linux-toradex.git/fs/pstore, branch v4.4.150

pstore: Use dynamic spinlock initializer

2017-08-07T02:19:43+00:00

commit e9a330c4289f2ba1ca4bf98c2b430ab165a8931b upstream.

The per-prz spinlock should be using the dynamic initializer so that
lockdep can correctly track it. Without this, under lockdep, we get a
warning at boot that the lock is in non-static memory.

Fixes: 109704492ef6 ("pstore: Make spinlock per zone instead of global")
Fixes: 76d5692a5803 ("pstore: Correctly initialize spinlock and flags")
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore: Correctly initialize spinlock and flags

2017-08-07T02:19:43+00:00

commit 76d5692a58031696e282384cbd893832bc92bd76 upstream.

The ram backend wasn't always initializing its spinlock correctly. Since
it was coming from kzalloc memory, though, it was harmless on
architectures that initialize unlocked spinlocks to 0 (at least x86 and
ARM). This also fixes a possibly ignored flag setting too.

When running under CONFIG_DEBUG_SPINLOCK, the following Oops was visible:

[    0.760836] persistent_ram: found existing buffer, size 29988, start 29988
[    0.765112] persistent_ram: found existing buffer, size 30105, start 30105
[    0.769435] persistent_ram: found existing buffer, size 118542, start 118542
[    0.785960] persistent_ram: found existing buffer, size 0, start 0
[    0.786098] persistent_ram: found existing buffer, size 0, start 0
[    0.786131] pstore: using zlib compression
[    0.790716] BUG: spinlock bad magic on CPU#0, swapper/0/1
[    0.790729]  lock: 0xffffffc0d1ca9bb0, .magic: 00000000, .owner: /-1, .owner_cpu: 0
[    0.790742] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.10.0-rc2+ #913
[    0.790747] Hardware name: Google Kevin (DT)
[    0.790750] Call trace:
[    0.790768] [] dump_backtrace+0x0/0x2bc
[    0.790780] [] show_stack+0x20/0x28
[    0.790794] [] dump_stack+0xa4/0xcc
[    0.790809] [] spin_dump+0xe0/0xf0
[    0.790821] [] spin_bug+0x30/0x3c
[    0.790834] [] do_raw_spin_lock+0x50/0x1b8
[    0.790846] [] _raw_spin_lock_irqsave+0x54/0x6c
[    0.790862] [] buffer_size_add+0x48/0xcc
[    0.790875] [] persistent_ram_write+0x60/0x11c
[    0.790888] [] ramoops_pstore_write_buf+0xd4/0x2a4
[    0.790900] [] pstore_console_write+0xf0/0x134
[    0.790912] [] console_unlock+0x48c/0x5e8
[    0.790923] [] register_console+0x3b0/0x4d4
[    0.790935] [] pstore_register+0x1a8/0x234
[    0.790947] [] ramoops_probe+0x6b8/0x7d4
[    0.790961] [] platform_drv_probe+0x7c/0xd0
[    0.790972] [] driver_probe_device+0x1b4/0x3bc
[    0.790982] [] __device_attach_driver+0xc8/0xf4
[    0.790996] [] bus_for_each_drv+0xb4/0xe4
[    0.791006] [] __device_attach+0xd0/0x158
[    0.791016] [] device_initial_probe+0x24/0x30
[    0.791026] [] bus_probe_device+0x50/0xe4
[    0.791038] [] device_add+0x3a4/0x76c
[    0.791051] [] of_device_add+0x74/0x84
[    0.791062] [] of_platform_device_create_pdata+0xc0/0x100
[    0.791073] [] of_platform_device_create+0x34/0x40
[    0.791086] [] of_platform_default_populate_init+0x58/0x78
[    0.791097] [] do_one_initcall+0x88/0x160
[    0.791109] [] kernel_init_freeable+0x264/0x31c
[    0.791123] [] kernel_init+0x18/0x11c
[    0.791133] [] ret_from_fork+0x10/0x50
[    0.793717] console [pstore-1] enabled
[    0.797845] pstore: Registered ramoops as persistent store backend
[    0.804647] ramoops: attached 0x100000@0xf7edc000, ecc: 0/0

Fixes: 663deb47880f ("pstore: Allow prz to control need for locking")
Fixes: 109704492ef6 ("pstore: Make spinlock per zone instead of global")
Reported-by: Brian Norris 
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore: Allow prz to control need for locking

2017-08-07T02:19:43+00:00

commit 663deb47880f2283809669563c5a52ac7c6aef1a upstream.

In preparation of not locking at all for certain buffers depending on if
there's contention, make locking optional depending on the initialization
of the prz.

Signed-off-by: Joel Fernandes 
[kees: moved locking flag into prz instead of via caller arguments]
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore: Make spinlock per zone instead of global

2017-08-07T02:19:38+00:00

commit 109704492ef637956265ec2eb72ae7b3b39eb6f4 upstream.

Currently pstore has a global spinlock for all zones. Since the zones
are independent and modify different areas of memory, there's no need
to have a global lock, so we should use a per-zone lock as introduced
here. Also, when ramoops's ftrace use-case has a FTRACE_PER_CPU flag
introduced later, which splits the ftrace memory area into a single zone
per CPU, it will eliminate the need for locking. In preparation for this,
make the locking optional.

Signed-off-by: Joel Fernandes 
[kees: updated commit message]
Signed-off-by: Kees Cook 
Cc: Leo Yan 
Signed-off-by: Greg Kroah-Hartman

pstore/ram: Use memcpy_fromio() to save old buffer

2016-10-28T07:01:27+00:00

commit d771fdf94180de2bd811ac90cba75f0f346abf8d upstream.

The ramoops buffer may be mapped as either I/O memory or uncached
memory.  On ARM64, this results in a device-type (strongly-ordered)
mapping.  Since unnaligned accesses to device-type memory will
generate an alignment fault (regardless of whether or not strict
alignment checking is enabled), it is not safe to use memcpy().
memcpy_fromio() is guaranteed to only use aligned accesses, so use
that instead.

Signed-off-by: Andrew Bresticker 
Signed-off-by: Enric Balletbo Serra 
Reviewed-by: Puneet Kumar 
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore/ram: Use memcpy_toio instead of memcpy

2016-10-28T07:01:27+00:00

commit 7e75678d23167c2527e655658a8ef36a36c8b4d9 upstream.

persistent_ram_update uses vmap / iomap based on whether the buffer is in
memory region or reserved region. However, both map it as non-cacheable
memory. For armv8 specifically, non-cacheable mapping requests use a
memory type that has to be accessed aligned to the request size. memcpy()
doesn't guarantee that.

Signed-off-by: Furquan Shaikh 
Signed-off-by: Enric Balletbo Serra 
Reviewed-by: Aaron Durbin 
Reviewed-by: Olof Johansson 
Tested-by: Furquan Shaikh 
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore/core: drop cmpxchg based updates

2016-10-28T07:01:27+00:00

commit d5a9bf0b38d2ac85c9a693c7fb851f74fd2a2494 upstream.

I have here a FPGA behind PCIe which exports SRAM which I use for
pstore. Now it seems that the FPGA no longer supports cmpxchg based
updates and writes back 0xff…ff and returns the same.  This leads to
crash during crash rendering pstore useless.
Since I doubt that there is much benefit from using cmpxchg() here, I am
dropping this atomic access and use the spinlock based version.

Cc: Anton Vorontsov 
Cc: Colin Cross 
Cc: Kees Cook 
Cc: Tony Luck 
Cc: Rabin Vincent 
Tested-by: Rabin Vincent 
Signed-off-by: Sebastian Andrzej Siewior 
Reviewed-by: Guenter Roeck 
[kees: remove "_locked" suffix since it's the only option now]
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore/ramoops: fixup driver removal

2016-10-28T07:01:27+00:00

commit 4407de74df18ed405cc5998990004c813ccfdbde upstream.

A basic rmmod ramoops segfaults. Let's see why.

Since commit 34f0ec82e0a9 ("pstore: Correct the max_dump_cnt clearing of
ramoops") sets ->max_dump_cnt to zero before looping over ->przs but we
didn't use it before that either.

And since commit ee1d267423a1 ("pstore: add pstore unregister") we free
that memory on rmmod.

But even then, we looped until a NULL pointer or ERR. I don't see where
it is ensured that the last member is NULL. Let's try this instead:
simply error recovery and free. Clean up in error case where resources
were allocated. And then, in the free path, rely on ->max_dump_cnt in
the free path.

Cc: Anton Vorontsov 
Cc: Colin Cross 
Cc: Kees Cook 
Cc: Tony Luck 
Cc: Namhyung Kim 
Acked-by: Namhyung Kim 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore: drop file opened reference count

2016-10-07T13:23:44+00:00

commit 52d210d961a62a9662e27f14d6505d6741b2fb02 upstream.

In ee1d267423a1 ("pstore: add pstore unregister") I added:
	.owner = THIS_MODULE,
in both pstore_fs_type and pstore_file_operations to increase a reference
count when pstore filesystem is mounted and pstore file is opened.

But, it's repetitive. There is no need to increase the opened reference
count. We only need to increase the mounted reference count. When a file
is opened, the filesystem can't be unmounted. Hence the pstore module
can't be unloaded either.

So I drop the opened reference count in this patch.

Fixes: ee1d267423a1 ("pstore: add pstore unregister")
Signed-off-by: Geliang Tang 
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore: fix code comment to match code

2015-11-02T21:41:52+00:00

Fix code comment about kmsg_dump register so it matches the code.

Signed-off-by: Geliang Tang 
Signed-off-by: Tony Luck