// SPDX-License-Identifier: GPL-1.0+
/*
* zcore module to export memory content and register sets for creating system
* dumps on SCSI/NVMe disks (zfcp/nvme dump).
*
* For more information please refer to Documentation/arch/s390/zfcpdump.rst
*
* 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/debugfs.h>
#include <linux/panic_notifier.h>
#include <linux/reboot.h>
#include <linux/uio.h>
#include <asm/asm-offsets.h>
#include <asm/ipl.h>
#include <asm/sclp.h>
#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/debug.h>
#include <asm/processor.h>
#include <asm/irqflags.h>
#include <asm/checksum.h>
#include <asm/os_info.h>
#include <asm/maccess.h>
#include "sclp.h"
#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
enum arch_id {
ARCH_S390 = 0,
ARCH_S390X = 1,
};
struct ipib_info {
unsigned long ipib;
u32 checksum;
} __attribute__((packed));
static struct debug_info *zcore_dbf;
static int hsa_available;
static struct dentry *zcore_dir;
static struct dentry *zcore_reipl_file;
static struct dentry *zcore_hsa_file;
static struct ipl_parameter_block *zcore_ipl_block;
static unsigned long os_info_flags;
static DEFINE_MUTEX(hsa_buf_mutex);
static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
/*
* Copy memory from HSA to iterator (not reentrant):
*
* @iter: Iterator where memory should be copied to
* @src: Start address within HSA where data should be copied
* @count: Size of buffer, which should be copied
*/
size_t memcpy_hsa_iter(struct iov_iter *iter, unsigned long src, size_t count)
{
size_t bytes, copied, res = 0;
unsigned long offset;
if (!hsa_available)
return 0;
mutex_lock(&hsa_buf_mutex);
while (count) {
if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
TRACE("sclp_sdias_copy() failed\n");
break;
}
offset = src % PAGE_SIZE;
bytes = min(PAGE_SIZE - offset, count);
copied = copy_to_iter(hsa_buf + offset, bytes, iter);
count -= copied;
src += copied;
res += copied;
if (copied < bytes)
break;
}
mutex_unlock(&hsa_buf_mutex);
return res;
}
/*
* Copy memory from HSA to kernel 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
*/
static inline int memcpy_hsa_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 (memcpy_hsa_iter(&iter, src, count) < count)
return -EIO;
return 0;
}
static int __init init_cpu_info(void)
{
struct save_area *sa;
/* get info for boot cpu from lowcore, stored in the HSA */
sa = save_area_boot_cpu();
if (!sa)
return -ENOMEM;
if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) {
TRACE("could not copy from HSA\n");
return -EIO;
}
save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */
return 0;
}
/*
* Release the HSA
*/
static void release_hsa(void)
{
diag308(DIAG308_REL_HSA, NULL);
hsa_available = 0;
}
static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
size_t count, loff_t *ppos)
{
if (zcore_ipl_block) {
diag308(DIAG308_SET, zcore_ipl_block);
if (os_info_flags & OS_INFO_FLAG_REIPL_CLEAR)
diag308(DIAG308_LOAD_CLEAR, NULL);
/* Use special diag308 subcode for CCW normal ipl */
if (zcore_ipl_block->pb0_hdr.pbt == IPL_PBT_CCW)
diag308(DIAG308_LOAD_NORMAL_DUMP, NULL);
else
diag308(DIAG308_LOAD_NORMAL, NULL);
}
return count;
}
static int zcore_reipl_open(struct inode *inode, struct file *filp)
{
return stream_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", sclp.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,
};
static int __init check_sdias(void)
{
if (!sclp.hsa_size) {
TRACE("Could not determine HSA size\n");
return -ENODEV;
}
return 0;
}
/*
* Provide IPL parameter information block from either HSA or memory
* for future reipl
*/
static int __init zcore_reipl_init(void)
{
struct os_info_entry *entry;
struct ipib_info ipib_info;
unsigned long os_info_addr;
struct os_info *os_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;
zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);
if (!zcore_ipl_block)
return -ENOMEM;
if (ipib_info.ipib < sclp.hsa_size)
rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
PAGE_SIZE);
else
rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE);
if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
ipib_info.checksum) {
TRACE("Checksum does not match\n");
free_page((unsigned long) zcore_ipl_block);
zcore_ipl_block = NULL;
}
/*
* Read the bit-flags field from os_info flags entry.
* Return zero even for os_info read or entry checksum errors in order
* to continue dump processing, considering that os_info could be
* corrupted on the panicked system.
*/
os_info = (void *)__get_free_page(GFP_KERNEL);
if (!os_info)
return -ENOMEM;
rc = memcpy_hsa_kernel(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr));
if (rc)
goto out;
if (os_info_addr < sclp.hsa_size)
rc = memcpy_hsa_kernel(os_info, os_info_addr, PAGE_SIZE);
else
rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE);
if (rc || os_info_csum(os_info) != os_info->csum)
goto out;
entry = &os_info->entry[OS_INFO_FLAGS_ENTRY];
if (entry->addr && entry->size) {
if (entry->addr < sclp.hsa_size)
rc = memcpy_hsa_kernel(&os_info_flags, entry->addr, sizeof(os_info_flags));
else
rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags));
if (rc || (__force u32)csum_partial(&os_info_flags, entry->size, 0) != entry->csum)
os_info_flags = 0;
}
out:
free_page((unsigned long)os_info);
return 0;
}
static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
unsigned long event,
void *data)
{
if (hsa_available)
release_hsa();
return NOTIFY_OK;
}
static struct notifier_block zcore_reboot_notifier = {
.notifier_call = zcore_reboot_and_on_panic_handler,
/* we need to be notified before reipl and kdump */
.priority = INT_MAX,
};
static struct notifier_block zcore_on_panic_notifier = {
.notifier_call = zcore_reboot_and_on_panic_handler,
/* we need to be notified before reipl and kdump */
.priority = INT_MAX,
};
static int __init zcore_init(void)
{
unsigned char arch;
int rc;
if (!is_ipl_type_dump())
return -ENODATA;
if (oldmem_data.start)
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);
if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
TRACE("type: fcp\n");
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);
} else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {
TRACE("type: nvme\n");
TRACE("fid: %x\n", ipl_info.data.nvme.fid);
TRACE("nsid: %x\n", ipl_info.data.nvme.nsid);
} else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) {
TRACE("type: eckd\n");
TRACE("devno: %x\n", ipl_info.data.eckd.dev_id.devno);
TRACE("ssid: %x\n", ipl_info.data.eckd.dev_id.ssid);
}
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;
if (arch == ARCH_S390) {
pr_alert("The 64-bit dump tool cannot be used for a "
"32-bit system\n");
rc = -EINVAL;
goto fail;
}
pr_alert("The dump process started for a 64-bit operating system\n");
rc = init_cpu_info();
if (rc)
goto fail;
rc = zcore_reipl_init();
if (rc)
goto fail;
zcore_dir = debugfs_create_dir("zcore" , NULL);
zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
NULL, &zcore_reipl_fops);
zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
NULL, &zcore_hsa_fops);
register_reboot_notifier(&zcore_reboot_notifier);
atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
return 0;
fail:
diag308(DIAG308_REL_HSA, NULL);
return rc;
}
subsys_initcall(zcore_init);
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