1 files changed, 373 insertions, 0 deletions
diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
new file mode 100644
index 0000000000..bc3be0330f
--- /dev/null
+++ b/drivers/s390/char/zcore.c
@@ -0,0 +1,373 @@
+// 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/switch_to.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);