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

arm64: vdso: don't free unallocated pages

2020-04-21T07:04:58+00:00

commit 9cc3d0c6915aee5140f8335d41bbc3ff1b79aa4e upstream.

The aarch32_vdso_pages[] array never has entries allocated in the C_VVAR
or C_VDSO slots, and as the array is zero initialized these contain
NULL.

However in __aarch32_alloc_vdso_pages() when
aarch32_alloc_kuser_vdso_page() fails we attempt to free the page whose
struct page is at NULL, which is obviously nonsensical.

This patch removes the erroneous page freeing.

Fixes: 7c1deeeb0130 ("arm64: compat: VDSO setup for compat layer")
Cc:  # 5.3.x-
Cc: Vincenzo Frascino 
Acked-by: Will Deacon 
Signed-off-by: Mark Rutland 
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

arm64: compat: VDSO setup for compat layer

2019-06-22T19:21:08+00:00

If CONFIG_GENERIC_COMPAT_VDSO is enabled, compat vDSO is installed in a
compat (32 bit) process instead of sigpage.

Add the necessary code to setup the vDSO required pages.

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/20190621095252.32307-13-vincenzo.frascino@arm.com

arm64: vdso: Refactor vDSO code

2019-06-22T19:21:08+00:00

Most of the code for initializing the vDSOs in arm64 and compat will be
shared, hence refactoring of the current code is required to avoid
duplication and to simplify maintainability.

No functional change.

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/20190621095252.32307-12-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: compat: Add KUSER_HELPERS config option

2019-04-23T17:01:58+00:00

When kuser helpers are enabled the kernel maps the relative code at
a fixed address (0xffff0000). Making configurable the option to disable
them means that the kernel can remove this mapping and any access to
this memory area results in a sigfault.

Add a KUSER_HELPERS config option that can be used to disable the
mapping when it is turned off.

This option can be turned off if and only if the applications are
designed specifically for the platform and they do not make use of the
kuser helpers code.

Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Vincenzo Frascino 
Reviewed-by: Catalin Marinas 
[will: Use IS_ENABLED() instead of #ifdef]
Signed-off-by: Will Deacon

arm64: compat: Refactor aarch32_alloc_vdso_pages()

2019-04-23T17:01:58+00:00

aarch32_alloc_vdso_pages() needs to be refactored to make it
easier to disable kuser helpers.

Divide the function in aarch32_alloc_kuser_vdso_page() and
aarch32_alloc_sigreturn_vdso_page().

Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Vincenzo Frascino 
Reviewed-by: Catalin Marinas 
[will: Inlined sigpage allocation to simplify error paths]
Signed-off-by: Will Deacon

arm64: compat: Alloc separate pages for vectors and sigpage

2019-04-23T17:01:31+00:00

For AArch32 tasks, we install a special "[vectors]" page that contains
the sigreturn trampolines and kuser helpers, which is mapped at a fixed
address specified by the kuser helpers ABI.

Having the sigreturn trampolines in the same page as the kuser helpers
makes it impossible to disable the kuser helpers independently.

Follow the Arm implementation, by moving the signal trampolines out of
the "[vectors]" page and into their own "[sigpage]".

Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Vincenzo Frascino 
Reviewed-by: Catalin Marinas 
[will: tweaked comments and fixed sparse warning]
Signed-off-by: Will Deacon

arm64: vdso: Fix clock_getres() for CLOCK_REALTIME

2019-04-16T17:15:56+00:00

clock_getres() in the vDSO library has to preserve the same behaviour
of posix_get_hrtimer_res().

In particular, posix_get_hrtimer_res() does:

    sec = 0;
    ns = hrtimer_resolution;

where 'hrtimer_resolution' depends on whether or not high resolution
timers are enabled, which is a runtime decision.

The vDSO incorrectly returns the constant CLOCK_REALTIME_RES. Fix this
by exposing 'hrtimer_resolution' in the vDSO datapage and returning that
instead.

Reviewed-by: Catalin Marinas 
Signed-off-by: Vincenzo Frascino 
[will: Use WRITE_ONCE(), move adr off COARSE path, renumber labels, use 'w' reg]
Signed-off-by: Will Deacon

arm64/vdso: don't leak kernel addresses

2019-04-03T12:22:20+00:00

Since commit ad67b74d2469d9b8 ("printk: hash addresses printed with %p"),
two obfuscated kernel pointer are printed at every boot:

    vdso: 2 pages (1 code @ (____ptrval____), 1 data @ (____ptrval____))

Remove the the print completely, as it's useless without the addresses.

Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
Acked-by: Mark Rutland 
Signed-off-by: Matteo Croce 
Signed-off-by: Will Deacon