This will slightly change the link order; drivers-y from arch Makefile
will be linked after virt/built-in.a, but I guess this is not a big
deal.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
No arch Makefile specifies init-y.
Merge init-y into core-y. This does not change the link order.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This hunk has two 'ifdef CONFIG_TRIM_UNUSED_KSYMS ... endif' blocks
with no other code interleaved. Merge them.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This code does not work as stated in the comment.
$(CONFIG_MODVERSIONS) is always empty because it is expanded before
include/config/auto.conf is included. Hence, 'make modules' with
CONFIG_MODVERSION=y cannot record the version CRCs.
This has been broken since 2003, commit ("kbuild: Enable modules to be
build using the "make dir/" syntax"). [1]
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=15c6240cdc44bbeef3c4797ec860f9765ef4f1a7
Cc: linux-stable <stable@vger.kernel.org> # v2.5.71+
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
As debug information gets larger and larger, it helps significantly save
the size of vmlinux images to compress the information in the debug
information sections. Note: this debug info is typically split off from
the final compressed kernel image, which is why vmlinux is what's used
in conjunction with GDB. Minimizing the debug info size should have no
impact on boot times, or final compressed kernel image size.
All of the debug sections will have a `C` flag set.
$ readelf -S <object file>
$ bloaty vmlinux.gcc75.compressed.dwarf4 -- \
vmlinux.gcc75.uncompressed.dwarf4
FILE SIZE VM SIZE
-------------- --------------
+0.0% +18 [ = ] 0 [Unmapped]
-73.3% -114Ki [ = ] 0 .debug_aranges
-76.2% -2.01Mi [ = ] 0 .debug_frame
-73.6% -2.89Mi [ = ] 0 .debug_str
-80.7% -4.66Mi [ = ] 0 .debug_abbrev
-82.9% -4.88Mi [ = ] 0 .debug_ranges
-70.5% -9.04Mi [ = ] 0 .debug_line
-79.3% -10.9Mi [ = ] 0 .debug_loc
-39.5% -88.6Mi [ = ] 0 .debug_info
-18.2% -123Mi [ = ] 0 TOTAL
$ bloaty vmlinux.clang11.compressed.dwarf4 -- \
vmlinux.clang11.uncompressed.dwarf4
FILE SIZE VM SIZE
-------------- --------------
+0.0% +23 [ = ] 0 [Unmapped]
-65.6% -871 [ = ] 0 .debug_aranges
-77.4% -1.84Mi [ = ] 0 .debug_frame
-82.9% -2.33Mi [ = ] 0 .debug_abbrev
-73.1% -2.43Mi [ = ] 0 .debug_str
-84.8% -3.07Mi [ = ] 0 .debug_ranges
-65.9% -8.62Mi [ = ] 0 .debug_line
-86.2% -40.0Mi [ = ] 0 .debug_loc
-42.0% -64.1Mi [ = ] 0 .debug_info
-22.1% -122Mi [ = ] 0 TOTAL
For x86_64 defconfig + LLVM=1 (before):
Elapsed (wall clock) time (h:mm:ss or m:ss): 3:22.03
Maximum resident set size (kbytes): 43856
For x86_64 defconfig + LLVM=1 (after):
Elapsed (wall clock) time (h:mm:ss or m:ss): 3:32.52
Maximum resident set size (kbytes): 1566776
Thanks to:
Nick Clifton helped us to provide the minimal binutils version.
Sedat Dilek found an increase in size of debug .deb package.
Cc: Nick Clifton <nickc@redhat.com>
Suggested-by: David Blaikie <blaikie@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
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>
This is a left-over of commit 39808e451f ("kbuild: do not read
$(KBUILD_EXTMOD)/Module.symvers").
Kbuild no longer supports this way.
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>
Some targets are internal-use only.
It is tedious to care about "what if __build_one_by_one is contained
in $(MAKECMDGOALS)?" etc.
Prefix internal targets with double underscores. Stop parsing Makefile
if they are directly run.
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>
It's not intuitively obvious that bpfilter_umh is a statically linked binary.
Mention the toolchain requirement in the Kconfig help, so people
have an easier time figuring out what's needed.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.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>
Merge {CLEAN,MRPROPER,DISTCLEAN}_DIRS into {CLEAN,MRPROPER,DISTCLEAN}_FILES
because the difference is just the -r option passed to the 'rm' command.
Do likewise as commit 1634f2bfdb ("kbuild: remove clean-dirs syntax").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
If include/generated/autoconf.h is accidentally lost somehow,
there is no clear way to fix it. Make it self-healing.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Kbuild now supports the 'userprogs' syntax to compile userspace
programs for the same architecture as the kernel.
Add the entry to samples/Makefile to put this into the build bot
coverage.
I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Kbuild now supports the 'userprogs' syntax to compile userspace
programs for the same architecture as the kernel.
Add the entry to samples/Makefile to put this into the build bot
coverage.
I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Kbuild now supports the 'userprogs' syntax to compile userspace
programs for the same architecture as the kernel.
Add the entry to samples/Makefile to put this into the build bot
coverage.
I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
This userspace program includes UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample program should be built for
the target as well. Kbuild now supports 'userprogs' for that.
I also guarded the CONFIG option by 'depends on CC_CAN_LINK' because
$(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
This userspace program includes UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample program should be built for
the target as well. Kbuild now supports 'userprogs' for that.
I also guarded the CONFIG option by 'depends on CC_CAN_LINK' because
$(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
These userspace programs include UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample programs should be built for
the target as well. Kbuild now supports 'userprogs' for that.
I also guarded the CONFIG option by 'depends on CC_CAN_LINK' because
$(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
This userspace program includes UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample program should be built for
the target as well. Kbuild now supports 'userprogs' for that.
$(CC) can always compile cn_text.o since it is the kenrel-space code,
but building ucon requires libc.
I guarded it by:
always-$(CONFIG_CC_CAN_LINK) := $(userprogs)
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
This userspace program includes UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample program should be built for
the target as well. Kbuild now supports 'userprogs' for that.
I also guarded the CONFIG option by 'depends on CC_CAN_LINK' because
$(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
This userspace program includes UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample program should be built for
the target as well. Kbuild now supports 'userprogs' for that.
Add the entry to samples/Makefile to put this into the build bot
coverage.
I also added the CONFIG option guarded by 'depends on CC_CAN_LINK'
because $(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Fix warnings seen when building for 32-bit architecture.
Use "%xd" for arguments of type size_t to fix the warnings.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Kbuild now supports the syntax 'userprogs' to compile userspace
programs for the same architecture as the kernel.
Insert the section '5 Userspace Program support' to explain it.
I copy-pasted '4 Host Program support' and fixed it up.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
These userspace programs include UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample programs should be built for
the target as well. Kbuild now supports 'userprogs' for that.
I also guarded the CONFIG option by 'depends on CC_CAN_LINK' because
$(CC) may not provide libc.
The 'ifndef CROSS_COMPILE' is no longer needed.
BTW, the -m31 for s390 is left-over code. Commit 5a79859ae0 ("s390:
remove 31 bit support") killed it.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
The user mode helper should be compiled for the same architecture as
the kernel.
This Makefile reused the 'hostprogs' syntax by overriding HOSTCC with CC.
Use the new syntax 'userprogs' to fix the Makefile mess.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.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>
On Fedora, linking static glibc requires the glibc-static RPM package,
which is not part of the glibc-devel package.
CONFIG_CC_CAN_LINK does not check the capability of static linking,
so you can enable CONFIG_BPFILTER_UMH, then fail to build:
HOSTLD net/bpfilter/bpfilter_umh
/usr/bin/ld: cannot find -lc
collect2: error: ld returned 1 exit status
Add CONFIG_CC_CAN_LINK_STATIC, and make CONFIG_BPFILTER_UMH depend
on it.
Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
bpfilter_umh is built for the default machine bit of the compiler,
which may not match to the bit size of the kernel.
This happens in the scenario below:
You can use biarch GCC that defaults to 64-bit for building the 32-bit
kernel. In this case, Kbuild passes -m32 to teach the compiler to
produce 32-bit kernel space objects. However, it is missing when
building bpfilter_umh. It is built as a 64-bit ELF, and then embedded
into the 32-bit kernel.
The 32-bit kernel and 64-bit umh is a bad combination.
In theory, we can have 32-bit umh running on 64-bit kernel, but we do
not have a good reason to support such a usecase.
The best is to match the bit size between them.
Pass -m32 or -m64 to the umh build command if it is found in
$(KBUILD_CFLAGS). Evaluate CC_CAN_LINK against the kernel bit-size.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.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>
$(AS) is not used anywhere in the kernel build, hence commit
aa824e0c96 ("kbuild: remove AS variable") killed it.
Remove the left-over code in arch/{arm,arm64}/Makefile.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Will Deacon <will@kernel.org>
Masahiro Yamada
Nick Desaulniers
Valdis Kl ē tnieks
Maninder Singh
Gustavo A. R. Silva
Siddharth Gupta
Sam Ravnborg