9b3c13c9ea
With ARCH=csky, make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing MODULE_DESCRIPTION() in fs/pstore/pstore.o Add the missing invocation of the MODULE_DESCRIPTION() macro. Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Link: https://lore.kernel.org/r/20240613-md-csky-fs-pstore-v1-1-c525f636b1cb@quicinc.com Signed-off-by: Kees Cook <kees@kernel.org>
766 lines
18 KiB
C
766 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Persistent Storage - platform driver interface parts.
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*
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* Copyright (C) 2007-2008 Google, Inc.
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* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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*/
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#define pr_fmt(fmt) "pstore: " fmt
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#include <linux/atomic.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/kmsg_dump.h>
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#include <linux/console.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/pstore.h>
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#include <linux/string.h>
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#include <linux/timer.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/jiffies.h>
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#include <linux/vmalloc.h>
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#include <linux/workqueue.h>
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#include <linux/zlib.h>
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#include "internal.h"
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/*
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* We defer making "oops" entries appear in pstore - see
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* whether the system is actually still running well enough
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* to let someone see the entry
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*/
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static int pstore_update_ms = -1;
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module_param_named(update_ms, pstore_update_ms, int, 0600);
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MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
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"(default is -1, which means runtime updates are disabled; "
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"enabling this option may not be safe; it may lead to further "
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"corruption on Oopses)");
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/* Names should be in the same order as the enum pstore_type_id */
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static const char * const pstore_type_names[] = {
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"dmesg",
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"mce",
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"console",
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"ftrace",
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"rtas",
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"powerpc-ofw",
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"powerpc-common",
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"pmsg",
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"powerpc-opal",
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};
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static int pstore_new_entry;
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static void pstore_timefunc(struct timer_list *);
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static DEFINE_TIMER(pstore_timer, pstore_timefunc);
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static void pstore_dowork(struct work_struct *);
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static DECLARE_WORK(pstore_work, pstore_dowork);
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/*
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* psinfo_lock protects "psinfo" during calls to
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* pstore_register(), pstore_unregister(), and
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* the filesystem mount/unmount routines.
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*/
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static DEFINE_MUTEX(psinfo_lock);
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struct pstore_info *psinfo;
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static char *backend;
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module_param(backend, charp, 0444);
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MODULE_PARM_DESC(backend, "specific backend to use");
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/*
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* pstore no longer implements compression via the crypto API, and only
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* supports zlib deflate compression implemented using the zlib library
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* interface. This removes additional complexity which is hard to justify for a
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* diagnostic facility that has to operate in conditions where the system may
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* have become unstable. Zlib deflate is comparatively small in terms of code
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* size, and compresses ASCII text comparatively well. In terms of compression
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* speed, deflate is not the best performer but for recording the log output on
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* a kernel panic, this is not considered critical.
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*
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* The only remaining arguments supported by the compress= module parameter are
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* 'deflate' and 'none'. To retain compatibility with existing installations,
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* all other values are logged and replaced with 'deflate'.
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*/
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static char *compress = "deflate";
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module_param(compress, charp, 0444);
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MODULE_PARM_DESC(compress, "compression to use");
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/* How much of the kernel log to snapshot */
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unsigned long kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES;
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module_param(kmsg_bytes, ulong, 0444);
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MODULE_PARM_DESC(kmsg_bytes, "amount of kernel log to snapshot (in bytes)");
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static void *compress_workspace;
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/*
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* Compression is only used for dmesg output, which consists of low-entropy
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* ASCII text, and so we can assume worst-case 60%.
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*/
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#define DMESG_COMP_PERCENT 60
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static char *big_oops_buf;
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static size_t max_compressed_size;
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void pstore_set_kmsg_bytes(int bytes)
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{
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kmsg_bytes = bytes;
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}
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/* Tag each group of saved records with a sequence number */
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static int oopscount;
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const char *pstore_type_to_name(enum pstore_type_id type)
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{
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BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
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if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
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return "unknown";
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return pstore_type_names[type];
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}
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EXPORT_SYMBOL_GPL(pstore_type_to_name);
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enum pstore_type_id pstore_name_to_type(const char *name)
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{
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int i;
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for (i = 0; i < PSTORE_TYPE_MAX; i++) {
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if (!strcmp(pstore_type_names[i], name))
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return i;
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}
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return PSTORE_TYPE_MAX;
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}
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EXPORT_SYMBOL_GPL(pstore_name_to_type);
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static void pstore_timer_kick(void)
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{
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if (pstore_update_ms < 0)
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return;
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mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
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}
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static bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
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{
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/*
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* In case of NMI path, pstore shouldn't be blocked
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* regardless of reason.
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*/
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if (in_nmi())
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return true;
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switch (reason) {
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/* In panic case, other cpus are stopped by smp_send_stop(). */
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case KMSG_DUMP_PANIC:
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/*
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* Emergency restart shouldn't be blocked by spinning on
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* pstore_info::buf_lock.
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*/
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case KMSG_DUMP_EMERG:
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return true;
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default:
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return false;
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}
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}
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static int pstore_compress(const void *in, void *out,
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unsigned int inlen, unsigned int outlen)
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{
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struct z_stream_s zstream = {
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.next_in = in,
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.avail_in = inlen,
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.next_out = out,
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.avail_out = outlen,
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.workspace = compress_workspace,
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};
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int ret;
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if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS))
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return -EINVAL;
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ret = zlib_deflateInit2(&zstream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
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-MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
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if (ret != Z_OK)
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return -EINVAL;
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ret = zlib_deflate(&zstream, Z_FINISH);
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if (ret != Z_STREAM_END)
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return -EINVAL;
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ret = zlib_deflateEnd(&zstream);
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if (ret != Z_OK)
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pr_warn_once("zlib_deflateEnd() failed: %d\n", ret);
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return zstream.total_out;
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}
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static void allocate_buf_for_compression(void)
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{
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size_t compressed_size;
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char *buf;
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/* Skip if not built-in or compression disabled. */
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if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !compress ||
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!strcmp(compress, "none")) {
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compress = NULL;
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return;
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}
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if (strcmp(compress, "deflate")) {
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pr_err("Unsupported compression '%s', falling back to deflate\n",
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compress);
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compress = "deflate";
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}
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/*
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* The compression buffer only needs to be as large as the maximum
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* uncompressed record size, since any record that would be expanded by
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* compression is just stored uncompressed.
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*/
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compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT;
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buf = kvzalloc(compressed_size, GFP_KERNEL);
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if (!buf) {
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pr_err("Failed %zu byte compression buffer allocation for: %s\n",
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psinfo->bufsize, compress);
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return;
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}
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compress_workspace =
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vmalloc(zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL));
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if (!compress_workspace) {
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pr_err("Failed to allocate zlib deflate workspace\n");
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kvfree(buf);
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return;
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}
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/* A non-NULL big_oops_buf indicates compression is available. */
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big_oops_buf = buf;
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max_compressed_size = compressed_size;
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pr_info("Using crash dump compression: %s\n", compress);
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}
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static void free_buf_for_compression(void)
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{
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if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress_workspace) {
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vfree(compress_workspace);
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compress_workspace = NULL;
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}
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kvfree(big_oops_buf);
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big_oops_buf = NULL;
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max_compressed_size = 0;
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}
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void pstore_record_init(struct pstore_record *record,
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struct pstore_info *psinfo)
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{
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memset(record, 0, sizeof(*record));
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record->psi = psinfo;
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/* Report zeroed timestamp if called before timekeeping has resumed. */
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record->time = ns_to_timespec64(ktime_get_real_fast_ns());
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}
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/*
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* callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
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* end of the buffer.
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*/
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static void pstore_dump(struct kmsg_dumper *dumper,
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enum kmsg_dump_reason reason)
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{
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struct kmsg_dump_iter iter;
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unsigned long total = 0;
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const char *why;
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unsigned int part = 1;
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unsigned long flags = 0;
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int saved_ret = 0;
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int ret;
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why = kmsg_dump_reason_str(reason);
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if (pstore_cannot_block_path(reason)) {
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if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
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pr_err("dump skipped in %s path because of concurrent dump\n",
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in_nmi() ? "NMI" : why);
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return;
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}
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} else {
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spin_lock_irqsave(&psinfo->buf_lock, flags);
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}
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kmsg_dump_rewind(&iter);
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oopscount++;
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while (total < kmsg_bytes) {
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char *dst;
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size_t dst_size;
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int header_size;
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int zipped_len = -1;
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size_t dump_size;
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struct pstore_record record;
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pstore_record_init(&record, psinfo);
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record.type = PSTORE_TYPE_DMESG;
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record.count = oopscount;
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record.reason = reason;
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record.part = part;
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record.buf = psinfo->buf;
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dst = big_oops_buf ?: psinfo->buf;
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dst_size = max_compressed_size ?: psinfo->bufsize;
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/* Write dump header. */
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header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
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oopscount, part);
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dst_size -= header_size;
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/* Write dump contents. */
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if (!kmsg_dump_get_buffer(&iter, true, dst + header_size,
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dst_size, &dump_size))
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break;
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if (big_oops_buf) {
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zipped_len = pstore_compress(dst, psinfo->buf,
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header_size + dump_size,
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psinfo->bufsize);
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if (zipped_len > 0) {
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record.compressed = true;
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record.size = zipped_len;
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} else {
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/*
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* Compression failed, so the buffer is most
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* likely filled with binary data that does not
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* compress as well as ASCII text. Copy as much
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* of the uncompressed data as possible into
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* the pstore record, and discard the rest.
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*/
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record.size = psinfo->bufsize;
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memcpy(psinfo->buf, dst, psinfo->bufsize);
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}
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} else {
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record.size = header_size + dump_size;
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}
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ret = psinfo->write(&record);
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if (ret == 0 && reason == KMSG_DUMP_OOPS) {
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pstore_new_entry = 1;
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pstore_timer_kick();
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} else {
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/* Preserve only the first non-zero returned value. */
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if (!saved_ret)
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saved_ret = ret;
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}
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total += record.size;
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part++;
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}
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spin_unlock_irqrestore(&psinfo->buf_lock, flags);
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if (saved_ret) {
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pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,
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saved_ret);
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}
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}
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static struct kmsg_dumper pstore_dumper = {
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.dump = pstore_dump,
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};
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/*
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* Register with kmsg_dump to save last part of console log on panic.
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*/
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static void pstore_register_kmsg(void)
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{
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kmsg_dump_register(&pstore_dumper);
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}
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static void pstore_unregister_kmsg(void)
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{
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kmsg_dump_unregister(&pstore_dumper);
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}
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#ifdef CONFIG_PSTORE_CONSOLE
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static void pstore_console_write(struct console *con, const char *s, unsigned c)
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{
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struct pstore_record record;
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if (!c)
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return;
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pstore_record_init(&record, psinfo);
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record.type = PSTORE_TYPE_CONSOLE;
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record.buf = (char *)s;
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record.size = c;
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psinfo->write(&record);
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}
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static struct console pstore_console = {
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.write = pstore_console_write,
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.index = -1,
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};
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static void pstore_register_console(void)
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{
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/* Show which backend is going to get console writes. */
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strscpy(pstore_console.name, psinfo->name,
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sizeof(pstore_console.name));
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/*
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* Always initialize flags here since prior unregister_console()
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* calls may have changed settings (specifically CON_ENABLED).
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*/
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pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
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register_console(&pstore_console);
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}
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static void pstore_unregister_console(void)
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{
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unregister_console(&pstore_console);
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}
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#else
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static void pstore_register_console(void) {}
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static void pstore_unregister_console(void) {}
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#endif
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static int pstore_write_user_compat(struct pstore_record *record,
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const char __user *buf)
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{
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int ret = 0;
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if (record->buf)
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return -EINVAL;
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record->buf = vmemdup_user(buf, record->size);
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if (IS_ERR(record->buf)) {
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ret = PTR_ERR(record->buf);
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goto out;
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}
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ret = record->psi->write(record);
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kvfree(record->buf);
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out:
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record->buf = NULL;
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return unlikely(ret < 0) ? ret : record->size;
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}
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/*
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* platform specific persistent storage driver registers with
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* us here. If pstore is already mounted, call the platform
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* read function right away to populate the file system. If not
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* then the pstore mount code will call us later to fill out
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* the file system.
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*/
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int pstore_register(struct pstore_info *psi)
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{
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char *new_backend;
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if (backend && strcmp(backend, psi->name)) {
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pr_warn("backend '%s' already in use: ignoring '%s'\n",
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backend, psi->name);
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return -EBUSY;
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}
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/* Sanity check flags. */
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if (!psi->flags) {
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pr_warn("backend '%s' must support at least one frontend\n",
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psi->name);
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return -EINVAL;
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}
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/* Check for required functions. */
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if (!psi->read || !psi->write) {
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pr_warn("backend '%s' must implement read() and write()\n",
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psi->name);
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return -EINVAL;
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}
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new_backend = kstrdup(psi->name, GFP_KERNEL);
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if (!new_backend)
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return -ENOMEM;
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mutex_lock(&psinfo_lock);
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if (psinfo) {
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pr_warn("backend '%s' already loaded: ignoring '%s'\n",
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psinfo->name, psi->name);
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mutex_unlock(&psinfo_lock);
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kfree(new_backend);
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return -EBUSY;
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}
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if (!psi->write_user)
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psi->write_user = pstore_write_user_compat;
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psinfo = psi;
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mutex_init(&psinfo->read_mutex);
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spin_lock_init(&psinfo->buf_lock);
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if (psi->flags & PSTORE_FLAGS_DMESG)
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allocate_buf_for_compression();
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pstore_get_records(0);
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if (psi->flags & PSTORE_FLAGS_DMESG) {
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pstore_dumper.max_reason = psinfo->max_reason;
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pstore_register_kmsg();
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}
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if (psi->flags & PSTORE_FLAGS_CONSOLE)
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pstore_register_console();
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if (psi->flags & PSTORE_FLAGS_FTRACE)
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pstore_register_ftrace();
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if (psi->flags & PSTORE_FLAGS_PMSG)
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pstore_register_pmsg();
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/* Start watching for new records, if desired. */
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pstore_timer_kick();
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/*
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* Update the module parameter backend, so it is visible
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* through /sys/module/pstore/parameters/backend
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*/
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backend = new_backend;
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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_DESCRIPTION("Persistent Storage - platform driver interface");
|
|
MODULE_LICENSE("GPL");
|