02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
30 Jun, 2017
3 commits
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The thin archives build currently puts all lib.a and built-in.o
files together and links them with --whole-archive.This works because thin archives can recursively refer to thin
archives. However some architectures include libgcc.a, which may
not be a thin archive, or it may not be constructed with the "P"
option, in which case its contents do not get linked correctly.So don't pull .a libs into the root built-in.o archive. These
libs should already have symbol tables and indexes built, so they
can be direct linker inputs. Move them out of the --whole-archive
option, which restore the conditional linking behaviour of lib.a
to thin archives builds.Signed-off-by: Nicholas Piggin
Signed-off-by: Masahiro Yamada -
The P option makes ar do full path name matching and can prevent ar
from discarding files with duplicate names in some cases of creating
thin archives from thin archives. The sh architecture in particular
loses some object files from its kernel/cpu/sh*/ directories without
this option.This could be a bug in binutils ar, but the P option should not cause
any negative effects so it is safe to use to work around this with.Signed-off-by: Nicholas Piggin
Signed-off-by: Masahiro Yamada -
Close the --whole-archives option with --no-whole-archive. Some
architectures end up including additional .o and files multiple
times after this, and they get duplicate symbols when they are
brought under the --whole-archives option.This matches more closely with the incremental final link.
Signed-off-by: Nicholas Piggin
Signed-off-by: Masahiro Yamada
29 Nov, 2016
2 commits
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The root built-in.o archive is currently generated before all object
files are built for the final link, due to final build of init/ after
version update. In practice it seems like it doesn't matter because
the archive symbol table does not change, but it is more logical to
create the final archive as the last step.Signed-off-by: Nicholas Piggin
Signed-off-by: Michal Marek -
kallsyms generation is not foolproof, due to some linkers adding
symbols (e.g., branch trampolines) when a binary size changes.
Have it attempt a 3rd pass automatically if the kallsyms size changes
in the 2nd pass.This allows powerpc64 allyesconfig to build without adding another
pass when it's not required.This can be solved other ways by directing the linker not to add labels
on branch stubs, or to move kallsyms near the end of the image. The
former is undesirable for debugging/tracing, and the latter is a more
significant change that requires more testing and review.Signed-off-by: Nicholas Piggin
Signed-off-by: Michal Marek
09 Sep, 2016
1 commit
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ld -r is an incremental link used to create built-in.o files in build
subdirectories. It produces relocatable object files containing all
its input files, and these are are then pulled together and relocated
in the final link. Aside from the bloat, this constrains the final
link relocations, which has bitten large powerpc builds with
unresolvable relocations in the final link.Alan Modra has recommended the kernel use thin archives for linking.
This is an alternative and means that the linker has more information
available to it when it links the kernel.This patch enables a config option architectures can select, which
causes all built-in.o files to be built as thin archives. built-in.o
files in subdirectories do not get symbol table or index attached,
which improves speed and size. The final link pass creates a
built-in.o archive in the root output directory which includes the
symbol table and index. The linker then uses takes this file to link.The --whole-archive linker option is required, because the linker now
has visibility to every individual object file, and it will otherwise
just completely avoid including those without external references
(consider a file with EXPORT_SYMBOL or initcall or hardware exceptions
as its only entry points). The traditional built works "by luck" as
built-in.o files are large enough that they're going to get external
references. However this optimisation is unpredictable for the kernel
(due to above external references), ineffective at culling unused, and
costly because the .o files have to be searched for references.
Superior alternatives for link-time culling should be used instead.Build characteristics for inclink vs thinarc, on a small powerpc64le
pseries VM with a modest .config:inclink thinarc
sizes
vmlinux 15 618 680 15 625 028
sum of all built-in.o 56 091 808 1 054 334
sum excluding root built-in.o 151 430find -name built-in.o | xargs rm ; time make vmlinux
real 22.772s 21.143s
user 13.280s 13.430s
sys 4.310s 2.750s- Final kernel pulled in only about 6K more, which shows how
ineffective the object file culling is.
- Build performance looks improved due to less pagecache activity.
On IO constrained systems it could be a bigger win.
- Build size saving is significant.Side note, the toochain understands archives, so there's some tricks,
$ ar t built-in.o # list all files you linked with
$ size built-in.o # and their sizes
$ objdump -d built-in.o # disassembly (unrelocated) with filenamesImplementation by sfr, minor tweaks by npiggin.
Signed-off-by: Stephen Rothwell
Signed-off-by: Nicholas Piggin
Signed-off-by: Michal Marek
08 Jun, 2016
1 commit
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This patch allows to build the whole kernel with GCC plugins. It was ported from
grsecurity/PaX. The infrastructure supports building out-of-tree modules and
building in a separate directory. Cross-compilation is supported too.
Currently the x86, arm, arm64 and uml architectures enable plugins.The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory
there. The plugins compile with these options:
* -fno-rtti: gcc is compiled with this option so the plugins must use it too
* -fno-exceptions: this is inherited from gcc too
* -fasynchronous-unwind-tables: this is inherited from gcc too
* -ggdb: it is useful for debugging a plugin (better backtrace on internal
errors)
* -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h)
* -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version
variable, plugin-version.h)The infrastructure introduces a new Makefile target called gcc-plugins. It
supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script
chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++).
This script also checks the availability of the included headers in
scripts/gcc-plugins/gcc-common.h.The gcc-common.h header contains frequently included headers for GCC plugins
and it has a compatibility layer for the supported gcc versions.The gcc-generate-*-pass.h headers automatically generate the registration
structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes.Note that 'make clean' keeps the *.so files (only the distclean or mrproper
targets clean all) because they are needed for out-of-tree modules.Based on work created by the PaX Team.
Signed-off-by: Emese Revfy
Acked-by: Kees Cook
Signed-off-by: Michal Marek
08 Apr, 2016
1 commit
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Now that we no longer emit .stubs symbols into a section VMA loaded
at absolute address 0x1000, we can drop the ARM-specific override that
sets a lower limit based on CONFIG_PAGE_OFFSET, below which symbols are
filtered from the kallsyms output.Acked-by: Nicolas Pitre
Acked-by: Chris Brandt
Signed-off-by: Ard Biesheuvel
Signed-off-by: Russell King
25 Mar, 2016
1 commit
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Pull kbuild updates from Michal Marek:
- make dtbs_install fix
- Error handling fix fixdep and link-vmlinux.sh
- __UNIQUE_ID fix for clang
- Fix for if_changed_* to suppress the "is up to date." message
- The kernel is built with -Werror=incompatible-pointer-types
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kbuild: Add option to turn incompatible pointer check into error
kbuild: suppress annoying "... is up to date." message
kbuild: fixdep: Check fstat(2) return value
scripts/link-vmlinux.sh: force error on kallsyms failure
Kbuild: provide a __UNIQUE_ID for clang
dtbsinstall: don't move target directory out of the way
16 Mar, 2016
2 commits
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Similar to how relative extables are implemented, it is possible to emit
the kallsyms table in such a way that it contains offsets relative to
some anchor point in the kernel image rather than absolute addresses.On 64-bit architectures, it cuts the size of the kallsyms address table
in half, since offsets between kernel symbols can typically be expressed
in 32 bits. This saves several hundreds of kilobytes of permanent
.rodata on average. In addition, the kallsyms address table is no
longer subject to dynamic relocation when CONFIG_RELOCATABLE is in
effect, so the relocation work done after decompression now doesn't have
to do relocation updates for all these values. This saves up to 24
bytes (i.e., the size of a ELF64 RELA relocation table entry) per value,
which easily adds up to a couple of megabytes of uncompressed __init
data on ppc64 or arm64. Even if these relocation entries typically
compress well, the combined size reduction of 2.8 MB uncompressed for a
ppc64_defconfig build (of which 2.4 MB is __init data) results in a ~500
KB space saving in the compressed image.Since it is useful for some architectures (like x86) to retain the
ability to emit absolute values as well, this patch also adds support
for capturing both absolute and relative values when
KALLSYMS_ABSOLUTE_PERCPU is in effect, by emitting absolute per-cpu
addresses as positive 32-bit values, and addresses relative to the
lowest encountered relative symbol as negative values, which are
subtracted from the runtime address of this base symbol to produce the
actual address.Support for the above is enabled by default for all architectures except
IA-64 and Tile-GX, whose symbols are too far apart to capture in this
manner.Signed-off-by: Ard Biesheuvel
Tested-by: Guenter Roeck
Reviewed-by: Kees Cook
Tested-by: Kees Cook
Cc: Heiko Carstens
Cc: Michael Ellerman
Cc: Ingo Molnar
Cc: H. Peter Anvin
Cc: Benjamin Herrenschmidt
Cc: Michal Marek
Cc: Rusty Russell
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
scripts/kallsyms.c has a special --absolute-percpu command line option
which deals with the zero based per cpu offsets that are used when
building for SMP on x86_64. This means that the option should only be
passed in that case, so add a Kconfig symbol with the correct predicate,
and use that instead.Signed-off-by: Ard Biesheuvel
Tested-by: Guenter Roeck
Reviewed-by: Kees Cook
Tested-by: Kees Cook
Acked-by: Rusty Russell
Cc: Heiko Carstens
Cc: Michael Ellerman
Cc: Ingo Molnar
Cc: H. Peter Anvin
Cc: Benjamin Herrenschmidt
Cc: Michal Marek
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 Feb, 2016
1 commit
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Since the output of the invocation of scripts/kallsyms is piped directly
into the assembler, error messages it emits are visible on stderr, but
a non-zero return code is ignored, and the build simply proceeds in that
case. However, the resulting kernel is most likely broken, and will crash
at boot.So instead, capture the output of kallsyms in a separate .S file, and pass
that to the assembler in a separate step.Signed-off-by: Ard Biesheuvel
Signed-off-by: Michal Marek
11 Jan, 2016
1 commit
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Similarly to commit fb1770aa78a43530940d0c2dd161e77bc705bdac, with gcc 5
on Ubuntu and CONFIG_STATIC_LINK=y I was seeing these linker errors:/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/librt.a(timer_create.o): In function `__timer_create_new':
(.text+0xcd): undefined reference to `pthread_once'
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/librt.a(timer_create.o): In function `__timer_create_new':
(.text+0x126): undefined reference to `pthread_attr_init'
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/librt.a(timer_create.o): In function `__timer_create_new':
(.text+0x168): undefined reference to `pthread_attr_setdetachstate'
[...]Obviously we also need -lpthread for librt.a.
Cc: stable@vger.kernel.org # 4.4
Signed-off-by: Vegard Nossum
Signed-off-by: Richard Weinberger
09 Dec, 2015
1 commit
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On gcc Ubuntu 4.8.4-2ubuntu1~14.04, linking vmlinux fails with:
arch/um/os-Linux/built-in.o: In function `os_timer_create':
/android/kernel/android/arch/um/os-Linux/time.c:51: undefined reference to `timer_create'
arch/um/os-Linux/built-in.o: In function `os_timer_set_interval':
/android/kernel/android/arch/um/os-Linux/time.c:84: undefined reference to `timer_settime'
arch/um/os-Linux/built-in.o: In function `os_timer_remain':
/android/kernel/android/arch/um/os-Linux/time.c:109: undefined reference to `timer_gettime'
arch/um/os-Linux/built-in.o: In function `os_timer_one_shot':
/android/kernel/android/arch/um/os-Linux/time.c:132: undefined reference to `timer_settime'
arch/um/os-Linux/built-in.o: In function `os_timer_disable':
/android/kernel/android/arch/um/os-Linux/time.c:145: undefined reference to `timer_settime'This is because -lrt appears in the generated link commandline
after arch/um/os-Linux/built-in.o. Fix this by removing -lrt from
arch/um/Makefile and adding it to the UM-specific section of
scripts/link-vmlinux.sh.Signed-off-by: Lorenzo Colitti
Signed-off-by: Richard Weinberger
21 May, 2015
1 commit
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When Kernel is executed in place from ROM, the symbol addresses can be
lower than the page offset.Tested-by: Chanwoo Choi
Signed-off-by: Maxime Coquelin
Tested-by: Andreas Färber
Signed-off-by: Michal Marek
07 May, 2015
1 commit
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While building linux with dash shell:
LINK vmlinux
trap: SIGHUP: bad trap
/src/linux-4.0/Makefile:933: recipe for target 'vmlinux' failed
make[1]: *** [vmlinux] Error 1See the following document for behavior of posix shell trap instruction:
http://pubs.opengroup.org/onlinepubs/000095399/utilities/trap.htmlCc: Ingo Molnar
Signed-off-by: Sylvain BERTRAND
Signed-off-by: Michal Marek
20 Aug, 2014
1 commit
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The Makefiles call the respective interpreter explicitly, but this makes
it easier to use the scripts manually.Signed-off-by: Michal Marek
17 Mar, 2014
1 commit
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x86-64 has a problem: per-cpu variables are actually represented by
their absolute offsets within the per-cpu area, but the symbols are
not emitted as absolute. Thus kallsyms naively creates them as offsets
from _text, meaning their values change if the kernel is relocated
(especially noticeable with CONFIG_RANDOMIZE_BASE):$ egrep ' (gdt_|_(stext|_per_cpu_))' /root/kallsyms.nokaslr
0000000000000000 D __per_cpu_start
0000000000004000 D gdt_page
0000000000014280 D __per_cpu_end
ffffffff810001c8 T _stext
ffffffff81ee53c0 D __per_cpu_offset
$ egrep ' (gdt_|_(stext|_per_cpu_))' /root/kallsyms.kaslr1
000000001f200000 D __per_cpu_start
000000001f204000 D gdt_page
000000001f214280 D __per_cpu_end
ffffffffa02001c8 T _stext
ffffffffa10e53c0 D __per_cpu_offsetMaking them absolute symbols is the Right Thing, but requires fixes to
the relocs tool. So for the moment, we add a --absolute-percpu option
which makes them absolute from a kallsyms perspective:$ egrep ' (gdt_|_(stext|_per_cpu_))' /proc/kallsyms # no KASLR
0000000000000000 A __per_cpu_start
000000000000a000 A gdt_page
0000000000013040 A __per_cpu_end
ffffffff802001c8 T _stext
ffffffff8099b180 D __per_cpu_offset
ffffffff809a3000 D __per_cpu_load
$ egrep ' (gdt_|_(stext|_per_cpu_))' /proc/kallsyms # With KASLR
0000000000000000 A __per_cpu_start
000000000000a000 A gdt_page
0000000000013040 A __per_cpu_end
ffffffff89c001c8 T _stext
ffffffff8a39d180 D __per_cpu_offset
ffffffff8a3a5000 D __per_cpu_loadBased-on-the-original-screenplay-by: Andy Honig
Signed-off-by: Rusty Russell
Acked-by: Kees Cook
10 Dec, 2013
1 commit
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Actually CONFIG_PAGE_OFFSET isn't same with PAGE_OFFSET, so
it isn't easy to figue out PAGE_OFFSET defined in header
file from scripts.Because CONFIG_PAGE_OFFSET may not be defined in some ARCHs(
64bit ARCH), or defined as bogus value in !MMU case, so
this patch only applys the filter on ARM when CONFIG_PAGE_OFFSET
is defined as the original problem is only on ARM.Cc:
Cc: Rusty Russell
Fixes: f6537f2f0eba4eba3354e48dbe3047db6d8b6254
Singed-off-by: Ming Lei
Signed-off-by: Rusty Russell
02 Nov, 2013
1 commit
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This patch uses CONFIG_PAGE_OFFSET to filter symbols which
are not in kernel address space because these symbols are
generally for generating code purpose and can't be run at
kernel mode, so we needn't keep them in /proc/kallsyms.For example, on ARM there are some symbols which may be
linked in relocatable code section, then perf can't parse
symbols any more from /proc/kallsyms, this patch fixes the
problem (introduced b9b32bf70f2fb710b07c94e13afbc729afe221da)Cc: Russell King
Cc: linux-arm-kernel@lists.infradead.org
Cc: Michal Marek
Signed-off-by: Ming Lei
Signed-off-by: Rusty Russell
Cc: stable@vger.kernel.org
15 Mar, 2013
1 commit
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We have CONFIG_SYMBOL_PREFIX, which three archs define to the string
"_". But Al Viro broke this in "consolidate cond_syscall and
SYSCALL_ALIAS declarations" (in linux-next), and he's not the first to
do so.Using CONFIG_SYMBOL_PREFIX is awkward, since we usually just want to
prefix it so something. So various places define helpers which are
defined to nothing if CONFIG_SYMBOL_PREFIX isn't set:1) include/asm-generic/unistd.h defines __SYMBOL_PREFIX.
2) include/asm-generic/vmlinux.lds.h defines VMLINUX_SYMBOL(sym)
3) include/linux/export.h defines MODULE_SYMBOL_PREFIX.
4) include/linux/kernel.h defines SYMBOL_PREFIX (which differs from #7)
5) kernel/modsign_certificate.S defines ASM_SYMBOL(sym)
6) scripts/modpost.c defines MODULE_SYMBOL_PREFIX
7) scripts/Makefile.lib defines SYMBOL_PREFIX on the commandline if
CONFIG_SYMBOL_PREFIX is set, so that we have a non-string version
for pasting.(arch/h8300/include/asm/linkage.h defines SYMBOL_NAME(), too).
Let's solve this properly:
1) No more generic prefix, just CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX.
2) Make linux/export.h usable from asm.
3) Define VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR().
4) Make everyone use them.Signed-off-by: Rusty Russell
Reviewed-by: James Hogan
Tested-by: James Hogan (metag)
25 Feb, 2013
1 commit
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The shell '.' command is not required to search the current directory as
a fallback and in fact newer versions of bash in sh-mode do not do this.
Force reading the file from the current directory if $KCONFIG_CONFIG
contains no '/'.Reported-by: Stephen Rothwell
Signed-off-by: Michal Marek
22 Feb, 2013
1 commit
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Its possible to superseed the config file with KCONFIG_CONFIG and have
completely no .config in the tree. The current script is sourcing
.config in every case, so the kernel will never build succesfully. This
patch fixes that issue by sourcing KCONFIG_CONFIG instead.Signed-off-by: Michael Grzeschik
Signed-off-by: Michal Marek
12 Sep, 2012
1 commit
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Pull blackfin updates from Bob Liu:
"One kbuild and a smp build fix."* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lliubbo/blackfin:
kbuild: add symbol prefix arg to kallsyms
blackfin: smp: adapt to generic smp helpers
11 Sep, 2012
1 commit
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Commit 1f2bfbd00e466ff3489b2ca5cc75b1cccd14c123 ("kbuild: link of
vmlinux moved to a script") introduced in v3.5-rc1 broke kallsyms on
architectures which have symbol prefixes.The --symbol-prefix argument used to be added to the KALLSYMS command
line from the architecture Makefile, however this isn't picked up by the
new scripts/link-vmlinux.sh. This resulted in symbols like
kallsyms_addresses being added which weren't correctly overriding the
weak symbols such as _kallsyms_addresses. These could then trigger
BUG_ONs in kallsyms code.This is fixed by removing the KALLSYMS addition from the architecture
Makefile, and using CONFIG_SYMBOL_PREFIX in the link-vmlinux.sh script
to determine whether to add the --symbol-prefix argument.Signed-off-by: James Hogan
Signed-off-by: Bob Liu
10 Aug, 2012
1 commit
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Reported-by: Jan Engelhardt
Signed-off-by: Michal Marek
08 Jul, 2012
1 commit
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... at least in the top-level Makefile and scripts/link-vmlinux.sh.
There are some more instances of the 'echo ; exit 1' pattern in
some arch Makefiles and kconfig.Reported-by: Linus Torvalds
Signed-off-by: Michal Marek
29 May, 2012
1 commit
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Pull kbuild updates from Michal Marek.
Fixed up nontrivial merge conflict in Makefile as per Stephen Rothwell
and linux-next (and trivial arch/sparc/Makefile changes due to removed
sparc32 logic).* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
mips: Fix KBUILD_CPPFLAGS definition
kbuild: fix ia64 link
kbuild: document KBUILD_LDS, KBUILD_VMLINUX_{INIT,MAIN} and LDFLAGS_vmlinux
kbuild: link of vmlinux moved to a script
kbuild: refactor final link of sparc32
kbuild: drop unused KBUILD_VMLINUX_OBJS from top-level Makefile
kbuild: Makefile: remove unnecessary check for m68knommu ARCH
10 May, 2012
1 commit
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ia64 build failed like this:
CC init/version.o
LD init/built-in.o
KSYM .tmp_kallsyms1.o
ld: .tmp_kallsyms1.o: linking constant-gp files with non-constant-gp files
ld: failed to merge target specific data of file .tmp_kallsyms1.o
make: *** [vmlinux] Error 1This was introduced when link of vmlinux was migrated to a script.
Add missing option to as to fix this.Reported-by: Tony Luck
Tested-by: Tony Luck
Signed-off-by: Sam Ravnborg
Signed-off-by: Michal Marek
06 May, 2012
1 commit
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Move the final link of vmlinux to a script to improve
readability and maintainability of the code.The Makefile fragments used to link vmlinux has over the
years seen far too many changes and the logic had become
hard to follow.As the process by nature is serialized there was
nothing gained including this in the Makefile."um" has special link requirments - and the
only way to handle this was to hard-code the linking
of "um" in the script.
This was better than trying to modularize it only for the
benefit of "um" anyway.The shell script has been improved after input from:
Arnaud Lacombe
Nick BowlerSigned-off-by: Sam Ravnborg
Cc: Arnaud Lacombe
Cc: Nick Bowler
Cc: Richard Weinberger
Signed-off-by: Michal Marek