Hi Calvin, Le 06/03/2024 à 21:05, Calvin Owens a écrit : > [Vous ne recevez pas souvent de courriers de jcalvinowens@xxxxxxxxx. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ] > > Both BPF_JIT and KPROBES depend on CONFIG_MODULES, but only require > module_alloc() itself, which can be easily separated into a standalone > allocator for executable kernel memory. Easily maybe, but not as easily as you think, see below. > > Thomas Gleixner sent a patch to do that for x86 as part of a larger > series a couple years ago: > > https://lore.kernel.org/all/20220716230953.442937066@xxxxxxxxxxxxx/ > > I've simply extended that approach to the whole kernel. > > Signed-off-by: Calvin Owens <jcalvinowens@xxxxxxxxx> > --- > arch/Kconfig | 2 +- > arch/arm/kernel/module.c | 35 --------- > arch/arm/mm/Makefile | 2 + > arch/arm/mm/module_alloc.c | 40 ++++++++++ > arch/arm64/kernel/module.c | 127 ------------------------------ > arch/arm64/mm/Makefile | 1 + > arch/arm64/mm/module_alloc.c | 130 +++++++++++++++++++++++++++++++ > arch/loongarch/kernel/module.c | 6 -- > arch/loongarch/mm/Makefile | 2 + > arch/loongarch/mm/module_alloc.c | 10 +++ > arch/mips/kernel/module.c | 10 --- > arch/mips/mm/Makefile | 2 + > arch/mips/mm/module_alloc.c | 13 ++++ > arch/nios2/kernel/module.c | 20 ----- > arch/nios2/mm/Makefile | 2 + > arch/nios2/mm/module_alloc.c | 22 ++++++ > arch/parisc/kernel/module.c | 12 --- > arch/parisc/mm/Makefile | 1 + > arch/parisc/mm/module_alloc.c | 15 ++++ > arch/powerpc/kernel/module.c | 36 --------- > arch/powerpc/mm/Makefile | 1 + > arch/powerpc/mm/module_alloc.c | 41 ++++++++++ Missing several powerpc changes to make it work. You must audit every use of CONFIG_MODULES inside powerpc. Here are a few exemples: Function get_patch_pfn() to enable text code patching. arch/powerpc/Kconfig : select KASAN_VMALLOC if KASAN && MODULES arch/powerpc/include/asm/kasan.h: #if defined(CONFIG_MODULES) && defined(CONFIG_PPC32) #define KASAN_KERN_START ALIGN_DOWN(PAGE_OFFSET - SZ_256M, SZ_256M) #else #define KASAN_KERN_START PAGE_OFFSET #endif arch/powerpc/kernel/head_8xx.S and arch/powerpc/kernel/head_book3s_32.S: InstructionTLBMiss interrupt handler must know that there is executable kernel text outside kernel core. Function is_module_segment() to identified segments used for module text and set NX (NoExec) MMU flag on non-module segments. > arch/riscv/kernel/module.c | 11 --- > arch/riscv/mm/Makefile | 1 + > arch/riscv/mm/module_alloc.c | 17 ++++ > arch/s390/kernel/module.c | 37 --------- > arch/s390/mm/Makefile | 1 + > arch/s390/mm/module_alloc.c | 42 ++++++++++ > arch/sparc/kernel/module.c | 31 -------- > arch/sparc/mm/Makefile | 2 + > arch/sparc/mm/module_alloc.c | 31 ++++++++ > arch/x86/kernel/ftrace.c | 2 +- > arch/x86/kernel/module.c | 56 ------------- > arch/x86/mm/Makefile | 2 + > arch/x86/mm/module_alloc.c | 59 ++++++++++++++ > fs/proc/kcore.c | 2 +- > kernel/module/Kconfig | 1 + > kernel/module/main.c | 17 ---- > mm/Kconfig | 3 + > mm/Makefile | 1 + > mm/module_alloc.c | 21 +++++ > mm/vmalloc.c | 2 +- > 42 files changed, 467 insertions(+), 402 deletions(-) ... > diff --git a/mm/Kconfig b/mm/Kconfig > index ffc3a2ba3a8c..92bfb5ae2e95 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -1261,6 +1261,9 @@ config LOCK_MM_AND_FIND_VMA > config IOMMU_MM_DATA > bool > > +config MODULE_ALLOC > + def_bool n > + I'd call it something else than CONFIG_MODULE_ALLOC as you want to use it when CONFIG_MODULE is not selected. Something like CONFIG_EXECMEM_ALLOC or CONFIG_DYNAMIC_EXECMEM ? Christophe
