kernel.git/fs/pstore/platform.c, branch linux-3.11.y

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

2013-07-04T17:29:23Z

Pull powerpc updates from Ben Herrenschmidt: "This is the powerpc changes for the 3.11 merge window. In addition to the usual bug fixes and small updates, the main highlights are: - Support for transparent huge pages by Aneesh Kumar for 64-bit server processors. This allows the use of 16M pages as transparent huge pages on kernels compiled with a 64K base page size. - Base VFIO support for KVM on power by Alexey Kardashevskiy - Wiring up of our nvram to the pstore infrastructure, including putting compressed oopses in there by Aruna Balakrishnaiah - Move, rework and improve our "EEH" (basically PCI error handling and recovery) infrastructure. It is no longer specific to pseries but is now usable by the new "powernv" platform as well (no hypervisor) by Gavin Shan. - I fixed some bugs in our math-emu instruction decoding and made it usable to emulate some optional FP instructions on processors with hard FP that lack them (such as fsqrt on Freescale embedded processors). - Support for Power8 "Event Based Branch" facility by Michael Ellerman. This facility allows what is basically "userspace interrupts" for performance monitor events. - A bunch of Transactional Memory vs. Signals bug fixes and HW breakpoint/watchpoint fixes by Michael Neuling. And more ... I appologize in advance if I've failed to highlight something that somebody deemed worth it." * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (156 commits) pstore: Add hsize argument in write_buf call of pstore_ftrace_call powerpc/fsl: add MPIC timer wakeup support powerpc/mpic: create mpic subsystem object powerpc/mpic: add global timer support powerpc/mpic: add irq_set_wake support powerpc/85xx: enable coreint for all the 64bit boards powerpc/8xx: Erroneous double irq_eoi() on CPM IRQ in MPC8xx powerpc/fsl: Enable CONFIG_E1000E in mpc85xx_smp_defconfig powerpc/mpic: Add get_version API both for internal and external use powerpc: Handle both new style and old style reserve maps powerpc/hw_brk: Fix off by one error when validating DAWR region end powerpc/pseries: Support compression of oops text via pstore powerpc/pseries: Re-organise the oops compression code pstore: Pass header size in the pstore write callback powerpc/powernv: Fix iommu initialization again powerpc/pseries: Inform the hypervisor we are using EBB regs powerpc/perf: Add power8 EBB support powerpc/perf: Core EBB support for 64-bit book3s powerpc/perf: Drop MMCRA from thread_struct powerpc/perf: Don't enable if we have zero events ...

pstore: Pass header size in the pstore write callback

2013-07-01T08:10:48Z

Header size is needed to distinguish between header and the dump data. Incorporate the addition of new argument (hsize) in the pstore write callback. Signed-off-by: Aruna Balakrishnaiah Acked-by: Kees Cook Signed-off-by: Benjamin Herrenschmidt

pstore: Return unique error if backend registration excluded by kernel param

2013-06-28T22:21:52Z

This is patch 1/3 of a patch set that avoids what misleadingly appears to be a error during boot: ERST: Could not register with persistent store This message is displayed if the system has a valid ACPI ERST table and the pstore.backend kernel parameter has been used to disable use of ERST by pstore. But this same message is used for errors that preclude registration. As part of fixing this, return a unique error status from pstore_register if the pstore.backend kernel parameter selects a specific facility other than the requesting facility and check for this condition before any others. This allows the caller to distinquish this benign case from the other failure cases. Also, print an informational console message about which facility successfully registered as the pstore backend. Since there are various kernel parameters, config build options, and boot-time errors that can influence which facility registers with pstore, it's useful to have a positive indication. Signed-off-by: Lenny Szubowicz Reported-by: Naotaka Hamaguchi Signed-off-by: Tony Luck

pstore: Avoid deadlock in panic and emergency-restart path

2013-01-11T18:20:50Z

[Issue] When pstore is in panic and emergency-restart paths, it may be blocked in those paths because it simply takes spin_lock. This is an example scenario which pstore may hang up in a panic path: - cpuA grabs psinfo->buf_lock - cpuB panics and calls smp_send_stop - smp_send_stop sends IRQ to cpuA - after 1 second, cpuB gives up on cpuA and sends an NMI instead - cpuA is now in an NMI handler while still holding buf_lock - cpuB is deadlocked This case may happen if a firmware has a bug and cpuA is stuck talking with it more than one second. Also, this is a similar scenario in an emergency-restart path: - cpuA grabs psinfo->buf_lock and stucks in a firmware - cpuB kicks emergency-restart via either sysrq-b or hangcheck timer. And then, cpuB is deadlocked by taking psinfo->buf_lock again. [Solution] This patch avoids the deadlocking issues in both panic and emergency_restart paths by introducing a function, is_non_blocking_path(), to check if a cpu can be blocked in current path. With this patch, pstore is not blocked even if another cpu has taken a spin_lock, in those paths by changing from spin_lock_irqsave to spin_trylock_irqsave. In addition, according to a comment of emergency_restart() in kernel/sys.c, spin_lock shouldn't be taken in an emergency_restart path to avoid deadlock. This patch fits the comment below. /** * emergency_restart - reboot the system * * Without shutting down any hardware or taking any locks * reboot the system. This is called when we know we are in * trouble so this is our best effort to reboot. This is * safe to call in interrupt context. */ void emergency_restart(void) Signed-off-by: Seiji Aguchi Acked-by: Don Zickus Signed-off-by: Tony Luck

efi_pstore: Add a sequence counter to a variable name

2012-11-27T00:07:44Z

[Issue] Currently, a variable name, which identifies each entry, consists of type, id and ctime. But if multiple events happens in a short time, a second/third event may fail to log because efi_pstore can't distinguish each event with current variable name. [Solution] A reasonable way to identify all events precisely is introducing a sequence counter to the variable name. The sequence counter has already supported in a pstore layer with "oopscount". So, this patch adds it to a variable name. Also, it is passed to read/erase callbacks of platform drivers in accordance with the modification of the variable name. a variable name of first event: dump-type0-1-12345678 a variable name of second event: dump-type0-1-12345678 type:0 id:1 ctime:12345678 If multiple events happen in a short time, efi_pstore can't distinguish them because variable names are same among them. it can be distinguishable by adding a sequence counter as follows. a variable name of first event: dump-type0-1-1-12345678 a variable name of Second event: dump-type0-1-2-12345678 type:0 id:1 sequence counter: 1(first event), 2(second event) ctime:12345678 In case of a write callback executed in pstore_console_write(), "0" is added to an argument of the write callback because it just logs all kernel messages and doesn't need to care about multiple events. Signed-off-by: Seiji Aguchi Acked-by: Rafael J. Wysocki Acked-by: Mike Waychison Signed-off-by: Tony Luck

pstore: Fix NULL pointer dereference in console writes

2012-11-15T02:30:21Z

Passing a NULL id causes a NULL pointer deference in writers such as erst_writer and efi_pstore_write because they expect to update this id. Pass a dummy id instead. This avoids a cascade of oopses caused when the initial pstore_console_write passes a null which in turn causes writes to the console causing further oopses in subsequent pstore_console_write calls. Signed-off-by: Colin Ian King Acked-by: Kees Cook Cc: stable@vger.kernel.org Signed-off-by: Anton Vorontsov

pstore: Avoid recursive spinlocks in the oops_in_progress case

2012-09-21T00:04:50Z

Like 8250 driver, when pstore is registered as a console, to avoid recursive spinlocks when panic happening, change the spin_lock_irqsave to spin_trylock_irqsave when oops_in_progress is true. Signed-off-by: liu chuansheng Signed-off-by: Anton Vorontsov

pstore/ftrace: Convert to its own enable/disable debugfs knob

2012-09-07T05:16:58Z

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 Signed-off-by: Anton Vorontsov

pstore: Add persistent function tracing

2012-07-17T17:05:52Z

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 (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman

pstore: Introduce write_buf backend callback

2012-07-17T16:51:38Z

For function tracing we need to stop using pstore.buf directly, since in a tracing callback we can't use spinlocks, and thus we can't safely use the global buffer. With write_buf callback, backends no longer need to access pstore.buf directly, and thus we can pass any buffers (e.g. allocated on stack). Signed-off-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman