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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/s390/kernel/crash_dump.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/s390/kernel/crash_dump.c')
-rw-r--r--arch/s390/kernel/crash_dump.c652
1 files changed, 652 insertions, 0 deletions
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
new file mode 100644
index 0000000000..7af69948b2
--- /dev/null
+++ b/arch/s390/kernel/crash_dump.c
@@ -0,0 +1,652 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * S390 kdump implementation
+ *
+ * Copyright IBM Corp. 2011
+ * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
+ */
+
+#include <linux/crash_dump.h>
+#include <asm/lowcore.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/memblock.h>
+#include <linux/elf.h>
+#include <linux/uio.h>
+#include <asm/asm-offsets.h>
+#include <asm/os_info.h>
+#include <asm/elf.h>
+#include <asm/ipl.h>
+#include <asm/sclp.h>
+#include <asm/maccess.h>
+
+#define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
+#define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
+#define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
+
+static struct memblock_region oldmem_region;
+
+static struct memblock_type oldmem_type = {
+ .cnt = 1,
+ .max = 1,
+ .total_size = 0,
+ .regions = &oldmem_region,
+ .name = "oldmem",
+};
+
+struct save_area {
+ struct list_head list;
+ u64 psw[2];
+ u64 ctrs[16];
+ u64 gprs[16];
+ u32 acrs[16];
+ u64 fprs[16];
+ u32 fpc;
+ u32 prefix;
+ u32 todpreg;
+ u64 timer;
+ u64 todcmp;
+ u64 vxrs_low[16];
+ __vector128 vxrs_high[16];
+};
+
+static LIST_HEAD(dump_save_areas);
+
+/*
+ * Allocate a save area
+ */
+struct save_area * __init save_area_alloc(bool is_boot_cpu)
+{
+ struct save_area *sa;
+
+ sa = memblock_alloc(sizeof(*sa), 8);
+ if (!sa)
+ return NULL;
+
+ if (is_boot_cpu)
+ list_add(&sa->list, &dump_save_areas);
+ else
+ list_add_tail(&sa->list, &dump_save_areas);
+ return sa;
+}
+
+/*
+ * Return the address of the save area for the boot CPU
+ */
+struct save_area * __init save_area_boot_cpu(void)
+{
+ return list_first_entry_or_null(&dump_save_areas, struct save_area, list);
+}
+
+/*
+ * Copy CPU registers into the save area
+ */
+void __init save_area_add_regs(struct save_area *sa, void *regs)
+{
+ struct lowcore *lc;
+
+ lc = (struct lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
+ memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
+ memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
+ memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
+ memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
+ memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
+ memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
+ memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
+ memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
+ memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
+ memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
+}
+
+/*
+ * Copy vector registers into the save area
+ */
+void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
+{
+ int i;
+
+ /* Copy lower halves of vector registers 0-15 */
+ for (i = 0; i < 16; i++)
+ sa->vxrs_low[i] = vxrs[i].low;
+ /* Copy vector registers 16-31 */
+ memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
+}
+
+static size_t copy_oldmem_iter(struct iov_iter *iter, unsigned long src, size_t count)
+{
+ size_t len, copied, res = 0;
+
+ while (count) {
+ if (!oldmem_data.start && src < sclp.hsa_size) {
+ /* Copy from zfcp/nvme dump HSA area */
+ len = min(count, sclp.hsa_size - src);
+ copied = memcpy_hsa_iter(iter, src, len);
+ } else {
+ /* Check for swapped kdump oldmem areas */
+ if (oldmem_data.start && src - oldmem_data.start < oldmem_data.size) {
+ src -= oldmem_data.start;
+ len = min(count, oldmem_data.size - src);
+ } else if (oldmem_data.start && src < oldmem_data.size) {
+ len = min(count, oldmem_data.size - src);
+ src += oldmem_data.start;
+ } else {
+ len = count;
+ }
+ copied = memcpy_real_iter(iter, src, len);
+ }
+ count -= copied;
+ src += copied;
+ res += copied;
+ if (copied < len)
+ break;
+ }
+ return res;
+}
+
+int copy_oldmem_kernel(void *dst, unsigned long src, size_t count)
+{
+ struct iov_iter iter;
+ struct kvec kvec;
+
+ kvec.iov_base = dst;
+ kvec.iov_len = count;
+ iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
+ if (copy_oldmem_iter(&iter, src, count) < count)
+ return -EFAULT;
+ return 0;
+}
+
+/*
+ * Copy one page from "oldmem"
+ */
+ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize,
+ unsigned long offset)
+{
+ unsigned long src;
+
+ src = pfn_to_phys(pfn) + offset;
+ return copy_oldmem_iter(iter, src, csize);
+}
+
+/*
+ * Remap "oldmem" for kdump
+ *
+ * For the kdump reserved memory this functions performs a swap operation:
+ * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
+ */
+static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
+ unsigned long from, unsigned long pfn,
+ unsigned long size, pgprot_t prot)
+{
+ unsigned long size_old;
+ int rc;
+
+ if (pfn < oldmem_data.size >> PAGE_SHIFT) {
+ size_old = min(size, oldmem_data.size - (pfn << PAGE_SHIFT));
+ rc = remap_pfn_range(vma, from,
+ pfn + (oldmem_data.start >> PAGE_SHIFT),
+ size_old, prot);
+ if (rc || size == size_old)
+ return rc;
+ size -= size_old;
+ from += size_old;
+ pfn += size_old >> PAGE_SHIFT;
+ }
+ return remap_pfn_range(vma, from, pfn, size, prot);
+}
+
+/*
+ * Remap "oldmem" for zfcp/nvme dump
+ *
+ * We only map available memory above HSA size. Memory below HSA size
+ * is read on demand using the copy_oldmem_page() function.
+ */
+static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
+ unsigned long from,
+ unsigned long pfn,
+ unsigned long size, pgprot_t prot)
+{
+ unsigned long hsa_end = sclp.hsa_size;
+ unsigned long size_hsa;
+
+ if (pfn < hsa_end >> PAGE_SHIFT) {
+ size_hsa = min(size, hsa_end - (pfn << PAGE_SHIFT));
+ if (size == size_hsa)
+ return 0;
+ size -= size_hsa;
+ from += size_hsa;
+ pfn += size_hsa >> PAGE_SHIFT;
+ }
+ return remap_pfn_range(vma, from, pfn, size, prot);
+}
+
+/*
+ * Remap "oldmem" for kdump or zfcp/nvme dump
+ */
+int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
+ unsigned long pfn, unsigned long size, pgprot_t prot)
+{
+ if (oldmem_data.start)
+ return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
+ else
+ return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
+ prot);
+}
+
+static const char *nt_name(Elf64_Word type)
+{
+ const char *name = "LINUX";
+
+ if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
+ name = KEXEC_CORE_NOTE_NAME;
+ return name;
+}
+
+/*
+ * Initialize ELF note
+ */
+static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
+ const char *name)
+{
+ Elf64_Nhdr *note;
+ u64 len;
+
+ note = (Elf64_Nhdr *)buf;
+ note->n_namesz = strlen(name) + 1;
+ note->n_descsz = d_len;
+ note->n_type = type;
+ len = sizeof(Elf64_Nhdr);
+
+ memcpy(buf + len, name, note->n_namesz);
+ len = roundup(len + note->n_namesz, 4);
+
+ memcpy(buf + len, desc, note->n_descsz);
+ len = roundup(len + note->n_descsz, 4);
+
+ return PTR_ADD(buf, len);
+}
+
+static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
+{
+ return nt_init_name(buf, type, desc, d_len, nt_name(type));
+}
+
+/*
+ * Calculate the size of ELF note
+ */
+static size_t nt_size_name(int d_len, const char *name)
+{
+ size_t size;
+
+ size = sizeof(Elf64_Nhdr);
+ size += roundup(strlen(name) + 1, 4);
+ size += roundup(d_len, 4);
+
+ return size;
+}
+
+static inline size_t nt_size(Elf64_Word type, int d_len)
+{
+ return nt_size_name(d_len, nt_name(type));
+}
+
+/*
+ * Fill ELF notes for one CPU with save area registers
+ */
+static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
+{
+ struct elf_prstatus nt_prstatus;
+ elf_fpregset_t nt_fpregset;
+
+ /* Prepare prstatus note */
+ memset(&nt_prstatus, 0, sizeof(nt_prstatus));
+ memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
+ memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
+ memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
+ nt_prstatus.common.pr_pid = cpu;
+ /* Prepare fpregset (floating point) note */
+ memset(&nt_fpregset, 0, sizeof(nt_fpregset));
+ memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
+ memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
+ /* Create ELF notes for the CPU */
+ ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
+ ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
+ ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
+ ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
+ ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
+ ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
+ ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
+ if (MACHINE_HAS_VX) {
+ ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
+ &sa->vxrs_high, sizeof(sa->vxrs_high));
+ ptr = nt_init(ptr, NT_S390_VXRS_LOW,
+ &sa->vxrs_low, sizeof(sa->vxrs_low));
+ }
+ return ptr;
+}
+
+/*
+ * Calculate size of ELF notes per cpu
+ */
+static size_t get_cpu_elf_notes_size(void)
+{
+ struct save_area *sa = NULL;
+ size_t size;
+
+ size = nt_size(NT_PRSTATUS, sizeof(struct elf_prstatus));
+ size += nt_size(NT_PRFPREG, sizeof(elf_fpregset_t));
+ size += nt_size(NT_S390_TIMER, sizeof(sa->timer));
+ size += nt_size(NT_S390_TODCMP, sizeof(sa->todcmp));
+ size += nt_size(NT_S390_TODPREG, sizeof(sa->todpreg));
+ size += nt_size(NT_S390_CTRS, sizeof(sa->ctrs));
+ size += nt_size(NT_S390_PREFIX, sizeof(sa->prefix));
+ if (MACHINE_HAS_VX) {
+ size += nt_size(NT_S390_VXRS_HIGH, sizeof(sa->vxrs_high));
+ size += nt_size(NT_S390_VXRS_LOW, sizeof(sa->vxrs_low));
+ }
+
+ return size;
+}
+
+/*
+ * Initialize prpsinfo note (new kernel)
+ */
+static void *nt_prpsinfo(void *ptr)
+{
+ struct elf_prpsinfo prpsinfo;
+
+ memset(&prpsinfo, 0, sizeof(prpsinfo));
+ prpsinfo.pr_sname = 'R';
+ strcpy(prpsinfo.pr_fname, "vmlinux");
+ return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
+}
+
+/*
+ * Get vmcoreinfo using lowcore->vmcore_info (new kernel)
+ */
+static void *get_vmcoreinfo_old(unsigned long *size)
+{
+ char nt_name[11], *vmcoreinfo;
+ unsigned long addr;
+ Elf64_Nhdr note;
+
+ if (copy_oldmem_kernel(&addr, __LC_VMCORE_INFO, sizeof(addr)))
+ return NULL;
+ memset(nt_name, 0, sizeof(nt_name));
+ if (copy_oldmem_kernel(&note, addr, sizeof(note)))
+ return NULL;
+ if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
+ sizeof(nt_name) - 1))
+ return NULL;
+ if (strcmp(nt_name, VMCOREINFO_NOTE_NAME) != 0)
+ return NULL;
+ vmcoreinfo = kzalloc(note.n_descsz, GFP_KERNEL);
+ if (!vmcoreinfo)
+ return NULL;
+ if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz)) {
+ kfree(vmcoreinfo);
+ return NULL;
+ }
+ *size = note.n_descsz;
+ return vmcoreinfo;
+}
+
+/*
+ * Initialize vmcoreinfo note (new kernel)
+ */
+static void *nt_vmcoreinfo(void *ptr)
+{
+ const char *name = VMCOREINFO_NOTE_NAME;
+ unsigned long size;
+ void *vmcoreinfo;
+
+ vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
+ if (vmcoreinfo)
+ return nt_init_name(ptr, 0, vmcoreinfo, size, name);
+
+ vmcoreinfo = get_vmcoreinfo_old(&size);
+ if (!vmcoreinfo)
+ return ptr;
+ ptr = nt_init_name(ptr, 0, vmcoreinfo, size, name);
+ kfree(vmcoreinfo);
+ return ptr;
+}
+
+static size_t nt_vmcoreinfo_size(void)
+{
+ const char *name = VMCOREINFO_NOTE_NAME;
+ unsigned long size;
+ void *vmcoreinfo;
+
+ vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
+ if (vmcoreinfo)
+ return nt_size_name(size, name);
+
+ vmcoreinfo = get_vmcoreinfo_old(&size);
+ if (!vmcoreinfo)
+ return 0;
+
+ kfree(vmcoreinfo);
+ return nt_size_name(size, name);
+}
+
+/*
+ * Initialize final note (needed for /proc/vmcore code)
+ */
+static void *nt_final(void *ptr)
+{
+ Elf64_Nhdr *note;
+
+ note = (Elf64_Nhdr *) ptr;
+ note->n_namesz = 0;
+ note->n_descsz = 0;
+ note->n_type = 0;
+ return PTR_ADD(ptr, sizeof(Elf64_Nhdr));
+}
+
+/*
+ * Initialize ELF header (new kernel)
+ */
+static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
+{
+ memset(ehdr, 0, sizeof(*ehdr));
+ memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
+ ehdr->e_ident[EI_CLASS] = ELFCLASS64;
+ ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
+ ehdr->e_ident[EI_VERSION] = EV_CURRENT;
+ memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
+ ehdr->e_type = ET_CORE;
+ ehdr->e_machine = EM_S390;
+ ehdr->e_version = EV_CURRENT;
+ ehdr->e_phoff = sizeof(Elf64_Ehdr);
+ ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+ ehdr->e_phentsize = sizeof(Elf64_Phdr);
+ ehdr->e_phnum = mem_chunk_cnt + 1;
+ return ehdr + 1;
+}
+
+/*
+ * Return CPU count for ELF header (new kernel)
+ */
+static int get_cpu_cnt(void)
+{
+ struct save_area *sa;
+ int cpus = 0;
+
+ list_for_each_entry(sa, &dump_save_areas, list)
+ if (sa->prefix != 0)
+ cpus++;
+ return cpus;
+}
+
+/*
+ * Return memory chunk count for ELF header (new kernel)
+ */
+static int get_mem_chunk_cnt(void)
+{
+ int cnt = 0;
+ u64 idx;
+
+ for_each_physmem_range(idx, &oldmem_type, NULL, NULL)
+ cnt++;
+ return cnt;
+}
+
+/*
+ * Initialize ELF loads (new kernel)
+ */
+static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
+{
+ phys_addr_t start, end;
+ u64 idx;
+
+ for_each_physmem_range(idx, &oldmem_type, &start, &end) {
+ phdr->p_filesz = end - start;
+ phdr->p_type = PT_LOAD;
+ phdr->p_offset = start;
+ phdr->p_vaddr = start;
+ phdr->p_paddr = start;
+ phdr->p_memsz = end - start;
+ phdr->p_flags = PF_R | PF_W | PF_X;
+ phdr->p_align = PAGE_SIZE;
+ phdr++;
+ }
+}
+
+/*
+ * Initialize notes (new kernel)
+ */
+static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
+{
+ struct save_area *sa;
+ void *ptr_start = ptr;
+ int cpu;
+
+ ptr = nt_prpsinfo(ptr);
+
+ cpu = 1;
+ list_for_each_entry(sa, &dump_save_areas, list)
+ if (sa->prefix != 0)
+ ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
+ ptr = nt_vmcoreinfo(ptr);
+ ptr = nt_final(ptr);
+ memset(phdr, 0, sizeof(*phdr));
+ phdr->p_type = PT_NOTE;
+ phdr->p_offset = notes_offset;
+ phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
+ phdr->p_memsz = phdr->p_filesz;
+ return ptr;
+}
+
+static size_t get_elfcorehdr_size(int mem_chunk_cnt)
+{
+ size_t size;
+
+ size = sizeof(Elf64_Ehdr);
+ /* PT_NOTES */
+ size += sizeof(Elf64_Phdr);
+ /* nt_prpsinfo */
+ size += nt_size(NT_PRPSINFO, sizeof(struct elf_prpsinfo));
+ /* regsets */
+ size += get_cpu_cnt() * get_cpu_elf_notes_size();
+ /* nt_vmcoreinfo */
+ size += nt_vmcoreinfo_size();
+ /* nt_final */
+ size += sizeof(Elf64_Nhdr);
+ /* PT_LOADS */
+ size += mem_chunk_cnt * sizeof(Elf64_Phdr);
+
+ return size;
+}
+
+/*
+ * Create ELF core header (new kernel)
+ */
+int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
+{
+ Elf64_Phdr *phdr_notes, *phdr_loads;
+ size_t alloc_size;
+ int mem_chunk_cnt;
+ void *ptr, *hdr;
+ u64 hdr_off;
+
+ /* If we are not in kdump or zfcp/nvme dump mode return */
+ if (!oldmem_data.start && !is_ipl_type_dump())
+ return 0;
+ /* If we cannot get HSA size for zfcp/nvme dump return error */
+ if (is_ipl_type_dump() && !sclp.hsa_size)
+ return -ENODEV;
+
+ /* For kdump, exclude previous crashkernel memory */
+ if (oldmem_data.start) {
+ oldmem_region.base = oldmem_data.start;
+ oldmem_region.size = oldmem_data.size;
+ oldmem_type.total_size = oldmem_data.size;
+ }
+
+ mem_chunk_cnt = get_mem_chunk_cnt();
+
+ alloc_size = get_elfcorehdr_size(mem_chunk_cnt);
+
+ hdr = kzalloc(alloc_size, GFP_KERNEL);
+
+ /* Without elfcorehdr /proc/vmcore cannot be created. Thus creating
+ * a dump with this crash kernel will fail. Panic now to allow other
+ * dump mechanisms to take over.
+ */
+ if (!hdr)
+ panic("s390 kdump allocating elfcorehdr failed");
+
+ /* Init elf header */
+ ptr = ehdr_init(hdr, mem_chunk_cnt);
+ /* Init program headers */
+ phdr_notes = ptr;
+ ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
+ phdr_loads = ptr;
+ ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
+ /* Init notes */
+ hdr_off = PTR_DIFF(ptr, hdr);
+ ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
+ /* Init loads */
+ hdr_off = PTR_DIFF(ptr, hdr);
+ loads_init(phdr_loads, hdr_off);
+ *addr = (unsigned long long) hdr;
+ *size = (unsigned long long) hdr_off;
+ BUG_ON(elfcorehdr_size > alloc_size);
+ return 0;
+}
+
+/*
+ * Free ELF core header (new kernel)
+ */
+void elfcorehdr_free(unsigned long long addr)
+{
+ kfree((void *)(unsigned long)addr);
+}
+
+/*
+ * Read from ELF header
+ */
+ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
+{
+ void *src = (void *)(unsigned long)*ppos;
+
+ memcpy(buf, src, count);
+ *ppos += count;
+ return count;
+}
+
+/*
+ * Read from ELF notes data
+ */
+ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
+{
+ void *src = (void *)(unsigned long)*ppos;
+
+ memcpy(buf, src, count);
+ *ppos += count;
+ return count;
+}