linux/drivers/s390/char/zcore.c
Heiko Carstens df1bd59c5c s390/mem_detect: limit memory detection loop to "mem=" parameter
The current memory detection loop will detect all present memory of
a machine. This is true even if the user specified the "mem=" parameter
on the kernel command line.
This can be a problem since the memory detection may cause a fully
populated host page table for the guest, even for those parts of the
memory that the guest will never use afterwards.

So fix this and only detect memory up to a user supplied "mem=" limit
if specified.

Reported-by: Michael Johanssen <johanssn@de.ibm.com>
Reviewed-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-05-02 15:50:26 +02:00

805 lines
18 KiB
C

/*
* zcore module to export memory content and register sets for creating system
* dumps on SCSI disks (zfcpdump). The "zcore/mem" debugfs file shows the same
* dump format as s390 standalone dumps.
*
* For more information please refer to Documentation/s390/zfcpdump.txt
*
* Copyright IBM Corp. 2003, 2008
* Author(s): Michael Holzheu
*/
#define KMSG_COMPONENT "zdump"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/miscdevice.h>
#include <linux/debugfs.h>
#include <linux/module.h>
#include <asm/asm-offsets.h>
#include <asm/ipl.h>
#include <asm/sclp.h>
#include <asm/setup.h>
#include <asm/uaccess.h>
#include <asm/debug.h>
#include <asm/processor.h>
#include <asm/irqflags.h>
#include <asm/checksum.h>
#include "sclp.h"
#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
#define TO_USER 0
#define TO_KERNEL 1
#define CHUNK_INFO_SIZE 34 /* 2 16-byte char, each followed by blank */
enum arch_id {
ARCH_S390 = 0,
ARCH_S390X = 1,
};
/* dump system info */
struct sys_info {
enum arch_id arch;
unsigned long sa_base;
u32 sa_size;
int cpu_map[NR_CPUS];
unsigned long mem_size;
struct save_area lc_mask;
};
struct ipib_info {
unsigned long ipib;
u32 checksum;
} __attribute__((packed));
static struct sys_info sys_info;
static struct debug_info *zcore_dbf;
static int hsa_available;
static struct dentry *zcore_dir;
static struct dentry *zcore_file;
static struct dentry *zcore_memmap_file;
static struct dentry *zcore_reipl_file;
static struct dentry *zcore_hsa_file;
static struct ipl_parameter_block *ipl_block;
/*
* Copy memory from HSA to kernel or user memory (not reentrant):
*
* @dest: Kernel or user buffer where memory should be copied to
* @src: Start address within HSA where data should be copied
* @count: Size of buffer, which should be copied
* @mode: Either TO_KERNEL or TO_USER
*/
static int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
{
int offs, blk_num;
static char buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
if (!hsa_available)
return -ENODATA;
if (count == 0)
return 0;
/* copy first block */
offs = 0;
if ((src % PAGE_SIZE) != 0) {
blk_num = src / PAGE_SIZE + 2;
if (sclp_sdias_copy(buf, blk_num, 1)) {
TRACE("sclp_sdias_copy() failed\n");
return -EIO;
}
offs = min((PAGE_SIZE - (src % PAGE_SIZE)), count);
if (mode == TO_USER) {
if (copy_to_user((__force __user void*) dest,
buf + (src % PAGE_SIZE), offs))
return -EFAULT;
} else
memcpy(dest, buf + (src % PAGE_SIZE), offs);
}
if (offs == count)
goto out;
/* copy middle */
for (; (offs + PAGE_SIZE) <= count; offs += PAGE_SIZE) {
blk_num = (src + offs) / PAGE_SIZE + 2;
if (sclp_sdias_copy(buf, blk_num, 1)) {
TRACE("sclp_sdias_copy() failed\n");
return -EIO;
}
if (mode == TO_USER) {
if (copy_to_user((__force __user void*) dest + offs,
buf, PAGE_SIZE))
return -EFAULT;
} else
memcpy(dest + offs, buf, PAGE_SIZE);
}
if (offs == count)
goto out;
/* copy last block */
blk_num = (src + offs) / PAGE_SIZE + 2;
if (sclp_sdias_copy(buf, blk_num, 1)) {
TRACE("sclp_sdias_copy() failed\n");
return -EIO;
}
if (mode == TO_USER) {
if (copy_to_user((__force __user void*) dest + offs, buf,
count - offs))
return -EFAULT;
} else
memcpy(dest + offs, buf, count - offs);
out:
return 0;
}
static int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
{
return memcpy_hsa((void __force *) dest, src, count, TO_USER);
}
static int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
{
return memcpy_hsa(dest, src, count, TO_KERNEL);
}
static int __init init_cpu_info(enum arch_id arch)
{
struct save_area *sa;
/* get info for boot cpu from lowcore, stored in the HSA */
sa = kmalloc(sizeof(*sa), GFP_KERNEL);
if (!sa)
return -ENOMEM;
if (memcpy_hsa_kernel(sa, sys_info.sa_base, sys_info.sa_size) < 0) {
TRACE("could not copy from HSA\n");
kfree(sa);
return -EIO;
}
zfcpdump_save_areas[0] = sa;
return 0;
}
static DEFINE_MUTEX(zcore_mutex);
#define DUMP_VERSION 0x5
#define DUMP_MAGIC 0xa8190173618f23fdULL
#define DUMP_ARCH_S390X 2
#define DUMP_ARCH_S390 1
#define HEADER_SIZE 4096
/* dump header dumped according to s390 crash dump format */
struct zcore_header {
u64 magic;
u32 version;
u32 header_size;
u32 dump_level;
u32 page_size;
u64 mem_size;
u64 mem_start;
u64 mem_end;
u32 num_pages;
u32 pad1;
u64 tod;
struct cpuid cpu_id;
u32 arch_id;
u32 volnr;
u32 build_arch;
u64 rmem_size;
u8 mvdump;
u16 cpu_cnt;
u16 real_cpu_cnt;
u8 end_pad1[0x200-0x061];
u64 mvdump_sign;
u64 mvdump_zipl_time;
u8 end_pad2[0x800-0x210];
u32 lc_vec[512];
} __attribute__((packed,__aligned__(16)));
static struct zcore_header zcore_header = {
.magic = DUMP_MAGIC,
.version = DUMP_VERSION,
.header_size = 4096,
.dump_level = 0,
.page_size = PAGE_SIZE,
.mem_start = 0,
#ifdef CONFIG_64BIT
.build_arch = DUMP_ARCH_S390X,
#else
.build_arch = DUMP_ARCH_S390,
#endif
};
/*
* Copy lowcore info to buffer. Use map in order to copy only register parts.
*
* @buf: User buffer
* @sa: Pointer to save area
* @sa_off: Offset in save area to copy
* @len: Number of bytes to copy
*/
static int copy_lc(void __user *buf, void *sa, int sa_off, int len)
{
int i;
char *lc_mask = (char*)&sys_info.lc_mask;
for (i = 0; i < len; i++) {
if (!lc_mask[i + sa_off])
continue;
if (copy_to_user(buf + i, sa + sa_off + i, 1))
return -EFAULT;
}
return 0;
}
/*
* Copy lowcores info to memory, if necessary
*
* @buf: User buffer
* @addr: Start address of buffer in dump memory
* @count: Size of buffer
*/
static int zcore_add_lc(char __user *buf, unsigned long start, size_t count)
{
unsigned long end;
int i = 0;
if (count == 0)
return 0;
end = start + count;
while (zfcpdump_save_areas[i]) {
unsigned long cp_start, cp_end; /* copy range */
unsigned long sa_start, sa_end; /* save area range */
unsigned long prefix;
unsigned long sa_off, len, buf_off;
prefix = zfcpdump_save_areas[i]->pref_reg;
sa_start = prefix + sys_info.sa_base;
sa_end = prefix + sys_info.sa_base + sys_info.sa_size;
if ((end < sa_start) || (start > sa_end))
goto next;
cp_start = max(start, sa_start);
cp_end = min(end, sa_end);
buf_off = cp_start - start;
sa_off = cp_start - sa_start;
len = cp_end - cp_start;
TRACE("copy_lc for: %lx\n", start);
if (copy_lc(buf + buf_off, zfcpdump_save_areas[i], sa_off, len))
return -EFAULT;
next:
i++;
}
return 0;
}
/*
* Release the HSA
*/
static void release_hsa(void)
{
diag308(DIAG308_REL_HSA, NULL);
hsa_available = 0;
}
/*
* Read routine for zcore character device
* First 4K are dump header
* Next 32MB are HSA Memory
* Rest is read from absolute Memory
*/
static ssize_t zcore_read(struct file *file, char __user *buf, size_t count,
loff_t *ppos)
{
unsigned long mem_start; /* Start address in memory */
size_t mem_offs; /* Offset in dump memory */
size_t hdr_count; /* Size of header part of output buffer */
size_t size;
int rc;
mutex_lock(&zcore_mutex);
if (*ppos > (sys_info.mem_size + HEADER_SIZE)) {
rc = -EINVAL;
goto fail;
}
count = min(count, (size_t) (sys_info.mem_size + HEADER_SIZE - *ppos));
/* Copy dump header */
if (*ppos < HEADER_SIZE) {
size = min(count, (size_t) (HEADER_SIZE - *ppos));
if (copy_to_user(buf, &zcore_header + *ppos, size)) {
rc = -EFAULT;
goto fail;
}
hdr_count = size;
mem_start = 0;
} else {
hdr_count = 0;
mem_start = *ppos - HEADER_SIZE;
}
mem_offs = 0;
/* Copy from HSA data */
if (*ppos < (ZFCPDUMP_HSA_SIZE + HEADER_SIZE)) {
size = min((count - hdr_count), (size_t) (ZFCPDUMP_HSA_SIZE
- mem_start));
rc = memcpy_hsa_user(buf + hdr_count, mem_start, size);
if (rc)
goto fail;
mem_offs += size;
}
/* Copy from real mem */
size = count - mem_offs - hdr_count;
rc = copy_to_user_real(buf + hdr_count + mem_offs,
(void *) mem_start + mem_offs, size);
if (rc)
goto fail;
/*
* Since s390 dump analysis tools like lcrash or crash
* expect register sets in the prefix pages of the cpus,
* we copy them into the read buffer, if necessary.
* buf + hdr_count: Start of memory part of output buffer
* mem_start: Start memory address to copy from
* count - hdr_count: Size of memory area to copy
*/
if (zcore_add_lc(buf + hdr_count, mem_start, count - hdr_count)) {
rc = -EFAULT;
goto fail;
}
*ppos += count;
fail:
mutex_unlock(&zcore_mutex);
return (rc < 0) ? rc : count;
}
static int zcore_open(struct inode *inode, struct file *filp)
{
if (!hsa_available)
return -ENODATA;
else
return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
}
static int zcore_release(struct inode *inode, struct file *filep)
{
if (hsa_available)
release_hsa();
return 0;
}
static loff_t zcore_lseek(struct file *file, loff_t offset, int orig)
{
loff_t rc;
mutex_lock(&zcore_mutex);
switch (orig) {
case 0:
file->f_pos = offset;
rc = file->f_pos;
break;
case 1:
file->f_pos += offset;
rc = file->f_pos;
break;
default:
rc = -EINVAL;
}
mutex_unlock(&zcore_mutex);
return rc;
}
static const struct file_operations zcore_fops = {
.owner = THIS_MODULE,
.llseek = zcore_lseek,
.read = zcore_read,
.open = zcore_open,
.release = zcore_release,
};
static ssize_t zcore_memmap_read(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
return simple_read_from_buffer(buf, count, ppos, filp->private_data,
MEMORY_CHUNKS * CHUNK_INFO_SIZE);
}
static int zcore_memmap_open(struct inode *inode, struct file *filp)
{
int i;
char *buf;
struct mem_chunk *chunk_array;
chunk_array = kzalloc(MEMORY_CHUNKS * sizeof(struct mem_chunk),
GFP_KERNEL);
if (!chunk_array)
return -ENOMEM;
detect_memory_layout(chunk_array, 0);
buf = kzalloc(MEMORY_CHUNKS * CHUNK_INFO_SIZE, GFP_KERNEL);
if (!buf) {
kfree(chunk_array);
return -ENOMEM;
}
for (i = 0; i < MEMORY_CHUNKS; i++) {
sprintf(buf + (i * CHUNK_INFO_SIZE), "%016llx %016llx ",
(unsigned long long) chunk_array[i].addr,
(unsigned long long) chunk_array[i].size);
if (chunk_array[i].size == 0)
break;
}
kfree(chunk_array);
filp->private_data = buf;
return nonseekable_open(inode, filp);
}
static int zcore_memmap_release(struct inode *inode, struct file *filp)
{
kfree(filp->private_data);
return 0;
}
static const struct file_operations zcore_memmap_fops = {
.owner = THIS_MODULE,
.read = zcore_memmap_read,
.open = zcore_memmap_open,
.release = zcore_memmap_release,
.llseek = no_llseek,
};
static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
size_t count, loff_t *ppos)
{
if (ipl_block) {
diag308(DIAG308_SET, ipl_block);
diag308(DIAG308_IPL, NULL);
}
return count;
}
static int zcore_reipl_open(struct inode *inode, struct file *filp)
{
return nonseekable_open(inode, filp);
}
static int zcore_reipl_release(struct inode *inode, struct file *filp)
{
return 0;
}
static const struct file_operations zcore_reipl_fops = {
.owner = THIS_MODULE,
.write = zcore_reipl_write,
.open = zcore_reipl_open,
.release = zcore_reipl_release,
.llseek = no_llseek,
};
static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
static char str[18];
if (hsa_available)
snprintf(str, sizeof(str), "%lx\n", ZFCPDUMP_HSA_SIZE);
else
snprintf(str, sizeof(str), "0\n");
return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
}
static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
size_t count, loff_t *ppos)
{
char value;
if (*ppos != 0)
return -EPIPE;
if (copy_from_user(&value, buf, 1))
return -EFAULT;
if (value != '0')
return -EINVAL;
release_hsa();
return count;
}
static const struct file_operations zcore_hsa_fops = {
.owner = THIS_MODULE,
.write = zcore_hsa_write,
.read = zcore_hsa_read,
.open = nonseekable_open,
.llseek = no_llseek,
};
#ifdef CONFIG_32BIT
static void __init set_lc_mask(struct save_area *map)
{
memset(&map->ext_save, 0xff, sizeof(map->ext_save));
memset(&map->timer, 0xff, sizeof(map->timer));
memset(&map->clk_cmp, 0xff, sizeof(map->clk_cmp));
memset(&map->psw, 0xff, sizeof(map->psw));
memset(&map->pref_reg, 0xff, sizeof(map->pref_reg));
memset(&map->acc_regs, 0xff, sizeof(map->acc_regs));
memset(&map->fp_regs, 0xff, sizeof(map->fp_regs));
memset(&map->gp_regs, 0xff, sizeof(map->gp_regs));
memset(&map->ctrl_regs, 0xff, sizeof(map->ctrl_regs));
}
#else /* CONFIG_32BIT */
static void __init set_lc_mask(struct save_area *map)
{
memset(&map->fp_regs, 0xff, sizeof(map->fp_regs));
memset(&map->gp_regs, 0xff, sizeof(map->gp_regs));
memset(&map->psw, 0xff, sizeof(map->psw));
memset(&map->pref_reg, 0xff, sizeof(map->pref_reg));
memset(&map->fp_ctrl_reg, 0xff, sizeof(map->fp_ctrl_reg));
memset(&map->tod_reg, 0xff, sizeof(map->tod_reg));
memset(&map->timer, 0xff, sizeof(map->timer));
memset(&map->clk_cmp, 0xff, sizeof(map->clk_cmp));
memset(&map->acc_regs, 0xff, sizeof(map->acc_regs));
memset(&map->ctrl_regs, 0xff, sizeof(map->ctrl_regs));
}
#endif /* CONFIG_32BIT */
/*
* Initialize dump globals for a given architecture
*/
static int __init sys_info_init(enum arch_id arch, unsigned long mem_end)
{
int rc;
switch (arch) {
case ARCH_S390X:
pr_alert("DETECTED 'S390X (64 bit) OS'\n");
break;
case ARCH_S390:
pr_alert("DETECTED 'S390 (32 bit) OS'\n");
break;
default:
pr_alert("0x%x is an unknown architecture.\n",arch);
return -EINVAL;
}
sys_info.sa_base = SAVE_AREA_BASE;
sys_info.sa_size = sizeof(struct save_area);
sys_info.arch = arch;
set_lc_mask(&sys_info.lc_mask);
rc = init_cpu_info(arch);
if (rc)
return rc;
sys_info.mem_size = mem_end;
return 0;
}
static int __init check_sdias(void)
{
int rc, act_hsa_size;
rc = sclp_sdias_blk_count();
if (rc < 0) {
TRACE("Could not determine HSA size\n");
return rc;
}
act_hsa_size = (rc - 1) * PAGE_SIZE;
if (act_hsa_size < ZFCPDUMP_HSA_SIZE) {
TRACE("HSA size too small: %i\n", act_hsa_size);
return -EINVAL;
}
return 0;
}
static int __init get_mem_info(unsigned long *mem, unsigned long *end)
{
int i;
struct mem_chunk *chunk_array;
chunk_array = kzalloc(MEMORY_CHUNKS * sizeof(struct mem_chunk),
GFP_KERNEL);
if (!chunk_array)
return -ENOMEM;
detect_memory_layout(chunk_array, 0);
for (i = 0; i < MEMORY_CHUNKS; i++) {
if (chunk_array[i].size == 0)
break;
*mem += chunk_array[i].size;
*end = max(*end, chunk_array[i].addr + chunk_array[i].size);
}
kfree(chunk_array);
return 0;
}
static void __init zcore_header_init(int arch, struct zcore_header *hdr,
unsigned long mem_size)
{
u32 prefix;
int i;
if (arch == ARCH_S390X)
hdr->arch_id = DUMP_ARCH_S390X;
else
hdr->arch_id = DUMP_ARCH_S390;
hdr->mem_size = mem_size;
hdr->rmem_size = mem_size;
hdr->mem_end = sys_info.mem_size;
hdr->num_pages = mem_size / PAGE_SIZE;
hdr->tod = get_tod_clock();
get_cpu_id(&hdr->cpu_id);
for (i = 0; zfcpdump_save_areas[i]; i++) {
prefix = zfcpdump_save_areas[i]->pref_reg;
hdr->real_cpu_cnt++;
if (!prefix)
continue;
hdr->lc_vec[hdr->cpu_cnt] = prefix;
hdr->cpu_cnt++;
}
}
/*
* Provide IPL parameter information block from either HSA or memory
* for future reipl
*/
static int __init zcore_reipl_init(void)
{
struct ipib_info ipib_info;
int rc;
rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));
if (rc)
return rc;
if (ipib_info.ipib == 0)
return 0;
ipl_block = (void *) __get_free_page(GFP_KERNEL);
if (!ipl_block)
return -ENOMEM;
if (ipib_info.ipib < ZFCPDUMP_HSA_SIZE)
rc = memcpy_hsa_kernel(ipl_block, ipib_info.ipib, PAGE_SIZE);
else
rc = memcpy_real(ipl_block, (void *) ipib_info.ipib, PAGE_SIZE);
if (rc || csum_partial(ipl_block, ipl_block->hdr.len, 0) !=
ipib_info.checksum) {
TRACE("Checksum does not match\n");
free_page((unsigned long) ipl_block);
ipl_block = NULL;
}
return 0;
}
static int __init zcore_init(void)
{
unsigned long mem_size, mem_end;
unsigned char arch;
int rc;
mem_size = mem_end = 0;
if (ipl_info.type != IPL_TYPE_FCP_DUMP)
return -ENODATA;
if (OLDMEM_BASE)
return -ENODATA;
zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
debug_register_view(zcore_dbf, &debug_sprintf_view);
debug_set_level(zcore_dbf, 6);
TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno);
TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
rc = sclp_sdias_init();
if (rc)
goto fail;
rc = check_sdias();
if (rc)
goto fail;
hsa_available = 1;
rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
if (rc)
goto fail;
#ifdef CONFIG_64BIT
if (arch == ARCH_S390) {
pr_alert("The 64-bit dump tool cannot be used for a "
"32-bit system\n");
rc = -EINVAL;
goto fail;
}
#else /* CONFIG_64BIT */
if (arch == ARCH_S390X) {
pr_alert("The 32-bit dump tool cannot be used for a "
"64-bit system\n");
rc = -EINVAL;
goto fail;
}
#endif /* CONFIG_64BIT */
rc = get_mem_info(&mem_size, &mem_end);
if (rc)
goto fail;
rc = sys_info_init(arch, mem_end);
if (rc)
goto fail;
zcore_header_init(arch, &zcore_header, mem_size);
rc = zcore_reipl_init();
if (rc)
goto fail;
zcore_dir = debugfs_create_dir("zcore" , NULL);
if (!zcore_dir) {
rc = -ENOMEM;
goto fail;
}
zcore_file = debugfs_create_file("mem", S_IRUSR, zcore_dir, NULL,
&zcore_fops);
if (!zcore_file) {
rc = -ENOMEM;
goto fail_dir;
}
zcore_memmap_file = debugfs_create_file("memmap", S_IRUSR, zcore_dir,
NULL, &zcore_memmap_fops);
if (!zcore_memmap_file) {
rc = -ENOMEM;
goto fail_file;
}
zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
NULL, &zcore_reipl_fops);
if (!zcore_reipl_file) {
rc = -ENOMEM;
goto fail_memmap_file;
}
zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
NULL, &zcore_hsa_fops);
if (!zcore_hsa_file) {
rc = -ENOMEM;
goto fail_reipl_file;
}
return 0;
fail_reipl_file:
debugfs_remove(zcore_reipl_file);
fail_memmap_file:
debugfs_remove(zcore_memmap_file);
fail_file:
debugfs_remove(zcore_file);
fail_dir:
debugfs_remove(zcore_dir);
fail:
diag308(DIAG308_REL_HSA, NULL);
return rc;
}
static void __exit zcore_exit(void)
{
debug_unregister(zcore_dbf);
sclp_sdias_exit();
free_page((unsigned long) ipl_block);
debugfs_remove(zcore_hsa_file);
debugfs_remove(zcore_reipl_file);
debugfs_remove(zcore_memmap_file);
debugfs_remove(zcore_file);
debugfs_remove(zcore_dir);
diag308(DIAG308_REL_HSA, NULL);
}
MODULE_AUTHOR("Copyright IBM Corp. 2003,2008");
MODULE_DESCRIPTION("zcore module for zfcpdump support");
MODULE_LICENSE("GPL");
subsys_initcall(zcore_init);
module_exit(zcore_exit);