linux-toradex.git/scripts/link-vmlinux.sh, branch v4.6-rc3

Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

2016-03-25T02:26:47+00:00

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

kallsyms: add support for relative offsets in kallsyms address table

2016-03-15T23:55:16+00:00

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

x86: kallsyms: disable absolute percpu symbols on !SMP

2016-03-15T23:55:16+00:00

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

scripts/link-vmlinux.sh: force error on kallsyms failure

2016-02-08T19:45:09+00:00

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

um: link with -lpthread

2016-01-10T20:49:48+00:00

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

arch: um: fix error when linking vmlinux.

2015-12-08T21:25:13+00:00

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

scripts: link-vmlinux: Don't pass page offset to kallsyms if XIP Kernel

2015-05-21T11:17:44+00:00

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

scripts: fix link-vmlinux.sh bash-ism

2015-05-07T10:42:03+00:00

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 1

See the following document for behavior of posix shell trap instruction:
http://pubs.opengroup.org/onlinepubs/000095399/utilities/trap.html

Cc: Ingo Molnar 
Signed-off-by: Sylvain BERTRAND 
Signed-off-by: Michal Marek

kbuild: Make scripts executable

2014-08-20T14:03:45+00:00

The Makefiles call the respective interpreter explicitly, but this makes
it easier to use the scripts manually.

Signed-off-by: Michal Marek

kallsyms: fix percpu vars on x86-64 with relocation.

2014-03-17T04:25:27+00:00

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_offset

Making 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_load

Based-on-the-original-screenplay-by: Andy Honig 
Signed-off-by: Rusty Russell 
Acked-by: Kees Cook