Commit Graph

5666 Commits

Author SHA1 Message Date
Linus Torvalds b23c4771ff A fair amount of stuff this time around, dominated by yet another massive
set from Mauro toward the completion of the RST conversion.  I *really*
 hope we are getting close to the end of this.  Meanwhile, those patches
 reach pretty far afield to update document references around the tree;
 there should be no actual code changes there.  There will be, alas, more of
 the usual trivial merge conflicts.
 
 Beyond that we have more translations, improvements to the sphinx
 scripting, a number of additions to the sysctl documentation, and lots of
 fixes.
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Merge tag 'docs-5.8' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A fair amount of stuff this time around, dominated by yet another
  massive set from Mauro toward the completion of the RST conversion. I
  *really* hope we are getting close to the end of this. Meanwhile,
  those patches reach pretty far afield to update document references
  around the tree; there should be no actual code changes there. There
  will be, alas, more of the usual trivial merge conflicts.

  Beyond that we have more translations, improvements to the sphinx
  scripting, a number of additions to the sysctl documentation, and lots
  of fixes"

* tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits)
  Documentation: fixes to the maintainer-entry-profile template
  zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst
  tracing: Fix events.rst section numbering
  docs: acpi: fix old http link and improve document format
  docs: filesystems: add info about efivars content
  Documentation: LSM: Correct the basic LSM description
  mailmap: change email for Ricardo Ribalda
  docs: sysctl/kernel: document unaligned controls
  Documentation: admin-guide: update bug-hunting.rst
  docs: sysctl/kernel: document ngroups_max
  nvdimm: fixes to maintainter-entry-profile
  Documentation/features: Correct RISC-V kprobes support entry
  Documentation/features: Refresh the arch support status files
  Revert "docs: sysctl/kernel: document ngroups_max"
  docs: move locking-specific documents to locking/
  docs: move digsig docs to the security book
  docs: move the kref doc into the core-api book
  docs: add IRQ documentation at the core-api book
  docs: debugging-via-ohci1394.txt: add it to the core-api book
  docs: fix references for ipmi.rst file
  ...
2020-06-01 15:45:27 -07:00
Linus Torvalds 69fc06f70f There are a lot of objtool changes in this cycle, all across the map:
- Speed up objtool significantly, especially when there are large number of sections
  - Improve objtool's understanding of special instructions such as IRET,
    to reduce the number of annotations required
  - Implement 'noinstr' validation
  - Do baby steps for non-x86 objtool use
  - Simplify/fix retpoline decoding
  - Add vmlinux validation
  - Improve documentation
  - Fix various bugs and apply smaller cleanups
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'objtool-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:
 "There are a lot of objtool changes in this cycle, all across the map:

   - Speed up objtool significantly, especially when there are large
     number of sections

   - Improve objtool's understanding of special instructions such as
     IRET, to reduce the number of annotations required

   - Implement 'noinstr' validation

   - Do baby steps for non-x86 objtool use

   - Simplify/fix retpoline decoding

   - Add vmlinux validation

   - Improve documentation

   - Fix various bugs and apply smaller cleanups"

* tag 'objtool-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
  objtool: Enable compilation of objtool for all architectures
  objtool: Move struct objtool_file into arch-independent header
  objtool: Exit successfully when requesting help
  objtool: Add check_kcov_mode() to the uaccess safelist
  samples/ftrace: Fix asm function ELF annotations
  objtool: optimize add_dead_ends for split sections
  objtool: use gelf_getsymshndx to handle >64k sections
  objtool: Allow no-op CFI ops in alternatives
  x86/retpoline: Fix retpoline unwind
  x86: Change {JMP,CALL}_NOSPEC argument
  x86: Simplify retpoline declaration
  x86/speculation: Change FILL_RETURN_BUFFER to work with objtool
  objtool: Add support for intra-function calls
  objtool: Move the IRET hack into the arch decoder
  objtool: Remove INSN_STACK
  objtool: Make handle_insn_ops() unconditional
  objtool: Rework allocating stack_ops on decode
  objtool: UNWIND_HINT_RET_OFFSET should not check registers
  objtool: is_fentry_call() crashes if call has no destination
  x86,smap: Fix smap_{save,restore}() alternatives
  ...
2020-06-01 13:13:00 -07:00
Linus Torvalds 0bd957eb11 Various kprobes updates, mostly centered around cleaning up the no-instrumentation
logic, instead of the current per debug facility blacklist, use the more generic
 .noinstr.text approach, combined with a 'noinstr' marker for functions.
 
 Also add instrumentation_begin()/end() to better manage the exact place in entry
 code where instrumentation may be used.
 
 Also add a kprobes blacklist for modules.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-kprobes-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull kprobes updates from Ingo Molnar:
 "Various kprobes updates, mostly centered around cleaning up the
  no-instrumentation logic.

  Instead of the current per debug facility blacklist, use the more
  generic .noinstr.text approach, combined with a 'noinstr' marker for
  functions.

  Also add instrumentation_begin()/end() to better manage the exact
  place in entry code where instrumentation may be used.

  And add a kprobes blacklist for modules"

* tag 'core-kprobes-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Prevent probes in .noinstr.text section
  vmlinux.lds.h: Create section for protection against instrumentation
  samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers.
  kprobes: Support NOKPROBE_SYMBOL() in modules
  kprobes: Support __kprobes blacklist in modules
  kprobes: Lock kprobe_mutex while showing kprobe_blacklist
2020-06-01 12:45:04 -07:00
Joe Perches bdc48fa11e checkpatch/coding-style: deprecate 80-column warning
Yes, staying withing 80 columns is certainly still _preferred_.  But
it's not the hard limit that the checkpatch warnings imply, and other
concerns can most certainly dominate.

Increase the default limit to 100 characters.  Not because 100
characters is some hard limit either, but that's certainly a "what are
you doing" kind of value and less likely to be about the occasional
slightly longer lines.

Miscellanea:

 - to avoid unnecessary whitespace changes in files, checkpatch will no
   longer emit a warning about line length when scanning files unless
   --strict is also used

 - Add a bit to coding-style about alignment to open parenthesis

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-31 11:00:42 -07:00
Thomas Gleixner 6553896666 vmlinux.lds.h: Create section for protection against instrumentation
Some code pathes, especially the low level entry code, must be protected
against instrumentation for various reasons:

 - Low level entry code can be a fragile beast, especially on x86.

 - With NO_HZ_FULL RCU state needs to be established before using it.

Having a dedicated section for such code allows to validate with tooling
that no unsafe functions are invoked.

Add the .noinstr.text section and the noinstr attribute to mark
functions. noinstr implies notrace. Kprobes will gain a section check
later.

Provide also a set of markers: instrumentation_begin()/end()

These are used to mark code inside a noinstr function which calls
into regular instrumentable text section as safe.

The instrumentation markers are only active when CONFIG_DEBUG_ENTRY is
enabled as the end marker emits a NOP to prevent the compiler from merging
the annotation points. This means the objtool verification requires a
kernel compiled with this option.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134100.075416272@linutronix.de
2020-05-19 15:47:20 +02:00
Ingo Molnar 7c0577f4e6 Linux 5.7-rc6
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Merge tag 'v5.7-rc6' into objtool/core, to pick up fixes and resolve semantic conflict

Resolve structural conflict between:

  59566b0b622e: ("x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up")

which introduced a new reference to 'ftrace_epilogue', and:

  0298739b7983: ("x86,ftrace: Fix ftrace_regs_caller() unwind")

Which renamed it to 'ftrace_caller_end'. Rename the new usage site in the merge commit.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-18 13:09:37 +03:00
Aymeric Agon-Rambosson 50e36be1fb scripts/gdb: repair rb_first() and rb_last()
The current implementations of the rb_first() and rb_last() gdb
functions have a variable that references itself in its instanciation,
which causes the function to throw an error if a specific condition on
the argument is met.  The original author rather intended to reference
the argument and made a typo.  Referring the argument instead makes the
function work as intended.

Signed-off-by: Aymeric Agon-Rambosson <aymeric.agon@yandex.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: Jackie Liu <liuyun01@kylinos.cn>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20200427051029.354840-1-aymeric.agon@yandex.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-07 19:27:20 -07:00
Ivan Delalande e08df079b2 scripts/decodecode: fix trapping instruction formatting
If the trapping instruction contains a ':', for a memory access through
segment registers for example, the sed substitution will insert the '*'
marker in the middle of the instruction instead of the line address:

	2b:   65 48 0f c7 0f          cmpxchg16b %gs:*(%rdi)          <-- trapping instruction

I started to think I had forgotten some quirk of the assembly syntax
before noticing that it was actually coming from the script.  Fix it to
add the address marker at the right place for these instructions:

	28:   49 8b 06                mov    (%r14),%rax
	2b:*  65 48 0f c7 0f          cmpxchg16b %gs:(%rdi)           <-- trapping instruction
	30:   0f 94 c0                sete   %al

Fixes: 18ff44b189 ("scripts/decodecode: make faulting insn ptr more robust")
Signed-off-by: Ivan Delalande <colona@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20200419223653.GA31248@visor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-07 19:27:20 -07:00
Linus Torvalds 9851a0dee7 GCC 10 fixes for gcc-plugins
- Adjust caller of cgraph_create_edge for GCC 10 argument usage
 - Update common headers to build under GCC 10 (Frédéric Pierret)
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Merge tag 'gcc-plugins-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc-plugins fixes from Kees Cook:
 "GCC 10 fixes for gcc-plugins:

   - Adjust caller of cgraph_create_edge for GCC 10 argument usage

   - Update common headers to build under GCC 10 (Frédéric Pierret)"

* tag 'gcc-plugins-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-common.h: Update for GCC 10
  gcc-plugins/stackleak: Avoid assignment for unused macro argument
2020-05-04 11:20:32 -07:00
Linus Torvalds 9d82973e03 gcc-10 warnings: fix low-hanging fruit
Due to a bug-report that was compiler-dependent, I updated one of my
machines to gcc-10.  That shows a lot of new warnings.  Happily they
seem to be mostly the valid kind, but it's going to cause a round of
churn for getting rid of them..

This is the really low-hanging fruit of removing a couple of zero-sized
arrays in some core code.  We have had a round of these patches before,
and we'll have many more coming, and there is nothing special about
these except that they were particularly trivial, and triggered more
warnings than most.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-04 09:16:37 -07:00
Mauro Carvalho Chehab ec43a27fff scripts: sphinx-pre-install: change the output order
When the script detects the need for an upgrade, it will
print either a warning or a note.

Let's change a little bit the order where messages will be
displayed, in order to make easier for the user to identify
the more important messages.

It should now be like this:

	Detected OS: Fedora release 31 (Thirty One).
	Sphinx version: 1.7.9

	Note: It is recommended at least Sphinx version 2.4.4 if you need PDF support.
	To upgrade Sphinx, use:

		/usr/bin/python3 -m venv sphinx_2.4.4
		. sphinx_2.4.4/bin/activate
		pip install -r ./Documentation/sphinx/requirements.txt

	If you want to exit the virtualenv, you can use:
		deactivate

All optional dependencies are met.
Needed package dependencies are met.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/20200421182758.04e0a53e@coco.lan
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-28 12:52:52 -06:00
Mauro Carvalho Chehab 412b09ddad scripts: sphinx-pre-install: fix a bug when using with venv
When python3 creates a venv, it adds python into it!

This causes any upgrade recommendation to look like this:

	/devel/v4l/docs/sphinx_1.7.9/bin/python3 -m venv sphinx_2.4.4
	. sphinx_2.4.4/bin/activate
	pip install -r ./Documentation/sphinx/requirements.txt

With is wrong (and it may not work). So, when recomending
an upgrade, exclude the venv dir from the search path, and
get the system's python.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/aa622ff71bebf6960fc0262fb90e7ebc7a999a02.1587478901.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-28 12:52:02 -06:00
Mauro Carvalho Chehab 2834a7412b scripts: sphinx-pre-install: change recommendation text if venv exists
If one is running a Sphinx version older than what's recommended,
but there's already a newer working virtual env, change the
text, as it is just a matter of switching to the new venv, instead
of creating a new one from scratch.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/bcf79d0399a1c3444ca938dcdce599c3273980ab.1587478901.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-28 12:52:02 -06:00
Mauro Carvalho Chehab 1ef70ced55 scripts: sphinx-pre-install: change the warning for version < 2.4.4
As requested by Jon, change the version check, in order to not
emit a warning if version is >= 1.7.9, but below 2.4.4.

After this patch, if someone used an older version, it will
say:

	./scripts/sphinx-pre-install
	Sphinx version 1.7.9
	Note: It is recommended at least Sphinx version 2.4.4 if you need PDF support.
	Detected OS: Fedora release 31 (Thirty One).

	To upgrade Sphinx, use:

		/devel/v4l/docs/sphinx_1.7.9/bin/python3 -m venv sphinx_2.4.4
		. sphinx_2.4.4/bin/activate
		pip install -r ./Documentation/sphinx/requirements.txt

	If you want to exit the virtualenv, you can use:
		deactivate

	All optional dependencies are met.
	Needed package dependencies are met.

If Sphinx is not detected at all, it

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/79584d317ba16f5d4f37801c5ee57cf04085f962.1587478901.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-28 12:52:02 -06:00
Mauro Carvalho Chehab a8b380c379 scripts: sphinx-pre-install: only ask to activate valid venvs
If a venv doesn't contain Sphinx, or has an older Sphinx
version, ignore it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/d11a00d88514e8a0357e1b0a05ebd518952a1d39.1587478901.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-28 12:52:02 -06:00
Linus Torvalds b9916af776 Kbuild fixes for v5.7
- fix scripts/config to properly handle ':' in string type CONFIG options
 
  - fix unneeded rebuilds of DT schema check rule
 
  - git rid of ordering dependency between <linux/vermagic.h> and
    <linux/module.h> to fix build errors in some network drivers
 
  - clean up generated headers of host arch with 'make ARCH=um mrproper'
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Merge tag 'kbuild-fixes-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - fix scripts/config to properly handle ':' in string type CONFIG
   options

 - fix unneeded rebuilds of DT schema check rule

 - git rid of ordering dependency between <linux/vermagic.h> and
   <linux/module.h> to fix build errors in some network drivers

 - clean up generated headers of host arch with 'make ARCH=um mrproper'

* tag 'kbuild-fixes-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  h8300: ignore vmlinux.lds
  Documentation: kbuild: fix the section title format
  um: ensure `make ARCH=um mrproper` removes arch/$(SUBARCH)/include/generated/
  arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h>
  kbuild: fix DT binding schema rule again to avoid needless rebuilds
  scripts/config: allow colons in option strings for sed
2020-04-24 10:39:32 -07:00
Masahiro Yamada 3d4b223868 kbuild: fix DT binding schema rule again to avoid needless rebuilds
Since commit 7a04960560 ("kbuild: fix DT binding schema rule to detect
command line changes"), this rule is every time re-run even if you change
nothing.

cmd_dtc takes one additional parameter to pass to the -O option of dtc.

We need to pass 'yaml' to if_changed_rule. Otherwise, cmd-check invoked
from if_changed_rule is false positive.

Fixes: 7a04960560 ("kbuild: fix DT binding schema rule to detect command line changes")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-23 10:50:26 +09:00
Jeremie Francois (on alpha) e461bc9f9a scripts/config: allow colons in option strings for sed
Sed broke on some strings as it used colon as a separator.
I made it more robust by using \001, which is legit POSIX AFAIK.

E.g. ./config --set-str CONFIG_USBNET_DEVADDR "de:ad:be:ef:00:01"
failed with: sed: -e expression #1, char 55: unknown option to `s'

Signed-off-by: Jeremie Francois (on alpha) <jeremie.francois@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-23 01:10:16 +09:00
Peter Zijlstra 6804c1afd7 kbuild/objtool: Add objtool-vmlinux.o pass
Now that objtool is capable of processing vmlinux.o and actually has
something useful to do there, (conditionally) add it to the final link
pass.

This will increase build time by a few seconds.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200416115119.287494491@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22 10:53:51 +02:00
Christophe JAILLET 461e156536 checkpatch: fix a typo in the regex for $allocFunctions
Here, we look for function such as 'netdev_alloc_skb_ip_align', so a '_'
is missing in the regex.

To make sure:
   grep -r --include=*.c skbip_a * | wc   ==>   0 results
   grep -r --include=*.c skb_ip_a * | wc  ==> 112 results

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200407190029.892-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-21 11:11:55 -07:00
Mauro Carvalho Chehab 0d55d48b19 scripts: kernel-doc: accept blank lines on parameter description
Sphinx is very pedantic with respect to blank lines. Sometimes,
in order to make it to properly handle something, we need to
add a blank line. However, currently, any blank line inside a
kernel-doc comment like:

	/*
	 * @foo: bar
         *
	 *       foobar
	 *
	 * some description

will be considered as if "foobar" was part of the description.

This patch changes kernel-doc behavior. After it, foobar will
be considered as part of the parameter text. The description
will only be considered as such if it starts with:

zero spaces after asterisk:

	*foo

one space after asterisk:
	* foo

or have a explicit Description section:

	*   Description:

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/c07d2862792d75a2691d69c9eceb7b89a0164cc0.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:35:58 -06:00
Mauro Carvalho Chehab ee2aa75903 scripts: kernel-doc: accept negation like !@var
On a few places, it sometimes need to indicate a negation of a
parameter, like:

	!@fshared

This pattern happens, for example, at:

	kernel/futex.c

and it is perfectly valid. However, kernel-doc currently
transforms it into:

	!**fshared**

This won't do what it would be expected.

Fortunately, fixing the script is a simple matter of storing
the "!" before "@" and adding it after the bold markup, like:

	**!fshared**

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/0314b47f8c3e1f9db00d5375a73dc3cddd8a21f2.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:35:58 -06:00
Mauro Carvalho Chehab 346282db9c scripts: kernel-doc: proper handle @foo->bar()
The pattern @foo->bar() is valid, as it can be used by a
function pointer inside a struct passed as a parameter.

Right now, it causes a warning:

	./drivers/firewire/core-transaction.c:606: WARNING: Inline strong start-string without end-string.

In this specific case, the kernel-doc markup is:

	/**
	 * fw_core_remove_address_handler() - unregister an address handler
	 * @handler: callback
	 *
	 * To be called in process context.
	 *
	 * When fw_core_remove_address_handler() returns, @handler->callback() is
	 * guaranteed to not run on any CPU anymore.
	 */

With seems valid on my eyes. So, instead of trying to hack
the kernel-doc markup, let's teach it about how to handle
such things. This should likely remove lots of other similar
warnings as well.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/48b46426d7bf6ff7529f20e5718fbf4e9758e62c.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:35:58 -06:00
Mauro Carvalho Chehab 2f9c502552 scripts: sphinx-pre-install: add support for python -m venv
Since python 3.3, the recommended way to setup a virtual env is
via "python -m venv".

Set this as a default, if python version is compatible with
such feature.

While here, add more comments to it, as the script is
getting more complex. So, better to add more things, to avoid
accidentally breaking it while improving it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/252cc849c79527ad496247e4c481961478adf41c.1586883286.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:19:13 -06:00
Mauro Carvalho Chehab d6ebf1890c scripts: sphinx-pre-install: add support for OpenMandriva
It seems that Mageia and OpenMandriva will reunite on a single
distribution. In any case, both came from Mandriva. So, it is
close enough to use the same logic.

So, add support for it.

Tested with OpenMandriva 4.1 and with Mageia 7.1.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/692809729c6818a0b0f75513da15970c53d5565c.1586883286.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:19:13 -06:00
Mauro Carvalho Chehab e45a631742 scripts: sphinx-pre-install: address some issues with Gentoo
There are some small misdetections with Gentoo. While they
don't cause too much trouble, it keeps recomending to
install things that are already there.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/7f631edce102b02ccbdbfb18be1376a86b41373d.1586883286.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:19:13 -06:00
Mauro Carvalho Chehab bfc7f42810 scripts: sphinx-pre-install: fix a dependency hint with Ubuntu 16.04
Avoid the scripts to keep asking to install fonts-noto-cjk
on Ubuntu 16.04.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/912b664a8ca54e8c5c5767c3fe9171973eeddd6b.1586883286.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:19:12 -06:00
Mauro Carvalho Chehab b3df6223bd scripts: sphinx-pre-install: improve openSuse Tumbleweed check
Currently, with openSUSE Tumbleweed 20200303, it keeps
recommending this forever:

	sudo zypper install --no-recommends rsvg-view

This dependency will never be fulfilled there, as the package
now is named as on other distros: rsvg-convert.

So, improve the detection to avoid such issue.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/c3774f72ac36c5e5b5f446ae5db5b795d1f274f4.1586883286.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:19:12 -06:00
Mauro Carvalho Chehab d14d0c1aea scripts: sphinx-pre-install: improve distro detection check
The Arch-linux detection is hit by catting /etc/issue, whose
contents is (nowadays):

	Arch Linux \r (\l)

It sounds a little ackward to print such string, so,
instead, let's use the /etc/os-release file, with exists
on lots of distributions and should provide a more reliable
result.

We'll keep the old tests before it, in order to avoid possible
regressions with the other distros, although the new way should
probably work on all the currently supported distributions.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/472924557afdf2b5492ae2a48c5ecfae216d54e2.1586883286.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:19:12 -06:00
Linus Torvalds 90280eaa88 A handful of fixes for reasonably obnoxious documentation issues.
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Merge tag 'docs-fixes' of git://git.lwn.net/linux

Pull documentation fixes from Jonathan Corbet:
 "A handful of fixes for reasonably obnoxious documentation issues"

* tag 'docs-fixes' of git://git.lwn.net/linux:
  scripts: documentation-file-ref-check: Add line break before exit
  scripts/kernel-doc: Add missing close-paren in c:function directives
  docs: admin-guide: merge sections for the kernel.modprobe sysctl
  docs: timekeeping: Use correct prototype for deprecated functions
2020-04-17 13:10:50 -07:00
Masahiro Yamada 0903060fe5 kbuild: check libyaml installation for 'make dt_binding_check'
If you run 'make dtbs_check' without installing the libyaml package,
the error message "dtc needs libyaml ..." is shown.

This should be checked also for 'make dt_binding_check' because dtc
needs to validate *.example.dts extracted from *.yaml files.

It is missing since commit 4f0e3a57d6 ("kbuild: Add support for DT
binding schema checks"), but this fix-up is applicable only after commit
e10c4321dc ("kbuild: allow to run dt_binding_check and dtbs_check
in a single command").

I gave the Fixes tag to the latter in case somebody is interested in
back-porting this.

Fixes: e10c4321dc ("kbuild: allow to run dt_binding_check and dtbs_check in a single command")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
2020-04-17 10:45:23 -05:00
Tiezhu Yang d98dbbe0d3 scripts: documentation-file-ref-check: Add line break before exit
If execute ./scripts/documentation-file-ref-check in a directory which is
not a git tree, it will exit without a line break, fix it.

Without this patch:

[loongson@localhost linux-5.7-rc1]$ ./scripts/documentation-file-ref-check
Warning: can't check if file exists, as this is not a git tree[loongson@localhost linux-5.7-rc1]$

With this patch:

[loongson@localhost linux-5.7-rc1]$ ./scripts/documentation-file-ref-check
Warning: can't check if file exists, as this is not a git tree
[loongson@localhost linux-5.7-rc1]$

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/1586857308-2040-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-15 15:13:13 -06:00
Peter Maydell e8f4ba8331 scripts/kernel-doc: Add missing close-paren in c:function directives
When kernel-doc generates a 'c:function' directive for a function
one of whose arguments is a function pointer, it fails to print
the close-paren after the argument list of the function pointer
argument. For instance:

 long work_on_cpu(int cpu, long (*fn) (void *, void * arg)

in driver-api/basics.html is missing a ')' separating the
"void *" of the 'fn' arguments from the ", void * arg" which
is an argument to work_on_cpu().

Add the missing close-paren, so that we render the prototype
correctly:

 long work_on_cpu(int cpu, long (*fn)(void *), void * arg)

(Note that Sphinx stops rendering a space between the '(fn*)' and the
'(void *)' once it gets something that's syntactically valid.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Link: https://lore.kernel.org/r/20200414143743.32677-1-peter.maydell@linaro.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-15 14:58:12 -06:00
Frédéric Pierret (fepitre) c7527373fe gcc-common.h: Update for GCC 10
Remove "params.h" include, which has been dropped in GCC 10.

Remove is_a_helper() macro, which is now defined in gimple.h, as seen
when running './scripts/gcc-plugin.sh g++ g++ gcc':

In file included from <stdin>:1:
./gcc-plugins/gcc-common.h:852:13: error: redefinition of ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’
  852 | inline bool is_a_helper<const ggoto *>::test(const_gimple gs)
      |             ^~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./gcc-plugins/gcc-common.h:125,
                 from <stdin>:1:
/usr/lib/gcc/x86_64-redhat-linux/10/plugin/include/gimple.h:1037:1: note: ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ previously declared here
 1037 | is_a_helper <const ggoto *>::test (const gimple *gs)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~

Add -Wno-format-diag to scripts/gcc-plugins/Makefile to avoid
meaningless warnings from error() formats used by plugins:

scripts/gcc-plugins/structleak_plugin.c: In function ‘int plugin_init(plugin_name_args*, plugin_gcc_version*)’:
scripts/gcc-plugins/structleak_plugin.c:253:12: warning: unquoted sequence of 2 consecutive punctuation characters ‘'-’ in format [-Wformat-diag]
  253 |   error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Frédéric Pierret (fepitre) <frederic.pierret@qubes-os.org>
Link: https://lore.kernel.org/r/20200407113259.270172-1-frederic.pierret@qubes-os.org
[kees: include -Wno-format-diag for plugin builds]
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-04-13 10:19:20 -07:00
Kees Cook 8d97fb393c gcc-plugins/stackleak: Avoid assignment for unused macro argument
With GCC version >= 8, the cgraph_create_edge() macro argument using
"frequency" goes unused. Instead of assigning a temporary variable for
the argument, pass the compute_call_stmt_bb_frequency() call directly
as the macro argument so that it will just not be called when it is
not wanted by the macros.

Silences the warning:

scripts/gcc-plugins/stackleak_plugin.c:54:6: warning: variable ‘frequency’ set but not used [-Wunused-but-set-variable]

Now builds cleanly with gcc-7 and gcc-9. Both boot and pass
STACKLEAK_ERASING LKDTM test.

Signed-off-by: Kees Cook <keescook@chromium.org>
2020-04-13 10:17:44 -07:00
Masahiro Yamada 76426e2388 kbuild: add dummy toolchains to enable all cc-option etc. in Kconfig
Staring v4.18, Kconfig evaluates compiler capabilities, and hides CONFIG
options your compiler does not support. This works well if you configure
and build the kernel on the same host machine.

It is inconvenient if you prepare the .config that is carried to a
different build environment (typically this happens when you package
the kernel for distros) because using a different compiler potentially
produces different CONFIG options than the real build environment.
So, you probably want to make as many options visible as possible.
In other words, you need to create a super-set of CONFIG options that
cover any build environment. If some of the CONFIG options turned out
to be unsupported on the build machine, they are automatically disabled
by the nature of Kconfig.

However, it is not feasible to get a full-featured compiler for every
arch.

This issue was discussed here:

  https://lkml.org/lkml/2019/12/9/620

Other than distros, savedefconfig is also a problem. Some arch sub-systems
periodically resync defconfig files. If you use a less-capable compiler
for savedefconfig, options that do not meet 'depends on $(cc-option,...)'
will be forcibly disabled. So, 'make defconfig && make savedefconfig'
may silently change the behavior.

This commit adds a set of dummy toolchains that pretend to support any
feature.

Most of compiler features are tested by cc-option, which simply checks
the exit code of $(CC). The dummy tools are shell scripts that always
exit with 0. So, $(cc-option, ...) is evaluated as 'y'.

There are more complicated checks such as:

  scripts/gcc-x86_{32,64}-has-stack-protector.sh
  scripts/gcc-plugin.sh
  scripts/tools-support-relr.sh

scripts/dummy-tools/gcc passes all checks.

From the top directory of the source tree, you can do:

   $ make CROSS_COMPILE=scripts/dummy-tools/ oldconfig

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Tested-by: Jeremy Cline <jcline@redhat.com>
2020-04-09 00:13:45 +09:00
Masahiro Yamada 7273ad2b08 kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y
Kbuild supports not only obj-y but also lib-y to list objects linked to
vmlinux.

The difference between them is that all the objects from obj-y are
forcibly linked to vmlinux, whereas the objects from lib-y are linked
as needed; if there is no user of a lib-y object, it is not linked.

lib-y is intended to list utility functions that may be called from all
over the place (and may be unused at all), but it is a problem for
EXPORT_SYMBOL(). Even if there is no call-site in the vmlinux, we need
to keep exported symbols for the use from loadable modules.

Commit 7f2084fa55 ("[kbuild] handle exports in lib-y objects reliably")
worked around it by linking a dummy object, lib-ksyms.o, which contains
references to all the symbols exported from lib.a in that directory.
It uses the linker script command, EXTERN. Unfortunately, the meaning of
EXTERN of ld.lld is different from that of ld.bfd. Therefore, this does
not work with LD=ld.lld (CBL issue #515).

Anyway, the build rule of lib-ksyms.o is somewhat tricky. So, I want to
get rid of it.

At first, I was thinking of accumulating lib-y objects into obj-y
(or even replacing lib-y with obj-y entirely), but the lib-y syntax
is used beyond the ordinary use in lib/ and arch/*/lib/.

Examples:

 - drivers/firmware/efi/libstub/Makefile builds lib.a, which is linked
   into vmlinux in the own way (arm64), or linked to the decompressor
   (arm, x86).

 - arch/alpha/lib/Makefile builds lib.a which is linked not only to
   vmlinux, but also to bootloaders in arch/alpha/boot/Makefile.

 - arch/xtensa/boot/lib/Makefile builds lib.a for use from
   arch/xtensa/boot/boot-redboot/Makefile.

One more thing, adding everything to obj-y would increase the vmlinux
size of allnoconfig (or tinyconfig).

For less impact, I tweaked the destination of lib.a at the top Makefile;
when CONFIG_MODULES=y, lib.a goes to KBUILD_VMLINUX_OBJS, which is
forcibly linked to vmlinux, otherwise lib.a goes to KBUILD_VMLINUX_LIBS
as before.

The size impact for normal usecases is quite small since at lease one
symbol in every lib-y object is eventually called by someone. In case
you are intrested, here are the figures.

x86_64_defconfig:

   text	   data	    bss	    dec	    hex	filename
19566602 5422072 1589328 26578002 1958c52 vmlinux.before
19566932 5422104 1589328 26578364 1958dbc vmlinux.after

The case with the biggest impact is allnoconfig + CONFIG_MODULES=y.

ARCH=x86 allnoconfig + CONFIG_MODULES=y:

   text	   data	    bss	    dec	    hex	filename
1175162	 254740	1220608	2650510	 28718e	vmlinux.before
1177974	 254836	1220608	2653418	 287cea	vmlinux.after

Hopefully this is still not a big deal. The per-file trimming with the
static library is not so effective after all.

If fine-grained optimization is desired, some architectures support
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, which trims dead code per-symbol
basis. When LTO is supported in mainline, even better optimization will
be possible.

Link: https://github.com/ClangBuiltLinux/linux/issues/515
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-04-09 00:13:45 +09:00
Masahiro Yamada c8bddf4fea kbuild: remove -I$(srctree)/tools/include from scripts/Makefile
I do not like to add an extra include path for every tool with no
good reason. This should be specified per file.

This line was added by commit 6520fe5564 ("x86, realmode: 16-bit
real-mode code support for relocs tool"), which did not touch
anything else in scripts/. I see no reason to add this.

Also, remove the comment about kallsyms because we do not have any
for the rest of programs.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Kees Cook 4dcc9a8844 kbuild: mkcompile_h: Include $LD version in /proc/version
When doing Clang builds of the kernel, it is possible to link with
either ld.bfd (binutils) or ld.lld (LLVM), but it is not possible to
discover this from a running kernel. Add the "$LD -v" output to
/proc/version.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Mauro Carvalho Chehab 60969f02f0 kconfig: qconf: Fix a few alignment issues
There are a few items with wrong alignments. Solve them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Mauro Carvalho Chehab e1f7769f60 kconfig: qconf: remove some old bogus TODOs
The items described on those TODOs are already solved. So,
remove the comments.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Mauro Carvalho Chehab b311142fcf kconfig: qconf: fix support for the split view mode
At least on my tests (building against Qt5.13), it seems to
me that, since Kernel 3.14, the split view mode is broken.

Maybe it was not a top priority during the conversion time.

Anyway, this patch changes the logic in order to properly
support the split view mode and the single view mode.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Mauro Carvalho Chehab cce1faba82 kconfig: qconf: fix the content of the main widget
The port to Qt5 tried to preserve the same way as it used
to work with Qt3 and Qt4. However, at least with newer
versions of Qt5 (5.13), this doesn't work properly.

Change the schema by adding a vertical layout, in order
for it to start working properly again.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Mauro Carvalho Chehab 5752ff07fd kconfig: qconf: Change title for the item window
Both main config window and the item window have "Option"
name. That sounds weird, and makes harder to debug issues
of a window appearing at the wrong place.

So, change the title to reflect the contents of each
window.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Mauro Carvalho Chehab cf497b9223 kconfig: qconf: clean deprecated warnings
The recommended way to initialize a null string is with
QString(). This is there at least since Qt5.5, with is
when qconf was ported to Qt5.

Fix those warnings:

	scripts/kconfig/qconf.cc: In member function ‘void ConfigItem::updateMenu()’:
	scripts/kconfig/qconf.cc:158:31: warning: ‘QString::null’ is deprecated: use QString() [-Wdeprecated-declarations]
	  158 |    setText(noColIdx, QString::null);
	      |                               ^~~~
	In file included from /usr/include/qt5/QtCore/qobject.h:47,
	                 from /usr/include/qt5/QtWidgets/qwidget.h:45,
	                 from /usr/include/qt5/QtWidgets/qmainwindow.h:44,
	                 from /usr/include/qt5/QtWidgets/QMainWindow:1,
	                 from scripts/kconfig/qconf.cc:9:

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Masahiro Yamada 77342a02ff gcc-plugins: drop support for GCC <= 4.7
Nobody was opposed to raising minimum GCC version to 4.8 [1]
So, we will drop GCC <= 4.7 support sooner or later.

We always use C++ compiler for building plugins for GCC >= 4.8.

This commit drops the plugin support for GCC <= 4.7 a bit earlier,
which allows us to dump lots of code.

[1] https://lkml.org/lkml/2020/1/23/545

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
2020-04-09 00:13:45 +09:00
Nathan Chancellor afe956c577 kbuild: Enable -Wtautological-compare
Currently, we disable -Wtautological-compare, which in turn disables a
bunch of more specific tautological comparison warnings that are useful
for the kernel such as -Wtautological-bitwise-compare. See clang's
documentation below for the other warnings that are suppressed by
-Wtautological-compare. Now that all of the major/noisy warnings have
been fixed, enable -Wtautological-compare so that more issues can be
caught at build time by various continuous integration setups.

-Wtautological-constant-out-of-range-compare is kept disabled under a
normal build but visible at W=1 because there are places in the kernel
where a constant or variable size can change based on the kernel
configuration. These are not fixed in a clean/concise way and the ones
I have audited so far appear to be harmless. It is not a subgroup but
rather just one warning so we do not lose out on much coverage by
default.

Link: https://github.com/ClangBuiltLinux/linux/issues/488
Link: http://releases.llvm.org/10.0.0/tools/clang/docs/DiagnosticsReference.html#wtautological-compare
Link: https://bugs.llvm.org/show_bug.cgi?id=42666
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-09 00:13:45 +09:00
Kees Cook 277a10850f ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.

For example, using this, we can start to expand the coverage syzkaller is
providing.  Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy.  This will let us focus on one feature
at a time.

For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference).  In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.

Some notes on the bounds checker:

- it does not instrument {mem,str}*()-family functions, it only
  instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
  the {mem,str}*()-family functions is a work-in-progress around
  CONFIG_FORTIFY_SOURCE[1].

- it ignores flexible array members, including the very old single
  byte (e.g. "int foo[1];") declarations. (Note that GCC's
  implementation appears to ignore _all_ trailing arrays, but Clang only
  ignores empty, 0, and 1 byte arrays[2].)

[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589

Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Kees Cook 0887a7ebc9 ubsan: add trap instrumentation option
Patch series "ubsan: Split out bounds checker", v5.

This splits out the bounds checker so it can be individually used.  This
is enabled in Android and hopefully for syzbot.  Includes LKDTM tests for
behavioral corner-cases (beyond just the bounds checker), and adjusts
ubsan and kasan slightly for correct panic handling.

This patch (of 6):

The Undefined Behavior Sanitizer can operate in two modes: warning
reporting mode via lib/ubsan.c handler calls, or trap mode, which uses
__builtin_trap() as the handler.  Using lib/ubsan.c means the kernel image
is about 5% larger (due to all the debugging text and reporting structures
to capture details about the warning conditions).  Using the trap mode,
the image size changes are much smaller, though at the loss of the
"warning only" mode.

In order to give greater flexibility to system builders that want minimal
changes to image size and are prepared to deal with kernel code being
aborted and potentially destabilizing the system, this introduces
CONFIG_UBSAN_TRAP.  The resulting image sizes comparison:

   text    data     bss       dec       hex     filename
19533663   6183037  18554956  44271656  2a38828 vmlinux.stock
19991849   7618513  18874448  46484810  2c54d4a vmlinux.ubsan
19712181   6284181  18366540  44362902  2a4ec96 vmlinux.ubsan-trap

CONFIG_UBSAN=y:      image +4.8% (text +2.3%, data +18.9%)
CONFIG_UBSAN_TRAP=y: image +0.2% (text +0.9%, data +1.6%)

Additionally adjusts the CONFIG_UBSAN Kconfig help for clarity and removes
the mention of non-existing boot param "ubsan_handle".

Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Link: http://lkml.kernel.org/r/20200227193516.32566-2-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Joe Perches 16b7f3c899 checkpatch: avoid warning about uninitialized_var()
WARNING: function definition argument 'flags' should also have an identifier name
#26: FILE: drivers/tty/serial/sh-sci.c:1348:
+       unsigned long uninitialized_var(flags);

Special-case uninitialized_var() to prevent this.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/7db7944761b0bd88c70eb17d4b7f40fe589e14ed.camel@perches.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00