lkml.org 
[lkml]   [2020]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH v4 00/14] arm64: Optimise and update memcpy, user copy and string routines
Date
Hi,

This contains an update to the cortex-strings patchset: the
correctness of the fixup routines are improved, with the aim being to
return the exact number of remaining bytes for all copy sizes.
To ensure they are exact - which the current fixups are not for some
copy sizes and are off by a few byes - is an extension to the
original intention of fixing an issue reported by an LTP run last
year, where the fixup routine in v2 of this patchset (which was
importing the cortex-strings memcpy implementation) would over-report
the number of bytes that successfully copied.
Version 3 addressed this but I later found some issues with the fixup
correctness after further testing, and have partially re-written them
here, and addressed some other behaviours of the copy algorithm.

Comments welcome,

Thanks
Oliver

v1: https://lore.kernel.org/linux-arm-kernel/cover.1571073960.git.robin.murphy@arm.com/
v2: https://lore.kernel.org/linux-arm-kernel/cover.1571421836.git.robin.murphy@arm.com/
v3: https://lore.kernel.org/linux-arm-kernel/20200514143227.605-1-oli.swede@arm.com/

Changes since v3:
* Improves the accuracy of the fixups in response to issues that
arose during futher testing
* Accounts for faults on store instructions on systems with UAO
enabled
* Expands on comments detailing the implementation

Changes since v2:
* Adds Robin's separate patch that fixes a compilation issue with
KProbes fixup [1]
* Imports the most recent memcpy implementation by updating Sam's
patch (and moves this patch to occur after the cortex-strings
importing so that it's closer to the patches containing its
corresponding fixups)
* Uses the stack to preserve the initial parameters
* Replaces the usercopy fixup routine in v2 with multiple longer
fixups that each make use of the fault address to return the exact
number of bytes that haven't yet copied.

[1] https://lore.kernel.org/linux-arm-kernel/e70f7b9de7e601b9e4a6fedad8eaf64d304b1637.1571326276.git.robin.murphy@arm.com/

Oliver Swede (5):
arm64: Store the arguments to copy_*_user on the stack
arm64: Use additional memcpy macros and fixups
arm64: Add fixup routines for usercopy load exceptions
arm64: Add fixup routines for usercopy store exceptions
arm64: Improve accuracy of fixup for UAO cases

Robin Murphy (2):
arm64: kprobes: Drop open-coded exception fixup
arm64: Tidy up _asm_extable_faultaddr usage

Sam Tebbs (7):
arm64: Allow passing fault address to fixup handlers
arm64: Import latest version of Cortex Strings' memcmp
arm64: Import latest version of Cortex Strings' memmove
arm64: Import latest version of Cortex Strings' strcmp
arm64: Import latest version of Cortex Strings' strlen
arm64: Import latest version of Cortex Strings' strncmp
arm64: Import latest optimization of memcpy

arch/arm64/include/asm/alternative.h | 36 ---
arch/arm64/include/asm/assembler.h | 13 +
arch/arm64/include/asm/extable.h | 10 +-
arch/arm64/kernel/probes/kprobes.c | 7 -
arch/arm64/lib/copy_from_user.S | 272 +++++++++++++++--
arch/arm64/lib/copy_in_user.S | 287 ++++++++++++++++--
arch/arm64/lib/copy_template.S | 377 +++++++++++++----------
arch/arm64/lib/copy_template_user.S | 50 ++++
arch/arm64/lib/copy_to_user.S | 273 +++++++++++++++--
arch/arm64/lib/copy_user_fixup.S | 433 +++++++++++++++++++++++++++
arch/arm64/lib/memcmp.S | 333 ++++++++------------
arch/arm64/lib/memcpy.S | 127 ++++++--
arch/arm64/lib/memmove.S | 232 +++++---------
arch/arm64/lib/strcmp.S | 272 +++++++----------
arch/arm64/lib/strlen.S | 247 ++++++++++-----
arch/arm64/lib/strncmp.S | 363 ++++++++++------------
arch/arm64/mm/extable.c | 13 +-
arch/arm64/mm/fault.c | 2 +-
18 files changed, 2228 insertions(+), 1119 deletions(-)
create mode 100644 arch/arm64/lib/copy_template_user.S
create mode 100644 arch/arm64/lib/copy_user_fixup.S

--
2.17.1

\
 
 \ /
  Last update: 2020-06-30 21:48    [W:0.415 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site