| Message ID | 20240411160051.2093261-1-rppt@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm: jit/text allocator | expand |
On Thu, Apr 11, 2024 at 07:00:36PM +0300, Mike Rapoport wrote: > From: "Mike Rapoport (IBM)" <rppt@kernel.org> > > Hi, > > Since v3 I looked into making execmem more of an utility toolbox, as we > discussed at LPC with Mark Rutland, but it was getting more hairier than > having a struct describing architecture constraints and a type identifying > the consumer of execmem. > > And I do think that having the description of architecture constraints for > allocations of executable memory in a single place is better that having it > spread all over the place. > > The patches available via git: > https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=execmem/v4 > > v4 changes: > * 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/79062fa3-3402-47b3-8920-9231ad05e964@csgroup.eu/ > > v3: https://lore.kernel.org/all/20230918072955.2507221-1-rppt@kernel.org > * add type parameter to execmem allocation APIs > * remove BPF dependency on modules > > v2: https://lore.kernel.org/all/20230616085038.4121892-1-rppt@kernel.org > * 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/20230601101257.530867-1-rppt@kernel.org > > = 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. It looks like you're just doing API cleanup first, then improving the implementation later? Patch set looks nice and clean; previous versions did seem to leak too much arch/module details (or perhaps we were just bikeshedding too much ;) - but the API first approach is nice. Looking forward to seeing this merged.
On Thu, Apr 11, 2024 at 07:00:36PM +0300, Mike Rapoport wrote: > From: "Mike Rapoport (IBM)" <rppt@kernel.org> > > Hi, > > Since v3 I looked into making execmem more of an utility toolbox, as we > discussed at LPC with Mark Rutland, but it was getting more hairier than > having a struct describing architecture constraints and a type identifying > the consumer of execmem. > > And I do think that having the description of architecture constraints for > allocations of executable memory in a single place is better that having it > spread all over the place. > > The patches available via git: > https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=execmem/v4 I've taken the first 5 patches through modules-next for now to get early exposure to testing. Of those I just had minor nit feedback on the 5th, but the rest look good. Let's wait for review for the rest of the patches 6-15. Luis
From: "Mike Rapoport (IBM)" <rppt@kernel.org> Hi, Since v3 I looked into making execmem more of an utility toolbox, as we discussed at LPC with Mark Rutland, but it was getting more hairier than having a struct describing architecture constraints and a type identifying the consumer of execmem. And I do think that having the description of architecture constraints for allocations of executable memory in a single place is better that having it spread all over the place. The patches available via git: https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=execmem/v4 v4 changes: * 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/79062fa3-3402-47b3-8920-9231ad05e964@csgroup.eu/ v3: https://lore.kernel.org/all/20230918072955.2507221-1-rppt@kernel.org * add type parameter to execmem allocation APIs * remove BPF dependency on modules v2: https://lore.kernel.org/all/20230616085038.4121892-1-rppt@kernel.org * 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/20230601101257.530867-1-rppt@kernel.org = 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/20201120202426.18009-1-rick.p.edgecombe@intel.com/ [2] https://lore.kernel.org/all/20221107223921.3451913-1-song@kernel.org/ [3] https://lore.kernel.org/all/87v8mndy3y.ffs@tglx/ [4] https://lore.kernel.org/all/20230526051529.3387103-1-song@kernel.org Mike Rapoport (IBM) (15): arm64: module: remove uneeded call to kasan_alloc_module_shadow() mips: module: rename MODULE_START to MODULES_VADDR nios2: define virtual address space for modules 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 arm64: extend execmem_info for generated code allocations riscv: extend execmem_params 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 appropiate kprobes: remove dependency on CONFIG_MODULES bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of arch/Kconfig | 8 +- arch/arm/kernel/module.c | 34 ------- arch/arm/mm/init.c | 40 ++++++++ arch/arm64/kernel/module.c | 126 ------------------------ arch/arm64/kernel/probes/kprobes.c | 7 -- arch/arm64/mm/init.c | 136 ++++++++++++++++++++++++++ arch/arm64/net/bpf_jit_comp.c | 11 --- arch/loongarch/kernel/module.c | 6 -- arch/loongarch/mm/init.c | 20 ++++ 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 | 22 +++++ arch/nios2/include/asm/pgtable.h | 5 +- arch/nios2/kernel/module.c | 20 ---- arch/nios2/mm/init.c | 19 ++++ arch/parisc/kernel/module.c | 12 --- arch/parisc/mm/init.c | 22 ++++- 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/kernel/module.c | 12 --- arch/riscv/kernel/probes/kprobes.c | 10 -- arch/riscv/mm/init.c | 41 ++++++++ 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 | 28 ++++++ arch/sparc/kernel/module.c | 30 ------ arch/sparc/mm/Makefile | 2 + arch/sparc/mm/execmem.c | 25 +++++ arch/sparc/net/bpf_jit_comp_32.c | 8 +- arch/x86/Kconfig | 2 + arch/x86/kernel/ftrace.c | 16 +-- arch/x86/kernel/kprobes/core.c | 4 +- arch/x86/kernel/module.c | 51 ---------- arch/x86/mm/init.c | 27 ++++++ include/linux/execmem.h | 132 +++++++++++++++++++++++++ include/linux/moduleloader.h | 15 --- kernel/bpf/Kconfig | 2 +- kernel/bpf/core.c | 6 +- kernel/kprobes.c | 51 +++++----- kernel/module/Kconfig | 1 + kernel/module/main.c | 105 +++++++++----------- kernel/trace/trace_kprobe.c | 11 +++ mm/Kconfig | 3 + mm/Makefile | 1 + mm/execmem.c | 139 +++++++++++++++++++++++++++ mm/mm_init.c | 2 + 56 files changed, 858 insertions(+), 577 deletions(-) create mode 100644 arch/sparc/mm/execmem.c create mode 100644 include/linux/execmem.h create mode 100644 mm/execmem.c base-commit: 39cd87c4eb2b893354f3b850f916353f2658ae6f