment - first 64K bytes of the crashing kernel */
        ret = load_backup_segment(image, kbuf);
        if (ret) {
                pr_err("Failed to load backup segment\n");
                return ret;
        }
        pr_debug("Loaded the backup region at 0x%lx\n", kbuf->mem);

        /* Load elfcorehdr segment - to export crashing kernel's vmcore */
        ret = load_elfcorehdr_segment(image, kbuf);
        if (ret) {
                pr_err("Failed to load elfcorehdr segment\n");
                return ret;
        }
        pr_debug("Loaded elf core header at 0x%lx, bufsz=0x%lx memsz=0x%lx\n",
                 image->elf_load_addr, kbuf->bufsz, kbuf->memsz);

        return 0;
}

/**
 * setup_purgatory_ppc64 - initialize PPC64 specific purgatory's global
 *                         variables and call setup_purgatory() to initialize
 *                         common global variable.
 * @image:                 kexec image.
 * @slave_code:            Slave code for the purgatory.
 * @fdt:                   Flattened device tree for the next kernel.
 * @kernel_load_addr:      Address where the kernel is loaded.
 * @fdt_load_addr:         Address where the flattened device tree is loaded.
 *
 * Returns 0 on success, negative errno on error.
 */
int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
                          const void *fdt, unsigned long kernel_load_addr,
                          unsigned long fdt_load_addr)
{
        struct device_node *dn = NULL;
        int ret;

        ret = setup_purgatory(image, slave_code, fdt, kernel_load_addr,
                              fdt_load_addr);
        if (ret)
                goto out;

        if (image->type == KEXEC_TYPE_CRASH) {
                u32 my_run_at_load = 1;

                /*
                 * Tell relocatable kernel to run at load address
                 * via the word meant for that at 0x5c.
                 */
                ret = kexec_purgatory_get_set_symbol(image, "run_at_load",
                                                     &my_run_at_load,
                                                     sizeof(my_run_at_load),
                                                     false);
                if (ret)
                        goto out;
        }

        /* Tell purgatory where to look for backup region */
        ret = kexec_purgatory_get_set_symbol(image, "backup_start",
                                             &image->arch.backup_start,
                                             sizeof(image->arch.backup_start),
                                             false);
        if (ret)
                goto out;

        /* Setup OPAL base & entry values */
        dn = of_find_node_by_path("/ibm,opal");
        if (dn) {
                u64 val;

                of_property_read_u64(dn, "opal-base-address", &val);
                ret = kexec_purgatory_get_set_symbol(image, "opal_base", &val,
                                                     sizeof(val), false);
                if (ret)
                        goto out;

                of_property_read_u64(dn, "opal-entry-address", &val);
                ret = kexec_purgatory_get_set_symbol(image, "opal_entry", &val,
                                                     sizeof(val), false);
        }
out:
        if (ret)
                pr_err("Failed to setup purgatory symbols");
        of_node_put(dn);
        return ret;
}

/**
 * kexec_extra_fdt_size_ppc64 - Return the estimated additional size needed to
 *                              setup FDT for kexec/kdump kernel.
 * @image:                      kexec image being loaded.
 *
 * Returns the estimated extra size needed for kexec/kdump kernel FDT.
 */
unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
{
        u64 usm_entries;

        if (image->type != KEXEC_TYPE_CRASH)
                return 0;

        /*
         * For kdump kernel, account for linux,usable-memory and
         * linux,drconf-usable-memory properties. Get an approximate on the
         * number of usable memory entries and use for FDT size estimation.
         */
        usm_entries = ((memblock_end_of_DRAM() / drmem_lmb_size()) +
                       (2 * (resource_size(&crashk_res) / drmem_lmb_size())));
        return (unsigned int)(usm_entries * sizeof(u64));
}

/**
 * add_node_props - Reads node properties from device node structure and add
 *                  them to fdt.
 * @fdt:            Flattened device tree of the kernel
 * @node_offset:    offset of the node to add a property at
 * @dn:             device node pointer
 *
 * Returns 0 on success, negative errno on error.
 */
static int add_node_props(void *fdt, int node_offset, const struct device_node *dn)
{
        int ret = 0;
        struct property *pp;

        if (!dn)
                return -EINVAL;

        for_each_property_of_node(dn, pp) {
                ret = fdt_setprop(fdt, node_offset, pp->name, pp->value, pp->length);
                if (ret < 0) {
                        pr_err("Unable to add %s property: %s\n", pp->name, fdt_strerror(ret));
                        return ret;
                }
        }
        return ret;
}

/**
 * update_cpus_node - Update cpus node of flattened device tree using of_root
 *                    device node.
 * @fdt:              Flattened device tree of the kernel.
 *
 * Returns 0 on success, negative errno on error.
 */
static int update_cpus_node(void *fdt)
{
        struct device_node *cpus_node, *dn;
        int cpus_offset, cpus_subnode_offset, ret = 0;

        cpus_offset = fdt_path_offset(fdt, "/cpus");
        if (cpus_offset < 0 && cpus_offset != -FDT_ERR_NOTFOUND) {
                pr_err("Malformed device tree: error reading /cpus node: %s\n",
                       fdt_strerror(cpus_offset));
                return cpus_offset;
        }

        if (cpus_offset > 0) {
                ret = fdt_del_node(fdt, cpus_offset);

                if (ret < 0) {
                        pr_err("Error deleting /cpus node: %s\n", fdt_strerror(ret));
                        return -EINVAL;
                }
        }

        /* Add cpus node to fdt */
        cpus_offset = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), "cpus");
        if (cpus_offset < 0) {
                pr_err("Error creating /cpus node: %s\n", fdt_strerror(cpus_offset));
                return -EINVAL;
        }

        /* Add cpus node properties */
        cpus_node = of_find_node_by_path("/cpus");
        ret = add_node_props(fdt, cpus_offset, cpus_node);
        of_node_put(cpus_node);
        if (ret < 0)
                return ret;

        /* Loop through all subnodes of cpus and add them to fdt */
        for_each_node_by_type(dn, "cpu") {
                cpus_subnode_offset = fdt_add_subnode(fdt, cpus_offset, dn->full_name);
                if (cpus_subnode_offset < 0) {
                        pr_err("Unable to add %s subnode: %s\n", dn->full_name,
                               fdt_strerror(cpus_subnode_offset));
                        ret = cpus_subnode_offset;
                        goto out;
                }

                ret = add_node_props(fdt, cpus_subnode_offset, dn);
                if (ret < 0)
                        goto out;
        }
out:
        of_node_put(dn);
        return ret;
}

/**
 * setup_new_fdt_ppc64 - Update the flattend device-tree of the kernel
 *                       being loaded.
 * @image:               kexec image being loaded.
 * @fdt:                 Flattened device tree for the next kernel.
 * @initrd_load_addr:    Address where the next initrd will be loaded.
 * @initrd_len:          Size of the next initrd, or 0 if there will be none.
 * @cmdline:             Command line for the next kernel, or NULL if there will
 *                       be none.
 *
 * Returns 0 on success, negative errno on error.
 */
int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
                        unsigned long initrd_load_addr,
                        unsigned long initrd_len, const char *cmdline)
{
        struct crash_mem *umem = NULL, *rmem = NULL;
        int i, nr_ranges, ret;

        /*
         * Restrict memory usage for kdump kernel by setting up
         * usable memory ranges and memory reserve map.
         */
        if (image->type == KEXEC_TYPE_CRASH) {
                ret = get_usable_memory_ranges(&umem);
                if (ret)
                        goto out;

                ret = update_usable_mem_fdt(fdt, umem);
                if (ret) {
                        pr_err("Error setting up usable-memory property for kdump kernel\n");
                        goto out;
                }

                /*
                 * Ensure we don't touch crashed kernel's memory except the
                 * first 64K of RAM, which will be backed up.
                 */
                ret = fdt_add_mem_rsv(fdt, BACKUP_SRC_END + 1,
                                      crashk_res.start - BACKUP_SRC_SIZE);
                if (ret) {
                        pr_err("Error reserving crash memory: %s\n",
                               fdt_strerror(ret));
                        goto out;
                }

                /* Ensure backup region is not used by kdump/capture kernel */
                ret = fdt_add_mem_rsv(fdt, image->arch.backup_start,
                                      BACKUP_SRC_SIZE);
                if (ret) {
                        pr_err("Error reserving memory for backup: %s\n",
                               fdt_strerror(ret));
                        goto out;
                }
        }

        /* Update cpus nodes information to account hotplug CPUs. */
        ret =  update_cpus_node(fdt);
        if (ret < 0)
                goto out;

        /* Update memory reserve map */
        ret = get_reserved_memory_ranges(&rmem);
        if (ret)
                goto out;

        nr_ranges = rmem ? rmem->nr_ranges : 0;
        for (i = 0; i < nr_ranges; i++) {
                u64 base, size;

                base = rmem->ranges[i].start;
                size = rmem->ranges[i].end - base + 1;
                ret = fdt_add_mem_rsv(fdt, base, size);
                if (ret) {
                        pr_err("Error updating memory reserve map: %s\n",
                               fdt_strerror(ret));
                        goto out;
                }
        }

out:
        kfree(rmem);
        kfree(umem);
        return ret;
}

/**
 * arch_kexec_locate_mem_hole - Skip special memory regions like rtas, opal,
 *                              tce-table, reserved-ranges & such (exclude
 *                              memory ranges) as they can't be used for kexec
 *                              segment buffer. Sets kbuf->mem when a suitable
 *                              memory hole is found.
 * @kbuf:                       Buffer contents and memory parameters.
 *
 * Assumes minimum of PAGE_SIZE alignment for kbuf->memsz & kbuf->buf_align.
 *
 * Returns 0 on success, negative errno on error.
 */
int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
{
        struct crash_mem **emem;
        u64 buf_min, buf_max;
        int ret;

        /* Look up the exclude ranges list while locating the memory hole */
        emem = &(kbuf->image->arch.exclude_ranges);
        if (!(*emem) || ((*emem)->nr_ranges == 0)) {
                pr_warn("No exclude range list. Using the default locate mem hole method\n");
                return kexec_locate_mem_hole(kbuf);
        }

        buf_min = kbuf->buf_min;
        buf_max = kbuf->buf_max;
        /* Segments for kdump kernel should be within crashkernel region */
        if (kbuf->image->type == KEXEC_TYPE_CRASH) {
                buf_min = (buf_min < crashk_res.start ?
                           crashk_res.start : buf_min);
                buf_max = (buf_max > crashk_res.end ?
                           crashk_res.end : buf_max);
        }

        if (buf_min > buf_max) {
                pr_err("Invalid buffer min and/or max values\n");
                return -EINVAL;
        }

        if (kbuf->top_down)
                ret = locate_mem_hole_top_down_ppc64(kbuf, buf_min, buf_max,
                                                     *emem);
        else
                ret = locate_mem_hole_bottom_up_ppc64(kbuf, buf_min, buf_max,
                                                      *emem);

        /* Add the buffer allocated to the exclude list for the next lookup */
        if (!ret) {
                add_mem_range(emem, kbuf->mem, kbuf->memsz);
                sort_memory_ranges(*emem, true);
        } else {
                pr_err("Failed to locate memory buffer of size %lu\n",
                       kbuf->memsz);
        }
        return ret;
}

/**
 * arch_kexec_kernel_image_probe - Does additional handling needed to setup
 *                                 kexec segments.
 * @image:                         kexec image being loaded.
 * @buf:                           Buffer pointing to elf data.
 * @buf_len:                       Length of the buffer.
 *
 * Returns 0 on success, negative errno on error.
 */
int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
                                  unsigned long buf_len)
{
        int ret;

        /* Get exclude memory ranges needed for setting up kexec segments */
        ret = get_exclude_memory_ranges(&(image->arch.exclude_ranges));
        if (ret) {
                pr_err("Failed to setup exclude memory ranges for buffer lookup\n");
                return ret;
        }

        return kexec_image_probe_default(image, buf, buf_len);
}

/**
 * arch_kimage_file_post_load_cleanup - Frees up all the allocations done
 *                                      while loading the image.
 * @image:                              kexec image being loaded.
 *
 * Returns 0 on success, negative errno on error.
 */
int arch_kimage_file_post_load_cleanup(struct kimage *image)
{
        kfree(image->arch.exclude_ranges);
        image->arch.exclude_ranges = NULL;

        vfree(image->arch.backup_buf);
        image->arch.backup_buf = NULL;

        vfree(image->elf_headers);
        image->elf_headers = NULL;
        image->elf_headers_sz = 0;

        kvfree(image->arch.fdt);
        image->arch.fdt = NULL;

        return kexec_image_post_load_cleanup_default(image);
}