// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Firmware Assisted dump: A robust mechanism to get reliable kernel crash
* dump with assistance from firmware. This approach does not use kexec,
* instead firmware assists in booting the kdump kernel while preserving
* memory contents. The most of the code implementation has been adapted
* from phyp assisted dump implementation written by Linas Vepstas and
* Manish Ahuja
*
* Copyright 2011 IBM Corporation
* Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
*/
#undef DEBUG
#define pr_fmt(fmt) "fadump: " fmt
#include <linux/string.h>
#include <linux/memblock.h>
#include <linux/delay.h>
#include <linux/seq_file.h>
#include <linux/crash_dump.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/cma.h>
#include <linux/hugetlb.h>
#include <asm/debugfs.h>
#include <asm/page.h>
#include <asm/prom.h>
#include <asm/fadump.h>
#include <asm/fadump-internal.h>
#include <asm/setup.h>
static struct fw_dump fw_dump;
static void __init fadump_reserve_crash_area(u64 base);
#ifndef CONFIG_PRESERVE_FA_DUMP
static DEFINE_MUTEX(fadump_mutex);
struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0, false };
#define RESERVED_RNGS_SZ 16384 /* 16K - 128 entries */
#define RESERVED_RNGS_CNT (RESERVED_RNGS_SZ / \
sizeof(struct fadump_memory_range))
static struct fadump_memory_range rngs[RESERVED_RNGS_CNT];
struct fadump_mrange_info reserved_mrange_info = { "reserved", rngs,
RESERVED_RNGS_SZ, 0,
RESERVED_RNGS_CNT, true };
static void __init early_init_dt_scan_reserved_ranges(unsigned long node);
#ifdef CONFIG_CMA
static struct cma *fadump_cma;
/*
* fadump_cma_init() - Initialize CMA area from a fadump reserved memory
*
* This function initializes CMA area from fadump reserved memory.
* The total size of fadump reserved memory covers for boot memory size
* + cpu data size + hpte size and metadata.
* Initialize only the area equivalent to boot memory size for CMA use.
* The reamining portion of fadump reserved memory will be not given
* to CMA and pages for thoes will stay reserved. boot memory size is
* aligned per CMA requirement to satisy cma_init_reserved_mem() call.
* But for some reason even if it fails we still have the memory reservation
* with us and we can still continue doing fadump.
*/
int __init fadump_cma_init(void)
{
unsigned long long base, size;
int rc;
if (!fw_dump.fadump_enabled)
return 0;
/*
* Do not use CMA if user has provided fadump=nocma kernel parameter.
* Return 1 to continue with fadump old behaviour.
*/
if (fw_dump.nocma)
return 1;
base = fw_dump.reserve_dump_area_start;
size = fw_dump.boot_memory_size;
if (!size)
return 0;
rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma);
if (rc) {
pr_err("Failed to init cma area for firmware-assisted dump,%d\n", rc);
/*
* Though the CMA init has failed we still have memory
* reservation with us. The reserved memory will be
* blocked from production system usage. Hence return 1,
* so that we can continue with fadump.
*/
return 1;
}
/*
* So we now have successfully initialized cma area for fadump.
*/
pr_info("Initialized 0x%lx bytes cma area at %ldMB from 0x%lx "
"bytes of memory reserved for firmware-assisted dump\n",
cma_get_size(fadump_cma),
(unsigned long)cma_get_base(fadump_cma) >> 20,
fw_dump.reserve_dump_area
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