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linux-next/fs/pstore/internal.h

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pstore: Add persistent function tracing With this support kernel can save function call chain log into a persistent ram buffer that can be decoded and dumped after reboot through pstore filesystem. It can be used to determine what function was last called before a reset or panic. We store the log in a binary format and then decode it at read time. p.s. Mostly the code comes from trace_persistent.c driver found in the Android git tree, written by Colin Cross <ccross@android.com> (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-10 08:10:41 +08:00
#ifndef __PSTORE_INTERNAL_H__
#define __PSTORE_INTERNAL_H__
pstore: Headers should include all stuff they use Headers should really include all the needed prototypes, types, defines etc. to be self-contained. This is a long-standing issue, but apparently the new tracing code unearthed it (SMP=n is also a prerequisite): In file included from fs/pstore/internal.h:4:0, from fs/pstore/ftrace.c:21: include/linux/pstore.h:43:15: error: field ‘read_mutex’ has incomplete type While at it, I also added the following: linux/types.h -> size_t, phys_addr_t, uXX and friends linux/spinlock.h -> spinlock_t linux/errno.h -> Exxxx linux/time.h -> struct timespec (struct passed by value) struct module and rs_control forward declaration (passed via pointers). Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-18 02:37:07 +08:00
#include <linux/types.h>
#include <linux/time.h>
pstore: Add persistent function tracing With this support kernel can save function call chain log into a persistent ram buffer that can be decoded and dumped after reboot through pstore filesystem. It can be used to determine what function was last called before a reset or panic. We store the log in a binary format and then decode it at read time. p.s. Mostly the code comes from trace_persistent.c driver found in the Android git tree, written by Colin Cross <ccross@android.com> (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-10 08:10:41 +08:00
#include <linux/pstore.h>
pstore: Implement show_options Implement the show_options superblock op for pstore as part of a bid to get rid of s_options and generic_show_options() to make it easier to implement a context-based mount where the mount options can be passed individually over a file descriptor. Signed-off-by: David Howells <dhowells@redhat.com> cc: Kees Cook <keescook@chromium.org> cc: Anton Vorontsov <anton@enomsg.org> cc: Colin Cross <ccross@android.com> cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-07-05 23:24:34 +08:00
#define PSTORE_DEFAULT_KMSG_BYTES 10240
extern unsigned long kmsg_bytes;
pstore/ftrace: Convert to its own enable/disable debugfs knob With this patch we no longer reuse function tracer infrastructure, now we register our own tracer back-end via a debugfs knob. It's a bit more code, but that is the only downside. On the bright side we have: - Ability to make persistent_ram module removable (when needed, we can move ftrace_ops struct into a module). Note that persistent_ram is still not removable for other reasons, but with this patch it's just one thing less to worry about; - Pstore part is more isolated from the generic function tracer. We tried it already by registering our own tracer in available_tracers, but that way we're loosing ability to see the traces while we record them to pstore. This solution is somewhere in the middle: we only register "internal ftracer" back-end, but not the "front-end"; - When there is only pstore tracing enabled, the kernel will only write to the pstore buffer, omitting function tracer buffer (which, of course, still can be enabled via 'echo function > current_tracer'). Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-07-18 05:26:15 +08:00
#ifdef CONFIG_PSTORE_FTRACE
extern void pstore_register_ftrace(void);
pstore: add pstore unregister pstore doesn't support unregistering yet. It was marked as TODO. This patch adds some code to fix it: 1) Add functions to unregister kmsg/console/ftrace/pmsg. 2) Add a function to free compression buffer. 3) Unmap the memory and free it. 4) Add a function to unregister pstore filesystem. Signed-off-by: Geliang Tang <geliangtang@163.com> Acked-by: Kees Cook <keescook@chromium.org> [Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann] Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-10-20 15:39:03 +08:00
extern void pstore_unregister_ftrace(void);
pstore/ftrace: Convert to its own enable/disable debugfs knob With this patch we no longer reuse function tracer infrastructure, now we register our own tracer back-end via a debugfs knob. It's a bit more code, but that is the only downside. On the bright side we have: - Ability to make persistent_ram module removable (when needed, we can move ftrace_ops struct into a module). Note that persistent_ram is still not removable for other reasons, but with this patch it's just one thing less to worry about; - Pstore part is more isolated from the generic function tracer. We tried it already by registering our own tracer in available_tracers, but that way we're loosing ability to see the traces while we record them to pstore. This solution is somewhere in the middle: we only register "internal ftracer" back-end, but not the "front-end"; - When there is only pstore tracing enabled, the kernel will only write to the pstore buffer, omitting function tracer buffer (which, of course, still can be enabled via 'echo function > current_tracer'). Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-07-18 05:26:15 +08:00
#else
static inline void pstore_register_ftrace(void) {}
pstore: add pstore unregister pstore doesn't support unregistering yet. It was marked as TODO. This patch adds some code to fix it: 1) Add functions to unregister kmsg/console/ftrace/pmsg. 2) Add a function to free compression buffer. 3) Unmap the memory and free it. 4) Add a function to unregister pstore filesystem. Signed-off-by: Geliang Tang <geliangtang@163.com> Acked-by: Kees Cook <keescook@chromium.org> [Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann] Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-10-20 15:39:03 +08:00
static inline void pstore_unregister_ftrace(void) {}
pstore/ftrace: Convert to its own enable/disable debugfs knob With this patch we no longer reuse function tracer infrastructure, now we register our own tracer back-end via a debugfs knob. It's a bit more code, but that is the only downside. On the bright side we have: - Ability to make persistent_ram module removable (when needed, we can move ftrace_ops struct into a module). Note that persistent_ram is still not removable for other reasons, but with this patch it's just one thing less to worry about; - Pstore part is more isolated from the generic function tracer. We tried it already by registering our own tracer in available_tracers, but that way we're loosing ability to see the traces while we record them to pstore. This solution is somewhere in the middle: we only register "internal ftracer" back-end, but not the "front-end"; - When there is only pstore tracing enabled, the kernel will only write to the pstore buffer, omitting function tracer buffer (which, of course, still can be enabled via 'echo function > current_tracer'). Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-07-18 05:26:15 +08:00
#endif
pstore: Add pmsg - user-space accessible pstore object A secured user-space accessible pstore object. Writes to /dev/pmsg0 are appended to the buffer, on reboot the persistent contents are available in /sys/fs/pstore/pmsg-ramoops-[ID]. One possible use is syslogd, or other daemon, can write messages, then on reboot provides a means to triage user-space activities leading up to a panic as a companion to the pstore dmesg or console logs. Signed-off-by: Mark Salyzyn <salyzyn@android.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-01-17 08:01:10 +08:00
#ifdef CONFIG_PSTORE_PMSG
extern void pstore_register_pmsg(void);
pstore: add pstore unregister pstore doesn't support unregistering yet. It was marked as TODO. This patch adds some code to fix it: 1) Add functions to unregister kmsg/console/ftrace/pmsg. 2) Add a function to free compression buffer. 3) Unmap the memory and free it. 4) Add a function to unregister pstore filesystem. Signed-off-by: Geliang Tang <geliangtang@163.com> Acked-by: Kees Cook <keescook@chromium.org> [Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann] Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-10-20 15:39:03 +08:00
extern void pstore_unregister_pmsg(void);
pstore: Add pmsg - user-space accessible pstore object A secured user-space accessible pstore object. Writes to /dev/pmsg0 are appended to the buffer, on reboot the persistent contents are available in /sys/fs/pstore/pmsg-ramoops-[ID]. One possible use is syslogd, or other daemon, can write messages, then on reboot provides a means to triage user-space activities leading up to a panic as a companion to the pstore dmesg or console logs. Signed-off-by: Mark Salyzyn <salyzyn@android.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-01-17 08:01:10 +08:00
#else
static inline void pstore_register_pmsg(void) {}
pstore: add pstore unregister pstore doesn't support unregistering yet. It was marked as TODO. This patch adds some code to fix it: 1) Add functions to unregister kmsg/console/ftrace/pmsg. 2) Add a function to free compression buffer. 3) Unmap the memory and free it. 4) Add a function to unregister pstore filesystem. Signed-off-by: Geliang Tang <geliangtang@163.com> Acked-by: Kees Cook <keescook@chromium.org> [Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann] Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-10-20 15:39:03 +08:00
static inline void pstore_unregister_pmsg(void) {}
pstore: Add pmsg - user-space accessible pstore object A secured user-space accessible pstore object. Writes to /dev/pmsg0 are appended to the buffer, on reboot the persistent contents are available in /sys/fs/pstore/pmsg-ramoops-[ID]. One possible use is syslogd, or other daemon, can write messages, then on reboot provides a means to triage user-space activities leading up to a panic as a companion to the pstore dmesg or console logs. Signed-off-by: Mark Salyzyn <salyzyn@android.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-01-17 08:01:10 +08:00
#endif
pstore: Add persistent function tracing With this support kernel can save function call chain log into a persistent ram buffer that can be decoded and dumped after reboot through pstore filesystem. It can be used to determine what function was last called before a reset or panic. We store the log in a binary format and then decode it at read time. p.s. Mostly the code comes from trace_persistent.c driver found in the Android git tree, written by Colin Cross <ccross@android.com> (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-10 08:10:41 +08:00
extern struct pstore_info *psinfo;
pstore: use mount option instead sysfs to tweak kmsg_bytes /sys/fs is a somewhat strange way to tweak what could more obviously be tuned with a mount option. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-19 06:33:43 +08:00
extern void pstore_set_kmsg_bytes(int);
pstore: defer inserting OOPS entries into pstore Life is simple for all the kernel terminating types of kmsg_dump call backs - pstore just saves the tail end of the console log. But for "oops" the situation is more complex - the kernel may carry on running (possibly for ever). So we'd like to make the logged copy of the oops appear in the pstore filesystem - so that the user has a handle to clear the entry from the persistent backing store (if we don't, the store may fill with "oops" entries (that are also safely stashed in /var/log/messages) leaving no space for real errors. Current code calls pstore_mkfile() immediately. But this may not be safe. The oops could have happened with arbitrary locks held, or in interrupt or NMI context. So allocating memory and calling into generic filesystem code seems unwise. This patch defers making the entry appear. At the time of the oops, we merely set a flag "pstore_new_entry" noting that a new entry has been added. A periodic timer checks once a minute to see if the flag is set - if so, it schedules a work queue to rescan the backing store and make all new entries appear in the pstore filesystem. Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-08-12 06:14:39 +08:00
extern void pstore_get_records(int);
pstore: Solve lockdep warning by moving inode locks Lockdep complains about a possible deadlock between mount and unlink (which is technically impossible), but fixing this improves possible future multiple-backend support, and keeps locking in the right order. The lockdep warning could be triggered by unlinking a file in the pstore filesystem: -> #1 (&sb->s_type->i_mutex_key#14){++++++}: lock_acquire+0xc9/0x220 down_write+0x3f/0x70 pstore_mkfile+0x1f4/0x460 pstore_get_records+0x17a/0x320 pstore_fill_super+0xa4/0xc0 mount_single+0x89/0xb0 pstore_mount+0x13/0x20 mount_fs+0xf/0x90 vfs_kern_mount+0x66/0x170 do_mount+0x190/0xd50 SyS_mount+0x90/0xd0 entry_SYSCALL_64_fastpath+0x1c/0xb1 -> #0 (&psinfo->read_mutex){+.+.+.}: __lock_acquire+0x1ac0/0x1bb0 lock_acquire+0xc9/0x220 __mutex_lock+0x6e/0x990 mutex_lock_nested+0x16/0x20 pstore_unlink+0x3f/0xa0 vfs_unlink+0xb5/0x190 do_unlinkat+0x24c/0x2a0 SyS_unlinkat+0x16/0x30 entry_SYSCALL_64_fastpath+0x1c/0xb1 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#14); lock(&psinfo->read_mutex); lock(&sb->s_type->i_mutex_key#14); lock(&psinfo->read_mutex); Reported-by: Marta Lofstedt <marta.lofstedt@intel.com> Reported-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Namhyung Kim <namhyung@kernel.org>
2017-04-28 06:53:21 +08:00
extern void pstore_get_backend_records(struct pstore_info *psi,
struct dentry *root, int quiet);
extern int pstore_mkfile(struct dentry *root,
struct pstore_record *record);
pstore: Fix return type of pstore_is_mounted() This patch changes return type of pstore_is_mounted from int to bool. Signed-off-by: Geliang Tang <geliangtang@163.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2015-10-22 16:02:33 +08:00
extern bool pstore_is_mounted(void);
pstore: Create common record initializer In preparation for setting timestamps in the pstore core, create a common initializer routine, instead of using static initializers. Signed-off-by: Kees Cook <keescook@chromium.org>
2017-05-20 06:10:31 +08:00
extern void pstore_record_init(struct pstore_record *record,
struct pstore_info *psi);
pstore: Add persistent function tracing With this support kernel can save function call chain log into a persistent ram buffer that can be decoded and dumped after reboot through pstore filesystem. It can be used to determine what function was last called before a reset or panic. We store the log in a binary format and then decode it at read time. p.s. Mostly the code comes from trace_persistent.c driver found in the Android git tree, written by Colin Cross <ccross@android.com> (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-10 08:10:41 +08:00
#endif
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