path: root/arch/powerpc/kexec/file_load_64.c

// 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.h>
#include <linux/of_address.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/setup.h>
#include <asm/drmem.h>
#include <asm/firmware.h>
#include <asm/kexec_ranges.h>
#include <asm/crashdump-ppc64.h>
#include <asm/mmzone.h>
#include <asm/iommu.h>
#include <asm/prom.h>
#include <asm/plpks.h>
#include <asm/cputhreads.h>

struct umem_info {
	__be64 *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 range *ranges;
};

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

/**
 * __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 */