The meaning of sym->kernel is obscure; it is set for in-kernel symbols
loaded from Modules.symvers. This happens only when we are building
external modules, and it is used to determine whether to dump symbols
to $(KBUILD_EXTMOD)/Modules.symvers
It is clearer to remember whether the symbol or module came from a dump
file or ELF object.
This changes the KBUILD_EXTRA_SYMBOLS behavior. Previously, symbols
loaded from KBUILD_EXTRA_SYMBOLS are accumulated into the current
$(KBUILD_EXTMOD)/Modules.symvers
Going forward, they will be only used to check symbol references, but
not dumped into the current $(KBUILD_EXTMOD)/Modules.symvers. I believe
this makes more sense.
sym->vmlinux will have no user. Remove it too.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, modpost reads extra symbol dump files in the reverse order.
If '-e foo -e bar' is given, modpost reads bar, foo, in this order.
This is probably not a big deal, but there is no good reason to reverse
the order. Read files in the given order.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The built-in only code is not required to have MODULE_IMPORT_NS() to
use symbols. So, the namespace is not checked for vmlinux(.o).
Do not pass the meaningless -N option to the first pass of modpost.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The '-T -' option reads the file list from stdin.
It is clearer to put it close to the piped command.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
$(filter -i,$(MAKEFLAGS)) works only in limited use-cases.
The representation of $(MAKEFLAGS) depends on various factors:
- GNU Make version (version 3.8x or version 4.x)
- The presence of other flags like -j
In my experiments, $(MAKEFLAGS) is expanded as follows:
* GNU Make 3.8x:
* without -j option:
--no-print-directory -Rri
* with -j option:
--no-print-directory -Rr --jobserver-fds=3,4 -j -i
* GNU Make 4.x:
* without -j option:
irR --no-print-directory
* with -j option:
irR -j --jobserver-fds=3,4 --no-print-directory
For GNU Make 4.x, the flags are grouped as 'irR', which does not work.
For the single thread build with GNU Make 3.8x, the flags are grouped
as '-Rri', which does not work either.
To make it work for all cases, do likewise as commit 6f0fa58e45
("kbuild: simplify silent build (-s) detection").
BTW, since commit ff9b45c55b ("kbuild: modpost: read modules.order
instead of $(MODVERDIR)/*.mod"), you also need to pass -k option to
build final *.ko files. 'make -i -k' ignores compile errors in modules,
and build as many remaining *.ko as possible.
Please note this feature is kind of dangerous if other modules depend
on the broken module because the generated modules will lack the correct
module dependency or CRC. Honestly, I am not a big fan of it, but I am
keeping this feature.
Fixes: eed380f3f5 ("modpost: Optionally ignore secondary errors seen if a single module build fails")
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Make modules.order depend on $(obj-m), and use if_changed to build it.
This will avoid unneeded update of modules.order, which will be useful
to optimize the modpost stage.
Currently, the second pass of modpost is always invoked. By checking the
timestamp of modules.order, we can avoid the unneeded modpost.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Use sym_get_data_by_offset() helper to get access to the .shstrtab
section data. No functional change is intended because
elf->sechdrs[elf->secindex_strings].sh_addr is 0 for both ET_REL
and ET_EXEC object types.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This may not be a practical problem, but the second pass of ARCH=i386
modpost causes segmentation fault if the -s option is not passed.
MODPOST 12 modules
Segmentation fault (core dumped)
make[2]: *** [scripts/Makefile.modpost:94: __modpost] Error 139
make[1]: *** [Makefile:1339: modules] Error 2
make[1]: *** Waiting for unfinished jobs....
The segmentation fault occurs when section_rel() is called for vmlinux,
which is untested in regular builds. The cause of the problem is
reloc_location() returning a wrong pointer for ET_EXEC object type.
In this case, you need to subtract sechdr->sh_addr, otherwise it would
get access beyond the mmap'ed memory.
Add sym_get_data_by_offset() helper to avoid code duplication.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
$(firstword ...) in scripts/Makefile.modpost was added by commit
3f3fd3c055 ("[PATCH] kbuild: allow multi-word $M in Makefile.modpost")
to build multiple external module directories.
It was a solution to resolve symbol dependencies when an external
module depends on another external module.
Commit 0d96fb20b7 ("kbuild: Add new Kbuild variable
KBUILD_EXTRA_SYMBOLS") introduced another solution by passing symbol
info via KBUILD_EXTRA_SYMBOLS, then broke the multi-word M= support.
include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
$(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
... does not work if KBUILD_EXTMOD contains multiple words.
This feature has been broken for more than a decade. Remove the
bitrotten code, and stop parsing if M or KBUILD_EXTMOD contains
multiple words.
As Documentation/kbuild/modules.rst explains, if your module depends
on another one, there are two solutions:
- add a common top-level Kbuild file
- use KBUILD_EXTRA_SYMBOLS
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
built-in.a contains the built-in object paths from the current and sub
directories.
module.order collects the module paths from the current and sub
directories.
Make their build rules look more symmetrical.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
I think all the warnings have been fixed by now. Make it a fatal error.
Check it before modpost because we need to stop building *.ko files.
Also, pass modules.order via a script parameter.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This is the remnant of commit c17d6179ad ("gcc-plugins: remove unused
GCC_PLUGIN_SUBDIR").
The conditional $(if $(findstring /,$(p)),...) is always false because
none of plugins contains '/' in the file name.
Clean up the code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Add arguments support to print stacks which are greater than
argument value only.
Co-developed-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
currently script prints stack usage for functions
in two ways:($re and $dre)
dre breaks sorting mechanism.
0xffffa00011f26f88 sunxi_mux_clk_setup.isra.0 [vmlinux]:Dynamic (0x140)
..
0xffffa00011f27210 sunxi_divs_clk_setup [vmlinux]: Dynamic (0x1d0)
so we can print it in decimal only.
Also address before function name is changed to function
start address rather than stack consumption address.
Because in next patch, arm has two ways to use stack
which can be clubbed and printed in one function only.
All symbols whose stack by adding(re and dre) is greater than
100, will be printed.
0xffffa00011f2720c0 sunxi_divs_clk_setup [vmlinux]: 464
...
0xffffa00011f26f840 sunxi_mux_clk_setup.isra.0 [vmlinux]:320
Co-developed-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Misuse of CONFIG_* in UAPI headers should result in an error. These config
options can be set in userspace by the user application which includes
these headers to control the APIs and structures being used in a kernel
which supports multiple targets.
Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Kbuild supports the infrastructure to build host programs, but there
was no support to build userspace programs for the target architecture
(i.e. the same architecture as the kernel).
Sam Ravnborg worked on this in 2014 (https://lkml.org/lkml/2014/7/13/154),
but it was not merged. One problem at that time was, there was no good way
to know whether $(CC) can link standalone programs. In fact, pre-built
kernel.org toolchains [1] are often used for building the kernel, but they
do not provide libc.
Now, we can handle this cleanly because the compiler capability is
evaluated at the Kconfig time. If $(CC) cannot link standalone programs,
the relevant options are hidden by 'depends on CC_CAN_LINK'.
The implementation just mimics scripts/Makefile.host
The userspace programs are compiled with the same flags as the host
programs. In addition, it uses -m32 or -m64 if it is found in
$(KBUILD_CFLAGS).
This new syntax has two usecases.
- Sample programs
Several userspace programs under samples/ include UAPI headers
installed in usr/include. Most of them were previously built for
the host architecture just to use the 'hostprogs' syntax.
However, 'make headers' always works for the target architecture.
This caused the arch mismatch in cross-compiling. To fix this
distortion, sample code should be built for the target architecture.
- Bpfilter
net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper,
and embeds it into the kernel. Currently, it overrides HOSTCC with
CC to use the 'hostprogs' syntax. This hack should go away.
[1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
always, hostprogs-y, and hostprogs-m are deprecated.
There is no user in upstream code, but I will keep them for external
modules. I want to remove them entirely someday. Prompt downstream
users for the migration.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
cmd_dtc takes the additional parameter $(2) to select the target
format, dtb or yaml. This makes things complicated when it is used
with cmd_and_fixdep and if_changed_rule. I actually stumbled on this.
See commit 3d4b223868 ("kbuild: fix DT binding schema rule again to
avoid needless rebuilds").
Extract the suffix part of the target instead of passing the parameter.
Fortunately, this works for both $(obj)/%.dtb and $(obj)/%.dt.yaml .
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
scripts/mkcompile_h runs $(CC) just for getting the version string.
Reuse CONFIG_CC_VERSION_TEXT for optimization.
For GCC, this slightly changes the version string. I do not think it
is a big deal as we do not have the defined format for LINUX_COMPILER.
In fact, the recent commit 4dcc9a8844 ("kbuild: mkcompile_h:
Include $LD version in /proc/version") added the linker version.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This omits system headers from the generated header dependency.
System headers are not updated unless you upgrade the compiler. Nor do
they contain CONFIG options, so fixdep does not need to parse them.
Having said that, the effect of this optimization will be quite small
because the kernel code generally does not include system headers
except <stdarg.h>. Host programs include a lot of system headers,
but there are not so many in the kernel tree.
At first, keeping system headers in .*.cmd files might be useful to
detect the compiler update, but there is no guarantee that <stdarg.h>
is included from every file. So, I implemented a more reliable way in
the previous commit.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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>
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>
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>
- 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
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>
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>
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>
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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
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
