linux.git/fs/pstore, branch v3.6

pstore/ram: Make tracing log versioned

2012-07-17T23:48:09+00:00

Decoding the binary trace w/ a different kernel might be troublesome
since we convert addresses to symbols. For kernels with minimal changes,
the mappings would probably match, but it's not guaranteed at all.
(But still we could convert the addresses by hand, since we do print
raw addresses.)

If we use modules, the symbols could be loaded at different addresses
from the previously booted kernel, and so this would also fail, but
there's nothing we can do about it.

Also, the binary data format that pstore/ram is using in its ringbuffer
may change between the kernels, so here we too must ensure that we're
running the same kernel.

So, there are two questions really:

1. How to compute the unique kernel tag;
2. Where to store it.

In this patch we're using LINUX_VERSION_CODE, just as hibernation
(suspend-to-disk) does. This way we are protecting from the kernel
version mismatch, making sure that we're running the same kernel
version and patch level. We could use CRC of a symbol table (as
suggested by Tony Luck), but for now let's not be that strict.

And as for storing, we are using a small trick here. Instead of
allocating a dedicated buffer for the tag (i.e. another prz), or
hacking ram_core routines to "reserve" some control data in the
buffer, we are just encoding the tag into the buffer signature
(and XOR'ing it with the actual signature value, so that buffers
not needing a tag can just pass zero, which will result into the
plain old PRZ signature).

Suggested-by: Steven Rostedt 
Suggested-by: Tony Luck 
Suggested-by: Colin Cross 
Signed-off-by: Anton Vorontsov 
Signed-off-by: Greg Kroah-Hartman

pstore: Headers should include all stuff they use

2012-07-17T19:15:30+00:00

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 
Signed-off-by: Greg Kroah-Hartman

pstore/ram: Add ftrace messages handling

2012-07-17T17:14:17+00:00

The ftrace log size is configurable via ramoops.ftrace_size
module option, and the log itself is available via
/ftrace-ramoops file.

Signed-off-by: Anton Vorontsov 
Signed-off-by: Greg Kroah-Hartman

pstore/ram: Convert to write_buf callback

2012-07-17T17:07:09+00:00

Don't use pstore.buf directly, instead convert the code to write_buf callback
which passes a pointer to a buffer as an argument.

Signed-off-by: Anton Vorontsov 
Signed-off-by: Greg Kroah-Hartman

pstore: Add persistent function tracing

2012-07-17T17:05:52+00:00

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

2012-07-17T16:51:38+00:00

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

pstore/ram_core: Get rid of prz->ecc enable/disable flag

2012-07-17T16:46:52+00:00

Nowadays we can use prz->ecc_size as a flag, no need for the special
member in the prz struct.

Signed-off-by: Anton Vorontsov 
Acked-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore/ram: Make ECC size configurable

2012-07-17T16:46:52+00:00

This is now pretty straightforward: instead of using bool, just pass
an integer. For backwards compatibility ramoops.ecc=1 means 16 bytes
ECC (using 1 byte for ECC isn't much of use anyway).

Suggested-by: Arve Hjønnevåg 
Signed-off-by: Anton Vorontsov 
Acked-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

pstore/ram_core: Get rid of prz->ecc_symsize and prz->ecc_poly

2012-07-17T16:46:52+00:00

The struct members were never used anywhere outside of
persistent_ram_init_ecc(), so there's actually no need for them
to be in the struct.

If we ever want to make polynomial or symbol size configurable,
it would make more sense to just pass initialized rs_decoder
to the persistent_ram init functions.

Signed-off-by: Anton Vorontsov 
Acked-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

Merge 3.5-rc4 into staging-next

2012-06-25T16:31:00+00:00

This picks up the staging changes made in 3.5-rc4 so that everyone can sync up
properly.

Signed-off-by: Greg Kroah-Hartman