OSCL-LXR linux-6.0.1/​arch/​powerpc/​kernel/​fadump.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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 <linux/debugfs.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 
 #include <asm/page.h>
 #include <asm/fadump.h>
 #include <asm/fadump-internal.h>
 #include <asm/setup.h>
 #include <asm/interrupt.h>
 
 /*
  * The CPU who acquired the lock to trigger the fadump crash should
  * wait for other CPUs to enter.
  *
  * The timeout is in milliseconds.
  */
 #define CRASH_TIMEOUT       500
 
 static struct fw_dump fw_dump;
 
 static void __init fadump_reserve_crash_area(u64 base);
 
 #ifndef CONFIG_PRESERVE_FA_DUMP
 
 static struct kobject *fadump_kobj;
 
 static atomic_t cpus_in_fadump;
 static DEFINE_MUTEX(fadump_mutex);
 
 static 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];
 static 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 remaining portion of fadump reserved memory will be not given
  * to CMA and pages for those 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.
  */
 static 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;
     }
 
     /*
      *  If CMA activation fails, keep the pages reserved, instead of
      *  exposing them to buddy allocator. Same as 'fadump=nocma' case.
      */
     cma_reserve_pages_on_error(fadump_cma);
 
     /*
      * 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 == 0) {
         early_init_dt_scan_reserved_ranges(node);
         return 0;
     }
 
     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)
 {
     phys_addr_t reg_start, reg_end;
     bool ret = false;
     u64 i, start, end;
 
     for_each_mem_range(i, &reg_start, &reg_end) {
         start = max_t(u64, d_start, reg_start);
         end = min_t(u64, d_end, reg_end);
         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 __init 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 __init 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 __init get_fadump_area_size(void)
 {
     unsigned long size = 0;
 
     size += fw_dump.cpu_state_data_size;
     size += fw_dump.hpte_region_size;
     /*
      * Account for pagesize alignment of boot memory area destination address.
      * This faciliates in mmap reading of first kernel's memory.
      */
     size = PAGE_ALIGN(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 size, cur_size, hole_size, last_end;
     unsigned long mem_size = fw_dump.boot_memory_size;
     phys_addr_t reg_start, reg_end;
     int ret = 1;
     u64 i;
 
     fw_dump.boot_mem_regs_cnt = 0;
 
     last_end = 0;
     hole_size = 0;
     cur_size = 0;
     for_each_mem_range(i, &reg_start, &reg_end) {
         size = reg_end - reg_start;
         hole_size += (reg_start - last_end);
 
         if ((cur_size + size) >= mem_size) {
             size = (mem_size - cur_size);
             ret = add_boot_mem_regions(reg_start, size);
             break;
         }
 
         mem_size -= size;
         cur_size += size;
         ret = add_boot_mem_regions(reg_start, size);
         if (!ret)
             break;
 
         last_end = reg_end;
     }
     fw_dump.boot_mem_top = PAGE_ALIGN(fw_dump.boot_memory_size + hole_size);
 
     return ret;
 }
 
 /*
  * Returns true, if the given range overlaps with reserved memory ranges
  * starting at idx. Also, updates idx to index of overlapping memory range
  * with the given memory range.
  * False, otherwise.
  */
 static bool __init overlaps_reserved_ranges(u64 base, u64 end, int *idx)
 {
     bool ret = false;
     int i;
 
     for (i = *idx; i < reserved_mrange_info.mem_range_cnt; i++) {
         u64 rbase = reserved_mrange_info.mem_ranges[i].base;
         u64 rend = rbase + reserved_mrange_info.mem_ranges[i].size;
 
         if (end <= rbase)
             break;
 
         if ((end > rbase) &&  (base < rend)) {
             *idx = i;
             ret = true;
             break;
         }
     }
 
     return ret;
 }
 
 /*
  * Locate a suitable memory area to reserve memory for FADump. While at it,
  * lookup reserved-ranges & avoid overlap with them, as they are used by F/W.
  */
 static u64 __init fadump_locate_reserve_mem(u64 base, u64 size)
 {
     struct fadump_memory_range *mrngs;
     phys_addr_t mstart, mend;
     int idx = 0;
     u64 i, ret = 0;
 
     mrngs = reserved_mrange_info.mem_ranges;
     for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
                 &mstart, &mend, NULL) {
         pr_debug("%llu) mstart: %llx, mend: %llx, base: %llx\n",
              i, mstart, mend, base);
 
         if (mstart > base)
             base = PAGE_ALIGN(mstart);
 
         while ((mend > base) && ((mend - base) >= size)) {
             if (!overlaps_reserved_ranges(base, base+size, &idx)) {
                 ret = base;
                 goto out;
             }
 
             base = mrngs[idx].base + mrngs[idx].size;
             base = PAGE_ALIGN(base);
         }
     }
 
 out:
     return ret;
 }
 
 int __init fadump_reserve_mem(void)
 {
     u64 base, size, mem_boundary, bootmem_min;
     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) {
             fw_dump.boot_memory_size =
                 ALIGN(fw_dump.boot_memory_size,
                       CMA_MIN_ALIGNMENT_BYTES);
         }
 #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.
          */
         base = fadump_locate_reserve_mem(base, size);
 
         if (!base || (base + size > mem_boundary)) {
             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)
 {
     unsigned int msecs;
     struct fadump_crash_info_header *fdh = NULL;
     int old_cpu, this_cpu;
     /* Do not include first CPU */
     unsigned int ncpus = num_online_cpus() - 1;
 
     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) {
         atomic_inc(&cpus_in_fadump);
 
         /*
          * 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->cpu_mask = *cpu_online_mask;
 
     /*
      * If we came in via system reset, wait a while for the secondary
      * CPUs to enter.
      */
     if (TRAP(&(fdh->regs)) == INTERRUPT_SYSTEM_RESET) {
         msecs = CRASH_TIMEOUT;
         while ((atomic_read(&cpus_in_fadump) < ncpus) && (--msecs > 0))
             mdelay(1);
     }
 
     fw_dump.ops->fadump_trigger(fdh, str);
 }
 
 u32 *__init 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_regs(&prstatus.pr_reg, regs);
     buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
                   &prstatus, sizeof(prstatus));
     return buf;
 }
 
 void __init fadump_update_elfcore_header(char *bufp)
 {
     struct elf_phdr *phdr;
 
     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 *__init 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 __init 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)
 {
     if (mrange_info->is_static) {
         mrange_info->mem_range_cnt = 0;
         return;
     }
 
     kfree(mrange_info->mem_ranges);
     memset((void *)((u64)mrange_info + RNG_NAME_SZ), 0,
            (sizeof(struct fadump_mrange_info) - RNG_NAME_SZ));
 }
 
 /*
  * 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;
 
         /*
          * Boot memory area needs separate PT_LOAD segment(s) as it
          * is moved to a different location at the time of crash.
          * So, fold only if the region is not boot memory area.
          */
         if ((start + size) == base && start >= fw_dump.boot_mem_top)
             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;
 
             if (mrange_info->is_static) {
                 pr_err("Reached array size limit for %s memory ranges\n",
                        mrange_info->name);
                 return -ENOSPC;
             }
 
             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 (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
         elf->e_flags = 2;
     else if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1))
         elf->e_flags = 1;
     else
         elf->e_flags = 0;
 
     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)
 {
     u64 i, start, end;
     int 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_mem_range(i, &start, &end) {
         /*
          * 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;
     /*
      * When LPAR is terminated by PYHP, ensure all possible CPUs'
      * register data is processed while exporting the vmcore.
      */
     fdh->cpu_mask = *cpu_possible_mask;
 
     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)
 {
     unsigned long reg_spfn, reg_epfn;
     u64 tstart, tend, spfn, epfn;
     int i;
 
     spfn = PHYS_PFN(start);
     epfn = PHYS_PFN(end);
 
     for_each_mem_pfn_range(i, MAX_NUMNODES, &reg_spfn, &reg_epfn, NULL) {
         tstart = max_t(u64, spfn, reg_spfn);
         tend   = min_t(u64, epfn, reg_epfn);
 
         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;
     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)
             swap(mem_ranges[idx], mem_ranges[i]);
     }
 
     /* 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 void __init early_init_dt_scan_reserved_ranges(unsigned long node)
 {
     const __be32 *prop;
     int len, ret = -1;
     unsigned long i;
 
     /* reserved-ranges already scanned */
     if (reserved_mrange_info.mem_range_cnt != 0)
         return;
 
     prop = of_get_flat_dt_prop(node, "reserved-ranges", &len);
     if (!prop)
         return;
 
     /*
      * 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;
             }
         }
     }
 
     /* Compact reserved ranges */
     sort_and_merge_mem_ranges(&reserved_mrange_info);
 }
 
 /*
  * 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;
 
     ra_start = fw_dump.reserve_dump_area_start;
     ra_end = ra_start + fw_dump.reserve_dump_area_size;
 
     /*
      * If reserved ranges array limit is hit, overwrite the last reserved
      * memory range with reserved dump area to ensure it is excluded from
      * the memory being released (reused for next FADump registration).
      */
     if (reserved_mrange_info.mem_range_cnt ==
         reserved_mrange_info.max_mem_ranges)
         reserved_mrange_info.mem_range_cnt--;
 
     ret = fadump_add_mem_range(&reserved_mrange_info, ra_start, ra_end);
     if (ret != 0)
         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 __init 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 __init 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, arch_debugfs_dir, 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 and register with f/w */
     else if (fw_dump.reserve_dump_area_size) {
         fw_dump.ops->fadump_init_mem_struct(&fw_dump);
         register_fadump();
     }
 
     /*
      * In case of panic, fadump is triggered via ppc_panic_event()
      * panic notifier. Setting crash_kexec_post_notifiers to 'true'
      * lets panic() function take crash friendly path before panic
      * notifiers are invoked.
      */
     crash_kexec_post_notifiers = true;
 
     return 1;
 }
 /*
  * Use subsys_initcall_sync() here because there is dependency with
  * crash_save_vmcoreinfo_init(), which must run first to ensure vmcoreinfo initialization
  * is done before registering with f/w.
  */
 subsys_initcall_sync(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)
 {
     u64 i, mstart, mend, msize;
 
     for_each_mem_range(i, &mstart, &mend) {
         msize  = mend - mstart;
 
         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;
 }

This page was automatically generated by the 2.1.0 LXR engine. The LXR team