linux-stable.git/arch/mips/vdso, branch linux-5.2.y

page flags: prioritize kasan bits over last-cpuid

2019-08-25T14:10:34+00:00

[ Upstream commit ee38d94a0ad89890b770f6c876263cf9fcbfde84 ]

ARM64 randdconfig builds regularly run into a build error, especially
when NUMA_BALANCING and SPARSEMEM are enabled but not SPARSEMEM_VMEMMAP:

  #error "KASAN: not enough bits in page flags for tag"

The last-cpuid bits are already contitional on the available space, so
the result of the calculation is a bit random on whether they were
already left out or not.

Adding the kasan tag bits before last-cpuid makes it much more likely to
end up with a successful build here, and should be reliable for
randconfig at least, as long as that does not randomize NR_CPUS or
NODES_SHIFT but uses the defaults.

In order for the modified check to not trigger in the x86 vdso32 code
where all constants are wrong (building with -m32), enclose all the
definitions with an #ifdef.

[arnd@arndb.de: build fix]
  Link: http://lkml.kernel.org/r/CAK8P3a3Mno1SWTcuAOT0Wa9VS15pdU6EfnkxLbDpyS55yO04+g@mail.gmail.com
Link: http://lkml.kernel.org/r/20190722115520.3743282-1-arnd@arndb.de
Link: https://lore.kernel.org/lkml/20190618095347.3850490-1-arnd@arndb.de/
Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Arnd Bergmann 
Signed-off-by: Arnd Bergmann 
Reviewed-by: Andrey Konovalov 
Reviewed-by: Andrey Ryabinin 
Cc: Andrey Konovalov 
Cc: Dmitry Vyukov 
Cc: Will Deacon 
Cc: Christoph Lameter 
Cc: Mark Rutland 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman

mips: vdso: drop unnecessary cc-ldoption

2019-04-23T21:53:54+00:00

Towards the goal of removing cc-ldoption, it seems that --hash-style=
was added to binutils 2.17.50.0.2 in 2006. The minimal required version
of binutils for the kernel according to
Documentation/process/changes.rst is 2.20.

--build-id was added in 2.18 according to binutils-gdb/ld/NEWS.

Link: https://gcc.gnu.org/ml/gcc/2007-01/msg01141.html
Cc: clang-built-linux@googlegroups.com
Suggested-by: Masahiro Yamada 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Paul Burton 
Cc: ralf@linux-mips.org
Cc: jhogan@kernel.org
Cc: Matt Redfearn 
Cc: Joel Stanley 
Cc: Hassan Naveed 
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

MIPS: VDSO: Include $(ccflags-vdso) in o32,n32 .lds builds

2019-01-29T19:50:58+00:00

When generating vdso-o32.lds & vdso-n32.lds for use with programs
running as compat ABIs under 64b kernels, we previously haven't included
the compiler flags that are supposedly common to all ABIs - ie. those in
the ccflags-vdso variable.

This is problematic in cases where we need to provide the -m%-float flag
in order to ensure that we don't attempt to use a floating point ABI
that's incompatible with the target CPU & ABI. For example a toolchain
using current gcc trunk configured --with-fp-32=xx fails to build a
64r6el_defconfig kernel with the following error:

  cc1: error: '-march=mips1' requires '-mfp32'
  make[2]: *** [arch/mips/vdso/Makefile:135: arch/mips/vdso/vdso-o32.lds] Error 1

Include $(ccflags-vdso) for the compat VDSO .lds builds, just as it is
included for the native VDSO .lds & when compiling objects for the
compat VDSOs. This ensures we consistently provide the -msoft-float flag
amongst others, avoiding the problem by ensuring we're agnostic to the
toolchain defaults.

Signed-off-by: Paul Burton 
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Cc: linux-mips@vger.kernel.org
Cc: Kevin Hilman 
Cc: Guenter Roeck 
Cc: Maciej W . Rozycki 
Cc: stable@vger.kernel.org # v4.4+

MIPS: VDSO: Use same -m%-float cflag as the kernel proper

2019-01-29T19:50:41+00:00

The MIPS VDSO build currently doesn't provide the -msoft-float flag to
the compiler as the kernel proper does. This results in an attempt to
use the compiler's default floating point configuration, which can be
problematic in cases where this is incompatible with the target CPU's
-march= flag. For example decstation_defconfig fails to build using
toolchains in which gcc was configured --with-fp-32=xx with the
following error:

    LDS     arch/mips/vdso/vdso.lds
  cc1: error: '-march=r3000' requires '-mfp32'
  make[2]: *** [scripts/Makefile.build:379: arch/mips/vdso/vdso.lds] Error 1

The kernel proper avoids this error because we build with the
-msoft-float compiler flag, rather than using the compiler's default.
Pass this flag through to the VDSO build so that it too becomes agnostic
to the toolchain's floating point configuration.

Note that this is filtered out from KBUILD_CFLAGS rather than simply
always using -msoft-float such that if we switch the kernel to use
-mno-float in the future the VDSO will automatically inherit the change.

The VDSO doesn't actually include any floating point code, and its
.MIPS.abiflags section is already manually generated to specify that
it's compatible with any floating point ABI. As such this change should
have no effect on the resulting VDSO, apart from fixing the build
failure for affected toolchains.

Signed-off-by: Paul Burton 
Reported-by: Kevin Hilman 
Reported-by: Guenter Roeck 
Tested-by: Kevin Hilman 
References: https://lore.kernel.org/linux-mips/1477843551-21813-1-git-send-email-linux@roeck-us.net/
References: https://kernelci.org/build/id/5c4e4ae059b5142a249ad004/logs/
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Cc: Maciej W. Rozycki 
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v4.4+

MIPS: Enable Undefined Behavior Sanitizer UBSAN

2018-11-20T20:23:06+00:00

Select ARCH_HAS_UBSAN_SANITIZE_ALL in order to allow the user to
enable CONFIG_UBSAN_SANITIZE_ALL and instrument the entire kernel for
ubsan checks.
We exclude the VDSO from this because its build doesn't include the
__ubsan_handle_*() functions that the kernel proper defines in from
lib/ubsan.c, and the VDSO would have no sane way to report errors even
if it had definitions of these functions.

Signed-off-by: Hassan Naveed 
Reviewed-by: Paul Burton 
Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/21179/
Cc:

kbuild: replace cc-name test with CONFIG_CC_IS_CLANG

2018-11-02T13:49:00+00:00

Evaluating cc-name invokes the compiler every time even when you are
not compiling anything, like 'make help'. This is not efficient.

The compiler type has been already detected in the Kconfig stage.
Use CONFIG_CC_IS_CLANG, instead.

Signed-off-by: Masahiro Yamada 
Acked-by: Michael Ellerman  (powerpc)
Acked-by: Paul Burton  (MIPS)
Acked-by: Joel Stanley

MIPS: VDSO: Force link endianness

2018-08-07T23:16:13+00:00

When building the VDSO with clang it appears to invoke ld without
specifying endianness, even though clang itself was provided with a -EB
or -EL flag. This results in the build failing due to a mismatch between
the objects that are the input to ld, and the output it is attempting to
create:

  VDSO    arch/mips/vdso/vdso.so.dbg.raw
  mips-linux-ld: arch/mips/vdso/elf.o: compiled for a big endian system
    and target is little endian
  mips-linux-ld: arch/mips/vdso/elf.o: endianness incompatible with that
    of the selected emulation
  mips-linux-ld: failed to merge target specific data of file
    arch/mips/vdso/elf.o
  ...

Work around this problem by explicitly specifying the link endianness
using -Wl,-EB or -Wl,-EL when -EB or -EL are part of KBUILD_CFLAGS. This
resolves the build failure when using clang, and doesn't have any
negative effect on gcc.

Signed-off-by: Paul Burton

MIPS: vdso: Allow clang's --target flag in VDSO cflags

2018-08-06T22:53:33+00:00

The MIPS VDSO code filters out a subset of known-good flags from
KBUILD_CFLAGS to use when building VDSO libraries. When we build using
clang we need to allow the --target flag through, otherwise we'll
generally attempt to build the VDSO for the architecture of the build
machine rather than for MIPS.

Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/20154/
Cc: James Hogan 
Cc: Ralf Baechle 
Cc: linux-mips@linux-mips.org

MIPS: genvdso: Remove GOT checks

2018-08-06T22:28:46+00:00

Our genvdso tool performs some rather paranoid checking that the VDSO
library isn't attempting to make use of a GOT by constraining the number
of entries that the GOT is allowed to contain to the minimum 2 entries
that are always generated by binutils.

Unfortunately lld prior to revision 334390 generates a third entry,
which is unused & thus harmless but falls foul of genvdso's checks &
causes the build to fail.

Since we already check that the VDSO contains no relocations it seems
reasonable to presume that it also doesn't contain use of a GOT, which
would involve relocations. Thus rather than attempting to work around
this issue by allowing 3 GOT entries when using lld, simply remove the
GOT checks which seem overly paranoid.

Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/20152/
Cc: James Hogan 
Cc: Ralf Baechle 
Cc: linux-mips@linux-mips.org