linux/include
Ard Biesheuvel 29905b52fa log2: make order_base_2() behave correctly on const input value zero
The function order_base_2() is defined (according to the comment block)
as returning zero on input zero, but subsequently passes the input into
roundup_pow_of_two(), which is explicitly undefined for input zero.

This has gone unnoticed until now, but optimization passes in GCC 7 may
produce constant folded function instances where a constant value of
zero is passed into order_base_2(), resulting in link errors against the
deliberately undefined '____ilog2_NaN'.

So update order_base_2() to adhere to its own documented interface.

[ See

     http://marc.info/?l=linux-kernel&m=147672952517795&w=2

  and follow-up discussion for more background. The gcc "optimization
  pass" is really just broken, but now the GCC trunk problem seems to
  have escaped out of just specially built daily images, so we need to
  work around it in mainline.    - Linus ]

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-03 09:56:43 -08:00
..
acpi More ACPI updates for v4.10-rc1 2016-12-22 10:19:32 -08:00
asm-generic asm-prototypes: Clear any CPP defines before declaring the functions 2017-01-05 12:57:42 +01:00
clocksource
crypto This pull contains one set of changes: a conversion of the crypto DocBook 2016-12-17 16:00:34 -08:00
drm Merge tag 'drm-misc-fixes-2017-01-23' of git://anongit.freedesktop.org/git/drm-misc into drm-fixes 2017-01-27 10:16:56 +10:00
dt-bindings dt-bindings: mfd: Remove TPS65217 interrupts 2016-12-27 10:06:00 -08:00
keys
kvm KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems 2017-01-13 11:19:25 +00:00
linux log2: make order_base_2() behave correctly on const input value zero 2017-02-03 09:56:43 -08:00
math-emu
media [media] cec: pass parent device in register(), not allocate() 2016-11-29 12:07:17 -02:00
memory
misc
net ipv6: fix flow labels when the traffic class is non-0 2017-01-31 13:16:59 -05:00
pcmcia
ras
rdma RDMA/core: Add the function ib_mtu_int_to_enum 2017-01-24 15:34:22 -05:00
rxrpc
scsi Merge remote-tracking branch 'mkp-scsi/fixes' into fixes 2017-01-17 17:32:54 -05:00
soc ARCv2: MCIP: update the BCR per current changes 2017-01-24 11:05:59 -08:00
sound Merge remote-tracking branches 'asoc/fix/arizona', 'asoc/fix/dpcm', 'asoc/fix/dwc', 'asoc/fix/fsl-ssi' and 'asoc/fix/hdmi-codec' into asoc-linus 2017-01-10 10:47:50 +00:00
target target: add XCOPY target/segment desc sense codes 2017-01-10 08:40:32 -08:00
trace Merge branch 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2017-01-13 17:40:22 -08:00
uapi net: ethtool: add support for 2500BaseT and 5000BaseT link modes 2017-01-30 10:14:28 -05:00
video Merge branch 'drm/next/du' of git://linuxtv.org/pinchartl/media into drm-next 2016-11-16 09:39:21 +10:00
xen xen: features and fixes for 4.10 rc0 2016-12-13 16:07:55 -08:00
Kbuild