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1// SPDX-License-Identifier: GPL-1.0+2/*3 * zcore module to export memory content and register sets for creating system4 * dumps on SCSI/NVMe disks (zfcp/nvme dump).5 *6 * For more information please refer to Documentation/arch/s390/zfcpdump.rst7 *8 * Copyright IBM Corp. 2003, 20089 * Author(s): Michael Holzheu10 */11 12#define KMSG_COMPONENT "zdump"13#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt14 15#include <linux/init.h>16#include <linux/slab.h>17#include <linux/debugfs.h>18#include <linux/panic_notifier.h>19#include <linux/reboot.h>20#include <linux/uio.h>21 22#include <asm/asm-offsets.h>23#include <asm/ipl.h>24#include <asm/sclp.h>25#include <asm/setup.h>26#include <linux/uaccess.h>27#include <asm/debug.h>28#include <asm/processor.h>29#include <asm/irqflags.h>30#include <asm/checksum.h>31#include <asm/os_info.h>32#include <asm/maccess.h>33#include "sclp.h"34 35#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)36 37enum arch_id {38 ARCH_S390 = 0,39 ARCH_S390X = 1,40};41 42struct ipib_info {43 unsigned long ipib;44 u32 checksum;45} __attribute__((packed));46 47static struct debug_info *zcore_dbf;48static int hsa_available;49static struct dentry *zcore_dir;50static struct dentry *zcore_reipl_file;51static struct dentry *zcore_hsa_file;52static struct ipl_parameter_block *zcore_ipl_block;53static unsigned long os_info_flags;54 55static DEFINE_MUTEX(hsa_buf_mutex);56static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);57 58/*59 * Copy memory from HSA to iterator (not reentrant):60 *61 * @iter: Iterator where memory should be copied to62 * @src: Start address within HSA where data should be copied63 * @count: Size of buffer, which should be copied64 */65size_t memcpy_hsa_iter(struct iov_iter *iter, unsigned long src, size_t count)66{67 size_t bytes, copied, res = 0;68 unsigned long offset;69 70 if (!hsa_available)71 return 0;72 73 mutex_lock(&hsa_buf_mutex);74 while (count) {75 if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {76 TRACE("sclp_sdias_copy() failed\n");77 break;78 }79 offset = src % PAGE_SIZE;80 bytes = min(PAGE_SIZE - offset, count);81 copied = copy_to_iter(hsa_buf + offset, bytes, iter);82 count -= copied;83 src += copied;84 res += copied;85 if (copied < bytes)86 break;87 }88 mutex_unlock(&hsa_buf_mutex);89 return res;90}91 92/*93 * Copy memory from HSA to kernel memory (not reentrant):94 *95 * @dest: Kernel or user buffer where memory should be copied to96 * @src: Start address within HSA where data should be copied97 * @count: Size of buffer, which should be copied98 */99static inline int memcpy_hsa_kernel(void *dst, unsigned long src, size_t count)100{101 struct iov_iter iter;102 struct kvec kvec;103 104 kvec.iov_base = dst;105 kvec.iov_len = count;106 iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);107 if (memcpy_hsa_iter(&iter, src, count) < count)108 return -EIO;109 return 0;110}111 112static int __init init_cpu_info(void)113{114 struct save_area *sa;115 116 /* get info for boot cpu from lowcore, stored in the HSA */117 sa = save_area_boot_cpu();118 if (!sa)119 return -ENOMEM;120 if (memcpy_hsa_kernel(hsa_buf, __LC_FPREGS_SAVE_AREA, 512) < 0) {121 TRACE("could not copy from HSA\n");122 return -EIO;123 }124 save_area_add_regs(sa, hsa_buf); /* vx registers are saved in smp.c */125 return 0;126}127 128/*129 * Release the HSA130 */131static void release_hsa(void)132{133 diag308(DIAG308_REL_HSA, NULL);134 hsa_available = 0;135}136 137static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,138 size_t count, loff_t *ppos)139{140 if (zcore_ipl_block) {141 diag308(DIAG308_SET, zcore_ipl_block);142 if (os_info_flags & OS_INFO_FLAG_REIPL_CLEAR)143 diag308(DIAG308_LOAD_CLEAR, NULL);144 /* Use special diag308 subcode for CCW normal ipl */145 if (zcore_ipl_block->pb0_hdr.pbt == IPL_PBT_CCW)146 diag308(DIAG308_LOAD_NORMAL_DUMP, NULL);147 else148 diag308(DIAG308_LOAD_NORMAL, NULL);149 }150 return count;151}152 153static int zcore_reipl_open(struct inode *inode, struct file *filp)154{155 return stream_open(inode, filp);156}157 158static int zcore_reipl_release(struct inode *inode, struct file *filp)159{160 return 0;161}162 163static const struct file_operations zcore_reipl_fops = {164 .owner = THIS_MODULE,165 .write = zcore_reipl_write,166 .open = zcore_reipl_open,167 .release = zcore_reipl_release,168};169 170static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,171 size_t count, loff_t *ppos)172{173 static char str[18];174 175 if (hsa_available)176 snprintf(str, sizeof(str), "%lx\n", sclp.hsa_size);177 else178 snprintf(str, sizeof(str), "0\n");179 return simple_read_from_buffer(buf, count, ppos, str, strlen(str));180}181 182static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,183 size_t count, loff_t *ppos)184{185 char value;186 187 if (*ppos != 0)188 return -EPIPE;189 if (copy_from_user(&value, buf, 1))190 return -EFAULT;191 if (value != '0')192 return -EINVAL;193 release_hsa();194 return count;195}196 197static const struct file_operations zcore_hsa_fops = {198 .owner = THIS_MODULE,199 .write = zcore_hsa_write,200 .read = zcore_hsa_read,201 .open = nonseekable_open,202};203 204static int __init check_sdias(void)205{206 if (!sclp.hsa_size) {207 TRACE("Could not determine HSA size\n");208 return -ENODEV;209 }210 return 0;211}212 213/*214 * Provide IPL parameter information block from either HSA or memory215 * for future reipl216 */217static int __init zcore_reipl_init(void)218{219 struct os_info_entry *entry;220 struct ipib_info ipib_info;221 unsigned long os_info_addr;222 struct os_info *os_info;223 int rc;224 225 rc = memcpy_hsa_kernel(&ipib_info, __LC_DUMP_REIPL, sizeof(ipib_info));226 if (rc)227 return rc;228 if (ipib_info.ipib == 0)229 return 0;230 zcore_ipl_block = (void *) __get_free_page(GFP_KERNEL);231 if (!zcore_ipl_block)232 return -ENOMEM;233 if (ipib_info.ipib < sclp.hsa_size)234 rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,235 PAGE_SIZE);236 else237 rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE);238 if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=239 ipib_info.checksum) {240 TRACE("Checksum does not match\n");241 free_page((unsigned long) zcore_ipl_block);242 zcore_ipl_block = NULL;243 }244 /*245 * Read the bit-flags field from os_info flags entry.246 * Return zero even for os_info read or entry checksum errors in order247 * to continue dump processing, considering that os_info could be248 * corrupted on the panicked system.249 */250 os_info = (void *)__get_free_page(GFP_KERNEL);251 if (!os_info)252 return -ENOMEM;253 rc = memcpy_hsa_kernel(&os_info_addr, __LC_OS_INFO, sizeof(os_info_addr));254 if (rc)255 goto out;256 if (os_info_addr < sclp.hsa_size)257 rc = memcpy_hsa_kernel(os_info, os_info_addr, PAGE_SIZE);258 else259 rc = memcpy_real(os_info, os_info_addr, PAGE_SIZE);260 if (rc || os_info_csum(os_info) != os_info->csum)261 goto out;262 entry = &os_info->entry[OS_INFO_FLAGS_ENTRY];263 if (entry->addr && entry->size) {264 if (entry->addr < sclp.hsa_size)265 rc = memcpy_hsa_kernel(&os_info_flags, entry->addr, sizeof(os_info_flags));266 else267 rc = memcpy_real(&os_info_flags, entry->addr, sizeof(os_info_flags));268 if (rc || (__force u32)csum_partial(&os_info_flags, entry->size, 0) != entry->csum)269 os_info_flags = 0;270 }271out:272 free_page((unsigned long)os_info);273 return 0;274}275 276static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,277 unsigned long event,278 void *data)279{280 if (hsa_available)281 release_hsa();282 283 return NOTIFY_OK;284}285 286static struct notifier_block zcore_reboot_notifier = {287 .notifier_call = zcore_reboot_and_on_panic_handler,288 /* we need to be notified before reipl and kdump */289 .priority = INT_MAX,290};291 292static struct notifier_block zcore_on_panic_notifier = {293 .notifier_call = zcore_reboot_and_on_panic_handler,294 /* we need to be notified before reipl and kdump */295 .priority = INT_MAX,296};297 298static int __init zcore_init(void)299{300 unsigned char arch;301 int rc;302 303 if (!is_ipl_type_dump())304 return -ENODATA;305 if (oldmem_data.start)306 return -ENODATA;307 308 zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));309 debug_register_view(zcore_dbf, &debug_sprintf_view);310 debug_set_level(zcore_dbf, 6);311 312 if (ipl_info.type == IPL_TYPE_FCP_DUMP) {313 TRACE("type: fcp\n");314 TRACE("devno: %x\n", ipl_info.data.fcp.dev_id.devno);315 TRACE("wwpn: %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);316 TRACE("lun: %llx\n", (unsigned long long) ipl_info.data.fcp.lun);317 } else if (ipl_info.type == IPL_TYPE_NVME_DUMP) {318 TRACE("type: nvme\n");319 TRACE("fid: %x\n", ipl_info.data.nvme.fid);320 TRACE("nsid: %x\n", ipl_info.data.nvme.nsid);321 } else if (ipl_info.type == IPL_TYPE_ECKD_DUMP) {322 TRACE("type: eckd\n");323 TRACE("devno: %x\n", ipl_info.data.eckd.dev_id.devno);324 TRACE("ssid: %x\n", ipl_info.data.eckd.dev_id.ssid);325 }326 327 rc = sclp_sdias_init();328 if (rc)329 goto fail;330 331 rc = check_sdias();332 if (rc)333 goto fail;334 hsa_available = 1;335 336 rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);337 if (rc)338 goto fail;339 340 if (arch == ARCH_S390) {341 pr_alert("The 64-bit dump tool cannot be used for a "342 "32-bit system\n");343 rc = -EINVAL;344 goto fail;345 }346 347 pr_alert("The dump process started for a 64-bit operating system\n");348 rc = init_cpu_info();349 if (rc)350 goto fail;351 352 rc = zcore_reipl_init();353 if (rc)354 goto fail;355 356 zcore_dir = debugfs_create_dir("zcore" , NULL);357 zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,358 NULL, &zcore_reipl_fops);359 zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,360 NULL, &zcore_hsa_fops);361 362 register_reboot_notifier(&zcore_reboot_notifier);363 atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);364 365 return 0;366fail:367 diag308(DIAG308_REL_HSA, NULL);368 return rc;369}370subsys_initcall(zcore_init);371