From: "Mike Rapoport (Microsoft)" rppt@kernel.org
Hi,
Following Peter's comments [1] these patches rework handling of ROX caches for module text allocations.
Instead of using a writable copy that really complicates alternatives patching, temporarily remap parts of a large ROX page as RW for the time of module formation and then restore it's ROX protections when the module is ready.
To keep the ROX memory mapped with large pages, make set_memory_rox() capable of restoring large pages (more details are in patch 3).
Since this is really about x86, I believe this should go in via tip tree.
The patches also available in git https://git.kernel.org/rppt/h/execmem/x86-rox/v10
v3 changes: * instead of adding a new module state handle ROX restoration locally in load_module() as Petr suggested
v2: https://lore.kernel.org/all/20250121095739.986006-1-rppt@kernel.org * only collapse large mappings in set_memory_rox() * simplify RW <-> ROX remapping * don't remove ROX cache pages from the direct map (patch 4)
v1: https://lore.kernel.org/all/20241227072825.1288491-1-rppt@kernel.org
[1] https://lore.kernel.org/all/20241209083818.GK8562@noisy.programming.kicks-as...
Kirill A. Shutemov (1): x86/mm/pat: restore large ROX pages after fragmentation
Mike Rapoport (Microsoft) (8): x86/mm/pat: cpa-test: fix length for CPA_ARRAY test x86/mm/pat: drop duplicate variable in cpa_flush() execmem: don't remove ROX cache from the direct map execmem: add API for temporal remapping as RW and restoring ROX afterwards module: switch to execmem API for remapping as RW and restoring ROX Revert "x86/module: prepare module loading for ROX allocations of text" module: drop unused module_writable_address() x86: re-enable EXECMEM_ROX support
arch/um/kernel/um_arch.c | 11 +- arch/x86/Kconfig | 1 + arch/x86/entry/vdso/vma.c | 3 +- arch/x86/include/asm/alternative.h | 14 +- arch/x86/include/asm/pgtable_types.h | 2 + arch/x86/kernel/alternative.c | 181 +++++++++------------- arch/x86/kernel/ftrace.c | 30 ++-- arch/x86/kernel/module.c | 45 ++---- arch/x86/mm/pat/cpa-test.c | 2 +- arch/x86/mm/pat/set_memory.c | 220 ++++++++++++++++++++++++++- include/linux/execmem.h | 31 ++++ include/linux/module.h | 16 -- include/linux/moduleloader.h | 4 - include/linux/vm_event_item.h | 2 + kernel/module/main.c | 78 +++------- kernel/module/strict_rwx.c | 9 +- mm/execmem.c | 39 +++-- mm/vmstat.c | 2 + 18 files changed, 422 insertions(+), 268 deletions(-)
base-commit: ffd294d346d185b70e28b1a28abe367bbfe53c04