linux.git/arch/arm64/kernel/vdso.c, branch v4.16

arm64/vdso: Support mremap() for vDSO

2017-08-09T11:16:28+00:00

vDSO VMA address is saved in mm_context for the purpose of using
restorer from vDSO page to return to userspace after signal handling.

In Checkpoint Restore in Userspace (CRIU) project we place vDSO VMA
on restore back to the place where it was on the dump.
With the exception for x86 (where there is API to map vDSO with
arch_prctl()), we move vDSO inherited from CRIU task to restoree
position by mremap().

CRIU does support arm64 architecture, but kernel doesn't update
context.vdso pointer after mremap(). Which results in translation
fault after signal handling on restored application:
https://github.com/xemul/criu/issues/288

Make vDSO code track the VMA address by supplying .mremap() fops
the same way it's done for x86 and arm32 by:
commit b059a453b1cf ("x86/vdso: Add mremap hook to vm_special_mapping")
commit 280e87e98c09 ("ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO").

Cc: Russell King 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Cyrill Gorcunov 
Cc: Pavel Emelyanov 
Cc: Christopher Covington 
Reviewed-by: Will Deacon 
Signed-off-by: Dmitry Safonov 
Signed-off-by: Catalin Marinas

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2017-07-06T00:09:27+00:00

Pull arm64 updates from Will Deacon:

 - RAS reporting via GHES/APEI (ACPI)

 - Indirect ftrace trampolines for modules

 - Improvements to kernel fault reporting

 - Page poisoning

 - Sigframe cleanups and preparation for SVE context

 - Core dump fixes

 - Sparse fixes (mainly relating to endianness)

 - xgene SoC PMU v3 driver

 - Misc cleanups and non-critical fixes

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (75 commits)
  arm64: fix endianness annotation for 'struct jit_ctx' and friends
  arm64: cpuinfo: constify attribute_group structures.
  arm64: ptrace: Fix incorrect get_user() use in compat_vfp_set()
  arm64: ptrace: Remove redundant overrun check from compat_vfp_set()
  arm64: ptrace: Avoid setting compat FP[SC]R to garbage if get_user fails
  arm64: fix endianness annotation for __apply_alternatives()/get_alt_insn()
  arm64: fix endianness annotation in get_kaslr_seed()
  arm64: add missing conversion to __wsum in ip_fast_csum()
  arm64: fix endianness annotation in acpi_parking_protocol.c
  arm64: use readq() instead of readl() to read 64bit entry_point
  arm64: fix endianness annotation for reloc_insn_movw() & reloc_insn_imm()
  arm64: fix endianness annotation for aarch64_insn_write()
  arm64: fix endianness annotation in aarch64_insn_read()
  arm64: fix endianness annotation in call_undef_hook()
  arm64: fix endianness annotation for debug-monitors.c
  ras: mark stub functions as 'inline'
  arm64: pass endianness info to sparse
  arm64: ftrace: fix !CONFIG_ARM64_MODULE_PLTS kernels
  arm64: signal: Allow expansion of the signal frame
  acpi: apei: check for pending errors when probing GHES entries
  ...

time: Clean up CLOCK_MONOTONIC_RAW time handling

2017-06-21T05:13:59+00:00

Now that we fixed the sub-ns handling for CLOCK_MONOTONIC_RAW,
remove the duplicitive tk->raw_time.tv_nsec, which can be
stored in tk->tkr_raw.xtime_nsec (similarly to how its handled
for monotonic time).

Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Miroslav Lichvar 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Cc: Stephen Boyd 
Cc: Kevin Brodsky 
Cc: Will Deacon 
Cc: Daniel Mentz 
Tested-by: Daniel Mentz 
Signed-off-by: John Stultz

arm64/vdso: Fix nsec handling for CLOCK_MONOTONIC_RAW

2017-06-20T08:41:51+00:00

Recently vDSO support for CLOCK_MONOTONIC_RAW was added in
49eea433b326 ("arm64: Add support for CLOCK_MONOTONIC_RAW in
clock_gettime() vDSO"). Noticing that the core timekeeping code
never set tkr_raw.xtime_nsec, the vDSO implementation didn't
bother exposing it via the data page and instead took the
unshifted tk->raw_time.tv_nsec value which was then immediately
shifted left in the vDSO code.

Unfortunately, by accellerating the MONOTONIC_RAW clockid, it
uncovered potential 1ns time inconsistencies caused by the
timekeeping core not handing sub-ns resolution.

Now that the core code has been fixed and is actually setting
tkr_raw.xtime_nsec, we need to take that into account in the
vDSO by adding it to the shifted raw_time value, in order to
fix the user-visible inconsistency. Rather than do that at each
use (and expand the data page in the process), instead perform
the shift/addition operation when populating the data page and
remove the shift from the vDSO code entirely.

[jstultz: minor whitespace tweak, tried to improve commit
 message to make it more clear this fixes a regression]
Reported-by: John Stultz 
Signed-off-by: Will Deacon 
Signed-off-by: John Stultz 
Tested-by: Daniel Mentz 
Acked-by: Kevin Brodsky 
Cc: Prarit Bhargava 
Cc: Richard Cochran 
Cc: Stephen Boyd 
Cc: "stable #4 . 8+" 
Cc: Miroslav Lichvar 
Link: http://lkml.kernel.org/r/1496965462-20003-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner

arm64, vdso: Define vdso_{start,end} as array

2017-06-06T16:49:55+00:00

Adjust vdso_{start|end} to be char arrays to avoid compile-time analysis
that flags "too large" memcmp() calls with CONFIG_FORTIFY_SOURCE.

Cc: Jisheng Zhang 
Acked-by: Catalin Marinas 
Suggested-by: Mark Rutland 
Signed-off-by: Kees Cook 
Signed-off-by: Will Deacon

arm64: Use __pa_symbol for kernel symbols

2017-01-12T15:05:39+00:00

__pa_symbol is technically the marcro that should be used for kernel
symbols. Switch to this as a pre-requisite for DEBUG_VIRTUAL which
will do bounds checking.

Reviewed-by: Mark Rutland 
Tested-by: Mark Rutland 
Signed-off-by: Laura Abbott 
Signed-off-by: Will Deacon

arm/arm64: arch_timer: Use archdata to indicate vdso suitability

2016-09-23T16:19:25+00:00

Instead of comparing the name to a magic string, use archdata to
explicitly communicate whether the arch timer is suitable for
direct vdso access.

Acked-by: Will Deacon 
Acked-by: Russell King 
Acked-by: Marc Zyngier 
Signed-off-by: Scott Wood 
Signed-off-by: Will Deacon

arm64: apply __ro_after_init to some objects

2016-08-22T11:32:29+00:00

These objects are set during initialization, thereafter are read only.

Previously I only want to mark vdso_pages, vdso_spec, vectors_page and
cpu_ops as __read_mostly from performance point of view. Then inspired
by Kees's patch[1] to apply more __ro_after_init for arm, I think it's
better to mark them as __ro_after_init. What's more, I find some more
objects are also read only after init. So apply __ro_after_init to all
of them.

This patch also removes global vdso_pagelist and tries to clean up
vdso_spec[] assignment code.

[1] http://www.spinics.net/lists/arm-kernel/msg523188.html

Acked-by: Mark Rutland 
Signed-off-by: Jisheng Zhang 
Signed-off-by: Will Deacon

arm64: vdso: constify vm_special_mapping used for aarch32 vectors page

2016-08-22T11:32:22+00:00

The vm_special_mapping spec which is used for aarch32 vectors page is
never modified, so mark it as const.

Acked-by: Mark Rutland 
Signed-off-by: Jisheng Zhang 
Signed-off-by: Will Deacon

arm64: vdso: add __init section marker to alloc_vectors_page

2016-08-22T11:32:01+00:00

It is not needed after booting, this patch moves the alloc_vectors_page
function to the __init section.

Acked-by: Mark Rutland 
Signed-off-by: Jisheng Zhang 
Signed-off-by: Will Deacon