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.mur...@arm.com/ v2: https://lore.kernel.org/linux-arm-kernel/cover.1571421836.git.robin.mur...@arm.com/ v3: https://lore.kernel.org/linux-arm-kernel/20200514143227.605-1-oli.sw...@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.mur...@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
