The changes to automatically test for working stack protector compiler
support in the Kconfig files removed the special STACKPROTECTOR_AUTO
option that picked the strongest stack protector that the compiler
supported.
That was all a nice cleanup - it makes no sense to have the AUTO case
now that the Kconfig phase can just determine the compiler support
directly.
HOWEVER.
It also meant that doing "make oldconfig" would now _disable_ the strong
stackprotector if you had AUTO enabled, because in a legacy config file,
the sane stack protector configuration would look like
CONFIG_HAVE_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR_NONE is not set
# CONFIG_CC_STACKPROTECTOR_REGULAR is not set
# CONFIG_CC_STACKPROTECTOR_STRONG is not set
CONFIG_CC_STACKPROTECTOR_AUTO=y
and when you ran this through "make oldconfig" with the Kbuild changes,
it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had
been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just
CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version
used to be disabled (because it was really enabled by AUTO), and would
disable it in the new config, resulting in:
CONFIG_HAVE_CC_STACKPROTECTOR=y
CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
CONFIG_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR_STRONG is not set
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
That's dangerously subtle - people could suddenly find themselves with
the weaker stack protector setup without even realizing.
The solution here is to just rename not just the old RECULAR stack
protector option, but also the strong one. This does that by just
removing the CC_ prefix entirely for the user choices, because it really
is not about the compiler support (the compiler support now instead
automatially impacts _visibility_ of the options to users).
This results in "make oldconfig" actually asking the user for their
choice, so that we don't have any silent subtle security model changes.
The end result would generally look like this:
CONFIG_HAVE_CC_STACKPROTECTOR=y
CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
CONFIG_STACKPROTECTOR=y
CONFIG_STACKPROTECTOR_STRONG=y
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
where the "CC_" versions really are about internal compiler
infrastructure, not the user selections.
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As Documentation/kbuild/kconfig-language.txt notes, 'select' should be
be used with care - it forces a lower limit of another symbol, ignoring
the dependency. Currently, KCOV can select GCC_PLUGINS even if arch
does not select HAVE_GCC_PLUGINS. This could cause the unmet direct
dependency.
Now that Kconfig can test compiler capability, let's handle this in a
more sophisticated way.
There are two ways to enable KCOV; use the compiler that natively
supports -fsanitize-coverage=trace-pc, or build the SANCOV plugin if
the compiler has ability to build GCC plugins. Hence, the correct
dependency for KCOV is:
depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
You do not need to build the SANCOV plugin if the compiler already
supports -fsanitize-coverage=trace-pc. Hence, the select should be:
select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
With this, GCC_PLUGIN_SANCOV is selected only when necessary, so
scripts/Makefile.gcc-plugins can be cleaner.
I also cleaned up Kconfig and scripts/Makefile.kcov as well.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Move the test for -fstack-protector(-strong) option to Kconfig.
If the compiler does not support the option, the corresponding menu
is automatically hidden. If STRONG is not supported, it will fall
back to REGULAR. If REGULAR is not supported, it will be disabled.
This means, AUTO is implicitly handled by the dependency solver of
Kconfig, hence removed.
I also turned the 'choice' into only two boolean symbols. The use of
'choice' is not a good idea here, because all of all{yes,mod,no}config
would choose the first visible value, while we want allnoconfig to
disable as many features as possible.
X86 has additional shell scripts in case the compiler supports those
options, but generates broken code. I added CC_HAS_SANE_STACKPROTECTOR
to test this. I had to add -m32 to gcc-x86_32-has-stack-protector.sh
to make it work correctly.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
Commit 21c54b7747 ("kconfig: show compiler version text in the top
comment") was intended to detect the compiler upgrade, but Geert
reported a breakage on the m68k build.
The compiler upgrade is detected by the change of the environment
variable, CC_VERSION_TEXT, which contains the first line of the output
from $(CC) --version. Currently, this works well when CROSS_COMPILE
is given via the environment variable or the Make command line.
However, some architectures such as m68k can specify CROSS_COMPILE
from arch/$(SRCARCH)/Makefile as well. In this case, "make ARCH=m68k"
ends up with endless syncconfig loop.
$ make ARCH=m68k defconfig
*** Default configuration is based on 'multi_defconfig'
#
# configuration written to .config
#
$ make ARCH=m68k
scripts/kconfig/conf --syncconfig Kconfig
scripts/kconfig/conf --syncconfig Kconfig
scripts/kconfig/conf --syncconfig Kconfig
scripts/kconfig/conf --syncconfig Kconfig
Things are happening like this:
Because arch/$(SRCARCH)/Makefile is included after CC_VERSION_TEXT
is set, it contains the host compiler version in the defconfig phase.
To create or update auto.conf, the following line is triggered:
include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd
$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
This recurses the top Makefile after arch/$(SRCARCH)/Makefile is
included. CROSS_COMPILE is set to a m68k toolchain prefix and
exported to the recursed Make. Then, syncconfig is invoked with
the target compiler version in CC_VERSION_TEXT.
The Make will restart because auto.conf and auto.conf.cmd have been
updated. At this point, CROSS_COMPILE is reset, so CC_VERSION_TEXT
is set to the host compiler version again. Then, syncconfig is
triggered due to the change of CC_VERSION_TEXT. This loop continues
eternally.
To fix this problem, $(CC_VERSION_TEXT) must be evaluated only after
arch/$(SRCARCH)/Makefile. Setting it earlier is OK as long as it is
defined by using the '=' operator instead of ':='.
For the defconfig phase, $(CC_VERSION_TEXT) is evaluated when Kbuild
descends into scripts/kconfig/, so it contains the target compiler
version correctly.
include/config/auto.conf.cmd references $(CC_VERSION_TEXT) as well,
so it must be included after arch/$(SRCARCH)/Makefile.
Fixes: 21c54b7747 ("kconfig: show compiler version text in the top comment")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Pull networking updates from David Miller:
1) Add Maglev hashing scheduler to IPVS, from Inju Song.
2) Lots of new TC subsystem tests from Roman Mashak.
3) Add TCP zero copy receive and fix delayed acks and autotuning with
SO_RCVLOWAT, from Eric Dumazet.
4) Add XDP_REDIRECT support to mlx5 driver, from Jesper Dangaard
Brouer.
5) Add ttl inherit support to vxlan, from Hangbin Liu.
6) Properly separate ipv6 routes into their logically independant
components. fib6_info for the routing table, and fib6_nh for sets of
nexthops, which thus can be shared. From David Ahern.
7) Add bpf_xdp_adjust_tail helper, which can be used to generate ICMP
messages from XDP programs. From Nikita V. Shirokov.
8) Lots of long overdue cleanups to the r8169 driver, from Heiner
Kallweit.
9) Add BTF ("BPF Type Format"), from Martin KaFai Lau.
10) Add traffic condition monitoring to iwlwifi, from Luca Coelho.
11) Plumb extack down into fib_rules, from Roopa Prabhu.
12) Add Flower classifier offload support to igb, from Vinicius Costa
Gomes.
13) Add UDP GSO support, from Willem de Bruijn.
14) Add documentation for eBPF helpers, from Quentin Monnet.
15) Add TLS tx offload to mlx5, from Ilya Lesokhin.
16) Allow applications to be given the number of bytes available to read
on a socket via a control message returned from recvmsg(), from
Soheil Hassas Yeganeh.
17) Add x86_32 eBPF JIT compiler, from Wang YanQing.
18) Add AF_XDP sockets, with zerocopy support infrastructure as well.
From Björn Töpel.
19) Remove indirect load support from all of the BPF JITs and handle
these operations in the verifier by translating them into native BPF
instead. From Daniel Borkmann.
20) Add GRO support to ipv6 gre tunnels, from Eran Ben Elisha.
21) Allow XDP programs to do lookups in the main kernel routing tables
for forwarding. From David Ahern.
22) Allow drivers to store hardware state into an ELF section of kernel
dump vmcore files, and use it in cxgb4. From Rahul Lakkireddy.
23) Various RACK and loss detection improvements in TCP, from Yuchung
Cheng.
24) Add TCP SACK compression, from Eric Dumazet.
25) Add User Mode Helper support and basic bpfilter infrastructure, from
Alexei Starovoitov.
26) Support ports and protocol values in RTM_GETROUTE, from Roopa
Prabhu.
27) Support bulking in ->ndo_xdp_xmit() API, from Jesper Dangaard
Brouer.
28) Add lots of forwarding selftests, from Petr Machata.
29) Add generic network device failover driver, from Sridhar Samudrala.
* ra.kernel.org:/pub/scm/linux/kernel/git/davem/net-next: (1959 commits)
strparser: Add __strp_unpause and use it in ktls.
rxrpc: Fix terminal retransmission connection ID to include the channel
net: hns3: Optimize PF CMDQ interrupt switching process
net: hns3: Fix for VF mailbox receiving unknown message
net: hns3: Fix for VF mailbox cannot receiving PF response
bnx2x: use the right constant
Revert "net: sched: cls: Fix offloading when ingress dev is vxlan"
net: dsa: b53: Fix for brcm tag issue in Cygnus SoC
enic: fix UDP rss bits
netdev-FAQ: clarify DaveM's position for stable backports
rtnetlink: validate attributes in do_setlink()
mlxsw: Add extack messages for port_{un, }split failures
netdevsim: Add extack error message for devlink reload
devlink: Add extack to reload and port_{un, }split operations
net: metrics: add proper netlink validation
ipmr: fix error path when ipmr_new_table fails
ip6mr: only set ip6mr_table from setsockopt when ip6mr_new_table succeeds
net: hns3: remove unused hclgevf_cfg_func_mta_filter
netfilter: provide udp*_lib_lookup for nf_tproxy
qed*: Utilize FW 8.37.2.0
...
Pull Kconfig updates from Masahiro Yamada:
"Kconfig now supports new functionality to perform textual
substitution. It has been a while since Linus suggested to move
compiler option tests from makefiles to Kconfig. Finally, here it is.
The implementation has been generalized into a Make-like macro
language.
Some built-in functions such as 'shell' are provided. Variables and
user-defined functions are also supported so that 'cc-option',
'ld-option', etc. are implemented as macros.
Summary:
- refactor package checks for building {m,n,q,g}conf
- remove unused/unmaintained localization support
- remove Kbuild cache
- drop CONFIG_CROSS_COMPILE support
- replace 'option env=' with direct variable expansion
- add built-in functions such as 'shell'
- support variables and user-defined functions
- add helper macros as as 'cc-option'
- add unit tests and a document of the new macro language
- add 'testconfig' to help
- fix warnings from GCC 8.1"
* tag 'kconfig-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits)
kconfig: Avoid format overflow warning from GCC 8.1
kbuild: Move last word of nconfig help to the previous line
kconfig: Add testconfig into make help output
kconfig: add basic helper macros to scripts/Kconfig.include
kconfig: show compiler version text in the top comment
kconfig: test: add Kconfig macro language tests
Documentation: kconfig: document a new Kconfig macro language
kconfig: error out if a recursive variable references itself
kconfig: add 'filename' and 'lineno' built-in variables
kconfig: add 'info', 'warning-if', and 'error-if' built-in functions
kconfig: expand lefthand side of assignment statement
kconfig: support append assignment operator
kconfig: support simply expanded variable
kconfig: support user-defined function and recursively expanded variable
kconfig: begin PARAM state only when seeing a command keyword
kconfig: replace $(UNAME_RELEASE) with function call
kconfig: add 'shell' built-in function
kconfig: add built-in function support
kconfig: make default prompt of mainmenu less specific
kconfig: remove sym_expand_string_value()
...
Pull Kbuild updates from Masahiro Yamada:
- improve fixdep to coalesce consecutive slashes in dep-files
- fix some issues of the maintainer string generation in deb-pkg script
- remove unused CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX and clean-up
several tools and linker scripts
- clean-up modpost
- allow to enable the dead code/data elimination for PowerPC in EXPERT
mode
- improve two coccinelle scripts for better performance
- pass endianness and machine size flags to sparse for all architecture
- misc fixes
* tag 'kbuild-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits)
kbuild: add machine size to CHECKFLAGS
kbuild: add endianness flag to CHEKCFLAGS
kbuild: $(CHECK) doesnt need NOSTDINC_FLAGS twice
scripts: Fixed printf format mismatch
scripts/tags.sh: use `find` for $ALLSOURCE_ARCHS generation
coccinelle: deref_null: improve performance
coccinelle: mini_lock: improve performance
powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected
kbuild: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selectable if enabled
kbuild: LD_DEAD_CODE_DATA_ELIMINATION no -ffunction-sections/-fdata-sections for module build
kbuild: Fix asm-generic/vmlinux.lds.h for LD_DEAD_CODE_DATA_ELIMINATION
modpost: constify *modname function argument where possible
modpost: remove redundant is_vmlinux() test
modpost: use strstarts() helper more widely
modpost: pass struct elf_info pointer to get_modinfo()
checkpatch: remove VMLINUX_SYMBOL() check
vmlinux.lds.h: remove no-op macro VMLINUX_SYMBOL()
kbuild: remove CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
export.h: remove code for prefixing symbols with underscore
depmod.sh: remove symbol prefix support
...
check that CC can build executables and use that compiler instead of HOSTCC
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
By default, sparse assumes a 64bit machine when compiled on x86-64
and 32bit when compiled on anything else.
This can of course create all sort of problems for the other archs, like
issuing false warnings ('shift too big (32) for type unsigned long'), or
worse, failing to emit legitimate warnings.
Fix this by adding the -m32/-m64 flag, depending on CONFIG_64BIT,
to CHECKFLAGS in the main Makefile (and so for all archs).
Also, remove the now unneeded -m32/-m64 in arch specific Makefiles.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The kernel depends on macros like __BYTE_ORDER__,
__BIG_ENDIAN__ or __LITTLE_ENDIAN__.
OTOH, sparse doesn't know about the endianness of the kernel and
by default uses the same as the machine on which sparse was built.
Ensure that sparse can predefine the macros corresponding to
how the kernel was configured by adding -m{big,little}-endian
to CHECKFLAGS in the main Makefile (and so for all archs).
Also, remove the equivalent done in arch specific Makefiles.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Currently, $(CHECK) receives NOSTDINC_FLAGS twice:
* first directly in the main Makefile via CHECKFLAGS,
* then indirectly in scripts/Makefile.build via c_flags.
Since once is enough, leave the occurence via c_flags and
remove the one via CHECKFLAGS.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
The kernel configuration phase is now tightly coupled with the compiler
in use. It will be nice to show the compiler information in Kconfig.
The compiler information will be displayed like this:
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- config
scripts/kconfig/conf --oldaskconfig Kconfig
*
* Linux/arm64 4.16.0-rc1 Kernel Configuration
*
*
* Compiler: aarch64-linux-gnu-gcc (Linaro GCC 7.2-2017.11) 7.2.1 20171011
*
*
* General setup
*
Compile also drivers which will not load (COMPILE_TEST) [N/y/?]
If you use GUI methods such as menuconfig, it will be displayed in the
top menu.
This is simply implemented by using the 'comment' statement. So, it
will be saved into the .config file as well.
This commit has a very important meaning. If the compiler is upgraded,
Kconfig must be re-run since different compilers have different sets
of supported options.
All referenced environments are written to include/config/auto.conf.cmd
so that any environment change triggers syncconfig, and prompt the user
to input new values if needed.
With this commit, something like follows will be added to
include/config/auto.conf.cmd
ifneq "$(CC_VERSION_TEXT)" "aarch64-linux-gnu-gcc (Linaro GCC 7.2-2017.11) 7.2.1 20171011"
include/config/auto.conf: FORCE
endif
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
To get access to environment variables, Kconfig needs to define a
symbol using "option env=" syntax. It is tedious to add a symbol entry
for each environment variable given that we need to define much more
such as 'CC', 'AS', 'srctree' etc. to evaluate the compiler capability
in Kconfig.
Adding '$' for symbol references is grammatically inconsistent.
Looking at the code, the symbols prefixed with 'S' are expanded by:
- conf_expand_value()
This is used to expand 'arch/$ARCH/defconfig' and 'defconfig_list'
- sym_expand_string_value()
This is used to expand strings in 'source' and 'mainmenu'
All of them are fixed values independent of user configuration. So,
they can be changed into the direct expansion instead of symbols.
This change makes the code much cleaner. The bounce symbols 'SRCARCH',
'ARCH', 'SUBARCH', 'KERNELVERSION' are gone.
sym_init() hard-coding 'UNAME_RELEASE' is also gone. 'UNAME_RELEASE'
should be replaced with an environment variable.
ARCH_DEFCONFIG is a normal symbol, so it should be simply referenced
without '$' prefix.
The new syntax is addicted by Make. The variable reference needs
parentheses, like $(FOO), but you can omit them for single-letter
variables, like $F. Yet, in Makefiles, people tend to use the
parenthetical form for consistency / clarification.
At this moment, only the environment variable is supported, but I will
extend the concept of 'variable' later on.
The variables are expanded in the lexer so we can simplify the token
handling on the parser side.
For example, the following code works.
[Example code]
config MY_TOOLCHAIN_LIST
string
default "My tools: CC=$(CC), AS=$(AS), CPP=$(CPP)"
[Result]
$ make -s alldefconfig && tail -n 1 .config
CONFIG_MY_TOOLCHAIN_LIST="My tools: CC=gcc, AS=as, CPP=gcc -E"
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Kbuild provides a couple of ways to specify CROSS_COMPILE:
[1] Command line
[2] Environment
[3] arch/*/Makefile (only some architectures)
[4] CONFIG_CROSS_COMPILE
[4] is problematic for the compiler capability tests in Kconfig.
CONFIG_CROSS_COMPILE allows users to change the compiler prefix from
'make menuconfig', etc. It means, the compiler options would have
to be all re-calculated everytime CONFIG_CROSS_COMPILE is changed.
To avoid complexity and performance issues, I'd like to evaluate
the shell commands statically, i.e. only parsing Kconfig files.
I guess the majority is [1] or [2]. Currently, there are only
5 defconfig files that specify CONFIG_CROSS_COMPILE.
arch/arm/configs/lpc18xx_defconfig
arch/hexagon/configs/comet_defconfig
arch/nds32/configs/defconfig
arch/openrisc/configs/or1ksim_defconfig
arch/openrisc/configs/simple_smp_defconfig
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
The kbuild cache was introduced to remember the result of shell
commands, some of which are expensive to compute, such as
$(call cc-option,...).
However, this turned out not so clever as I had first expected.
Actually, it is problematic. For example, "$(CC) -print-file-name"
is cached. If the compiler is updated, the stale search path causes
build error, which is difficult to figure out. Another problem
scenario is cache files could be touched while install targets are
running under the root permission. We can patch them if desired,
but the build infrastructure is getting uglier and uglier.
Now, we are going to move compiler flag tests to the configuration
phase. If this is completed, the result of compiler tests will be
naturally cached in the .config file. We will not have performance
issues of incremental building since this testing only happens at
Kconfig time.
To start this work with a cleaner code base, remove the kbuild
cache first.
Revert the following commits:
Commit 9a234a2e38 ("kbuild: create directory for make cache only when necessary")
Commit e17c400ae1 ("kbuild: shrink .cache.mk when it exceeds 1000 lines")
Commit 4e56207130 ("kbuild: Cache a few more calls to the compiler")
Commit 3298b690b2 ("kbuild: Add a cache for generated variables")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Pull more Kbuild fixes from Masahiro Yamada:
- enable '-fno-tree-loop-im' only when supported
- add '-fno-PIE' option before the asm-goto test
* tag 'kbuild-fixes-v4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
Makefile: disable PIE before testing asm goto
kbuild: gcov: enable -fno-tree-loop-im if supported
Modules do not tend to cope with -ffunction-sections, even though they
do not link with -gc-sections. It may be possible for unused symbols to
be trimmed from modules, but in general that would take much more work
in architecture module linker scripts.
For now, enable these only for kernel build.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG.
They were removed by commit 4ba66a9760 ("arch: remove blackfin port"),
commit bb6fb6dfcc ("metag: Remove arch/metag/"), respectively.
No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX,
hence the last argument of scripts/depmod.sh can be removed.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
