26 Commits

Author SHA1 Message Date
Ivaylo Georgiev
2857d83eee Merge android-4.19-q.77 (cd1eb9f) into msm-4.19
* refs/heads/tmp-cd1eb9f:
  Revert "net: qrtr: Stop rx_worker before freeing node"
  Linux 4.19.77
  drm/amd/display: Restore backlight brightness after system resume
  mm/compaction.c: clear total_{migrate,free}_scanned before scanning a new zone
  fuse: fix deadlock with aio poll and fuse_iqueue::waitq.lock
  md/raid0: avoid RAID0 data corruption due to layout confusion.
  CIFS: Fix oplock handling for SMB 2.1+ protocols
  CIFS: fix max ea value size
  i2c: riic: Clear NACK in tend isr
  hwrng: core - don't wait on add_early_randomness()
  quota: fix wrong condition in is_quota_modification()
  ext4: fix punch hole for inline_data file systems
  ext4: fix warning inside ext4_convert_unwritten_extents_endio
  /dev/mem: Bail out upon SIGKILL.
  cfg80211: Purge frame registrations on iftype change
  md: only call set_in_sync() when it is expected to succeed.
  md: don't report active array_state until after revalidate_disk() completes.
  md/raid6: Set R5_ReadError when there is read failure on parity disk
  Btrfs: fix race setting up and completing qgroup rescan workers
  btrfs: qgroup: Fix reserved data space leak if we have multiple reserve calls
  btrfs: qgroup: Fix the wrong target io_tree when freeing reserved data space
  btrfs: Relinquish CPUs in btrfs_compare_trees
  Btrfs: fix use-after-free when using the tree modification log
  btrfs: fix allocation of free space cache v1 bitmap pages
  ovl: filter of trusted xattr results in audit
  ovl: Fix dereferencing possible ERR_PTR()
  smb3: allow disabling requesting leases
  block: fix null pointer dereference in blk_mq_rq_timed_out()
  i40e: check __I40E_VF_DISABLE bit in i40e_sync_filters_subtask
  memcg, kmem: do not fail __GFP_NOFAIL charges
  memcg, oom: don't require __GFP_FS when invoking memcg OOM killer
  gfs2: clear buf_in_tr when ending a transaction in sweep_bh_for_rgrps
  efifb: BGRT: Improve efifb_bgrt_sanity_check
  regulator: Defer init completion for a while after late_initcall
  alarmtimer: Use EOPNOTSUPP instead of ENOTSUPP
  arm64: dts: rockchip: limit clock rate of MMC controllers for RK3328
  arm64: tlb: Ensure we execute an ISB following walk cache invalidation
  Revert "arm64: Remove unnecessary ISBs from set_{pte,pmd,pud}"
  ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up
  ARM: samsung: Fix system restart on S3C6410
  ASoC: Intel: Fix use of potentially uninitialized variable
  ASoC: Intel: Skylake: Use correct function to access iomem space
  ASoC: Intel: NHLT: Fix debug print format
  binfmt_elf: Do not move brk for INTERP-less ET_EXEC
  media: don't drop front-end reference count for ->detach
  media: sn9c20x: Add MSI MS-1039 laptop to flip_dmi_table
  KVM: x86: Manually calculate reserved bits when loading PDPTRS
  KVM: x86: set ctxt->have_exception in x86_decode_insn()
  KVM: x86: always stop emulation on page fault
  parisc: Disable HP HSC-PCI Cards to prevent kernel crash
  fuse: fix missing unlock_page in fuse_writepage()
  powerpc/imc: Dont create debugfs files for cpu-less nodes
  scsi: implement .cleanup_rq callback
  blk-mq: add callback of .cleanup_rq
  ALSA: hda/realtek - PCI quirk for Medion E4254
  ceph: use ceph_evict_inode to cleanup inode's resource
  Revert "ceph: use ceph_evict_inode to cleanup inode's resource"
  randstruct: Check member structs in is_pure_ops_struct()
  IB/hfi1: Define variables as unsigned long to fix KASAN warning
  IB/mlx5: Free mpi in mp_slave mode
  printk: Do not lose last line in kmsg buffer dump
  scsi: qla2xxx: Fix Relogin to prevent modifying scan_state flag
  scsi: scsi_dh_rdac: zero cdb in send_mode_select()
  ALSA: firewire-tascam: check intermediate state of clock status and retry
  ALSA: firewire-tascam: handle error code when getting current source of clock
  iwlwifi: fw: don't send GEO_TX_POWER_LIMIT command to FW version 36
  PM / devfreq: passive: fix compiler warning
  media: omap3isp: Set device on omap3isp subdevs
  btrfs: extent-tree: Make sure we only allocate extents from block groups with the same type
  iommu/amd: Override wrong IVRS IOAPIC on Raven Ridge systems
  ALSA: hda/realtek - Blacklist PC beep for Lenovo ThinkCentre M73/93
  media: ttusb-dec: Fix info-leak in ttusb_dec_send_command()
  drm/amd/powerplay/smu7: enforce minimal VBITimeout (v2)
  ALSA: hda - Drop unsol event handler for Intel HDMI codecs
  e1000e: add workaround for possible stalled packet
  libertas: Add missing sentinel at end of if_usb.c fw_table
  raid5: don't increment read_errors on EILSEQ return
  mmc: dw_mmc: Re-store SDIO IRQs mask at system resume
  mmc: core: Add helper function to indicate if SDIO IRQs is enabled
  mmc: sdhci: Fix incorrect switch to HS mode
  mmc: core: Clarify sdio_irq_pending flag for MMC_CAP2_SDIO_IRQ_NOTHREAD
  raid5: don't set STRIPE_HANDLE to stripe which is in batch list
  ASoC: dmaengine: Make the pcm->name equal to pcm->id if the name is not set
  platform/x86: intel_pmc_core: Do not ioremap RAM
  x86/cpu: Add Tiger Lake to Intel family
  s390/crypto: xts-aes-s390 fix extra run-time crypto self tests finding
  kprobes: Prohibit probing on BUG() and WARN() address
  dmaengine: ti: edma: Do not reset reserved paRAM slots
  md/raid1: fail run raid1 array when active disk less than one
  hwmon: (acpi_power_meter) Change log level for 'unsafe software power cap'
  closures: fix a race on wakeup from closure_sync
  ACPI / PCI: fix acpi_pci_irq_enable() memory leak
  ACPI: custom_method: fix memory leaks
  ARM: dts: exynos: Mark LDO10 as always-on on Peach Pit/Pi Chromebooks
  libtraceevent: Change users plugin directory
  iommu/iova: Avoid false sharing on fq_timer_on
  libata/ahci: Drop PCS quirk for Denverton and beyond
  iommu/amd: Silence warnings under memory pressure
  ALSA: firewire-motu: add support for MOTU 4pre
  nvme-multipath: fix ana log nsid lookup when nsid is not found
  nvmet: fix data units read and written counters in SMART log
  x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable()
  ASoC: fsl_ssi: Fix clock control issue in master mode
  x86/mm/pti: Do not invoke PTI functions when PTI is disabled
  arm64: kpti: ensure patched kernel text is fetched from PoU
  x86/apic/vector: Warn when vector space exhaustion breaks affinity
  sched/cpufreq: Align trace event behavior of fast switching
  ACPI / CPPC: do not require the _PSD method
  ASoC: es8316: fix headphone mixer volume table
  media: ov9650: add a sanity check
  perf trace beauty ioctl: Fix off-by-one error in cmd->string table
  media: saa7134: fix terminology around saa7134_i2c_eeprom_md7134_gate()
  media: cpia2_usb: fix memory leaks
  media: saa7146: add cleanup in hexium_attach()
  media: cec-notifier: clear cec_adap in cec_notifier_unregister
  PM / devfreq: exynos-bus: Correct clock enable sequence
  PM / devfreq: passive: Use non-devm notifiers
  EDAC/amd64: Decode syndrome before translating address
  EDAC/amd64: Recognize DRAM device type ECC capability
  libperf: Fix alignment trap with xyarray contents in 'perf stat'
  media: dvb-core: fix a memory leak bug
  posix-cpu-timers: Sanitize bogus WARNONS
  media: dvb-frontends: use ida for pll number
  media: mceusb: fix (eliminate) TX IR signal length limit
  nbd: add missing config put
  led: triggers: Fix a memory leak bug
  ASoC: sun4i-i2s: Don't use the oversample to calculate BCLK
  tools headers: Fixup bitsperlong per arch includes
  ASoC: uniphier: Fix double reset assersion when transitioning to suspend state
  media: hdpvr: add terminating 0 at end of string
  media: radio/si470x: kill urb on error
  ARM: dts: imx7-colibri: disable HS400
  ARM: dts: imx7d: cl-som-imx7: make ethernet work again
  m68k: Prevent some compiler warnings in Coldfire builds
  net: lpc-enet: fix printk format strings
  media: imx: mipi csi-2: Don't fail if initial state times-out
  media: omap3isp: Don't set streaming state on random subdevs
  media: i2c: ov5645: Fix power sequence
  media: vsp1: fix memory leak of dl on error return path
  perf record: Support aarch64 random socket_id assignment
  dmaengine: iop-adma: use correct printk format strings
  media: rc: imon: Allow iMON RC protocol for ffdc 7e device
  media: em28xx: modules workqueue not inited for 2nd device
  media: fdp1: Reduce FCP not found message level to debug
  media: mtk-mdp: fix reference count on old device tree
  perf test vfs_getname: Disable ~/.perfconfig to get default output
  perf config: Honour $PERF_CONFIG env var to specify alternate .perfconfig
  media: gspca: zero usb_buf on error
  idle: Prevent late-arriving interrupts from disrupting offline
  sched/fair: Use rq_lock/unlock in online_fair_sched_group
  firmware: arm_scmi: Check if platform has released shmem before using
  efi: cper: print AER info of PCIe fatal error
  EDAC, pnd2: Fix ioremap() size in dnv_rd_reg()
  loop: Add LOOP_SET_DIRECT_IO to compat ioctl
  ACPI / processor: don't print errors for processorIDs == 0xff
  media: media/platform: fsl-viu.c: fix build for MICROBLAZE
  md: don't set In_sync if array is frozen
  md: don't call spare_active in md_reap_sync_thread if all member devices can't work
  md/raid1: end bio when the device faulty
  arm64/prefetch: fix a -Wtype-limits warning
  ASoC: rsnd: don't call clk_get_rate() under atomic context
  EDAC/altera: Use the proper type for the IRQ status bits
  ia64:unwind: fix double free for mod->arch.init_unw_table
  ALSA: usb-audio: Skip bSynchAddress endpoint check if it is invalid
  base: soc: Export soc_device_register/unregister APIs
  media: iguanair: add sanity checks
  EDAC/mc: Fix grain_bits calculation
  ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls()
  ALSA: hda - Show the fatal CORB/RIRB error more clearly
  x86/apic: Soft disable APIC before initializing it
  x86/reboot: Always use NMI fallback when shutdown via reboot vector IPI fails
  sched/deadline: Fix bandwidth accounting at all levels after offline migration
  x86/apic: Make apic_pending_intr_clear() more robust
  sched/core: Fix CPU controller for !RT_GROUP_SCHED
  sched/fair: Fix imbalance due to CPU affinity
  time/tick-broadcast: Fix tick_broadcast_offline() lockdep complaint
  media: i2c: ov5640: Check for devm_gpiod_get_optional() error
  media: hdpvr: Add device num check and handling
  media: exynos4-is: fix leaked of_node references
  media: mtk-cir: lower de-glitch counter for rc-mm protocol
  media: dib0700: fix link error for dibx000_i2c_set_speed
  leds: leds-lp5562 allow firmware files up to the maximum length
  dmaengine: bcm2835: Print error in case setting DMA mask fails
  firmware: qcom_scm: Use proper types for dma mappings
  ASoC: sgtl5000: Fix charge pump source assignment
  ASoC: sgtl5000: Fix of unmute outputs on probe
  ASoC: tlv320aic31xx: suppress error message for EPROBE_DEFER
  regulator: lm363x: Fix off-by-one n_voltages for lm3632 ldo_vpos/ldo_vneg
  ALSA: hda: Flush interrupts on disabling
  nfp: flower: prevent memory leak in nfp_flower_spawn_phy_reprs
  nfc: enforce CAP_NET_RAW for raw sockets
  ieee802154: enforce CAP_NET_RAW for raw sockets
  ax25: enforce CAP_NET_RAW for raw sockets
  appletalk: enforce CAP_NET_RAW for raw sockets
  mISDN: enforce CAP_NET_RAW for raw sockets
  net/mlx5: Add device ID of upcoming BlueField-2
  tcp: better handle TCP_USER_TIMEOUT in SYN_SENT state
  net: sched: fix possible crash in tcf_action_destroy()
  usbnet: sanity checking of packet sizes and device mtu
  usbnet: ignore endpoints with invalid wMaxPacketSize
  skge: fix checksum byte order
  sch_netem: fix a divide by zero in tabledist()
  ppp: Fix memory leak in ppp_write
  openvswitch: change type of UPCALL_PID attribute to NLA_UNSPEC
  nfp: flower: fix memory leak in nfp_flower_spawn_vnic_reprs
  net_sched: add max len check for TCA_KIND
  net/sched: act_sample: don't push mac header on ip6gre ingress
  net: qrtr: Stop rx_worker before freeing node
  net/phy: fix DP83865 10 Mbps HDX loopback disable function
  macsec: drop skb sk before calling gro_cells_receive
  cdc_ncm: fix divide-by-zero caused by invalid wMaxPacketSize
  arcnet: provide a buffer big enough to actually receive packets
  ANDROID: properly export new symbols with _GPL tag

Conflicts:
	kernel/sched/cpufreq_schedutil.c
	mm/compaction.c

Change-Id: I3f2cc4a1421480479b9040aa5eefe7e17437021d
Signed-off-by: Ivaylo Georgiev <irgeorgiev@codeaurora.org>
2019-10-14 00:52:41 -07:00
Masami Hiramatsu
fad90d4bfa kprobes: Prohibit probing on BUG() and WARN() address
[ Upstream commit e336b4027775cb458dc713745e526fa1a1996b2a ]

Since BUG() and WARN() may use a trap (e.g. UD2 on x86) to
get the address where the BUG() has occurred, kprobes can not
do single-step out-of-line that instruction. So prohibit
probing on such address.

Without this fix, if someone put a kprobe on WARN(), the
kernel will crash with invalid opcode error instead of
outputing warning message, because kernel can not find
correct bug address.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/156750890133.19112.3393666300746167111.stgit@devnote2
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-05 13:09:54 +02:00
Syed Rameez Mustafa
8af9942b43 kernel/lib: add additional debug capabilities for data corruption
Data corruptions in the kernel often end up in system crashes that
are easier to debug closer to the time of detection. Specifically,
if we do not panic immediately after lock or list corruptions have been
detected, the problem context is lost in the ensuing system mayhem.
Add support for BUG_ON immediately after such corruptions are detected.
The CONFIG option controls the enabling/disabling of the feature.

Change-Id: I9b2eb62da506a13007acff63e85e9515145909ff
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
2019-02-18 15:18:48 -08:00
Andi Kleen
aaf5dcfb22 kernel debug: support resetting WARN_ONCE for all architectures
Some architectures store the WARN_ONCE state in the flags field of the
bug_entry.  Clear that one too when resetting once state through
/sys/kernel/debug/clear_warn_once

Pointed out by Michael Ellerman

Improves the earlier patch that add clear_warn_once.

[ak@linux.intel.com: add a missing ifdef CONFIG_MODULES]
  Link: http://lkml.kernel.org/r/20171020170633.9593-1-andi@firstfloor.org
[akpm@linux-foundation.org: fix unused var warning]
[akpm@linux-foundation.org: Use 0200 for clear_warn_once file, per mpe]
[akpm@linux-foundation.org: clear BUGFLAG_DONE in clear_once_table(), per mpe]
Link: http://lkml.kernel.org/r/20171019204642.7404-1-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:01 -08:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Ian Abbott
bc6245e5ef bug: split BUILD_BUG stuff out into <linux/build_bug.h>
Including <linux/bug.h> pulls in a lot of bloat from <asm/bug.h> and
<asm-generic/bug.h> that is not needed to call the BUILD_BUG() family of
macros.  Split them out into their own header, <linux/build_bug.h>.

Also correct some checkpatch.pl errors for the BUILD_BUG_ON_ZERO() and
BUILD_BUG_ON_NULL() macros by adding parentheses around the bitfield
widths that begin with a minus sign.

Link: http://lkml.kernel.org/r/20170525120316.24473-6-abbotti@mev.co.uk
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:34 -07:00
Ian Abbott
47e81e59d9 linux/bug.h: correct "space required before that '-'"
Correct these checkpatch.pl errors:

|ERROR: space required before that '-' (ctx:OxO)
|#37: FILE: include/linux/bug.h:37:
|+#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))

|ERROR: space required before that '-' (ctx:OxO)
|#38: FILE: include/linux/bug.h:38:
|+#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))

I decided to wrap the bitfield expressions that begin with minus signs
in parentheses rather than insert spaces before the minus signs.

Link: http://lkml.kernel.org/r/20170525120316.24473-5-abbotti@mev.co.uk
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:34 -07:00
Ian Abbott
8cdd7cca92 linux/bug.h: correct "(foo*)" should be "(foo *)"
Correct this checkpatch.pl error:

|ERROR: "(foo*)" should be "(foo *)"
|#19: FILE: include/linux/bug.h:19:
|+#define BUILD_BUG_ON_NULL(e) ((void*)0)

Link: http://lkml.kernel.org/r/20170525120316.24473-4-abbotti@mev.co.uk
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:34 -07:00
Ian Abbott
e9d5a48499 linux/bug.h: correct formatting of block comment
Correct these checkpatch.pl warnings:

|WARNING: Block comments use * on subsequent lines
|#34: FILE: include/linux/bug.h:34:
|+/* Force a compilation error if condition is true, but also produce a
|+   result (of value 0 and type size_t), so the expression can be used

|WARNING: Block comments use a trailing */ on a separate line
|#36: FILE: include/linux/bug.h:36:
|+   aren't permitted). */

Link: http://lkml.kernel.org/r/20170525120316.24473-3-abbotti@mev.co.uk
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:34 -07:00
Peter Zijlstra
19d436268d debug: Add _ONCE() logic to report_bug()
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 <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-30 09:37:20 +02:00
Kees Cook
85caa95b9f bug: switch data corruption check to __must_check
The CHECK_DATA_CORRUPTION() macro was designed to have callers do
something meaningful/protective on failure.  However, using "return
false" in the macro too strictly limits the design patterns of callers.
Instead, let callers handle the logic test directly, but make sure that
the result IS checked by forcing __must_check (which appears to not be
able to be used directly on macro expressions).

Link: http://lkml.kernel.org/r/20170206204547.GA125312@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Kees Cook
de54ebbe26 bug: Provide toggle for BUG on data corruption
The kernel checks for cases of data structure corruption under some
CONFIGs (e.g. CONFIG_DEBUG_LIST). When corruption is detected, some
systems may want to BUG() immediately instead of letting the system run
with known corruption.  Usually these kinds of manipulation primitives can
be used by security flaws to gain arbitrary memory write control. This
provides a new config CONFIG_BUG_ON_DATA_CORRUPTION and a corresponding
macro CHECK_DATA_CORRUPTION for handling these situations. Notably, even
if not BUGing, the kernel should not continue processing the corrupted
structure.

This is inspired by similar hardening by Syed Rameez Mustafa in MSM
kernels, and in PaX and Grsecurity, which is likely in response to earlier
removal of the BUG calls in commit 924d9addb9 ("list debugging: use
WARN() instead of BUG()").

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
2016-10-31 13:01:58 -07:00
Jakub Kicinski
3e9b3112ec add basic register-field manipulation macros
Common approach to accessing register fields is to define
structures or sets of macros containing mask and shift pair.
Operations on the register are then performed as follows:

 field = (reg >> shift) & mask;

 reg &= ~(mask << shift);
 reg |= (field & mask) << shift;

Defining shift and mask separately is tedious.  Ivo van Doorn
came up with an idea of computing them at compilation time
based on a single shifted mask (later refined by Felix) which
can be used like this:

 #define REG_FIELD 0x000ff000

 field = FIELD_GET(REG_FIELD, reg);

 reg &= ~REG_FIELD;
 reg |= FIELD_PREP(REG_FIELD, field);

FIELD_{GET,PREP} macros take care of finding out what the
appropriate shift is based on compilation time ffs operation.

GENMASK can be used to define registers (which is usually
less error-prone and easier to match with datasheets).

This approach is the most convenient I've seen so to limit code
multiplication let's move the macros to a global header file.
Attempts to use static inlines instead of macros failed due
to false positive triggering of BUILD_BUG_ON()s, especially with
GCC < 6.0.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dinan Gunawardena <dinan.gunawardena@netronome.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
2016-09-09 12:09:24 +03:00
Kirill A. Shutemov
ff20c2e0ac mm: Some arch may want to use HPAGE_PMD related values as variables
With next generation power processor, we are having a new mmu model
[1] that require us to maintain a different linux page table format.

Inorder to support both current and future ppc64 systems with a single
kernel we need to make sure kernel can select between different page
table format at runtime. With the new MMU (radix MMU) added, we will
have two different pmd hugepage size 16MB for hash model and 2MB for
Radix model. Hence make HPAGE_PMD related values as a variable.

Actual conversion of HPAGE_PMD to a variable for ppc64 happens in a
followup patch.

[1] http://ibm.biz/power-isa3 (Needs registration).

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-03-03 21:18:29 +11:00
Daniel Santos
9a8ab1c399 bug.h, compiler.h: introduce compiletime_assert & BUILD_BUG_ON_MSG
Introduce compiletime_assert to compiler.h, which moves the details of
how to break a build and emit an error message for a specific compiler
to the headers where these details should be.  Following in the
tradition of the POSIX assert macro, compiletime_assert creates a
build-time error when the supplied condition is *false*.

Next, we add BUILD_BUG_ON_MSG to bug.h which simply wraps
compiletime_assert, inverting the logic, so that it fails when the
condition is *true*, consistent with the language "build bug on." This
macro allows you to specify the error message you want emitted when the
supplied condition is true.

Finally, we remove all other code from bug.h that mucks with these
details (BUILD_BUG & BUILD_BUG_ON), and have them all call
BUILD_BUG_ON_MSG.  This not only reduces source code bloat, but also
prevents the possibility of code being changed for one macro and not for
the other (which was previously the case for BUILD_BUG and
BUILD_BUG_ON).

Since __compiletime_error_fallback is now only used in compiler.h, I'm
considering it a private macro and removing the double negation that's
now extraneous.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:16 -08:00
Daniel Santos
c361d3e543 compiler.h, bug.h: prevent double error messages with BUILD_BUG{,_ON}
Prior to the introduction of __attribute__((error("msg"))) in gcc 4.3,
creating compile-time errors required a little trickery.
BUILD_BUG{,_ON} uses this attribute when available to generate
compile-time errors, but also uses the negative-sized array trick for
older compilers, resulting in two error messages in some cases.  The
reason it's "some" cases is that as of gcc 4.4, the negative-sized array
will not create an error in some situations, like inline functions.

This patch replaces the negative-sized array code with the new
__compiletime_error_fallback() macro which expands to the same thing
unless the the error attribute is available, in which case it expands to
do{}while(0), resulting in exactly one compile-time error on all
versions of gcc.

Note that we are not changing the negative-sized array code for the
unoptimized version of BUILD_BUG_ON, since it has the potential to catch
problems that would be disabled in later versions of gcc were
__compiletime_error_fallback used.  The reason is that that an
unoptimized build can't always remove calls to an error-attributed
function call (like we are using) that should effectively become dead
code if it were optimized.  However, using a negative-sized array with a
similar value will not result in an false-positive (error).  The only
caveat being that it will also fail to catch valid conditions, which we
should be expecting in an unoptimized build anyway.

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:16 -08:00
Daniel Santos
a3ccc497cd bug.h: make BUILD_BUG_ON generate compile-time error
Negative sized arrays wont create a compile-time error in some cases
starting with gcc 4.4 (e.g., inlined functions), but gcc 4.3 introduced
the error function attribute that will.

This patch modifies BUILD_BUG_ON to behave like BUILD_BUG already does,
using the error function attribute so that you don't have to build the
entire kernel to discover that you have a problem, and then enjoy trying
to track it down from a link-time error.

Also, we are only including asm/bug.h and then expecting that
linux/compiler.h will eventually be included to define __linktime_error
(used in BUILD_BUG_ON).  This patch includes it directly for clarity and
to avoid the possibility of changes in <arch>/*/include/asm/bug.h being
changed or not including linux/compiler.h for some reason.

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:16 -08:00
Daniel Santos
1d6a0d19c8 bug.h: prevent double evaulation of `condition' in BUILD_BUG_ON
When calling BUILD_BUG_ON in an optimized build using gcc 4.3 and later,
the condition will be evaulated twice, possibily with side-effects.  This
patch eliminates that error.

[akpm@linux-foundation.org: tweak code layout]
Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:16 -08:00
Daniel Santos
ca623c914e bug.h: fix BUILD_BUG_ON macro in __CHECKER__
When __CHECKER__ is defined, we disable all of the BUILD_BUG.* macros.
However, both BUILD_BUG_ON_NOT_POWER_OF_2 and BUILD_BUG_ON was evaluating
to nothing in this case, and we want (0) since this is a function-like
macro that will be followed by a semicolon.

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:15 -08:00
Daniel Santos
6ae8d04871 compiler{,-gcc4}.h, bug.h: Remove duplicate macros
__linktime_error() does the same thing as __compiletime_error() and is
only used in bug.h.  Since the macro defines a function attribute that
will cause a failure at compile-time (not link-time), it makes more sense
to keep __compiletime_error(), which is also neatly mated with
__compiletime_warning().

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:15 -08:00
Tushar Behera
c5782e9f5a include/linux/bug.h: fix sparse warning related to BUILD_BUG_ON_INVALID
Commit baf05aa927 ("bug: introduce BUILD_BUG_ON_INVALID() macro")
introduces this macro only when _CHECKER_ is not defined.  Define a
silent macro in the else condition to fix following sparse warning:

  mm/filemap.c:395:9: error: undefined identifier 'BUILD_BUG_ON_INVALID'
  mm/filemap.c:396:9: error: undefined identifier 'BUILD_BUG_ON_INVALID'
  mm/filemap.c:397:9: error: undefined identifier 'BUILD_BUG_ON_INVALID'
  include/linux/mm.h:419:9: error: undefined identifier 'BUILD_BUG_ON_INVALID'
  include/linux/mm.h:419:9: error: not a function <noident>

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-11-26 17:41:24 -08:00
Konstantin Khlebnikov
baf05aa927 bug: introduce BUILD_BUG_ON_INVALID() macro
Sometimes we want to check some expressions correctness at compile time.
"(void)(e);" or "if (e);" can be dangerous if the expression has
side-effects, and gcc sometimes generates a lot of code, even if the
expression has no effect.

This patch introduces macro BUILD_BUG_ON_INVALID() for such checks, it
forces a compilation error if expression is invalid without any extra
code.

[Cast to "long" required because sizeof does not work for bit-fields.]

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:20 -07:00
Paul Gortmaker
35edd9103c bug: consolidate BUILD_BUG_ON with other bug code
The support for BUILD_BUG in linux/kernel.h predates the
addition of linux/bug.h -- with this chunk off separate,
you can run into situations where a person gets a compile
fail even when they've included linux/bug.h, like this:

    CC      lib/string.o
  lib/string.c: In function 'strlcat':
  lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON'
  make[2]: *** [lib/string.o] Error 1
  $
  $ grep linux/bug.h lib/string.c
  #include <linux/bug.h>
  $

Since the above violates the principle of least surprise, move
the BUG chunks from kernel.h to bug.h so it is all together.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-03-04 17:54:35 -05:00
Andrew Morton
0d9c25dde8 headers: move module_bug_finalize()/module_bug_cleanup() definitions into module.h
They're in linux/bug.h at present, which causes include order tangles.  In
particular, linux/bug.h cannot be used by linux/atomic.h because,
according to Nikanth:

linux/bug.h pulls in linux/module.h => linux/spinlock.h => asm/spinlock.h
(which uses atomic_inc) => asm/atomic.h.

bug.h is a pretty low-level thing and module.h is a higher-level thing,
IMO.

Cc: Nikanth Karthikesan <knikanth@novell.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:48 -07:00
Heiko Carstens
608e261968 generic bug: use show_regs() instead of dump_stack()
The current generic bug implementation has a call to dump_stack() in case a
WARN_ON(whatever) gets hit.  Since report_bug(), which calls dump_stack(),
gets called from an exception handler we can do better: just pass the
pt_regs structure to report_bug() and pass it to show_regs() in case of a
warning.  This will give more debug informations like register contents,
etc...  In addition this avoids some pointless lines that dump_stack()
emits, since it includes a stack backtrace of the exception handler which
is of no interest in case of a warning.  E.g.  on s390 the following lines
are currently always present in a stack backtrace if dump_stack() gets
called from report_bug():

 [<000000000001517a>] show_trace+0x92/0xe8)
 [<0000000000015270>] show_stack+0xa0/0xd0
 [<00000000000152ce>] dump_stack+0x2e/0x3c
 [<0000000000195450>] report_bug+0x98/0xf8
 [<0000000000016cc8>] illegal_op+0x1fc/0x21c
 [<00000000000227d6>] sysc_return+0x0/0x10

Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:51 -07:00
Jeremy Fitzhardinge
7664c5a1da [PATCH] Generic BUG implementation
This patch adds common handling for kernel BUGs, for use by architectures as
they wish.  The code is derived from arch/powerpc.

The advantages of having common BUG handling are:
 - consistent BUG reporting across architectures
 - shared implementation of out-of-line file/line data
 - implement CONFIG_DEBUG_BUGVERBOSE consistently

This means that in inline impact of BUG is just the illegal instruction
itself, which is an improvement for i386 and x86-64.

A BUG is represented in the instruction stream as an illegal instruction,
which has file/line information associated with it.  This extra information is
stored in the __bug_table section in the ELF file.

When the kernel gets an illegal instruction, it first confirms it might
possibly be from a BUG (ie, in kernel mode, the right illegal instruction).
It then calls report_bug().  This searches __bug_table for a matching
instruction pointer, and if found, prints the corresponding file/line
information.  If report_bug() determines that it wasn't a BUG which caused the
trap, it returns BUG_TRAP_TYPE_NONE.

Some architectures (powerpc) implement WARN using the same mechanism; if the
illegal instruction was the result of a WARN, then report_bug(Q) returns
CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG.

lib/bug.c keeps a list of loaded modules which can be searched for __bug_table
entries.  The architecture must call
module_bug_finalize()/module_bug_cleanup() from its corresponding
module_finalize/cleanup functions.

Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount.
At the very least, filename and line information will not be recorded for each
but, but architectures may decide to store no extra information per BUG at
all.

Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so
architectures will generally have to include an infinite loop (or similar) in
the BUG code, so that gcc knows execution won't continue beyond that point.
gcc does have a __builtin_trap() operator which may be useful to achieve the
same effect, unfortunately it cannot be used to actually implement the BUG
itself, because there's no way to get the instruction's address for use in
generating the __bug_table entry.

[randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors]
[bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:39 -08:00