linux-stable.git/arch/arm64/kernel/vdso, branch linux-5.4.y

arm64/vdso: Discard .note.gnu.property sections in vDSO

2021-05-11T12:04:14+00:00

[ Upstream commit 388708028e6937f3fc5fc19aeeb847f8970f489c ]

The arm64 assembler in binutils 2.32 and above generates a program
property note in a note section, .note.gnu.property, to encode used x86
ISAs and features. But the kernel linker script only contains a single
NOTE segment:

  PHDRS
  {
    text    PT_LOAD    FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
    dynamic PT_DYNAMIC FLAGS(4);               /* PF_R */
    note    PT_NOTE    FLAGS(4);               /* PF_R */
  }

The NOTE segment generated by the vDSO linker script is aligned to 4 bytes.
But the .note.gnu.property section must be aligned to 8 bytes on arm64.

  $ readelf -n vdso64.so

  Displaying notes found in: .note
    Owner                Data size      Description
    Linux                0x00000004     Unknown note type: (0x00000000)
     description data: 06 00 00 00
  readelf: Warning: note with invalid namesz and/or descsz found at offset 0x20
  readelf: Warning:  type: 0x78, namesize: 0x00000100, descsize: 0x756e694c, alignment: 8

Since the note.gnu.property section in the vDSO is not checked by the
dynamic linker, discard the .note.gnu.property sections in the vDSO.

Similar to commit 4caffe6a28d31 ("x86/vdso: Discard .note.gnu.property
sections in vDSO"), but for arm64.

Signed-off-by: Bill Wendling 
Reviewed-by: Kees Cook 
Acked-by: Ard Biesheuvel 
Link: https://lore.kernel.org/r/20210423205159.830854-1-morbo@google.com
Signed-off-by: Catalin Marinas 
Signed-off-by: Sasha Levin

arm64: vdso: Add -fasynchronous-unwind-tables to cflags

2020-05-06T06:15:17+00:00

commit 1578e5d03112e3e9d37e1c4d95b6dfb734c73955 upstream.

On arm64 linux gcc uses -fasynchronous-unwind-tables -funwind-tables
by default since gcc-8, so now the de facto platform ABI is to allow
unwinding from async signal handlers.

However on bare metal targets (aarch64-none-elf), and on old gcc,
async and sync unwind tables are not enabled by default to avoid
runtime memory costs.

This means if linux is built with a baremetal toolchain the vdso.so
may not have unwind tables which breaks the gcc platform ABI guarantee
in userspace.

Add -fasynchronous-unwind-tables explicitly to the vgettimeofday.o
cflags to address the ABI change.

Fixes: 28b1a824a4f4 ("arm64: vdso: Substitute gettimeofday() with C implementation")
Cc: Will Deacon 
Reported-by: Szabolcs Nagy 
Signed-off-by: Vincenzo Frascino 
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

arm64: vdso: Remove stale files from old assembly implementation

2019-10-07T10:07:16+00:00

Moving over to the generic C implementation of the vDSO inadvertently
left some stale files behind which are no longer used. Remove them.

Cc: Will Deacon 
Cc: Catalin Marinas 
Signed-off-by: Vincenzo Frascino 
Acked-by: Catalin Marinas 
Tested-by: Catalin Marinas 
Signed-off-by: Will Deacon

arm64: vdso: Cleanup Makefiles

2019-07-22T09:37:33+00:00

The recent changes to the vdso library for arm64 and the introduction of
the compat vdso library have generated some misalignment in the
Makefiles.

Cleanup the Makefiles for vdso and vdso32 libraries:
  * Removing unused rules.
  * Unifying the displayed compilation messages.
  * Simplifying the generic library inclusion path for
    arm64 vdso.

Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Vincenzo Frascino 
Signed-off-by: Will Deacon

arm64: vdso: fix flip/flop vdso build bug

2019-07-22T09:33:42+00:00

Running "make" on an already compiled kernel tree will rebuild the kernel
even without any modifications:

$ make ARCH=arm64 CROSS_COMPILE=/usr/bin/aarch64-unknown-linux-gnu-
arch/arm64/Makefile:58: CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built
  CALL    scripts/checksyscalls.sh
  CALL    scripts/atomic/check-atomics.sh
  VDSOCHK arch/arm64/kernel/vdso/vdso.so.dbg
  VDSOSYM include/generated/vdso-offsets.h
  CHK     include/generated/compile.h
  CC      arch/arm64/kernel/signal.o
  CC      arch/arm64/kernel/vdso.o
  CC      arch/arm64/kernel/signal32.o
  LD      arch/arm64/kernel/vdso/vdso.so.dbg
  OBJCOPY arch/arm64/kernel/vdso/vdso.so
  AS      arch/arm64/kernel/vdso/vdso.o
  AR      arch/arm64/kernel/vdso/built-in.a
  AR      arch/arm64/kernel/built-in.a
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
  AR      init/built-in.a
  LD      vmlinux.o

This is the same bug fixed in commit 92a4728608a8 ("x86/boot: Fix
if_changed build flip/flop bug"). We cannot use two "if_changed" in one
target. Fix this build bug by merging two commands into one function.

Fixes: a7f71a2c8903 ("arm64: compat: Add vDSO")
Fixes: 28b1a824a4f4 ("arm64: vdso: Substitute gettimeofday() with C implementation")
Reviewed-by: Masahiro Yamada 
Reviewed-by: Vincenzo Frascino 
Tested-by: Vincenzo Frascino 
Co-developed-by: Vincenzo Frascino 
Signed-off-by: Vincenzo Frascino 
Signed-off-by: Naohiro Aota 
[will: merged in compat fix from Vincenzo and made rule names consistent]
Signed-off-by: Will Deacon

arm64: vdso: Fix compilation with clang older than 8

2019-06-26T12:26:55+00:00

clang versions older than 8 do not support -mcmodel=tiny.

Add a check to the vDSO Makefile for arm64 to remove the flag when
these versions of the compiler are detected.

Reported-by: Qian Cai 
Signed-off-by: Vincenzo Frascino 
Signed-off-by: Thomas Gleixner 
Tested-by: Qian Cai 
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: catalin.marinas@arm.com
Cc: will.deacon@arm.com
Cc: arnd@arndb.de
Cc: linux@armlinux.org.uk
Cc: ralf@linux-mips.org
Cc: paul.burton@mips.com
Cc: daniel.lezcano@linaro.org
Cc: salyzyn@android.com
Cc: pcc@google.com
Cc: shuah@kernel.org
Cc: 0x7f454c46@gmail.com
Cc: linux@rasmusvillemoes.dk
Cc: huw@codeweavers.com
Cc: sthotton@marvell.com
Cc: andre.przywara@arm.com
Cc: luto@kernel.org
Link: https://lkml.kernel.org/r/20190626113632.9295-1-vincenzo.frascino@arm.com

arm64: vdso: Build vDSO with -ffixed-x18

2019-06-22T19:21:06+00:00

The vDSO needs to be built with x18 reserved in order to accommodate
userspace platform ABIs built on top of Linux that use the register
to carry inter-procedural state, as provided for by the AAPCS.
An example of such a platform ABI is the one that will be used by an
upcoming version of Android.

Although this change is currently a no-op due to the fact that the vDSO
is currently implemented in pure assembly on arm64, it is necessary
in order to prepare for using the generic C implementation of the vDSO.

[ tglx: Massaged changelog ]

Signed-off-by: Peter Collingbourne 
Signed-off-by: Vincenzo Frascino 
Signed-off-by: Thomas Gleixner 
Tested-by: Shijith Thotton 
Tested-by: Andre Przywara 
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Arnd Bergmann 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: Paul Burton 
Cc: Daniel Lezcano 
Cc: Mark Salyzyn 
Cc: Shuah Khan 
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Rasmus Villemoes 
Cc: Huw Davies 
Cc: Mark Salyzyn 
Link: https://lkml.kernel.org/r/20190621095252.32307-6-vincenzo.frascino@arm.com

arm64: vdso: Substitute gettimeofday() with C implementation

2019-06-22T19:21:06+00:00

To take advantage of the commonly defined vdso interface for gettimeofday()
the architectural code requires an adaptation.

Re-implement the gettimeofday VDSO in C in order to use lib/vdso.

With the new implementation arm64 gains support for CLOCK_BOOTTIME
and CLOCK_TAI.

[ tglx: Reformatted the function line breaks ]

Signed-off-by: Vincenzo Frascino 
Signed-off-by: Thomas Gleixner 
Tested-by: Shijith Thotton 
Tested-by: Andre Przywara 
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Arnd Bergmann 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: Paul Burton 
Cc: Daniel Lezcano 
Cc: Mark Salyzyn 
Cc: Peter Collingbourne 
Cc: Shuah Khan 
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Rasmus Villemoes 
Cc: Huw Davies 
Link: https://lkml.kernel.org/r/20190621095252.32307-5-vincenzo.frascino@arm.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

2019-06-19T15:09:07+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 version 2 as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not see http www gnu org
  licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Alexios Zavras 
Reviewed-by: Allison Randal 
Reviewed-by: Enrico Weigelt 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman

arm64: vdso: Explicitly add build-id option

2019-05-16T10:45:36+00:00

Commit 691efbedc60d ("arm64: vdso: use $(LD) instead of $(CC) to
link VDSO") switched to using LD explicitly. The --build-id option
needs to be passed explicitly, similar to x86. Add this option.

Fixes: 691efbedc60d ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO")
Reviewed-by: Masahiro Yamada 
Signed-off-by: Laura Abbott 
[will: drop redundant use of 'call ld-option' as requested by Masahiro]
Signed-off-by: Will Deacon