linux/tools
Josh Poimboeuf 8133fbb424 objtool: Fix false positive warnings for functions with multiple switch statements
Ingo reported [1] some false positive objtool warnings:

  drivers/net/wireless/realtek/rtlwifi/base.o: warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
  drivers/net/wireless/realtek/rtlwifi/base.o: warning: objtool: rtlwifi_rate_mapping()+0x2f3: frame pointer state mismatch
  ...

And so did the 0-day bot [2]:

  drivers/gpu/drm/radeon/cik.o: warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup
  drivers/gpu/drm/radeon/cik.o: warning: objtool: cik_tiling_mode_table_init()+0x72b: call without frame pointer save/setup
  ...

Both sets of warnings involve functions which have multiple switch
statements.  When there's more than one switch statement in a function,
objtool interprets all the switch jump tables as a single table.  If the
targets of one jump table assume a stack frame and the targets of
another one don't, it prints false positive warnings.

Fix the bug by detecting the size of each switch jump table.  For
multiple tables, each one ends where the next one begins.

[1] https://lkml.kernel.org/r/20160308103716.GA9618@gmail.com
[2] https://lists.01.org/pipermail/kbuild-all/2016-March/018124.html

Reported-by: Ingo Molnar <mingo@kernel.org>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/2d7eecc6bc52d301f494b80f5fd62c2b6c895658.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-09 10:48:09 +01:00
..
arch tools include: Add basic atomic.h implementation from the kernel sources 2015-05-08 16:11:05 -03:00
build tools build: Add BPF feature check to test-all 2016-01-11 19:22:21 -03:00
cgroup
firewire
hv tools: hv: vss: fix the write()'s argument: error -> vss_msg 2015-12-14 19:15:05 -08:00
iio iio: generic_buffer: be helpful about enabling channels 2015-08-16 10:51:26 +01:00
include tools: Make list.h self-sufficient 2016-01-12 12:42:07 -03:00
laptop/freefall Move freefall program from Documentation/ to tools/ 2015-06-08 16:42:07 -06:00
lguest tools/lguest: Clean up include dir 2015-08-26 06:12:35 +02:00
lib objtool: Support CROSS_COMPILE 2016-03-03 16:13:00 +01:00
net tools/net: Use include/uapi with __EXPORTED_HEADERS__ 2015-11-15 17:24:33 -05:00
nfsd
objtool objtool: Fix false positive warnings for functions with multiple switch statements 2016-03-09 10:48:09 +01:00
perf x86/asm/decoder: Use explicitly signed chars 2016-03-03 16:13:00 +01:00
power Merge branch 'pm-tools' 2016-01-21 00:43:29 +01:00
scripts tools: Move Makefile.arch from perf/config to tools/scripts 2016-01-11 19:22:20 -03:00
spi spi: spidev_test: Fix typo in error message 2015-12-08 17:58:56 +00:00
testing Merge branch 'x86/debug' into core/objtool, to pick up frame pointer fixes 2016-02-25 09:00:38 +01:00
thermal/tmon tools/thermal: tmon: use pkg-config also for CFLAGS 2015-10-10 11:32:31 +08:00
time
usb usb: patches for v4.4 merge window 2015-10-22 17:19:33 -07:00
virtio tools/virtio: add ringtest utilities 2016-01-26 10:18:30 +02:00
vm tools/vm/page-types.c: support KPF_IDLE 2015-11-20 16:17:32 -08:00
Makefile objtool: Add tool to perform compile-time stack metadata validation 2016-02-29 08:35:12 +01:00