Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 764 insertions, 0 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
new file mode 100644
index 0000000000..03425928d2
--- /dev/null
+++ b/fs/pstore/platform.c
@@ -0,0 +1,764 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Persistent Storage - platform driver interface parts.
+ *
+ * Copyright (C) 2007-2008 Google, Inc.
+ * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
+ */
+
+#define pr_fmt(fmt) "pstore: " fmt
+
+#include <linux/atomic.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kmsg_dump.h>
+#include <linux/console.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/pstore.h>
+#include <linux/string.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/jiffies.h>
+#include <linux/vmalloc.h>
+#include <linux/workqueue.h>
+#include <linux/zlib.h>
+
+#include "internal.h"
+
+/*
+ * We defer making "oops" entries appear in pstore - see
+ * whether the system is actually still running well enough
+ * to let someone see the entry
+ */
+static int pstore_update_ms = -1;
+module_param_named(update_ms, pstore_update_ms, int, 0600);
+MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
+		 "(default is -1, which means runtime updates are disabled; "
+		 "enabling this option may not be safe; it may lead to further "
+		 "corruption on Oopses)");
+
+/* Names should be in the same order as the enum pstore_type_id */
+static const char * const pstore_type_names[] = {
+	"dmesg",
+	"mce",
+	"console",
+	"ftrace",
+	"rtas",
+	"powerpc-ofw",
+	"powerpc-common",
+	"pmsg",
+	"powerpc-opal",
+};
+
+static int pstore_new_entry;
+
+static void pstore_timefunc(struct timer_list *);
+static DEFINE_TIMER(pstore_timer, pstore_timefunc);
+
+static void pstore_dowork(struct work_struct *);
+static DECLARE_WORK(pstore_work, pstore_dowork);
+
+/*
+ * psinfo_lock protects "psinfo" during calls to
+ * pstore_register(), pstore_unregister(), and
+ * the filesystem mount/unmount routines.
+ */
+static DEFINE_MUTEX(psinfo_lock);
+struct pstore_info *psinfo;
+
+static char *backend;
+module_param(backend, charp, 0444);
+MODULE_PARM_DESC(backend, "specific backend to use");
+
+/*
+ * pstore no longer implements compression via the crypto API, and only
+ * supports zlib deflate compression implemented using the zlib library
+ * interface. This removes additional complexity which is hard to justify for a
+ * diagnostic facility that has to operate in conditions where the system may
+ * have become unstable. Zlib deflate is comparatively small in terms of code
+ * size, and compresses ASCII text comparatively well. In terms of compression
+ * speed, deflate is not the best performer but for recording the log output on
+ * a kernel panic, this is not considered critical.
+ *
+ * The only remaining arguments supported by the compress= module parameter are
+ * 'deflate' and 'none'. To retain compatibility with existing installations,
+ * all other values are logged and replaced with 'deflate'.
+ */
+static char *compress = "deflate";
+module_param(compress, charp, 0444);
+MODULE_PARM_DESC(compress, "compression to use");
+
+/* How much of the kernel log to snapshot */
+unsigned long kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES;
+module_param(kmsg_bytes, ulong, 0444);
+MODULE_PARM_DESC(kmsg_bytes, "amount of kernel log to snapshot (in bytes)");
+
+static void *compress_workspace;
+
+/*
+ * Compression is only used for dmesg output, which consists of low-entropy
+ * ASCII text, and so we can assume worst-case 60%.
+ */
+#define DMESG_COMP_PERCENT	60
+
+static char *big_oops_buf;
+static size_t max_compressed_size;
+
+void pstore_set_kmsg_bytes(int bytes)
+{
+	kmsg_bytes = bytes;
+}
+
+/* Tag each group of saved records with a sequence number */
+static int	oopscount;
+
+const char *pstore_type_to_name(enum pstore_type_id type)
+{
+	BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
+
+	if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
+		return "unknown";
+
+	return pstore_type_names[type];
+}
+EXPORT_SYMBOL_GPL(pstore_type_to_name);
+
+enum pstore_type_id pstore_name_to_type(const char *name)
+{
+	int i;
+
+	for (i = 0; i < PSTORE_TYPE_MAX; i++) {
+		if (!strcmp(pstore_type_names[i], name))
+			return i;
+	}
+
+	return PSTORE_TYPE_MAX;
+}
+EXPORT_SYMBOL_GPL(pstore_name_to_type);
+
+static void pstore_timer_kick(void)
+{
+	if (pstore_update_ms < 0)
+		return;
+
+	mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
+}
+
+static bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
+{
+	/*
+	 * In case of NMI path, pstore shouldn't be blocked
+	 * regardless of reason.
+	 */
+	if (in_nmi())
+		return true;
+
+	switch (reason) {
+	/* In panic case, other cpus are stopped by smp_send_stop(). */
+	case KMSG_DUMP_PANIC:
+	/*
+	 * Emergency restart shouldn't be blocked by spinning on
+	 * pstore_info::buf_lock.
+	 */
+	case KMSG_DUMP_EMERG:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static int pstore_compress(const void *in, void *out,
+			   unsigned int inlen, unsigned int outlen)
+{
+	struct z_stream_s zstream = {
+		.next_in	= in,
+		.avail_in	= inlen,
+		.next_out	= out,
+		.avail_out	= outlen,
+		.workspace	= compress_workspace,
+	};
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS))
+		return -EINVAL;
+
+	ret = zlib_deflateInit2(&zstream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+				-MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
+	if (ret != Z_OK)
+		return -EINVAL;
+
+	ret = zlib_deflate(&zstream, Z_FINISH);
+	if (ret != Z_STREAM_END)
+		return -EINVAL;
+
+	ret = zlib_deflateEnd(&zstream);
+	if (ret != Z_OK)
+		pr_warn_once("zlib_deflateEnd() failed: %d\n", ret);
+
+	return zstream.total_out;
+}
+
+static void allocate_buf_for_compression(void)
+{
+	size_t compressed_size;
+	char *buf;
+
+	/* Skip if not built-in or compression disabled. */
+	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !compress ||
+	    !strcmp(compress, "none")) {
+		compress = NULL;
+		return;
+	}
+
+	if (strcmp(compress, "deflate")) {
+		pr_err("Unsupported compression '%s', falling back to deflate\n",
+		       compress);
+		compress = "deflate";
+	}
+
+	/*
+	 * The compression buffer only needs to be as large as the maximum
+	 * uncompressed record size, since any record that would be expanded by
+	 * compression is just stored uncompressed.
+	 */
+	compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT;
+	buf = kvzalloc(compressed_size, GFP_KERNEL);
+	if (!buf) {
+		pr_err("Failed %zu byte compression buffer allocation for: %s\n",
+		       psinfo->bufsize, compress);
+		return;
+	}
+
+	compress_workspace =
+		vmalloc(zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL));
+	if (!compress_workspace) {
+		pr_err("Failed to allocate zlib deflate workspace\n");
+		kvfree(buf);
+		return;
+	}
+
+	/* A non-NULL big_oops_buf indicates compression is available. */
+	big_oops_buf = buf;
+	max_compressed_size = compressed_size;
+
+	pr_info("Using crash dump compression: %s\n", compress);
+}
+
+static void free_buf_for_compression(void)
+{
+	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress_workspace) {
+		vfree(compress_workspace);
+		compress_workspace = NULL;
+	}
+
+	kvfree(big_oops_buf);
+	big_oops_buf = NULL;
+	max_compressed_size = 0;
+}
+
+void pstore_record_init(struct pstore_record *record,
+			struct pstore_info *psinfo)
+{
+	memset(record, 0, sizeof(*record));
+
+	record->psi = psinfo;
+
+	/* Report zeroed timestamp if called before timekeeping has resumed. */
+	record->time = ns_to_timespec64(ktime_get_real_fast_ns());
+}
+
+/*
+ * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
+ * end of the buffer.
+ */
+static void pstore_dump(struct kmsg_dumper *dumper,
+			enum kmsg_dump_reason reason)
+{
+	struct kmsg_dump_iter iter;
+	unsigned long	total = 0;
+	const char	*why;
+	unsigned int	part = 1;
+	unsigned long	flags = 0;
+	int		saved_ret = 0;
+	int		ret;
+
+	why = kmsg_dump_reason_str(reason);
+
+	if (pstore_cannot_block_path(reason)) {
+		if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
+			pr_err("dump skipped in %s path because of concurrent dump\n",
+					in_nmi() ? "NMI" : why);
+			return;
+		}
+	} else {
+		spin_lock_irqsave(&psinfo->buf_lock, flags);
+	}
+
+	kmsg_dump_rewind(&iter);
+
+	oopscount++;
+	while (total < kmsg_bytes) {
+		char *dst;
+		size_t dst_size;
+		int header_size;
+		int zipped_len = -1;
+		size_t dump_size;
+		struct pstore_record record;
+
+		pstore_record_init(&record, psinfo);
+		record.type = PSTORE_TYPE_DMESG;
+		record.count = oopscount;
+		record.reason = reason;
+		record.part = part;
+		record.buf = psinfo->buf;
+
+		dst = big_oops_buf ?: psinfo->buf;
+		dst_size = max_compressed_size ?: psinfo->bufsize;
+
+		/* Write dump header. */
+		header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
+				 oopscount, part);
+		dst_size -= header_size;
+
+		/* Write dump contents. */
+		if (!kmsg_dump_get_buffer(&iter, true, dst + header_size,
+					  dst_size, &dump_size))
+			break;
+
+		if (big_oops_buf) {
+			zipped_len = pstore_compress(dst, psinfo->buf,
+						header_size + dump_size,
+						psinfo->bufsize);
+
+			if (zipped_len > 0) {
+				record.compressed = true;
+				record.size = zipped_len;
+			} else {
+				/*
+				 * Compression failed, so the buffer is most
+				 * likely filled with binary data that does not
+				 * compress as well as ASCII text. Copy as much
+				 * of the uncompressed data as possible into
+				 * the pstore record, and discard the rest.
+				 */
+				record.size = psinfo->bufsize;
+				memcpy(psinfo->buf, dst, psinfo->bufsize);
+			}
+		} else {
+			record.size = header_size + dump_size;
+		}
+
+		ret = psinfo->write(&record);
+		if (ret == 0 && reason == KMSG_DUMP_OOPS) {
+			pstore_new_entry = 1;
+			pstore_timer_kick();
+		} else {
+			/* Preserve only the first non-zero returned value. */
+			if (!saved_ret)
+				saved_ret = ret;
+		}
+
+		total += record.size;
+		part++;
+	}
+	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
+
+	if (saved_ret) {
+		pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,
+			    saved_ret);
+	}
+}
+
+static struct kmsg_dumper pstore_dumper = {
+	.dump = pstore_dump,
+};
+
+/*
+ * Register with kmsg_dump to save last part of console log on panic.
+ */
+static void pstore_register_kmsg(void)
+{
+	kmsg_dump_register(&pstore_dumper);
+}
+
+static void pstore_unregister_kmsg(void)
+{
+	kmsg_dump_unregister(&pstore_dumper);
+}
+
+#ifdef CONFIG_PSTORE_CONSOLE
+static void pstore_console_write(struct console *con, const char *s, unsigned c)
+{
+	struct pstore_record record;
+
+	if (!c)
+		return;
+
+	pstore_record_init(&record, psinfo);
+	record.type = PSTORE_TYPE_CONSOLE;
+
+	record.buf = (char *)s;
+	record.size = c;
+	psinfo->write(&record);
+}
+
+static struct console pstore_console = {
+	.write	= pstore_console_write,
+	.index	= -1,
+};
+
+static void pstore_register_console(void)
+{
+	/* Show which backend is going to get console writes. */
+	strscpy(pstore_console.name, psinfo->name,
+		sizeof(pstore_console.name));
+	/*
+	 * Always initialize flags here since prior unregister_console()
+	 * calls may have changed settings (specifically CON_ENABLED).
+	 */
+	pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
+	register_console(&pstore_console);
+}
+
+static void pstore_unregister_console(void)
+{
+	unregister_console(&pstore_console);
+}
+#else
+static void pstore_register_console(void) {}
+static void pstore_unregister_console(void) {}
+#endif
+
+static int pstore_write_user_compat(struct pstore_record *record,
+				    const char __user *buf)
+{
+	int ret = 0;
+
+	if (record->buf)
+		return -EINVAL;
+
+	record->buf = vmemdup_user(buf, record->size);
+	if (IS_ERR(record->buf)) {
+		ret = PTR_ERR(record->buf);
+		goto out;
+	}
+
+	ret = record->psi->write(record);
+
+	kvfree(record->buf);
+out:
+	record->buf = NULL;
+
+	return unlikely(ret < 0) ? ret : record->size;
+}
+
+/*
+ * platform specific persistent storage driver registers with
+ * us here. If pstore is already mounted, call the platform
+ * read function right away to populate the file system. If not
+ * then the pstore mount code will call us later to fill out
+ * the file system.
+ */
+int pstore_register(struct pstore_info *psi)
+{
+	char *new_backend;
+
+	if (backend && strcmp(backend, psi->name)) {
+		pr_warn("backend '%s' already in use: ignoring '%s'\n",
+			backend, psi->name);
+		return -EBUSY;
+	}
+
+	/* Sanity check flags. */
+	if (!psi->flags) {
+		pr_warn("backend '%s' must support at least one frontend\n",
+			psi->name);
+		return -EINVAL;
+	}
+
+	/* Check for required functions. */
+	if (!psi->read || !psi->write) {
+		pr_warn("backend '%s' must implement read() and write()\n",
+			psi->name);
+		return -EINVAL;
+	}
+
+	new_backend = kstrdup(psi->name, GFP_KERNEL);
+	if (!new_backend)
+		return -ENOMEM;
+
+	mutex_lock(&psinfo_lock);
+	if (psinfo) {
+		pr_warn("backend '%s' already loaded: ignoring '%s'\n",
+			psinfo->name, psi->name);
+		mutex_unlock(&psinfo_lock);
+		kfree(new_backend);
+		return -EBUSY;
+	}
+
+	if (!psi->write_user)
+		psi->write_user = pstore_write_user_compat;
+	psinfo = psi;
+	mutex_init(&psinfo->read_mutex);
+	spin_lock_init(&psinfo->buf_lock);
+
+	if (psi->flags & PSTORE_FLAGS_DMESG)
+		allocate_buf_for_compression();
+
+	pstore_get_records(0);
+
+	if (psi->flags & PSTORE_FLAGS_DMESG) {
+		pstore_dumper.max_reason = psinfo->max_reason;
+		pstore_register_kmsg();
+	}
+	if (psi->flags & PSTORE_FLAGS_CONSOLE)
+		pstore_register_console();
+	if (psi->flags & PSTORE_FLAGS_FTRACE)
+		pstore_register_ftrace();
+	if (psi->flags & PSTORE_FLAGS_PMSG)
+		pstore_register_pmsg();
+
+	/* Start watching for new records, if desired. */
+	pstore_timer_kick();
+
+	/*
+	 * Update the module parameter backend, so it is visible
+	 * through /sys/module/pstore/parameters/backend
+	 */
+	backend = new_backend;
+
+	pr_info("Registered %s as persistent store backend\n", psi->name);
+
+	mutex_unlock(&psinfo_lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pstore_register);
+
+void pstore_unregister(struct pstore_info *psi)
+{
+	/* It's okay to unregister nothing. */
+	if (!psi)
+		return;
+
+	mutex_lock(&psinfo_lock);
+
+	/* Only one backend can be registered at a time. */
+	if (WARN_ON(psi != psinfo)) {
+		mutex_unlock(&psinfo_lock);
+		return;
+	}
+
+	/* Unregister all callbacks. */
+	if (psi->flags & PSTORE_FLAGS_PMSG)
+		pstore_unregister_pmsg();
+	if (psi->flags & PSTORE_FLAGS_FTRACE)
+		pstore_unregister_ftrace();
+	if (psi->flags & PSTORE_FLAGS_CONSOLE)
+		pstore_unregister_console();
+	if (psi->flags & PSTORE_FLAGS_DMESG)
+		pstore_unregister_kmsg();
+
+	/* Stop timer and make sure all work has finished. */
+	del_timer_sync(&pstore_timer);
+	flush_work(&pstore_work);
+
+	/* Remove all backend records from filesystem tree. */
+	pstore_put_backend_records(psi);
+
+	free_buf_for_compression();
+
+	psinfo = NULL;
+	kfree(backend);
+	backend = NULL;
+
+	pr_info("Unregistered %s as persistent store backend\n", psi->name);
+	mutex_unlock(&psinfo_lock);
+}
+EXPORT_SYMBOL_GPL(pstore_unregister);
+
+static void decompress_record(struct pstore_record *record,
+			      struct z_stream_s *zstream)
+{
+	int ret;
+	int unzipped_len;
+	char *unzipped, *workspace;
+	size_t max_uncompressed_size;
+
+	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
+		return;
+
+	/* Only PSTORE_TYPE_DMESG support compression. */
+	if (record->type != PSTORE_TYPE_DMESG) {
+		pr_warn("ignored compressed record type %d\n", record->type);
+		return;
+	}
+
+	/* Missing compression buffer means compression was not initialized. */
+	if (!zstream->workspace) {
+		pr_warn("no decompression method initialized!\n");
+		return;
+	}
+
+	ret = zlib_inflateReset(zstream);
+	if (ret != Z_OK) {
+		pr_err("zlib_inflateReset() failed, ret = %d!\n", ret);
+		return;
+	}
+
+	/* Allocate enough space to hold max decompression and ECC. */
+	max_uncompressed_size = 3 * psinfo->bufsize;
+	workspace = kvzalloc(max_uncompressed_size + record->ecc_notice_size,
+			     GFP_KERNEL);
+	if (!workspace)
+		return;
+
+	zstream->next_in	= record->buf;
+	zstream->avail_in	= record->size;
+	zstream->next_out	= workspace;
+	zstream->avail_out	= max_uncompressed_size;
+
+	ret = zlib_inflate(zstream, Z_FINISH);
+	if (ret != Z_STREAM_END) {
+		pr_err_ratelimited("zlib_inflate() failed, ret = %d!\n", ret);
+		kvfree(workspace);
+		return;
+	}
+
+	unzipped_len = zstream->total_out;
+
+	/* Append ECC notice to decompressed buffer. */
+	memcpy(workspace + unzipped_len, record->buf + record->size,
+	       record->ecc_notice_size);
+
+	/* Copy decompressed contents into an minimum-sized allocation. */
+	unzipped = kvmemdup(workspace, unzipped_len + record->ecc_notice_size,
+			    GFP_KERNEL);
+	kvfree(workspace);
+	if (!unzipped)
+		return;
+
+	/* Swap out compressed contents with decompressed contents. */
+	kvfree(record->buf);
+	record->buf = unzipped;
+	record->size = unzipped_len;
+	record->compressed = false;
+}
+
+/*
+ * Read all the records from one persistent store backend. Create
+ * files in our filesystem.  Don't warn about -EEXIST errors
+ * when we are re-scanning the backing store looking to add new
+ * error records.
+ */
+void pstore_get_backend_records(struct pstore_info *psi,
+				struct dentry *root, int quiet)
+{
+	int failed = 0;
+	unsigned int stop_loop = 65536;
+	struct z_stream_s zstream = {};
+
+	if (!psi || !root)
+		return;
+
+	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) {
+		zstream.workspace = kvmalloc(zlib_inflate_workspacesize(),
+					     GFP_KERNEL);
+		zlib_inflateInit2(&zstream, -DEF_WBITS);
+	}
+
+	mutex_lock(&psi->read_mutex);
+	if (psi->open && psi->open(psi))
+		goto out;
+
+	/*
+	 * Backend callback read() allocates record.buf. decompress_record()
+	 * may reallocate record.buf. On success, pstore_mkfile() will keep
+	 * the record.buf, so free it only on failure.
+	 */
+	for (; stop_loop; stop_loop--) {
+		struct pstore_record *record;
+		int rc;
+
+		record = kzalloc(sizeof(*record), GFP_KERNEL);
+		if (!record) {
+			pr_err("out of memory creating record\n");
+			break;
+		}
+		pstore_record_init(record, psi);
+
+		record->size = psi->read(record);
+
+		/* No more records left in backend? */
+		if (record->size <= 0) {
+			kfree(record);
+			break;
+		}
+
+		decompress_record(record, &zstream);
+		rc = pstore_mkfile(root, record);
+		if (rc) {
+			/* pstore_mkfile() did not take record, so free it. */
+			kvfree(record->buf);
+			kfree(record->priv);
+			kfree(record);
+			if (rc != -EEXIST || !quiet)
+				failed++;
+		}
+	}
+	if (psi->close)
+		psi->close(psi);
+out:
+	mutex_unlock(&psi->read_mutex);
+
+	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) {
+		if (zlib_inflateEnd(&zstream) != Z_OK)
+			pr_warn("zlib_inflateEnd() failed\n");
+		kvfree(zstream.workspace);
+	}
+
+	if (failed)
+		pr_warn("failed to create %d record(s) from '%s'\n",
+			failed, psi->name);
+	if (!stop_loop)
+		pr_err("looping? Too many records seen from '%s'\n",
+			psi->name);
+}
+
+static void pstore_dowork(struct work_struct *work)
+{
+	pstore_get_records(1);
+}
+
+static void pstore_timefunc(struct timer_list *unused)
+{
+	if (pstore_new_entry) {
+		pstore_new_entry = 0;
+		schedule_work(&pstore_work);
+	}
+
+	pstore_timer_kick();
+}
+
+static int __init pstore_init(void)
+{
+	int ret;
+
+	ret = pstore_init_fs();
+	if (ret)
+		free_buf_for_compression();
+
+	return ret;
+}
+late_initcall(pstore_init);
+
+static void __exit pstore_exit(void)
+{
+	pstore_exit_fs();
+}
+module_exit(pstore_exit)
+
+MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
+MODULE_LICENSE("GPL");