linux.git/arch/powerpc/include/asm/bug.h, branch v4.13

debug: Fix WARN_ON_ONCE() for modules

2017-07-20T10:31:04+00:00

Mike Galbraith reported a situation where a WARN_ON_ONCE() call in DRM
code turned into an oops.  As it turns out, WARN_ON_ONCE() seems to be
completely broken when called from a module.

The bug was introduced with the following commit:

  19d436268dde ("debug: Add _ONCE() logic to report_bug()")

That commit changed WARN_ON_ONCE() to move its 'once' logic into the bug
trap handler.  It requires a writable bug table so that the BUGFLAG_DONE
bit can be written to the flags to indicate the first warning has
occurred.

The bug table was made writable for vmlinux, which relies on
vmlinux.lds.S and vmlinux.lds.h for laying out the sections.  However,
it wasn't made writable for modules, which rely on the ELF section
header flags.

Reported-by: Mike Galbraith 
Tested-by: Masami Hiramatsu 
Signed-off-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 19d436268dde ("debug: Add _ONCE() logic to report_bug()")
Link: http://lkml.kernel.org/r/a53b04235a65478dd9afc51f5b329fdc65c84364.1500095401.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

powerpc/debug: Add missing warn flag to WARN_ON's non-builtin path

2017-06-16T06:10:37+00:00

When trapped on WARN_ON(), report_bug() is expected to return
BUG_TRAP_TYPE_WARN so the caller will increment NIP by 4 and continue.
The __builtin_constant_p() path of the PPC's WARN_ON()
calls (indirectly) __WARN_FLAGS() which has BUGFLAG_WARNING set,
however the other branch does not which makes report_bug() report a
bug rather than a warning.

Fixes: f26dee15103f ("debug: Avoid setting BUGFLAG_WARNING twice")
Signed-off-by: Alexey Kardashevskiy 
Signed-off-by: Michael Ellerman

debug: Add _ONCE() logic to report_bug()

2017-03-30T07:37:20+00:00

Josh suggested moving the _ONCE logic inside the trap handler, using a
bit in the bug_entry::flags field, avoiding the need for the extra
variable.

Sadly this only works for WARN_ON_ONCE(), since the others have
printk() statements prior to triggering the trap.

Still, this saves a fair amount of text and some data:

  text         data       filename
  10682460     4530992    defconfig-build/vmlinux.orig
  10665111     4530096    defconfig-build/vmlinux.patched

Suggested-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andy Lutomirski 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Signed-off-by: Ingo Molnar

powerpc: Remove stale function prototypes

2014-09-25T13:14:43+00:00

There were a number of prototypes for functions that no longer
exist. Remove them.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

Disintegrate asm/system.h for PowerPC

2012-03-28T17:30:02+00:00

Disintegrate asm/system.h for PowerPC.

Signed-off-by: David Howells 
Acked-by: Benjamin Herrenschmidt 
cc: linuxppc-dev@lists.ozlabs.org

panic: Allow warnings to set different taint flags

2010-05-19T07:36:48+00:00

WARN() is used in some places to report firmware or hardware bugs that
are then worked-around.  These bugs do not affect the stability of the
kernel and should not set the flag for TAINT_WARN.  To allow for this,
add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint number
as argument.

Architectures that implement warnings using trap instructions instead
of calls to warn_slowpath_*() now implement __WARN_TAINT(taint)
instead of __WARN().

Signed-off-by: Ben Hutchings 
Acked-by: Helge Deller 
Tested-by: Paul Mundt 
Signed-off-by: David Woodhouse

powerpc: Convert BUG() to use unreachable()

2009-12-18T03:54:27+00:00

Use the new unreachable() macro instead of for(;;);

Signed-off-by: David Daney 
CC: Benjamin Herrenschmidt 
CC: Paul Mackerras 
CC: linuxppc-dev@ozlabs.org
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix asm EMIT_BUG_ENTRY with !CONFIG_BUG

2008-12-16T04:53:23+00:00

Instead of not defining it at all, this defines the macro as
being empty, thus avoiding ifdef's in call sites when CONFIG_BUG
is not set.

Also removes an extra whitespace in the existing definition.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras

powerpc: Move include files to arch/powerpc/include/asm

2008-08-04T02:02:00+00:00

from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where  was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell 
Signed-off-by: Paul Mackerras