linux-toradex.git/kernel/jump_label.c, branch v5.1-rc4

jump_label: move 'asm goto' support test to Kconfig

2019-01-06T00:46:51+00:00

Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".

The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:

  #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
  # define HAVE_JUMP_LABEL
  #endif

We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.

Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.

Signed-off-by: Masahiro Yamada 
Acked-by: Michael Ellerman  (powerpc)
Tested-by: Sedat Dilek

Merge branch 'x86/build' into locking/core, to pick up dependent patches and unify jump-label work

2018-10-16T15:30:11+00:00

Signed-off-by: Ingo Molnar

jump_label: Fix NULL dereference bug in __jump_label_mod_update()

2018-10-02T06:08:18+00:00

Commit 19483677684b ("jump_label: Annotate entries that operate on
__init code earlier") refactored the code that manages runtime
patching of jump labels in modules that are tied to static keys
defined in other modules or in the core kernel.

In the latter case, we may iterate over the static_key_mod linked
list until we hit the entry for the core kernel, whose 'mod' field
will be NULL, and attempt to dereference it to get at its 'state'
member.

So let's add a non-NULL check: this forces the 'init' argument of
__jump_label_update() to false for static keys that are defined in
the core kernel, which is appropriate given that __init annotated
jump_label entries in the core kernel should no longer be active
at this point (i.e., when loading modules).

Fixes: 19483677684b ("jump_label: Annotate entries that operate on ...")
Reported-by: Dan Carpenter 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kees Cook 
Cc: Jessica Yu 
Cc: Peter Zijlstra 
Link: https://lkml.kernel.org/r/20181001081324.11553-1-ard.biesheuvel@linaro.org

jump_label: Annotate entries that operate on __init code earlier

2018-09-27T15:56:48+00:00

Jump table entries are mostly read-only, with the exception of the
init and module loader code that defuses entries that point into init
code when the code being referred to is freed.

For robustness, it would be better to move these entries into the
ro_after_init section, but clearing the 'code' member of each jump
table entry referring to init code at module load time races with the
module_enable_ro() call that remaps the ro_after_init section read
only, so we'd like to do it earlier.

So given that whether such an entry refers to init code can be decided
much earlier, we can pull this check forward. Since we may still need
the code entry at this point, let's switch to setting a low bit in the
'key' member just like we do to annotate the default state of a jump
table entry.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kees Cook 
Acked-by: Peter Zijlstra (Intel) 
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann 
Cc: Heiko Carstens 
Cc: Will Deacon 
Cc: Catalin Marinas 
Cc: Steven Rostedt 
Cc: Martin Schwidefsky 
Cc: Jessica Yu 
Link: https://lkml.kernel.org/r/20180919065144.25010-8-ard.biesheuvel@linaro.org

jump_label: Implement generic support for relative references

2018-09-27T15:56:47+00:00

To reduce the size taken up by absolute references in jump label
entries themselves and the associated relocation records in the
.init segment, add support for emitting them as relative references
instead.

Note that this requires some extra care in the sorting routine, given
that the offsets change when entries are moved around in the jump_entry
table.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra (Intel) 
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann 
Cc: Heiko Carstens 
Cc: Kees Cook 
Cc: Will Deacon 
Cc: Catalin Marinas 
Cc: Steven Rostedt 
Cc: Martin Schwidefsky 
Cc: Jessica Yu 
Link: https://lkml.kernel.org/r/20180919065144.25010-3-ard.biesheuvel@linaro.org

jump_label: Abstract jump_entry member accessors

2018-09-27T15:56:46+00:00

In preparation of allowing architectures to use relative references
in jump_label entries [which can dramatically reduce the memory
footprint], introduce abstractions for references to the 'code' and
'key' members of struct jump_entry.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra (Intel) 
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann 
Cc: Heiko Carstens 
Cc: Kees Cook 
Cc: Will Deacon 
Cc: Catalin Marinas 
Cc: Steven Rostedt 
Cc: Martin Schwidefsky 
Cc: Jessica Yu 
Link: https://lkml.kernel.org/r/20180919065144.25010-2-ard.biesheuvel@linaro.org

jump_label/lockdep: Assert we hold the hotplug lock for _cpuslocked() operations

2018-09-10T08:16:38+00:00

Weirdly we seem to have forgotten this...

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Signed-off-by: Ingo Molnar

Merge branch 'locking/urgent' into locking/core, to pick up fixes

2018-09-10T08:16:22+00:00

Signed-off-by: Ingo Molnar

jump_label: Fix typo in warning message

2018-09-10T08:15:48+00:00

There's no 'allocatote' - use the next best thing: 'allocate' :-)

Signed-off-by: Borislav Petkov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Jason Baron 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Steven Rostedt (VMware) 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20180907103521.31344-1-bp@alien8.de
Signed-off-by: Ingo Molnar

jump_label: Use static_key_linked() accessor

2018-09-10T06:23:37+00:00

... instead of open-coding it, in static_key_mod().

No functional changes.

Signed-off-by: Borislav Petkov 
Cc: Andrew Morton 
Cc: Jason Baron 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Steven Rostedt (VMware) 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20180909114252.17575-1-bp@alien8.de
Signed-off-by: Ingo Molnar