Pull Kbuild fixes from Masahiro Yamada:
- suppress sparse warnings about unknown attributes
- fix typos and stale comments
- fix build error of arch/sh
- fix wrong use of ld-option vs cc-ldoption
- remove redundant GCC_PLUGINS_CFLAGS assignment
- fix another memory leak of Kconfig
- fix line number in error messages of Kconfig
- do not write confusing CONFIG_DEFCONFIG_LIST out to .config
- add xstrdup() to Kconfig to handle memory shortage errors
- show also a Debian package name if ncurses is missing
* tag 'kbuild-fixes-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
MAINTAINERS: take over Kconfig maintainership
kconfig: fix line number in recursive inclusion error message
Coccinelle: memdup: Fix typo in warning messages
kconfig: Update ncurses package names for menuconfig
kbuild/kallsyms: trivial typo fix
kbuild: test --build-id linker flag by ld-option instead of cc-ldoption
kbuild: drop superfluous GCC_PLUGINS_CFLAGS assignment
kconfig: Don't leak choice names during parsing
sh: fix build error for empty CONFIG_BUILTIN_DTB_SOURCE
kconfig: set SYMBOL_AUTO to the symbol marked with defconfig_list
kconfig: add xstrdup() helper
kbuild: disable sparse warnings about unknown attributes
Makefile: Fix lying comment re. silentoldconfig
'--build-id' is passed to $(LD), so it should be tested by 'ld-option'.
This seems a kind of misconversion when ld-option was renamed to
cc-ldoption.
Commit f86fd30660 ("kbuild: rename ld-option to cc-ldoption") renamed
all instances of 'ld-option' to 'cc-ldoption'.
Then, commit 691ef3e7fd ("kbuild: introduce ld-option") re-added
'ld-option' as a new implementation.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Currently, sparse issues warnings on code using an attribute
it doesn't know about.
One of the problem with this is that these warnings have no
value for the developer, it's just noise for him. At best these
warnings tell something about some deficiencies of sparse itself
but not about a potential problem with code analyzed.
A second problem with this is that sparse release are, alas,
less frequent than new attributes are added to GCC.
So, avoid the noise by asking sparse to not warn about
attributes it doesn't know about.
Reference: https://marc.info/?l=linux-sparse&m=151871600016790
Reference: https://marc.info/?l=linux-sparse&m=151871725417322
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The comment above the silentoldconfig invocation is outdated.
'make oldconfig' updates just .config and doesn't touch the
include/config/ tree.
This came up in https://lkml.org/lkml/2018/2/12/415.
While fixing the comment, make it more informative by explaining the
purpose of the unfortunately named silentoldconfig.
I can't make sense of the comment re. auto.conf.cmd and a cleaned tree.
include/config/auto.conf and include/config/auto.conf.cmd are both
created simultaneously by silentoldconfig (in
scripts/kconfig/confdata.c, by conf_write_autoconf()), and nothing seems
to remove auto.conf.cmd that wouldn't remove auto.conf. Remove that part
of the comment rather than blindly copying it. It might be a leftover
from an older way of doing things.
The include/config/auto.conf.cmd prerequisite might be there to ensure
that silentoldconfig gets rerun if conf_write_autoconf() fails between
writing out auto.conf.cmd and auto.conf (a comment in the function
indicates that auto.conf is deliberately written out last to mark
completion of the operation). It seems the Makefile dependency between
include/config/auto.conf and .config would already take care of that
though, since include/config/auto.conf would still be out of date re.
.config if the operation fails.
Cop out and leave the prerequisite in for now.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull x86 fixes from Thomas Gleixner:
"Yet another pile of melted spectrum related changes:
- sanitize the array_index_nospec protection mechanism: Remove the
overengineered array_index_nospec_mask_check() magic and allow
const-qualified types as index to avoid temporary storage in a
non-const local variable.
- make the microcode loader more robust by properly propagating error
codes. Provide information about new feature bits after micro code
was updated so administrators can act upon.
- optimizations of the entry ASM code which reduce code footprint and
make the code simpler and faster.
- fix the {pmd,pud}_{set,clear}_flags() implementations to work
properly on paravirt kernels by removing the address translation
operations.
- revert the harmful vmexit_fill_RSB() optimization
- use IBRS around firmware calls
- teach objtool about retpolines and add annotations for indirect
jumps and calls.
- explicitly disable jumplabel patching in __init code and handle
patching failures properly instead of silently ignoring them.
- remove indirect paravirt calls for writing the speculation control
MSR as these calls are obviously proving the same attack vector
which is tried to be mitigated.
- a few small fixes which address build issues with recent compiler
and assembler versions"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
KVM/VMX: Optimize vmx_vcpu_run() and svm_vcpu_run() by marking the RDMSR path as unlikely()
KVM/x86: Remove indirect MSR op calls from SPEC_CTRL
objtool, retpolines: Integrate objtool with retpoline support more closely
x86/entry/64: Simplify ENCODE_FRAME_POINTER
extable: Make init_kernel_text() global
jump_label: Warn on failed jump_label patching attempt
jump_label: Explicitly disable jump labels in __init code
x86/entry/64: Open-code switch_to_thread_stack()
x86/entry/64: Move ASM_CLAC to interrupt_entry()
x86/entry/64: Remove 'interrupt' macro
x86/entry/64: Move the switch_to_thread_stack() call to interrupt_entry()
x86/entry/64: Move ENTER_IRQ_STACK from interrupt macro to interrupt_entry
x86/entry/64: Move PUSH_AND_CLEAR_REGS from interrupt macro to helper function
x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP
objtool: Add module specific retpoline rules
objtool: Add retpoline validation
objtool: Use existing global variables for options
x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute()
x86/boot, objtool: Annotate indirect jump in secondary_startup_64()
x86/paravirt, objtool: Annotate indirect calls
...
Pull more Kbuild updates from Masahiro Yamada:
"Makefile changes:
- enable unused-variable warning that was wrongly disabled for clang
Kconfig changes:
- warn about blank 'help' and fix existing instances
- fix 'choice' behavior to not write out invisible symbols
- fix misc weirdness
Coccinell changes:
- fix false positive of free after managed memory alloc detection
- improve performance of NULL dereference detection"
* tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
kconfig: remove const qualifier from sym_expand_string_value()
kconfig: add xrealloc() helper
kconfig: send error messages to stderr
kconfig: echo stdin to stdout if either is redirected
kconfig: remove check_stdin()
kconfig: remove 'config*' pattern from .gitignnore
kconfig: show '?' prompt even if no help text is available
kconfig: do not write choice values when their dependency becomes n
coccinelle: deref_null: avoid useless computation
coccinelle: devm_free: reduce false positives
kbuild: clang: disable unused variable warnings only when constant
kconfig: Warn if help text is blank
nios2: kconfig: Remove blank help text
arm: vt8500: kconfig: Remove blank help text
MIPS: kconfig: Remove blank help text
MIPS: BCM63XX: kconfig: Remove blank help text
lib/Kconfig.debug: Remove blank help text
Staging: rtl8192e: kconfig: Remove blank help text
Staging: rtl8192u: kconfig: Remove blank help text
mmc: kconfig: Remove blank help text
...
Nearly all modern compilers support a stack-protector option, and nearly
all modern distributions enable the kernel stack-protector, so enabling
this by default in kernel builds would make sense. However, Kconfig does
not have knowledge of available compiler features, so it isn't safe to
force on, as this would unconditionally break builds for the compilers or
architectures that don't have support. Instead, this introduces a new
option, CONFIG_CC_STACKPROTECTOR_AUTO, which attempts to discover the best
possible stack-protector available, and will allow builds to proceed even
if the compiler doesn't support any stack-protector.
This option is made the default so that kernels built with modern
compilers will be protected-by-default against stack buffer overflows,
avoiding things like the recent BlueBorne attack. Selection of a specific
stack-protector option remains available, including disabling it.
Additionally, tiny.config is adjusted to use CC_STACKPROTECTOR_NONE, since
that's the option with the least code size (and it used to be the default,
so we have to explicitly choose it there now).
Link: http://lkml.kernel.org/r/1510076320-69931-4-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, GCC disables -Wunused-const-variable, but not
-Wunused-variable, so warns unused variables if they are
non-constant.
While, Clang does not warn unused variables at all regardless of
the const qualifier because -Wno-unused-const-variable is implied
by the stronger option -Wno-unused-variable.
Disable -Wunused-const-variable instead of -Wunused-variable so that
GCC and Clang work in the same way.
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull Kconfig updates from Masahiro Yamada:
"A pretty big batch of Kconfig updates.
I have to mention the lexer and parser of Kconfig are now built from
real .l and .y sources. So, flex and bison are the requirement for
building the kernel. Both of them (unlike gperf) have been stable for
a long time. This change has been tested several weeks in linux-next,
and I did not receive any problem report about this.
Summary:
- add checks for mistakes, like the choice default is not in choice,
help is doubled
- document data structure and complex code
- fix various memory leaks
- change Makefile to build lexer and parser instead of using
pre-generated C files
- drop 'boolean' keyword, which is equivalent to 'bool'
- use default 'yy' prefix and remove unneeded Make variables
- fix gettext() check for xconfig
- announce that oldnoconfig will be finally removed
- make 'Selected by:' and 'Implied by' readable in help and search
result
- hide silentoldconfig from 'make help' to stop confusing people
- fix misc things and cleanups"
* tag 'kconfig-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (37 commits)
kconfig: Remove silentoldconfig from help and docs; fix kconfig/conf's help
kconfig: make "Selected by:" and "Implied by:" readable
kconfig: announce removal of oldnoconfig if used
kconfig: fix make xconfig when gettext is missing
kconfig: Clarify menu and 'if' dependency propagation
kconfig: Document 'if' flattening logic
kconfig: Clarify choice dependency propagation
kconfig: Document SYMBOL_OPTIONAL logic
kbuild: remove unnecessary LEX_PREFIX and YACC_PREFIX
kconfig: use default 'yy' prefix for lexer and parser
kconfig: make conf_unsaved a local variable of conf_read()
kconfig: make xfgets() really static
kconfig: make input_mode static
kconfig: Warn if there is more than one help text
kconfig: drop 'boolean' keyword
kconfig: use bool instead of boolean for type definition attributes, again
kconfig: Remove menu_end_entry()
kconfig: Document important expression functions
kconfig: Document automatic submenu creation code
kconfig: Fix choice symbol expression leak
...
Pull Kbuild fixes from Masahiro Yamada:
- fix cross-compilation for architectures that setup CROSS_COMPILE in
their arch Makefile
- fix Kconfig rational operators for bool / tristate
- drop a gperf-generated file from .gitignore
* tag 'kbuild-fixes-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
genksyms: drop *.hash.c from .gitignore
kconfig: fix relational operators for bool and tristate symbols
kbuild: move cc-option and cc-disable-warning after incl. arch Makefile
It appears that hardened gentoo enables "-fstack-check" by default for
gcc.
That doesn't work _at_all_ for the kernel, because the kernel stack
doesn't act like a user stack at all: it's much smaller, and it doesn't
auto-expand on use. So the extra "probe one page below the stack" code
generated by -fstack-check just breaks the kernel in horrible ways,
causing infinite double faults etc.
[ I have to say, that the particular code gcc generates looks very
stupid even for user space where it works, but that's a separate
issue. ]
Reported-and-tested-by: Alexander Tsoy <alexander@tsoy.me>
Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Cc: stable@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds
Masahiro Yamada
Luc Van Oostenryck
Ulf Magnusson
Peter Zijlstra
Kees Cook
Andrey Konovalov
Sodagudi Prasad