linux/arch/s390/kernel/crash_dump.c

427 lines
10 KiB
C

/*
* 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/module.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/crash_dump.h>
#include <linux/bootmem.h>
#include <linux/elf.h>
#include <asm/ipl.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))))
/*
* Copy one page from "oldmem"
*
* For the kdump reserved memory this functions performs a swap operation:
* - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE].
* - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
*/
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
size_t csize, unsigned long offset, int userbuf)
{
unsigned long src;
if (!csize)
return 0;
src = (pfn << PAGE_SHIFT) + offset;
if (src < OLDMEM_SIZE)
src += OLDMEM_BASE;
else if (src > OLDMEM_BASE &&
src < OLDMEM_BASE + OLDMEM_SIZE)
src -= OLDMEM_BASE;
if (userbuf)
copy_to_user_real((void __force __user *) buf, (void *) src,
csize);
else
memcpy_real(buf, (void *) src, csize);
return csize;
}
/*
* Copy memory from old kernel
*/
static int copy_from_oldmem(void *dest, void *src, size_t count)
{
unsigned long copied = 0;
int rc;
if ((unsigned long) src < OLDMEM_SIZE) {
copied = min(count, OLDMEM_SIZE - (unsigned long) src);
rc = memcpy_real(dest, src + OLDMEM_BASE, copied);
if (rc)
return rc;
}
return memcpy_real(dest + copied, src + copied, count - copied);
}
/*
* Alloc memory and panic in case of ENOMEM
*/
static void *kzalloc_panic(int len)
{
void *rc;
rc = kzalloc(len, GFP_KERNEL);
if (!rc)
panic("s390 kdump kzalloc (%d) failed", len);
return rc;
}
/*
* Get memory layout and create hole for oldmem
*/
static struct mem_chunk *get_memory_layout(void)
{
struct mem_chunk *chunk_array;
chunk_array = kzalloc_panic(MEMORY_CHUNKS * sizeof(struct mem_chunk));
detect_memory_layout(chunk_array);
create_mem_hole(chunk_array, OLDMEM_BASE, OLDMEM_SIZE, CHUNK_CRASHK);
return chunk_array;
}
/*
* Initialize ELF note
*/
static void *nt_init(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);
}
/*
* Initialize prstatus note
*/
static void *nt_prstatus(void *ptr, struct save_area *sa)
{
struct elf_prstatus nt_prstatus;
static int cpu_nr = 1;
memset(&nt_prstatus, 0, sizeof(nt_prstatus));
memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs));
memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs));
nt_prstatus.pr_pid = cpu_nr;
cpu_nr++;
return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus),
"CORE");
}
/*
* Initialize fpregset (floating point) note
*/
static void *nt_fpregset(void *ptr, struct save_area *sa)
{
elf_fpregset_t nt_fpregset;
memset(&nt_fpregset, 0, sizeof(nt_fpregset));
memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg));
memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs));
return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset),
"CORE");
}
/*
* Initialize timer note
*/
static void *nt_s390_timer(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer),
KEXEC_CORE_NOTE_NAME);
}
/*
* Initialize TOD clock comparator note
*/
static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp,
sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME);
}
/*
* Initialize TOD programmable register note
*/
static void *nt_s390_tod_preg(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg,
sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME);
}
/*
* Initialize control register note
*/
static void *nt_s390_ctrs(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs,
sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME);
}
/*
* Initialize prefix register note
*/
static void *nt_s390_prefix(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg,
sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME);
}
/*
* Fill ELF notes for one CPU with save area registers
*/
void *fill_cpu_elf_notes(void *ptr, struct save_area *sa)
{
ptr = nt_prstatus(ptr, sa);
ptr = nt_fpregset(ptr, sa);
ptr = nt_s390_timer(ptr, sa);
ptr = nt_s390_tod_cmp(ptr, sa);
ptr = nt_s390_tod_preg(ptr, sa);
ptr = nt_s390_ctrs(ptr, sa);
ptr = nt_s390_prefix(ptr, sa);
return ptr;
}
/*
* 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),
KEXEC_CORE_NOTE_NAME);
}
/*
* Initialize vmcoreinfo note (new kernel)
*/
static void *nt_vmcoreinfo(void *ptr)
{
char nt_name[11], *vmcoreinfo;
Elf64_Nhdr note;
void *addr;
if (copy_from_oldmem(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
return ptr;
memset(nt_name, 0, sizeof(nt_name));
if (copy_from_oldmem(&note, addr, sizeof(note)))
return ptr;
if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1))
return ptr;
if (strcmp(nt_name, "VMCOREINFO") != 0)
return ptr;
vmcoreinfo = kzalloc_panic(note.n_descsz + 1);
if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz))
return ptr;
vmcoreinfo[note.n_descsz + 1] = 0;
return nt_init(ptr, 0, vmcoreinfo, note.n_descsz, "VMCOREINFO");
}
/*
* 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)
{
int i, cpus = 0;
for (i = 0; zfcpdump_save_areas[i]; i++) {
if (zfcpdump_save_areas[i]->pref_reg == 0)
continue;
cpus++;
}
return cpus;
}
/*
* Return memory chunk count for ELF header (new kernel)
*/
static int get_mem_chunk_cnt(void)
{
struct mem_chunk *chunk_array, *mem_chunk;
int i, cnt = 0;
chunk_array = get_memory_layout();
for (i = 0; i < MEMORY_CHUNKS; i++) {
mem_chunk = &chunk_array[i];
if (chunk_array[i].type != CHUNK_READ_WRITE &&
chunk_array[i].type != CHUNK_READ_ONLY)
continue;
if (mem_chunk->size == 0)
continue;
cnt++;
}
kfree(chunk_array);
return cnt;
}
/*
* Relocate pointer in order to allow vmcore code access the data
*/
static inline unsigned long relocate(unsigned long addr)
{
return OLDMEM_BASE + addr;
}
/*
* Initialize ELF loads (new kernel)
*/
static int loads_init(Elf64_Phdr *phdr, u64 loads_offset)
{
struct mem_chunk *chunk_array, *mem_chunk;
int i;
chunk_array = get_memory_layout();
for (i = 0; i < MEMORY_CHUNKS; i++) {
mem_chunk = &chunk_array[i];
if (mem_chunk->size == 0)
break;
if (chunk_array[i].type != CHUNK_READ_WRITE &&
chunk_array[i].type != CHUNK_READ_ONLY)
continue;
else
phdr->p_filesz = mem_chunk->size;
phdr->p_type = PT_LOAD;
phdr->p_offset = mem_chunk->addr;
phdr->p_vaddr = mem_chunk->addr;
phdr->p_paddr = mem_chunk->addr;
phdr->p_memsz = mem_chunk->size;
phdr->p_flags = PF_R | PF_W | PF_X;
phdr->p_align = PAGE_SIZE;
phdr++;
}
kfree(chunk_array);
return i;
}
/*
* 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 i;
ptr = nt_prpsinfo(ptr);
for (i = 0; zfcpdump_save_areas[i]; i++) {
sa = zfcpdump_save_areas[i];
if (sa->pref_reg == 0)
continue;
ptr = fill_cpu_elf_notes(ptr, sa);
}
ptr = nt_vmcoreinfo(ptr);
memset(phdr, 0, sizeof(*phdr));
phdr->p_type = PT_NOTE;
phdr->p_offset = relocate(notes_offset);
phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
phdr->p_memsz = phdr->p_filesz;
return ptr;
}
/*
* Create ELF core header (new kernel)
*/
static void s390_elf_corehdr_create(char **elfcorebuf, size_t *elfcorebuf_sz)
{
Elf64_Phdr *phdr_notes, *phdr_loads;
int mem_chunk_cnt;
void *ptr, *hdr;
u32 alloc_size;
u64 hdr_off;
mem_chunk_cnt = get_mem_chunk_cnt();
alloc_size = 0x1000 + get_cpu_cnt() * 0x300 +
mem_chunk_cnt * sizeof(Elf64_Phdr);
hdr = kzalloc_panic(alloc_size);
/* 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, ((unsigned long) hdr) + hdr_off);
*elfcorebuf_sz = hdr_off;
*elfcorebuf = (void *) relocate((unsigned long) hdr);
BUG_ON(*elfcorebuf_sz > alloc_size);
}
/*
* Create kdump ELF core header in new kernel, if it has not been passed via
* the "elfcorehdr" kernel parameter
*/
static int setup_kdump_elfcorehdr(void)
{
size_t elfcorebuf_sz;
char *elfcorebuf;
if (!OLDMEM_BASE || is_kdump_kernel())
return -EINVAL;
s390_elf_corehdr_create(&elfcorebuf, &elfcorebuf_sz);
elfcorehdr_addr = (unsigned long long) elfcorebuf;
elfcorehdr_size = elfcorebuf_sz;
return 0;
}
subsys_initcall(setup_kdump_elfcorehdr);