Re: [PATCH v6 00/28] Initial Prefixed Instruction support

[Balamuruhan S <bala24@linux.ibm.com>]

On Tue, 2020-04-28 at 11:57 +1000, Jordan Niethe wrote:
> A future revision of the ISA will introduce prefixed instructions. A
> prefixed instruction is composed of a 4-byte prefix followed by a
> 4-byte suffix.
> 
> All prefixes have the major opcode 1. A prefix will never be a valid
> word instruction. A suffix may be an existing word instruction or a
> new instruction.
> 
> This series enables prefixed instructions and extends the instruction
> emulation to support them. Then the places where prefixed instructions
> might need to be emulated are updated.

Hi Jordan,

I tried to test Kprobes with prefixed instruction on this patchset and
observed that kprobe/uprobe enablement patches are missing from v4.
Till v3 it were available,

https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20200211053355.21574-11-jniethe5@gmail.com/

https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20200211053355.21574-12-jniethe5@gmail.com/

was it missed for any dependencies/reason ? or will you plan it include in next
version ?

please let me know if you need help on it.

-- Bala

> 
> v6 is based on feedback from Balamuruhan Suriyakumar, Alistair Popple,
> Christophe Leroy and Segher Boessenkool.
> The major changes:
>     - Use the instruction type in more places that had been missed before
>     - Fix issues with ppc32
>     - Introduce new self tests for code patching and feature fixups
> 
> v5 is based on feedback from Nick Piggins, Michael Ellerman, Balamuruhan
> Suriyakumar and Alistair Popple.
> The major changes:
>     - The ppc instruction type is now a struct
>     - Series now just based on next
>     - ppc_inst_masked() dropped
>     - Space for xmon breakpoints allocated in an assembly file
>     - "Add prefixed instructions to instruction data type" patch seperated in
>       to smaller patches
>     - Calling convention for create_branch() is changed
>     - Some places which had not been updated to use the data type are now
> updated
> 
> v4 is based on feedback from Nick Piggins, Christophe Leroy and Daniel
> Axtens.
> The major changes:
>     - Move xmon breakpoints from data section to text section
>     - Introduce a data type for instructions on powerpc
> 
> v3 is based on feedback from Christophe Leroy. The major changes:
>     - Completely replacing store_inst() with patch_instruction() in
>       xmon
>     - Improve implementation of mread_instr() to not use mread().
>     - Base the series on top of
>       https://patchwork.ozlabs.org/patch/1232619/ as this will effect
>       kprobes.
>     - Some renaming and simplification of conditionals.
> 
> v2 incorporates feedback from Daniel Axtens and and Balamuruhan
> S. The major changes are:
>     - Squashing together all commits about SRR1 bits
>     - Squashing all commits for supporting prefixed load stores
>     - Changing abbreviated references to sufx/prfx -> suffix/prefix
>     - Introducing macros for returning the length of an instruction
>     - Removing sign extension flag from pstd/pld in sstep.c
>     - Dropping patch  "powerpc/fault: Use analyse_instr() to check for
>       store with updates to sp" from the series, it did not really fit
>       with prefixed enablement in the first place and as reported by Greg
>       Kurz did not work correctly.
> 
> Alistair Popple (1):
>   powerpc: Enable Prefixed Instructions
> 
> Jordan Niethe (27):
>   powerpc/xmon: Remove store_inst() for patch_instruction()
>   powerpc/xmon: Move breakpoint instructions to own array
>   powerpc/xmon: Move breakpoints to text section
>   powerpc/xmon: Use bitwise calculations in_breakpoint_table()
>   powerpc: Change calling convention for create_branch() et. al.
>   powerpc: Use a macro for creating instructions from u32s
>   powerpc: Use an accessor for instructions
>   powerpc: Use a function for getting the instruction op code
>   powerpc: Use a function for byte swapping instructions
>   powerpc: Introduce functions for instruction equality
>   powerpc: Use a datatype for instructions
>   powerpc: Use a function for reading instructions
>   powerpc: Add a probe_user_read_inst() function
>   powerpc: Add a probe_kernel_read_inst() function
>   powerpc/kprobes: Use patch_instruction()
>   powerpc: Define and use __get_user_instr{,inatomic}()
>   powerpc: Introduce a function for reporting instruction length
>   powerpc/xmon: Use a function for reading instructions
>   powerpc/xmon: Move insertion of breakpoint for xol'ing
>   powerpc: Make test_translate_branch() independent of instruction
>     length
>   powerpc: Define new SRR1 bits for a future ISA version
>   powerpc: Add prefixed instructions to instruction data type
>   powerpc: Test prefixed code patching
>   powerpc: Test prefixed instructions in feature fixups
>   powerpc: Support prefixed instructions in alignment handler
>   powerpc sstep: Add support for prefixed load/stores
>   powerpc sstep: Add support for prefixed fixed-point arithmetic
> 
>  arch/powerpc/include/asm/code-patching.h |  37 +-
>  arch/powerpc/include/asm/inst.h          | 106 ++++++
>  arch/powerpc/include/asm/kprobes.h       |   2 +-
>  arch/powerpc/include/asm/reg.h           |   7 +-
>  arch/powerpc/include/asm/sstep.h         |  15 +-
>  arch/powerpc/include/asm/uaccess.h       |  35 ++
>  arch/powerpc/include/asm/uprobes.h       |   7 +-
>  arch/powerpc/kernel/align.c              |  13 +-
>  arch/powerpc/kernel/asm-offsets.c        |   8 +
>  arch/powerpc/kernel/epapr_paravirt.c     |   7 +-
>  arch/powerpc/kernel/hw_breakpoint.c      |   5 +-
>  arch/powerpc/kernel/jump_label.c         |   5 +-
>  arch/powerpc/kernel/kgdb.c               |   9 +-
>  arch/powerpc/kernel/kprobes.c            |  24 +-
>  arch/powerpc/kernel/mce_power.c          |   5 +-
>  arch/powerpc/kernel/module_64.c          |   3 +-
>  arch/powerpc/kernel/optprobes.c          |  91 +++--
>  arch/powerpc/kernel/optprobes_head.S     |   3 +
>  arch/powerpc/kernel/security.c           |   9 +-
>  arch/powerpc/kernel/setup_32.c           |   8 +-
>  arch/powerpc/kernel/trace/ftrace.c       | 160 ++++----
>  arch/powerpc/kernel/traps.c              |  20 +-
>  arch/powerpc/kernel/uprobes.c            |   5 +-
>  arch/powerpc/kernel/vecemu.c             |  20 +-
>  arch/powerpc/kvm/book3s_hv_nested.c      |   2 +-
>  arch/powerpc/kvm/book3s_hv_rm_mmu.c      |   2 +-
>  arch/powerpc/kvm/emulate_loadstore.c     |   2 +-
>  arch/powerpc/lib/Makefile                |   2 +-
>  arch/powerpc/lib/code-patching.c         | 305 ++++++++-------
>  arch/powerpc/lib/feature-fixups-test.S   |  68 ++++
>  arch/powerpc/lib/feature-fixups.c        | 159 ++++++--
>  arch/powerpc/lib/inst.c                  |  69 ++++
>  arch/powerpc/lib/sstep.c                 | 461 ++++++++++++++++-------
>  arch/powerpc/lib/test_code-patching.S    |  19 +
>  arch/powerpc/lib/test_emulate_step.c     |  56 +--
>  arch/powerpc/mm/fault.c                  |  15 +-
>  arch/powerpc/perf/core-book3s.c          |   4 +-
>  arch/powerpc/xmon/Makefile               |   2 +-
>  arch/powerpc/xmon/xmon.c                 |  94 +++--
>  arch/powerpc/xmon/xmon_bpts.S            |  11 +
>  arch/powerpc/xmon/xmon_bpts.h            |  14 +
>  41 files changed, 1307 insertions(+), 582 deletions(-)
>  create mode 100644 arch/powerpc/include/asm/inst.h
>  create mode 100644 arch/powerpc/lib/inst.c
>  create mode 100644 arch/powerpc/lib/test_code-patching.S
>  create mode 100644 arch/powerpc/xmon/xmon_bpts.S
>  create mode 100644 arch/powerpc/xmon/xmon_bpts.h
>