Subject: Re: [PATCH v8 00/17] mm: jit/text allocator

From: Mike Rapoport <[email-masked]>
Date: Sun, 5 May 2024 19:21:55 +0300

This is embarrassing, but these patches were from a wrong branch :(
Please ignore.

On Sun, May 05, 2024 at 05:25:43PM +0300, Mike Rapoport wrote:
> From: "Mike Rapoport (IBM)" <[email-masked]>
> 
> Hi,
> 
> The patches are also available in git:
> https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=execmem/v8
> 
> v8:
> * fix intialization of default_execmem_info
> 
> v7: https://lore.kernel.org/all/[email-masked]
> * define MODULE_{VADDR,END} for riscv32 to fix the build and avoid
>   #ifdefs in a function body
> * add Acks, thanks everybody
> 
> v6: https://lore.kernel.org/all/[email-masked]
> * restore patch "arm64: extend execmem_info for generated code
>   allocations" that disappeared in v5 rebase
> * update execmem initialization so that by default it will be
>   initialized early while late initialization will be an opt-in
> 
> v5: https://lore.kernel.org/all/[email-masked]
> * rebase on v6.9-rc4 to avoid a conflict in kprobes
> * add copyrights to mm/execmem.c (Luis)
> * fix spelling (Ingo)
> * define MODULES_VADDDR for sparc (Sam)
> * consistently initialize struct execmem_info (Peter)
> * reduce #ifdefs in function bodies in kprobes (Masami) 
> 
> v4: https://lore.kernel.org/all/[email-masked]
> * rebase on v6.9-rc2
> * rename execmem_params to execmem_info and execmem_arch_params() to
>   execmem_arch_setup()
> * use single execmem_alloc() API instead of execmem_{text,data}_alloc() (Song)
> * avoid extra copy of execmem parameters (Rick)
> * run execmem_init() as core_initcall() except for the architectures that
>   may allocated text really early (currently only x86) (Will)
> * add acks for some of arm64 and riscv changes, thanks Will and Alexandre
> * new commits:
>   - drop call to kasan_alloc_module_shadow() on arm64 because it's not
>     needed anymore
>   - rename MODULE_START to MODULES_VADDR on MIPS
>   - use CONFIG_EXECMEM instead of CONFIG_MODULES on powerpc as per Christophe:
>     https://lore.kernel.org/all/[email-masked]/
> 
> v3: https://lore.kernel.org/all/[email-masked]
> * add type parameter to execmem allocation APIs
> * remove BPF dependency on modules
> 
> v2: https://lore.kernel.org/all/[email-masked]
> * Separate "module" and "others" allocations with execmem_text_alloc()
> and jit_text_alloc()
> * Drop ROX entailment on x86
> * Add ack for nios2 changes, thanks Dinh Nguyen
> 
> v1: https://lore.kernel.org/all/[email-masked]
> 
> = Cover letter from v1 (sligtly updated) =
> 
> module_alloc() is used everywhere as a mean to allocate memory for code.
> 
> Beside being semantically wrong, this unnecessarily ties all subsystmes
> that need to allocate code, such as ftrace, kprobes and BPF to modules and
> puts the burden of code allocation to the modules code.
> 
> Several architectures override module_alloc() because of various
> constraints where the executable memory can be located and this causes
> additional obstacles for improvements of code allocation.
> 
> A centralized infrastructure for code allocation allows allocations of
> executable memory as ROX, and future optimizations such as caching large
> pages for better iTLB performance and providing sub-page allocations for
> users that only need small jit code snippets.
> 
> Rick Edgecombe proposed perm_alloc extension to vmalloc [1] and Song Liu
> proposed execmem_alloc [2], but both these approaches were targeting BPF
> allocations and lacked the ground work to abstract executable allocations
> and split them from the modules core.
> 
> Thomas Gleixner suggested to express module allocation restrictions and
> requirements as struct mod_alloc_type_params [3] that would define ranges,
> protections and other parameters for different types of allocations used by
> modules and following that suggestion Song separated allocations of
> different types in modules (commit ac3b43283923 ("module: replace
> module_layout with module_memory")) and posted "Type aware module
> allocator" set [4].
> 
> I liked the idea of parametrising code allocation requirements as a
> structure, but I believe the original proposal and Song's module allocator
> was too module centric, so I came up with these patches.
> 
> This set splits code allocation from modules by introducing execmem_alloc()
> and and execmem_free(), APIs, replaces call sites of module_alloc() and
> module_memfree() with the new APIs and implements core text and related
> allocations in a central place.
> 
> Instead of architecture specific overrides for module_alloc(), the
> architectures that require non-default behaviour for text allocation must
> fill execmem_info structure and implement execmem_arch_setup() that returns
> a pointer to that structure. If an architecture does not implement
> execmem_arch_setup(), the defaults compatible with the current
> modules::module_alloc() are used.
> 
> Since architectures define different restrictions on placement,
> permissions, alignment and other parameters for memory that can be used by
> different subsystems that allocate executable memory, execmem APIs
> take a type argument, that will be used to identify the calling subsystem
> and to allow architectures to define parameters for ranges suitable for that
> subsystem.
> 
> The new infrastructure allows decoupling of BPF, kprobes and ftrace from
> modules, and most importantly it paves the way for ROX allocations for
> executable memory.
> 
> [1] https://lore.kernel.org/lkml/[email-masked]/
> [2] https://lore.kernel.org/all/[email-masked]/
> [3] https://lore.kernel.org/all/87v8mndy3y.ffs@tglx/
> [4] https://lore.kernel.org/all/[email-masked]
> 
> 
> Mike Rapoport (IBM) (17):
>   arm64: module: remove unneeded call to kasan_alloc_module_shadow()
>   mips: module: rename MODULE_START to MODULES_VADDR
>   nios2: define virtual address space for modules
>   sparc: simplify module_alloc()
>   module: make module_memory_{alloc,free} more self-contained
>   mm: introduce execmem_alloc() and execmem_free()
>   mm/execmem, arch: convert simple overrides of module_alloc to execmem
>   mm/execmem, arch: convert remaining overrides of module_alloc to
>     execmem
>   riscv: extend execmem_params for generated code allocations
>   arm64: extend execmem_info for generated code allocations
>   powerpc: extend execmem_params for kprobes allocations
>   arch: make execmem setup available regardless of CONFIG_MODULES
>   x86/ftrace: enable dynamic ftrace without CONFIG_MODULES
>   powerpc: use CONFIG_EXECMEM instead of CONFIG_MODULES where
>     appropriate
>   kprobes: remove dependency on CONFIG_MODULES
>   bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of
>   fixup: convert remaining archs: defaults handling
> 
>  arch/Kconfig                         |  10 +-
>  arch/arm/kernel/module.c             |  34 -------
>  arch/arm/mm/init.c                   |  45 +++++++++
>  arch/arm64/Kconfig                   |   1 +
>  arch/arm64/kernel/module.c           | 126 -----------------------
>  arch/arm64/kernel/probes/kprobes.c   |   7 --
>  arch/arm64/mm/init.c                 | 140 ++++++++++++++++++++++++++
>  arch/arm64/net/bpf_jit_comp.c        |  11 ---
>  arch/loongarch/kernel/module.c       |   6 --
>  arch/loongarch/mm/init.c             |  21 ++++
>  arch/mips/include/asm/pgtable-64.h   |   4 +-
>  arch/mips/kernel/module.c            |  10 --
>  arch/mips/mm/fault.c                 |   4 +-
>  arch/mips/mm/init.c                  |  23 +++++
>  arch/nios2/include/asm/pgtable.h     |   5 +-
>  arch/nios2/kernel/module.c           |  20 ----
>  arch/nios2/mm/init.c                 |  21 ++++
>  arch/parisc/kernel/module.c          |  12 ---
>  arch/parisc/mm/init.c                |  23 ++++-
>  arch/powerpc/Kconfig                 |   2 +-
>  arch/powerpc/include/asm/kasan.h     |   2 +-
>  arch/powerpc/kernel/head_8xx.S       |   4 +-
>  arch/powerpc/kernel/head_book3s_32.S |   6 +-
>  arch/powerpc/kernel/kprobes.c        |  22 +----
>  arch/powerpc/kernel/module.c         |  38 -------
>  arch/powerpc/lib/code-patching.c     |   2 +-
>  arch/powerpc/mm/book3s32/mmu.c       |   2 +-
>  arch/powerpc/mm/mem.c                |  64 ++++++++++++
>  arch/riscv/include/asm/pgtable.h     |   3 +
>  arch/riscv/kernel/module.c           |  12 ---
>  arch/riscv/kernel/probes/kprobes.c   |  10 --
>  arch/riscv/mm/init.c                 |  35 +++++++
>  arch/riscv/net/bpf_jit_core.c        |  13 ---
>  arch/s390/kernel/ftrace.c            |   4 +-
>  arch/s390/kernel/kprobes.c           |   4 +-
>  arch/s390/kernel/module.c            |  42 +-------
>  arch/s390/mm/init.c                  |  30 ++++++
>  arch/sparc/include/asm/pgtable_32.h  |   2 +
>  arch/sparc/kernel/module.c           |  30 ------
>  arch/sparc/mm/Makefile               |   2 +
>  arch/sparc/mm/execmem.c              |  21 ++++
>  arch/sparc/net/bpf_jit_comp_32.c     |   8 +-
>  arch/x86/Kconfig                     |   1 +
>  arch/x86/kernel/ftrace.c             |  16 +--
>  arch/x86/kernel/kprobes/core.c       |   4 +-
>  arch/x86/kernel/module.c             |  51 ----------
>  arch/x86/mm/init.c                   |  29 ++++++
>  include/linux/execmem.h              | 132 +++++++++++++++++++++++++
>  include/linux/module.h               |   9 ++
>  include/linux/moduleloader.h         |  15 ---
>  kernel/bpf/Kconfig                   |   2 +-
>  kernel/bpf/core.c                    |   6 +-
>  kernel/kprobes.c                     |  63 +++++++-----
>  kernel/module/Kconfig                |   1 +
>  kernel/module/main.c                 | 105 +++++++++-----------
>  kernel/trace/trace_kprobe.c          |  20 +++-
>  mm/Kconfig                           |   3 +
>  mm/Makefile                          |   1 +
>  mm/execmem.c                         | 143 +++++++++++++++++++++++++++
>  mm/mm_init.c                         |   2 +
>  60 files changed, 903 insertions(+), 581 deletions(-)
>  create mode 100644 arch/sparc/mm/execmem.c
>  create mode 100644 include/linux/execmem.h
>  create mode 100644 mm/execmem.c
> 
> 
> base-commit: 0bbac3facb5d6cc0171c45c9873a2dc96bea9680
> -- 
> 2.43.0
> 
> 

-- 
Sincerely yours,
Mike.