pstore: replace spinlock_t by raw_spinlock_t

pstore_dump() is called when both preemption and local IRQ are disabled,
and a spinlock is obtained, which is problematic for the RT kernel because
in th

pstore: replace spinlock_t by raw_spinlock_t

pstore_dump() is called when both preemption and local IRQ are disabled,
and a spinlock is obtained, which is problematic for the RT kernel because
in this configuration, spinlocks are sleep locks.

Replace the spinlock_t with raw_spinlock_t to avoid sleeping in atomic context.

Signed-off-by: Wen Yang <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Guilherme G. Piccoli <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>

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pstore: Add priv field to pstore_record for backend specific use

The EFI pstore backend will need to store per-record variable name data
when we switch away from the efivars layer. Add a priv field

pstore: Add priv field to pstore_record for backend specific use

The EFI pstore backend will need to store per-record variable name data
when we switch away from the efivars layer. Add a priv field to struct
pstore_record, and document it as holding a backend specific pointer
that is assumed to be a kmalloc()d buffer, and will be kfree()d when the
entire record is freed.

Acked-by: Kees Cook <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>

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pstore: Don't use semaphores in always-atomic-context code

pstore_dump() is *always* invoked in atomic context (nowadays in an RCU
read-side critical section, before that under a spinlock).
It doesn

pstore: Don't use semaphores in always-atomic-context code

pstore_dump() is *always* invoked in atomic context (nowadays in an RCU
read-side critical section, before that under a spinlock).
It doesn't make sense to try to use semaphores here.

This is mostly a revert of commit ea84b580b955 ("pstore: Convert buf_lock
to semaphore"), except that two parts aren't restored back exactly as they
were:

- keep the lock initialization in pstore_register
- in efi_pstore_write(), always set the "block" flag to false
- omit "is_locked", that was unnecessary since
commit 959217c84c27 ("pstore: Actually give up during locking failure")
- fix the bailout message

The actual problem that the buggy commit was trying to address may have
been that the use of preemptible() in efi_pstore_write() was wrong - it
only looks at preempt_count() and the state of IRQs, but __rcu_read_lock()
doesn't touch either of those under CONFIG_PREEMPT_RCU.
(Sidenote: CONFIG_PREEMPT_RCU means that the scheduler can preempt tasks in
RCU read-side critical sections, but you're not allowed to actively
block/reschedule.)

Lockdep probably never caught the problem because it's very rare that you
actually hit the contended case, so lockdep always just sees the
down_trylock(), not the down_interruptible(), and so it can't tell that
there's a problem.

Fixes: ea84b580b955 ("pstore: Convert buf_lock to semaphore")
Cc: [email protected]
Acked-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Jann Horn <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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pstore/platform: Pass max_reason to kmesg dump

Add a new member to struct pstore_info for passing information about
kmesg dump maximum reason. This allows a finer control of what kmesg
dumps are sen

pstore/platform: Pass max_reason to kmesg dump

Add a new member to struct pstore_info for passing information about
kmesg dump maximum reason. This allows a finer control of what kmesg
dumps are sent to pstore storage backends.

Those backends that do not explicitly set this field (keeping it equal to
0), get the default behavior: store only Oopses and Panics, or everything
if the printk.always_kmsg_dump boot param is set.

Signed-off-by: Pavel Tatashin <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
Co-developed-by: Kees Cook <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

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pstore/platform: Switch pstore_info::name to const

In order to more cleanly pass around backend names, make the "name" member
const. This means the module param needs to be dynamic (technically, it

pstore/platform: Switch pstore_info::name to const

In order to more cleanly pass around backend names, make the "name" member
const. This means the module param needs to be dynamic (technically, it
was before, so this actually cleans up a minor memory leak if a backend
was specified and then gets unloaded.)

Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Kees Cook <[email protected]>

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 59 temple place suite 330 boston ma 02111
1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 136 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexios Zavras <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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pstore: Convert buf_lock to semaphore

Instead of running with interrupts disabled, use a semaphore. This should
make it easier for backends that may need to sleep (e.g. EFI) when
performing a write:

pstore: Convert buf_lock to semaphore

Instead of running with interrupts disabled, use a semaphore. This should
make it easier for backends that may need to sleep (e.g. EFI) when
performing a write:

|BUG: sleeping function called from invalid context at kernel/sched/completion.c:99
|in_atomic(): 1, irqs_disabled(): 1, pid: 2236, name: sig-xstate-bum
|Preemption disabled at:
|[<ffffffff99d60512>] pstore_dump+0x72/0x330
|CPU: 26 PID: 2236 Comm: sig-xstate-bum Tainted: G D 4.20.0-rc3 #45
|Call Trace:
| dump_stack+0x4f/0x6a
| ___might_sleep.cold.91+0xd3/0xe4
| __might_sleep+0x50/0x90
| wait_for_completion+0x32/0x130
| virt_efi_query_variable_info+0x14e/0x160
| efi_query_variable_store+0x51/0x1a0
| efivar_entry_set_safe+0xa3/0x1b0
| efi_pstore_write+0x109/0x140
| pstore_dump+0x11c/0x330
| kmsg_dump+0xa4/0xd0
| oops_exit+0x22/0x30
...

Reported-by: Sebastian Andrzej Siewior <[email protected]>
Fixes: 21b3ddd39fee ("efi: Don't use spinlocks for efi vars")
Signed-off-by: Kees Cook <[email protected]>

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pstore: Map PSTORE_TYPE_* to strings

In later patches we will need to map types to names, so create a
constant table for that which can also be used in different parts of
old and new code. This save

pstore: Map PSTORE_TYPE_* to strings

In later patches we will need to map types to names, so create a
constant table for that which can also be used in different parts of
old and new code. This saves the type in the PRZ which will be useful
in later patches.

Instead of having an explicit PSTORE_TYPE_UNKNOWN, just use ..._MAX.

This includes removing the now redundant filename templates which can use
a single format string. Also, there's no reason to limit the "is it still
compressed?" test to only PSTORE_TYPE_DMESG when building the pstorefs
filename. Records are zero-initialized, so a backend would need to have
explicitly set compressed=1.

Signed-off-by: Joel Fernandes (Google) <[email protected]>
Co-developed-by: Kees Cook <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

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pstore: Replace open-coded << with BIT()

Minor clean-up to use BIT() (as already done in pstore_ram.h).

Signed-off-by: Kees Cook <[email protected]>

pstore: Improve and update some comments and status output

This improves and updates some comments:
- dump handler comment out of sync from calling convention
- fix kern-doc typo

and improves sta

pstore: Improve and update some comments and status output

This improves and updates some comments:
- dump handler comment out of sync from calling convention
- fix kern-doc typo

and improves status output:
- reminder that only kernel crash dumps are compressed
- do not be silent about ECC infrastructure failures

Signed-off-by: Kees Cook <[email protected]>

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pstore/ram: Correctly calculate usable PRZ bytes

The actual number of bytes stored in a PRZ is smaller than the
bytes requested by platform data, since there is a header on each
PRZ. Additionally, i

pstore/ram: Correctly calculate usable PRZ bytes

The actual number of bytes stored in a PRZ is smaller than the
bytes requested by platform data, since there is a header on each
PRZ. Additionally, if ECC is enabled, there are trailing bytes used
as well. Normally this mismatch doesn't matter since PRZs are circular
buffers and the leading "overflow" bytes are just thrown away. However, in
the case of a compressed record, this rather badly corrupts the results.

This corruption was visible with "ramoops.mem_size=204800 ramoops.ecc=1".
Any stored crashes would not be uncompressable (producing a pstorefs
"dmesg-*.enc.z" file), and triggering errors at boot:

[ 2.790759] pstore: crypto_comp_decompress failed, ret = -22!

Backporting this depends on commit 70ad35db3321 ("pstore: Convert console
write to use ->write_buf")

Reported-by: Joel Fernandes <[email protected]>
Fixes: b0aad7a99c1d ("pstore: Add compression support to pstore")
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Joel Fernandes (Google) <[email protected]>

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pstore: Convert internal records to timespec64

This prepares pstore for converting the VFS layer to timespec64.

Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Deepa Dinamani <deepa

pstore: Convert internal records to timespec64

This prepares pstore for converting the VFS layer to timespec64.

Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Deepa Dinamani <[email protected]>

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pstore: Populate pstore record->time field

The current time will be initially available in the record->time field
for all pstore_read() and pstore_write() calls. Backends can either
update the field

pstore: Populate pstore record->time field

The current time will be initially available in the record->time field
for all pstore_read() and pstore_write() calls. Backends can either
update the field during read(), or use the field during write() instead
of fetching time themselves.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Remove write_buf() callback

Now that write() and write_buf() are functionally identical, this removes
write_buf(), and renames write_buf_user() to write_user(). Additionally
adds sanity-chec

pstore: Remove write_buf() callback

Now that write() and write_buf() are functionally identical, this removes
write_buf(), and renames write_buf_user() to write_user(). Additionally
adds sanity-checks for pstore_info's declared functions and flags at
registration time.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Replace arguments for write_buf_user() API

Removes argument list in favor of pstore record, though the user buffer
remains passed separately since it must carry the __user annotation.

Signe

pstore: Replace arguments for write_buf_user() API

Removes argument list in favor of pstore record, though the user buffer
remains passed separately since it must carry the __user annotation.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Replace arguments for write_buf() API

As with the other API updates, this removes the long argument list in favor
of passing a single pstore recaord.

Signed-off-by: Kees Cook <keescook@chro

pstore: Replace arguments for write_buf() API

As with the other API updates, this removes the long argument list in favor
of passing a single pstore recaord.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Replace arguments for erase() API

This removes the argument list for the erase() callback and replaces it
with a pointer to the backend record details to be removed.

Signed-off-by: Kees Coo

pstore: Replace arguments for erase() API

This removes the argument list for the erase() callback and replaces it
with a pointer to the backend record details to be removed.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Replace arguments for write() API

Similar to the pstore_info read() callback, there were too many arguments.
This switches to the new struct pstore_record pointer instead. This adds
"reason"

pstore: Replace arguments for write() API

Similar to the pstore_info read() callback, there were too many arguments.
This switches to the new struct pstore_record pointer instead. This adds
"reason" and "part" to the record structure as well.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Replace arguments for read() API

The argument list for the pstore_read() interface is unwieldy. This changes
passes the new struct pstore_record instead. The erst backend was already
doing s

pstore: Replace arguments for read() API

The argument list for the pstore_read() interface is unwieldy. This changes
passes the new struct pstore_record instead. The erst backend was already
doing something similar internally.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Extract common arguments into structure

The read/mkfile pair pass the same arguments and should be cleared
between calls. Move to a structure and wipe it after every loop.

Signed-off-by: Ke

pstore: Extract common arguments into structure

The read/mkfile pair pass the same arguments and should be cleared
between calls. Move to a structure and wipe it after every loop.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Add kernel-doc for struct pstore_info

This adds documentation for struct pstore_info, which also includes
the basic API the backends need to implement.

Signed-off-by: Kees Cook <keescook@ch

pstore: Add kernel-doc for struct pstore_info

This adds documentation for struct pstore_info, which also includes
the basic API the backends need to implement.

Signed-off-by: Kees Cook <[email protected]>

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pstore: Add ftrace timestamp counter

In preparation for merging the per CPU buffers into one buffer when
we retrieve the pstore ftrace data, we store the timestamp as a
counter in the ftrace pstore

pstore: Add ftrace timestamp counter

In preparation for merging the per CPU buffers into one buffer when
we retrieve the pstore ftrace data, we store the timestamp as a
counter in the ftrace pstore record. We store the CPU number as well
if !PSTORE_CPU_IN_IP, in this case we shift the counter and may lose
ordering there but we preserve the same record size. The timestamp counter
is also racy, and not doing any locking or synchronization here results
in the benefit of lower overhead. Since we don't care much here for exact
ordering of function traces across CPUs, we don't synchronize and may lose
some counter updates but I'm ok with that.

Using trace_clock() results in much lower performance so avoid using it
since we don't want accuracy in timestamp and need a rough ordering to
perform merge.

Signed-off-by: Joel Fernandes <[email protected]>
[kees: updated commit message, added comments]
Signed-off-by: Kees Cook <[email protected]>

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pstore/pmsg: drop bounce buffer

Removing a bounce buffer copy operation in the pmsg driver path is
always better. We also gain in overall performance by not requesting
a vmalloc on every write as th

pstore/pmsg: drop bounce buffer

Removing a bounce buffer copy operation in the pmsg driver path is
always better. We also gain in overall performance by not requesting
a vmalloc on every write as this can cause precious RT tasks, such
as user facing media operation, to stall while memory is being
reclaimed. Added a write_buf_user to the pstore functions, a backup
platform write_buf_user that uses the small buffer that is part of
the instance, and implemented a ramoops write_buf_user that only
supports PSTORE_TYPE_PMSG.

Signed-off-by: Mark Salyzyn <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

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pstore/ram: Set pstore flags dynamically

The ramoops can be configured to enable each pstore type by setting
their size. In that case, it'd be better not to register disabled types
in the first pla

pstore/ram: Set pstore flags dynamically

The ramoops can be configured to enable each pstore type by setting
their size. In that case, it'd be better not to register disabled types
in the first place.

Cc: Anton Vorontsov <[email protected]>
Cc: Colin Cross <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Tony Luck <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

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pstore: Split pstore fragile flags

This patch adds new PSTORE_FLAGS for each pstore type so that they can
be enabled separately. This is a preparation for ongoing virtio-pstore
work to support thos

pstore: Split pstore fragile flags

This patch adds new PSTORE_FLAGS for each pstore type so that they can
be enabled separately. This is a preparation for ongoing virtio-pstore
work to support those types flexibly.

The PSTORE_FLAGS_FRAGILE is changed to PSTORE_FLAGS_DMESG to preserve the
original behavior.

Cc: Anton Vorontsov <[email protected]>
Cc: Colin Cross <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Matt Fleming <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Namhyung Kim <[email protected]>
[kees: retained "FRAGILE" for now to make merges easier]
Signed-off-by: Kees Cook <[email protected]>

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