linux-toradex.git/arch/parisc/kernel/module.c, branch v3.0.16

[PARISC] only make executable areas executable

2011-04-15T17:55:18+00:00

Currently parisc has the whole kernel marked as RWX, meaning any
kernel page at all is eligible to be executed.  This can cause a
theoretical problem on systems with combined I/D TLB because the act
of referencing a page causes a TLB insertion with an executable bit.
This TLB entry may be used by the CPU as the basis for speculating the
page into the I-Cache.  If this speculated page is subsequently used
for a user process, there is the possibility we will get a stale
I-cache line picked up as the binary executes.

As a point of good practise, only mark actual kernel text pages as
executable.  The same has to be done for init_text pages, but they're
converted to data pages (and the I-Cache flushed) when the init memory
is released.

Signed-off-by: James Bottomley

modules: Fix module_bug_list list corruption race

2010-10-05T18:29:27+00:00

With all the recent module loading cleanups, we've minimized the code
that sits under module_mutex, fixing various deadlocks and making it
possible to do most of the module loading in parallel.

However, that whole conversion totally missed the rather obscure code
that adds a new module to the list for BUG() handling.  That code was
doubly obscure because (a) the code itself lives in lib/bugs.c (for
dubious reasons) and (b) it gets called from the architecture-specific
"module_finalize()" rather than from generic code.

Calling it from arch-specific code makes no sense what-so-ever to begin
with, and is now actively wrong since that code isn't protected by the
module loading lock any more.

So this commit moves the "module_bug_{finalize,cleanup}()" calls away
from the arch-specific code, and into the generic code - and in the
process protects it with the module_mutex so that the list operations
are now safe.

Future fixups:
 - move the module list handling code into kernel/module.c where it
   belongs.
 - get rid of 'module_bug_list' and just use the regular list of modules
   (called 'modules' - imagine that) that we already create and maintain
   for other reasons.

Reported-and-tested-by: Thomas Gleixner 
Cc: Rusty Russell 
Cc: Adrian Bunk 
Cc: Andrew Morton 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

parisc: correct use of SHF_ALLOC

2009-09-28T03:29:23+00:00

SHF_ALLOC is suitable for testing against the sh_flags field, not the
sh_type field.

Signed-off-by: Julia Lawall 
Signed-off-by: Kyle McMartin

parisc: Fix GOT overflow during module load on 64bit kernel

2009-08-02T10:34:08+00:00

Signed-off-by: John David Anglin 
Signed-off-by: Helge Deller

module: cleanup FIXME comments about trimming exception table entries.

2009-06-12T12:17:05+00:00

Everyone cut and paste this comment from my original one.  We now do
it generically, so cut the comments.

Signed-off-by: Rusty Russell 
Cc: Amerigo Wang

parisc: move dereference_function_descriptor to process.c

2009-04-02T04:16:27+00:00

Commit deac93df26b20cf8438339b5935b5f5643bc30c9 fixed up printing
of %pF on parisc, but added the dereference_function_descriptor
prototype to module.c... this isn't a particularly wise idea as
module.c might not always be compiled.

Signed-off-by: Kyle McMartin

parisc: Move kernel Elf_Fdesc define to

2009-04-02T04:16:24+00:00

elf.h probably won't be exported to userspace, but play it safe
and cram it in a #ifdef __KERNEL__ guard.

Signed-off-by: Kyle McMartin

parisc: fix module loading failure of large kernel modules

2009-01-04T22:10:14+00:00

On 32bit (and sometimes 64bit) and with big kernel modules like xfs or
ipv6 the relocation types R_PARISC_PCREL17F and R_PARISC_PCREL22F may
fail to reach their PLT stub if we only create one big stub array for
all sections at the beginning of the core or init section.

With this patch we now instead add individual PLT stub entries
directly in front of the code sections where the stubs are actually
called. This reduces the distance between the PCREL location and the
stub entry so that the relocations can be fulfilled.

While calculating the final layout of the kernel module in memory, the
kernel module loader calls arch_mod_section_prepend() to request the
to be reserved amount of memory in front of each individual section.

Tested with 32- and 64bit kernels.

Signed-off-by: Helge Deller 
Signed-off-by: Rusty Russell

lib: Correct printk %pF to work on all architectures

2008-09-09T18:51:15+00:00

It was introduced by "vsprintf: add support for '%pS' and '%pF' pointer
formats" in commit 0fe1ef24f7bd0020f29ffe287dfdb9ead33ca0b2.  However,
the current way its coded doesn't work on parisc64.  For two reasons: 1)
parisc isn't in the #ifdef and 2) parisc has a different format for
function descriptors

Make dereference_function_descriptor() more accommodating by allowing
architecture overrides.  I put the three overrides (for parisc64, ppc64
and ia64) in arch/kernel/module.c because that's where the kernel
internal linker which knows how to deal with function descriptors sits.

Signed-off-by: James Bottomley 
Acked-by: Benjamin Herrenschmidt 
Acked-by: Tony Luck 
Acked-by: Kyle McMartin 
Signed-off-by: Linus Torvalds