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// 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 <asm/asm-offsets.h>
#include <asm/os_info.h>
#include <asm/elf.h>
#include <asm/ipl.h>
#include <asm/sclp.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;
u64 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 = (void *) memblock_phys_alloc(sizeof(*sa), 8);
if (!sa)
panic("Failed to allocate save area\n");
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++)
memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
/* Copy vector registers 16-31 */
memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
}
/*
* Return physical address for virtual address
*/
static inline void *load_real_addr(void *addr)
{
unsigned long real_addr;
asm volatile(
" lra %0,0(%1)\n"
" jz 0f\n"
" la %0,0\n"
"0:"
: "=a" (real_addr) : "a" (addr) : "cc");
return (void *)real_addr;
}
/*
* Copy memory of the old, dumped system to a kernel space virtual address
*/
int copy_oldmem_kernel(void *dst, void *src, size_t count)
{
unsigned long from, len;
void *ra;
int rc;
while (count) {
from = __pa(src);
if (!OLDMEM_BASE && from < sclp.hsa_size) {
/* Copy from zfcp/nvme dump HSA area */
len = min(count, sclp.hsa_size - from);
rc = memcpy_hsa_kernel(dst, from, len);
if (rc)
return rc;
} else {
/* Check for swapped kdump oldmem areas */
if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
from -= OLDMEM_BASE;
len = min(count, OLDMEM_SIZE - from);
} else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
len = min(count, OLDMEM_SIZE - from);
from += OLDMEM_BASE;
} else {
len = count;
}
if (is_vmalloc_or_module_addr(dst)) {
ra = load_real_addr(dst);
len = min(PAGE_SIZE - offset_in_page(ra), len);
} else {
ra = dst;
}
if (memcpy_real(ra, (void *) from, len))
return -EFAULT;
}
dst += len;
src += len;
count -= len;
}
return 0;
}
/*
* Copy memory of the old, dumped system to a user space virtual address
*/
static int copy_oldmem_user(void __user *dst, void *src, size_t count)
{
unsigned long from, len;
int rc;
while (count) {
from = __pa(src);
if (!OLDMEM_BASE && from < sclp.hsa_size) {
/* Copy from zfcp/nvme dump HSA area */
len = min(count, sclp.hsa_size - from);
rc = memcpy_hsa_user(dst, from, len);
if (rc)
return rc;
} else {
/* Check for swapped kdump oldmem areas */
if (OLDMEM_BASE && from - OLDMEM_BASE < OLDMEM_SIZE) {
from -= OLDMEM_BASE;
len = min(count, OLDMEM_SIZE - from);
} else if (OLDMEM_BASE && from < OLDMEM_SIZE) {
len = min(count, OLDMEM_SIZE - from);
from += OLDMEM_BASE;
} else {
len = count;
}
rc = copy_to_user_real(dst, (void *) from, count);
if (rc)
return rc;
}
dst += len;
src += len;
count -= len;
}
return 0;
}
/*
* Copy one page from "oldmem"
*/
ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
unsigned long offset, int userbuf)
{
void *src;
int rc;
if (!csize)
return 0;
src = (void *) (pfn << PAGE_SHIFT) + offset;
if (userbuf)
rc = copy_oldmem_user((void __force __user *) buf, src, csize);
else
rc = copy_oldmem_kernel((void *) buf, src, csize);
return rc;
}
/*
* 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_SIZE >> PAGE_SHIFT) {
size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
rc = remap_pfn_range(vma, from,
pfn + (OLDMEM_BASE >> 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_BASE)
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;
Elf64_Nhdr note;
void *addr;
if (copy_oldmem_kernel(&addr, &S390_lowcore.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;
int mem_chunk_cnt;
void *ptr, *hdr;
u32 alloc_size;
u64 hdr_off;
/* If we are not in kdump or zfcp/nvme dump mode return */
if (!OLDMEM_BASE && !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_BASE) {
oldmem_region.base = OLDMEM_BASE;
oldmem_region.size = OLDMEM_SIZE;
oldmem_type.total_size = OLDMEM_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;
}