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linux-sg2042/arch/powerpc/kernel/fadump.c

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// 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);
struct kobject *fadump_kobj;
#ifndef CONFIG_PRESERVE_FA_DUMP
static DEFINE_MUTEX(fadump_mutex);
struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0 };
struct fadump_mrange_info reserved_mrange_info = { "reserved", NULL, 0, 0, 0 };
#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_size);
return 1;
}
#else
static int __init fadump_cma_init(void) { return 1; }
#endif /* CONFIG_CMA */
/* Scan the Firmware Assisted dump configuration details. */
int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
int depth, void *data)
{
if (depth != 1)
return 0;
if (strcmp(uname, "rtas") == 0) {
rtas_fadump_dt_scan(&fw_dump, node);
return 1;
}
if (strcmp(uname, "ibm,opal") == 0) {
opal_fadump_dt_scan(&fw_dump, node);
return 1;
}
return 0;
}
/*
* If fadump is registered, check if the memory provided
* falls within boot memory area and reserved memory area.
*/
int is_fadump_memory_area(u64 addr, unsigned long size)
{
u64 d_start, d_end;
if (!fw_dump.dump_registered)
return 0;
if (!size)
return 0;
d_start = fw_dump.reserve_dump_area_start;
d_end = d_start + fw_dump.reserve_dump_area_size;
if (((addr + size) > d_start) && (addr <= d_end))
return 1;
return (addr <= fw_dump.boot_mem_top);
}
int should_fadump_crash(void)
{
if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
return 0;
return 1;
}
int is_fadump_active(void)
{
return fw_dump.dump_active;
}
/*
* Returns true, if there are no holes in memory area between d_start to d_end,
* false otherwise.
*/
static bool is_fadump_mem_area_contiguous(u64 d_start, u64 d_end)
{
struct memblock_region *reg;
bool ret = false;
u64 start, end;
for_each_memblock(memory, reg) {
start = max_t(u64, d_start, reg->base);
end = min_t(u64, d_end, (reg->base + reg->size));
if (d_start < end) {
/* Memory hole from d_start to start */
if (start > d_start)
break;
if (end == d_end) {
ret = true;
break;
}
d_start = end + 1;
}
}
return ret;
}
/*
* Returns true, if there are no holes in boot memory area,
* false otherwise.
*/
bool is_fadump_boot_mem_contiguous(void)
{
unsigned long d_start, d_end;
bool ret = false;
int i;
for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
d_start = fw_dump.boot_mem_addr[i];
d_end = d_start + fw_dump.boot_mem_sz[i];
ret = is_fadump_mem_area_contiguous(d_start, d_end);
if (!ret)
break;
}
return ret;
}
/*
* Returns true, if there are no holes in reserved memory area,
* false otherwise.
*/
bool is_fadump_reserved_mem_contiguous(void)
{
u64 d_start, d_end;
d_start = fw_dump.reserve_dump_area_start;
d_end = d_start + fw_dump.reserve_dump_area_size;
return is_fadump_mem_area_contiguous(d_start, d_end);
}
/* Print firmware assisted dump configurations for debugging purpose. */
static void fadump_show_config(void)
{
int i;
pr_debug("Support for firmware-assisted dump (fadump): %s\n",
(fw_dump.fadump_supported ? "present" : "no support"));
if (!fw_dump.fadump_supported)
return;
pr_debug("Fadump enabled : %s\n",
(fw_dump.fadump_enabled ? "yes" : "no"));
pr_debug("Dump Active : %s\n",
(fw_dump.dump_active ? "yes" : "no"));
pr_debug("Dump section sizes:\n");
pr_debug(" CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
pr_debug(" HPTE region size : %lx\n", fw_dump.hpte_region_size);
pr_debug(" Boot memory size : %lx\n", fw_dump.boot_memory_size);
pr_debug(" Boot memory top : %llx\n", fw_dump.boot_mem_top);
pr_debug("Boot memory regions cnt: %llx\n", fw_dump.boot_mem_regs_cnt);
for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
pr_debug("[%03d] base = %llx, size = %llx\n", i,
fw_dump.boot_mem_addr[i], fw_dump.boot_mem_sz[i]);
}
}
/**
* fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
*
* Function to find the largest memory size we need to reserve during early
* boot process. This will be the size of the memory that is required for a
* kernel to boot successfully.
*
* This function has been taken from phyp-assisted dump feature implementation.
*
* returns larger of 256MB or 5% rounded down to multiples of 256MB.
*
* TODO: Come up with better approach to find out more accurate memory size
* that is required for a kernel to boot successfully.
*
*/
static inline u64 fadump_calculate_reserve_size(void)
{
u64 base, size, bootmem_min;
int ret;
if (fw_dump.reserve_bootvar)
pr_warn("'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter.\n");
/*
* Check if the size is specified through crashkernel= cmdline
* option. If yes, then use that but ignore base as fadump reserves
* memory at a predefined offset.
*/
ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
&size, &base);
if (ret == 0 && size > 0) {
unsigned long max_size;
if (fw_dump.reserve_bootvar)
pr_info("Using 'crashkernel=' parameter for memory reservation.\n");
fw_dump.reserve_bootvar = (unsigned long)size;
/*
* Adjust if the boot memory size specified is above
* the upper limit.
*/
max_size = memblock_phys_mem_size() / MAX_BOOT_MEM_RATIO;
if (fw_dump.reserve_bootvar > max_size) {
fw_dump.reserve_bootvar = max_size;
pr_info("Adjusted boot memory size to %luMB\n",
(fw_dump.reserve_bootvar >> 20));
}
return fw_dump.reserve_bootvar;
} else if (fw_dump.reserve_bootvar) {
/*
* 'fadump_reserve_mem=' is being used to reserve memory
* for firmware-assisted dump.
*/
return fw_dump.reserve_bootvar;
}
/* divide by 20 to get 5% of value */
size = memblock_phys_mem_size() / 20;
/* round it down in multiples of 256 */
size = size & ~0x0FFFFFFFUL;
/* Truncate to memory_limit. We don't want to over reserve the memory.*/
if (memory_limit && size > memory_limit)
size = memory_limit;
bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
return (size > bootmem_min ? size : bootmem_min);
}
/*
* Calculate the total memory size required to be reserved for
* firmware-assisted dump registration.
*/
static unsigned long get_fadump_area_size(void)
{
unsigned long size = 0;
size += fw_dump.cpu_state_data_size;
size += fw_dump.hpte_region_size;
size += fw_dump.boot_memory_size;
size += sizeof(struct fadump_crash_info_header);
size += sizeof(struct elfhdr); /* ELF core header.*/
size += sizeof(struct elf_phdr); /* place holder for cpu notes */
/* Program headers for crash memory regions. */
size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
size = PAGE_ALIGN(size);
/* This is to hold kernel metadata on platforms that support it */
size += (fw_dump.ops->fadump_get_metadata_size ?
fw_dump.ops->fadump_get_metadata_size() : 0);
return size;
}
static int __init add_boot_mem_region(unsigned long rstart,
unsigned long rsize)
{
int i = fw_dump.boot_mem_regs_cnt++;
if (fw_dump.boot_mem_regs_cnt > FADUMP_MAX_MEM_REGS) {
fw_dump.boot_mem_regs_cnt = FADUMP_MAX_MEM_REGS;
return 0;
}
pr_debug("Added boot memory range[%d] [%#016lx-%#016lx)\n",
i, rstart, (rstart + rsize));
fw_dump.boot_mem_addr[i] = rstart;
fw_dump.boot_mem_sz[i] = rsize;
return 1;
}
/*
* Firmware usually has a hard limit on the data it can copy per region.
* Honour that by splitting a memory range into multiple regions.
*/
static int __init add_boot_mem_regions(unsigned long mstart,
unsigned long msize)
{
unsigned long rstart, rsize, max_size;
int ret = 1;
rstart = mstart;
max_size = fw_dump.max_copy_size ? fw_dump.max_copy_size : msize;
while (msize) {
if (msize > max_size)
rsize = max_size;
else
rsize = msize;
ret = add_boot_mem_region(rstart, rsize);
if (!ret)
break;
msize -= rsize;
rstart += rsize;
}
return ret;
}
static int __init fadump_get_boot_mem_regions(void)
{
unsigned long base, size, cur_size, hole_size, last_end;
unsigned long mem_size = fw_dump.boot_memory_size;
struct memblock_region *reg;
int ret = 1;
fw_dump.boot_mem_regs_cnt = 0;
last_end = 0;
hole_size = 0;
cur_size = 0;
for_each_memblock(memory, reg) {
base = reg->base;
size = reg->size;
hole_size += (base - last_end);
if ((cur_size + size) >= mem_size) {
size = (mem_size - cur_size);
ret = add_boot_mem_regions(base, size);
break;
}
mem_size -= size;
cur_size += size;
ret = add_boot_mem_regions(base, size);
if (!ret)
break;
last_end = base + size;
}
fw_dump.boot_mem_top = PAGE_ALIGN(fw_dump.boot_memory_size + hole_size);
return ret;
}
int __init fadump_reserve_mem(void)
{
u64 base, size, mem_boundary, bootmem_min, align = PAGE_SIZE;
bool is_memblock_bottom_up = memblock_bottom_up();
int ret = 1;
if (!fw_dump.fadump_enabled)
return 0;
if (!fw_dump.fadump_supported) {
pr_info("Firmware-Assisted Dump is not supported on this hardware\n");
goto error_out;
}
/*
* Initialize boot memory size
* If dump is active then we have already calculated the size during
* first kernel.
*/
if (!fw_dump.dump_active) {
fw_dump.boot_memory_size =
PAGE_ALIGN(fadump_calculate_reserve_size());
#ifdef CONFIG_CMA
if (!fw_dump.nocma) {
align = FADUMP_CMA_ALIGNMENT;
fw_dump.boot_memory_size =
ALIGN(fw_dump.boot_memory_size, align);
}
#endif
bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
if (fw_dump.boot_memory_size < bootmem_min) {
pr_err("Can't enable fadump with boot memory size (0x%lx) less than 0x%llx\n",
fw_dump.boot_memory_size, bootmem_min);
goto error_out;
}
if (!fadump_get_boot_mem_regions()) {
pr_err("Too many holes in boot memory area to enable fadump\n");
goto error_out;
}
}
/*
* Calculate the memory boundary.
* If memory_limit is less than actual memory boundary then reserve
* the memory for fadump beyond the memory_limit and adjust the
* memory_limit accordingly, so that the running kernel can run with
* specified memory_limit.
*/
if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
size = get_fadump_area_size();
if ((memory_limit + size) < memblock_end_of_DRAM())
memory_limit += size;
else
memory_limit = memblock_end_of_DRAM();
printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
" dump, now %#016llx\n", memory_limit);
}
if (memory_limit)
mem_boundary = memory_limit;
else
mem_boundary = memblock_end_of_DRAM();
base = fw_dump.boot_mem_top;
size = get_fadump_area_size();
fw_dump.reserve_dump_area_size = size;
if (fw_dump.dump_active) {
pr_info("Firmware-assisted dump is active.\n");
#ifdef CONFIG_HUGETLB_PAGE
/*
* FADump capture kernel doesn't care much about hugepages.
* In fact, handling hugepages in capture kernel is asking for
* trouble. So, disable HugeTLB support when fadump is active.
*/
hugetlb_disabled = true;
#endif
/*
* If last boot has crashed then reserve all the memory
* above boot memory size so that we don't touch it until
* dump is written to disk by userspace tool. This memory
* can be released for general use by invalidating fadump.
*/
fadump_reserve_crash_area(base);
pr_debug("fadumphdr_addr = %#016lx\n", fw_dump.fadumphdr_addr);
pr_debug("Reserve dump area start address: 0x%lx\n",
fw_dump.reserve_dump_area_start);
} else {
/*
* Reserve memory at an offset closer to bottom of the RAM to
* minimize the impact of memory hot-remove operation.
*/
memblock_set_bottom_up(true);
base = memblock_find_in_range(base, mem_boundary, size, align);
/* Restore the previous allocation mode */
memblock_set_bottom_up(is_memblock_bottom_up);
if (!base) {
pr_err("Failed to find memory chunk for reservation!\n");
goto error_out;
}
fw_dump.reserve_dump_area_start = base;
/*
* Calculate the kernel metadata address and register it with
* f/w if the platform supports.
*/
if (fw_dump.ops->fadump_setup_metadata &&
(fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
goto error_out;
if (memblock_reserve(base, size)) {
pr_err("Failed to reserve memory!\n");
goto error_out;
}
pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
(size >> 20), base, (memblock_phys_mem_size() >> 20));
ret = fadump_cma_init();
}
return ret;
error_out:
fw_dump.fadump_enabled = 0;
return 0;
}
/* Look for fadump= cmdline option. */
static int __init early_fadump_param(char *p)
{
if (!p)
return 1;
if (strncmp(p, "on", 2) == 0)
fw_dump.fadump_enabled = 1;
else if (strncmp(p, "off", 3) == 0)
fw_dump.fadump_enabled = 0;
else if (strncmp(p, "nocma", 5) == 0) {
fw_dump.fadump_enabled = 1;
fw_dump.nocma = 1;
}
return 0;
}
early_param("fadump", early_fadump_param);
/*
* Look for fadump_reserve_mem= cmdline option
* TODO: Remove references to 'fadump_reserve_mem=' parameter,
* the sooner 'crashkernel=' parameter is accustomed to.
*/
static int __init early_fadump_reserve_mem(char *p)
{
if (p)
fw_dump.reserve_bootvar = memparse(p, &p);
return 0;
}
early_param("fadump_reserve_mem", early_fadump_reserve_mem);
void crash_fadump(struct pt_regs *regs, const char *str)
{
struct fadump_crash_info_header *fdh = NULL;
int old_cpu, this_cpu;
if (!should_fadump_crash())
return;
/*
* old_cpu == -1 means this is the first CPU which has come here,
* go ahead and trigger fadump.
*
* old_cpu != -1 means some other CPU has already on it's way
* to trigger fadump, just keep looping here.
*/
this_cpu = smp_processor_id();
old_cpu = cmpxchg(&crashing_cpu, -1, this_cpu);
if (old_cpu != -1) {
/*
* We can't loop here indefinitely. Wait as long as fadump
* is in force. If we race with fadump un-registration this
* loop will break and then we go down to normal panic path
* and reboot. If fadump is in force the first crashing
* cpu will definitely trigger fadump.
*/
while (fw_dump.dump_registered)
cpu_relax();
return;
}
fdh = __va(fw_dump.fadumphdr_addr);
fdh->crashing_cpu = crashing_cpu;
crash_save_vmcoreinfo();
if (regs)
fdh->regs = *regs;
else
ppc_save_regs(&fdh->regs);
fdh->online_mask = *cpu_online_mask;
fw_dump.ops->fadump_trigger(fdh, str);
}
u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
{
struct elf_prstatus prstatus;
memset(&prstatus, 0, sizeof(prstatus));
/*
* FIXME: How do i get PID? Do I really need it?
* prstatus.pr_pid = ????
*/
elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
&prstatus, sizeof(prstatus));
return buf;
}
void fadump_update_elfcore_header(char *bufp)
{
struct elfhdr *elf;
struct elf_phdr *phdr;
elf = (struct elfhdr *)bufp;
bufp += sizeof(struct elfhdr);
/* First note is a place holder for cpu notes info. */
phdr = (struct elf_phdr *)bufp;
if (phdr->p_type == PT_NOTE) {
phdr->p_paddr = __pa(fw_dump.cpu_notes_buf_vaddr);
phdr->p_offset = phdr->p_paddr;
phdr->p_filesz = fw_dump.cpu_notes_buf_size;
phdr->p_memsz = fw_dump.cpu_notes_buf_size;
}
return;
}
static void *fadump_alloc_buffer(unsigned long size)
{
unsigned long count, i;
struct page *page;
void *vaddr;
vaddr = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
if (!vaddr)
return NULL;
count = PAGE_ALIGN(size) / PAGE_SIZE;
page = virt_to_page(vaddr);
for (i = 0; i < count; i++)
mark_page_reserved(page + i);
return vaddr;
}
static void fadump_free_buffer(unsigned long vaddr, unsigned long size)
{
free_reserved_area((void *)vaddr, (void *)(vaddr + size), -1, NULL);
}
s32 fadump_setup_cpu_notes_buf(u32 num_cpus)
{
/* Allocate buffer to hold cpu crash notes. */
fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
fw_dump.cpu_notes_buf_vaddr =
(unsigned long)fadump_alloc_buffer(fw_dump.cpu_notes_buf_size);
if (!fw_dump.cpu_notes_buf_vaddr) {
pr_err("Failed to allocate %ld bytes for CPU notes buffer\n",
fw_dump.cpu_notes_buf_size);
return -ENOMEM;
}
pr_debug("Allocated buffer for cpu notes of size %ld at 0x%lx\n",
fw_dump.cpu_notes_buf_size,
fw_dump.cpu_notes_buf_vaddr);
return 0;
}
void fadump_free_cpu_notes_buf(void)
{
if (!fw_dump.cpu_notes_buf_vaddr)
return;
fadump_free_buffer(fw_dump.cpu_notes_buf_vaddr,
fw_dump.cpu_notes_buf_size);
fw_dump.cpu_notes_buf_vaddr = 0;
fw_dump.cpu_notes_buf_size = 0;
}
static void fadump_free_mem_ranges(struct fadump_mrange_info *mrange_info)
{
kfree(mrange_info->mem_ranges);
mrange_info->mem_ranges = NULL;
mrange_info->mem_ranges_sz = 0;
mrange_info->max_mem_ranges = 0;
}
/*
* Allocate or reallocate mem_ranges array in incremental units
* of PAGE_SIZE.
*/
static int fadump_alloc_mem_ranges(struct fadump_mrange_info *mrange_info)
{
struct fadump_memory_range *new_array;
u64 new_size;
new_size = mrange_info->mem_ranges_sz + PAGE_SIZE;
pr_debug("Allocating %llu bytes of memory for %s memory ranges\n",
new_size, mrange_info->name);
new_array = krealloc(mrange_info->mem_ranges, new_size, GFP_KERNEL);
if (new_array == NULL) {
pr_err("Insufficient memory for setting up %s memory ranges\n",
mrange_info->name);
fadump_free_mem_ranges(mrange_info);
return -ENOMEM;
}
mrange_info->mem_ranges = new_array;
mrange_info->mem_ranges_sz = new_size;
mrange_info->max_mem_ranges = (new_size /
sizeof(struct fadump_memory_range));
return 0;
}
static inline int fadump_add_mem_range(struct fadump_mrange_info *mrange_info,
u64 base, u64 end)
{
struct fadump_memory_range *mem_ranges = mrange_info->mem_ranges;
bool is_adjacent = false;
u64 start, size;
if (base == end)
return 0;
/*
* Fold adjacent memory ranges to bring down the memory ranges/
* PT_LOAD segments count.
*/
if (mrange_info->mem_range_cnt) {
start = mem_ranges[mrange_info->mem_range_cnt - 1].base;
size = mem_ranges[mrange_info->mem_range_cnt - 1].size;
if ((start + size) == base)
is_adjacent = true;
}
if (!is_adjacent) {
/* resize the array on reaching the limit */
if (mrange_info->mem_range_cnt == mrange_info->max_mem_ranges) {
int ret;
ret = fadump_alloc_mem_ranges(mrange_info);
if (ret)
return ret;
/* Update to the new resized array */
mem_ranges = mrange_info->mem_ranges;
}
start = base;
mem_ranges[mrange_info->mem_range_cnt].base = start;
mrange_info->mem_range_cnt++;
}
mem_ranges[mrange_info->mem_range_cnt - 1].size = (end - start);
pr_debug("%s_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
mrange_info->name, (mrange_info->mem_range_cnt - 1),
start, end - 1, (end - start));
return 0;
}
static int fadump_exclude_reserved_area(u64 start, u64 end)
{
u64 ra_start, ra_end;
int ret = 0;
ra_start = fw_dump.reserve_dump_area_start;
ra_end = ra_start + fw_dump.reserve_dump_area_size;
if ((ra_start < end) && (ra_end > start)) {
if ((start < ra_start) && (end > ra_end)) {
ret = fadump_add_mem_range(&crash_mrange_info,
start, ra_start);
if (ret)
return ret;
ret = fadump_add_mem_range(&crash_mrange_info,
ra_end, end);
} else if (start < ra_start) {
ret = fadump_add_mem_range(&crash_mrange_info,
start, ra_start);
} else if (ra_end < end) {
ret = fadump_add_mem_range(&crash_mrange_info,
ra_end, end);
}
} else
ret = fadump_add_mem_range(&crash_mrange_info, start, end);
return ret;
}
static int fadump_init_elfcore_header(char *bufp)
{
struct elfhdr *elf;
elf = (struct elfhdr *) bufp;
bufp += sizeof(struct elfhdr);
memcpy(elf->e_ident, ELFMAG, SELFMAG);
elf->e_ident[EI_CLASS] = ELF_CLASS;
elf->e_ident[EI_DATA] = ELF_DATA;
elf->e_ident[EI_VERSION] = EV_CURRENT;
elf->e_ident[EI_OSABI] = ELF_OSABI;
memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
elf->e_type = ET_CORE;
elf->e_machine = ELF_ARCH;
elf->e_version = EV_CURRENT;
elf->e_entry = 0;
elf->e_phoff = sizeof(struct elfhdr);
elf->e_shoff = 0;
#if defined(_CALL_ELF)
elf->e_flags = _CALL_ELF;
#else
elf->e_flags = 0;
#endif
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
elf->e_phnum = 0;
elf->e_shentsize = 0;
elf->e_shnum = 0;
elf->e_shstrndx = 0;
return 0;
}
/*
* Traverse through memblock structure and setup crash memory ranges. These
* ranges will be used create PT_LOAD program headers in elfcore header.
*/
static int fadump_setup_crash_memory_ranges(void)
{
struct memblock_region *reg;
u64 start, end;
int i, ret;
pr_debug("Setup crash memory ranges.\n");
crash_mrange_info.mem_range_cnt = 0;
/*
* Boot memory region(s) registered with firmware are moved to
* different location at the time of crash. Create separate program
* header(s) for this memory chunk(s) with the correct offset.
*/
for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
start = fw_dump.boot_mem_addr[i];
end = start + fw_dump.boot_mem_sz[i];
ret = fadump_add_mem_range(&crash_mrange_info, start, end);
if (ret)
return ret;
}
for_each_memblock(memory, reg) {
start = (u64)reg->base;
end = start + (u64)reg->size;
/*
* skip the memory chunk that is already added
* (0 through boot_memory_top).
*/
if (start < fw_dump.boot_mem_top) {
if (end > fw_dump.boot_mem_top)
start = fw_dump.boot_mem_top;
else
continue;
}
/* add this range excluding the reserved dump area. */
ret = fadump_exclude_reserved_area(start, end);
if (ret)
return ret;
}
return 0;
}
/*
* If the given physical address falls within the boot memory region then
* return the relocated address that points to the dump region reserved
* for saving initial boot memory contents.
*/
static inline unsigned long fadump_relocate(unsigned long paddr)
{
unsigned long raddr, rstart, rend, rlast, hole_size;
int i;
hole_size = 0;
rlast = 0;
raddr = paddr;
for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
rstart = fw_dump.boot_mem_addr[i];
rend = rstart + fw_dump.boot_mem_sz[i];
hole_size += (rstart - rlast);
if (paddr >= rstart && paddr < rend) {
raddr += fw_dump.boot_mem_dest_addr - hole_size;
break;
}
rlast = rend;
}
pr_debug("vmcoreinfo: paddr = 0x%lx, raddr = 0x%lx\n", paddr, raddr);
return raddr;
}
static int fadump_create_elfcore_headers(char *bufp)
{
unsigned long long raddr, offset;
struct elf_phdr *phdr;
struct elfhdr *elf;
int i, j;
fadump_init_elfcore_header(bufp);
elf = (struct elfhdr *)bufp;
bufp += sizeof(struct elfhdr);
/*
* setup ELF PT_NOTE, place holder for cpu notes info. The notes info
* will be populated during second kernel boot after crash. Hence
* this PT_NOTE will always be the first elf note.
*
* NOTE: Any new ELF note addition should be placed after this note.
*/
phdr = (struct elf_phdr *)bufp;
bufp += sizeof(struct elf_phdr);
phdr->p_type = PT_NOTE;
phdr->p_flags = 0;
phdr->p_vaddr = 0;
phdr->p_align = 0;
phdr->p_offset = 0;
phdr->p_paddr = 0;
phdr->p_filesz = 0;
phdr->p_memsz = 0;
(elf->e_phnum)++;
/* setup ELF PT_NOTE for vmcoreinfo */
phdr = (struct elf_phdr *)bufp;
bufp += sizeof(struct elf_phdr);
phdr->p_type = PT_NOTE;
phdr->p_flags = 0;
phdr->p_vaddr = 0;
phdr->p_align = 0;
phdr->p_paddr = fadump_relocate(paddr_vmcoreinfo_note());
phdr->p_offset = phdr->p_paddr;
phdr->p_memsz = phdr->p_filesz = VMCOREINFO_NOTE_SIZE;
/* Increment number of program headers. */
(elf->e_phnum)++;
/* setup PT_LOAD sections. */
j = 0;
offset = 0;
raddr = fw_dump.boot_mem_addr[0];
for (i = 0; i < crash_mrange_info.mem_range_cnt; i++) {
u64 mbase, msize;
mbase = crash_mrange_info.mem_ranges[i].base;
msize = crash_mrange_info.mem_ranges[i].size;
if (!msize)
continue;
phdr = (struct elf_phdr *)bufp;
bufp += sizeof(struct elf_phdr);
phdr->p_type = PT_LOAD;
phdr->p_flags = PF_R|PF_W|PF_X;
phdr->p_offset = mbase;
if (mbase == raddr) {
/*
* The entire real memory region will be moved by
* firmware to the specified destination_address.
* Hence set the correct offset.
*/
phdr->p_offset = fw_dump.boot_mem_dest_addr + offset;
if (j < (fw_dump.boot_mem_regs_cnt - 1)) {
offset += fw_dump.boot_mem_sz[j];
raddr = fw_dump.boot_mem_addr[++j];
}
}
phdr->p_paddr = mbase;
phdr->p_vaddr = (unsigned long)__va(mbase);
phdr->p_filesz = msize;
phdr->p_memsz = msize;
phdr->p_align = 0;
/* Increment number of program headers. */
(elf->e_phnum)++;
}
return 0;
}
static unsigned long init_fadump_header(unsigned long addr)
{
struct fadump_crash_info_header *fdh;
if (!addr)
return 0;
fdh = __va(addr);
addr += sizeof(struct fadump_crash_info_header);
memset(fdh, 0, sizeof(struct fadump_crash_info_header));
fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
fdh->elfcorehdr_addr = addr;
/* We will set the crashing cpu id in crash_fadump() during crash. */
fdh->crashing_cpu = FADUMP_CPU_UNKNOWN;
return addr;
}
static int register_fadump(void)
{
unsigned long addr;
void *vaddr;
int ret;
/*
* If no memory is reserved then we can not register for firmware-
* assisted dump.
*/
if (!fw_dump.reserve_dump_area_size)
return -ENODEV;
ret = fadump_setup_crash_memory_ranges();
if (ret)
return ret;
addr = fw_dump.fadumphdr_addr;
/* Initialize fadump crash info header. */
addr = init_fadump_header(addr);
vaddr = __va(addr);
pr_debug("Creating ELF core headers at %#016lx\n", addr);
fadump_create_elfcore_headers(vaddr);
/* register the future kernel dump with firmware. */
pr_debug("Registering for firmware-assisted kernel dump...\n");
return fw_dump.ops->fadump_register(&fw_dump);
}
void fadump_cleanup(void)
{
if (!fw_dump.fadump_supported)
return;
/* Invalidate the registration only if dump is active. */
if (fw_dump.dump_active) {
pr_debug("Invalidating firmware-assisted dump registration\n");
fw_dump.ops->fadump_invalidate(&fw_dump);
} else if (fw_dump.dump_registered) {
/* Un-register Firmware-assisted dump if it was registered. */
fw_dump.ops->fadump_unregister(&fw_dump);
fadump_free_mem_ranges(&crash_mrange_info);
}
if (fw_dump.ops->fadump_cleanup)
fw_dump.ops->fadump_cleanup(&fw_dump);
}
static void fadump_free_reserved_memory(unsigned long start_pfn,
unsigned long end_pfn)
{
unsigned long pfn;
unsigned long time_limit = jiffies + HZ;
pr_info("freeing reserved memory (0x%llx - 0x%llx)\n",
PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
free_reserved_page(pfn_to_page(pfn));
if (time_after(jiffies, time_limit)) {
cond_resched();
time_limit = jiffies + HZ;
}
}
}
/*
* Skip memory holes and free memory that was actually reserved.
*/
static void fadump_release_reserved_area(u64 start, u64 end)
{
u64 tstart, tend, spfn, epfn;
struct memblock_region *reg;
spfn = PHYS_PFN(start);
epfn = PHYS_PFN(end);
for_each_memblock(memory, reg) {
tstart = max_t(u64, spfn, memblock_region_memory_base_pfn(reg));
tend = min_t(u64, epfn, memblock_region_memory_end_pfn(reg));
if (tstart < tend) {
fadump_free_reserved_memory(tstart, tend);
if (tend == epfn)
break;
spfn = tend;
}
}
}
/*
* Sort the mem ranges in-place and merge adjacent ranges
* to minimize the memory ranges count.
*/
static void sort_and_merge_mem_ranges(struct fadump_mrange_info *mrange_info)
{
struct fadump_memory_range *mem_ranges;
struct fadump_memory_range tmp_range;
u64 base, size;
int i, j, idx;
if (!reserved_mrange_info.mem_range_cnt)
return;
/* Sort the memory ranges */
mem_ranges = mrange_info->mem_ranges;
for (i = 0; i < mrange_info->mem_range_cnt; i++) {
idx = i;
for (j = (i + 1); j < mrange_info->mem_range_cnt; j++) {
if (mem_ranges[idx].base > mem_ranges[j].base)
idx = j;
}
if (idx != i) {
tmp_range = mem_ranges[idx];
mem_ranges[idx] = mem_ranges[i];
mem_ranges[i] = tmp_range;
}
}
/* Merge adjacent reserved ranges */
idx = 0;
for (i = 1; i < mrange_info->mem_range_cnt; i++) {
base = mem_ranges[i-1].base;
size = mem_ranges[i-1].size;
if (mem_ranges[i].base == (base + size))
mem_ranges[idx].size += mem_ranges[i].size;
else {
idx++;
if (i == idx)
continue;
mem_ranges[idx] = mem_ranges[i];
}
}
mrange_info->mem_range_cnt = idx + 1;
}
/*
* Scan reserved-ranges to consider them while reserving/releasing
* memory for FADump.
*/
static inline int fadump_scan_reserved_mem_ranges(void)
{
struct device_node *root;
const __be32 *prop;
int len, ret = -1;
unsigned long i;
root = of_find_node_by_path("/");
if (!root)
return ret;
prop = of_get_property(root, "reserved-ranges", &len);
if (!prop)
return ret;
/*
* Each reserved range is an (address,size) pair, 2 cells each,
* totalling 4 cells per range.
*/
for (i = 0; i < len / (sizeof(*prop) * 4); i++) {
u64 base, size;
base = of_read_number(prop + (i * 4) + 0, 2);
size = of_read_number(prop + (i * 4) + 2, 2);
if (size) {
ret = fadump_add_mem_range(&reserved_mrange_info,
base, base + size);
if (ret < 0) {
pr_warn("some reserved ranges are ignored!\n");
break;
}
}
}
return ret;
}
/*
* Release the memory that was reserved during early boot to preserve the
* crash'ed kernel's memory contents except reserved dump area (permanent
* reservation) and reserved ranges used by F/W. The released memory will
* be available for general use.
*/
static void fadump_release_memory(u64 begin, u64 end)
{
u64 ra_start, ra_end, tstart;
int i, ret;
fadump_scan_reserved_mem_ranges();
ra_start = fw_dump.reserve_dump_area_start;
ra_end = ra_start + fw_dump.reserve_dump_area_size;
/*
* Add reserved dump area to reserved ranges list
* and exclude all these ranges while releasing memory.
*/
ret = fadump_add_mem_range(&reserved_mrange_info, ra_start, ra_end);
if (ret != 0) {
/*
* Not enough memory to setup reserved ranges but the system is
* running shortage of memory. So, release all the memory except
* Reserved dump area (reused for next fadump registration).
*/
if (begin < ra_end && end > ra_start) {
if (begin < ra_start)
fadump_release_reserved_area(begin, ra_start);
if (end > ra_end)
fadump_release_reserved_area(ra_end, end);
} else
fadump_release_reserved_area(begin, end);
return;
}
/* Get the reserved ranges list in order first. */
sort_and_merge_mem_ranges(&reserved_mrange_info);
/* Exclude reserved ranges and release remaining memory */
tstart = begin;
for (i = 0; i < reserved_mrange_info.mem_range_cnt; i++) {
ra_start = reserved_mrange_info.mem_ranges[i].base;
ra_end = ra_start + reserved_mrange_info.mem_ranges[i].size;
if (tstart >= ra_end)
continue;
if (tstart < ra_start)
fadump_release_reserved_area(tstart, ra_start);
tstart = ra_end;
}
if (tstart < end)
fadump_release_reserved_area(tstart, end);
}
static void fadump_invalidate_release_mem(void)
{
mutex_lock(&fadump_mutex);
if (!fw_dump.dump_active) {
mutex_unlock(&fadump_mutex);
return;
}
fadump_cleanup();
mutex_unlock(&fadump_mutex);
fadump_release_memory(fw_dump.boot_mem_top, memblock_end_of_DRAM());
fadump_free_cpu_notes_buf();
/*
* Setup kernel metadata and initialize the kernel dump
* memory structure for FADump re-registration.
*/
if (fw_dump.ops->fadump_setup_metadata &&
(fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
pr_warn("Failed to setup kernel metadata!\n");
fw_dump.ops->fadump_init_mem_struct(&fw_dump);
}
static ssize_t release_mem_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int input = -1;
if (!fw_dump.dump_active)
return -EPERM;
if (kstrtoint(buf, 0, &input))
return -EINVAL;
if (input == 1) {
/*
* Take away the '/proc/vmcore'. We are releasing the dump
* memory, hence it will not be valid anymore.
*/
#ifdef CONFIG_PROC_VMCORE
vmcore_cleanup();
#endif
fadump_invalidate_release_mem();
} else
return -EINVAL;
return count;
}
/* Release the reserved memory and disable the FADump */
static void unregister_fadump(void)
{
fadump_cleanup();
fadump_release_memory(fw_dump.reserve_dump_area_start,
fw_dump.reserve_dump_area_size);
fw_dump.fadump_enabled = 0;
kobject_put(fadump_kobj);
}
static ssize_t enabled_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
}
static ssize_t mem_reserved_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
}
static ssize_t registered_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", fw_dump.dump_registered);
}
static ssize_t registered_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int ret = 0;
int input = -1;
if (!fw_dump.fadump_enabled || fw_dump.dump_active)
return -EPERM;
if (kstrtoint(buf, 0, &input))
return -EINVAL;
mutex_lock(&fadump_mutex);
switch (input) {
case 0:
if (fw_dump.dump_registered == 0) {
goto unlock_out;
}
/* Un-register Firmware-assisted dump */
pr_debug("Un-register firmware-assisted dump\n");
fw_dump.ops->fadump_unregister(&fw_dump);
break;
case 1:
if (fw_dump.dump_registered == 1) {
/* Un-register Firmware-assisted dump */
fw_dump.ops->fadump_unregister(&fw_dump);
}
/* Register Firmware-assisted dump */
ret = register_fadump();
break;
default:
ret = -EINVAL;
break;
}
unlock_out:
mutex_unlock(&fadump_mutex);
return ret < 0 ? ret : count;
}
static int fadump_region_show(struct seq_file *m, void *private)
{
if (!fw_dump.fadump_enabled)
return 0;
mutex_lock(&fadump_mutex);
fw_dump.ops->fadump_region_show(&fw_dump, m);
mutex_unlock(&fadump_mutex);
return 0;
}
static struct kobj_attribute release_attr = __ATTR_WO(release_mem);
static struct kobj_attribute enable_attr = __ATTR_RO(enabled);
static struct kobj_attribute register_attr = __ATTR_RW(registered);
static struct kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved);
static struct attribute *fadump_attrs[] = {
&enable_attr.attr,
&register_attr.attr,
&mem_reserved_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(fadump);
DEFINE_SHOW_ATTRIBUTE(fadump_region);
static void fadump_init_files(void)
{
int rc = 0;
fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
if (!fadump_kobj) {
pr_err("failed to create fadump kobject\n");
return;
}
debugfs_create_file("fadump_region", 0444, powerpc_debugfs_root, NULL,
&fadump_region_fops);
if (fw_dump.dump_active) {
rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
if (rc)
pr_err("unable to create release_mem sysfs file (%d)\n",
rc);
}
rc = sysfs_create_groups(fadump_kobj, fadump_groups);
if (rc) {
pr_err("sysfs group creation failed (%d), unregistering FADump",
rc);
unregister_fadump();
return;
}
/*
* The FADump sysfs are moved from kernel_kobj to fadump_kobj need to
* create symlink at old location to maintain backward compatibility.
*
* - fadump_enabled -> fadump/enabled
* - fadump_registered -> fadump/registered
* - fadump_release_mem -> fadump/release_mem
*/
rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
"enabled", "fadump_enabled");
if (rc) {
pr_err("unable to create fadump_enabled symlink (%d)", rc);
return;
}
rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
"registered",
"fadump_registered");
if (rc) {
pr_err("unable to create fadump_registered symlink (%d)", rc);
sysfs_remove_link(kernel_kobj, "fadump_enabled");
return;
}
if (fw_dump.dump_active) {
rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj,
fadump_kobj,
"release_mem",
"fadump_release_mem");
if (rc)
pr_err("unable to create fadump_release_mem symlink (%d)",
rc);
}
return;
}
/*
* Prepare for firmware-assisted dump.
*/
int __init setup_fadump(void)
{
if (!fw_dump.fadump_supported)
return 0;
fadump_init_files();
fadump_show_config();
if (!fw_dump.fadump_enabled)
return 1;
/*
* If dump data is available then see if it is valid and prepare for
* saving it to the disk.
*/
if (fw_dump.dump_active) {
/*
* if dump process fails then invalidate the registration
* and release memory before proceeding for re-registration.
*/
if (fw_dump.ops->fadump_process(&fw_dump) < 0)
fadump_invalidate_release_mem();
}
/* Initialize the kernel dump memory structure for FAD registration. */
else if (fw_dump.reserve_dump_area_size)
fw_dump.ops->fadump_init_mem_struct(&fw_dump);
return 1;
}
subsys_initcall(setup_fadump);
#else /* !CONFIG_PRESERVE_FA_DUMP */
/* Scan the Firmware Assisted dump configuration details. */
int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
int depth, void *data)
{
if ((depth != 1) || (strcmp(uname, "ibm,opal") != 0))
return 0;
opal_fadump_dt_scan(&fw_dump, node);
return 1;
}
/*
* When dump is active but PRESERVE_FA_DUMP is enabled on the kernel,
* preserve crash data. The subsequent memory preserving kernel boot
* is likely to process this crash data.
*/
int __init fadump_reserve_mem(void)
{
if (fw_dump.dump_active) {
/*
* If last boot has crashed then reserve all the memory
* above boot memory to preserve crash data.
*/
pr_info("Preserving crash data for processing in next boot.\n");
fadump_reserve_crash_area(fw_dump.boot_mem_top);
} else
pr_debug("FADump-aware kernel..\n");
return 1;
}
#endif /* CONFIG_PRESERVE_FA_DUMP */
/* Preserve everything above the base address */
static void __init fadump_reserve_crash_area(u64 base)
{
struct memblock_region *reg;
u64 mstart, msize;
for_each_memblock(memory, reg) {
mstart = reg->base;
msize = reg->size;
if ((mstart + msize) < base)
continue;
if (mstart < base) {
msize -= (base - mstart);
mstart = base;
}
pr_info("Reserving %lluMB of memory at %#016llx for preserving crash data",
(msize >> 20), mstart);
memblock_reserve(mstart, msize);
}
}
unsigned long __init arch_reserved_kernel_pages(void)
{
return memblock_reserved_size() / PAGE_SIZE;
}
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