The basic idea is to implement the same logic as pgtable-nop4d.h provides, but at runtime. Runtime folding is only implemented for CONFIG_X86_5LEVEL=y case. With the option disabled, we do compile-time folding as before.. Initially, I tried to fold pgd instread. I've got to shell, but it required a lot of hacks as kernel threats pgd in a special way. Please review and consider applying. v3: - Make sparsemem data stuctures allocation dynamic to lower memory overhead on 4-level paging machines; - Allow XEN_PV and XEN_PVH to be enabled with X86_5LEVEL; - XEN cleanups; Kirill A. Shutemov (13): mm, sparsemem: Allocate mem_section at runtime for SPARSEMEM_EXTREME x86/kasan: Use the same shadow offset for 4- and 5-level paging x86/xen: Provide pre-built page tables only for XEN_PV and XEN_PVH x86/xen: Drop 5-level paging support code from XEN_PV code x86/boot/compressed/64: Detect and handle 5-level paging at boot-time x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable x86/mm: Handle boot-time paging mode switching at early boot x86/mm: Fold p4d page table layer at runtime x86/mm: Replace compile-time checks for 5-level with runtime-time x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y x86/xen: Allow XEN_PV and XEN_PVH to be enabled with X86_5LEVEL x86/mm: Offset boot-time paging mode switching cost Documentation/x86/x86_64/5level-paging.txt | 9 +- arch/x86/Kconfig | 5 +- arch/x86/boot/compressed/head_64.S | 24 ++++ arch/x86/boot/compressed/kaslr.c | 14 +++ arch/x86/boot/compressed/misc.h | 5 + arch/x86/entry/entry_64.S | 12 ++ arch/x86/include/asm/kaslr.h | 4 - arch/x86/include/asm/page_64.h | 4 + arch/x86/include/asm/page_64_types.h | 15 +-- arch/x86/include/asm/paravirt.h | 21 ++-- arch/x86/include/asm/pgalloc.h | 5 +- arch/x86/include/asm/pgtable.h | 10 +- arch/x86/include/asm/pgtable_32.h | 2 + arch/x86/include/asm/pgtable_32_types.h | 2 + arch/x86/include/asm/pgtable_64_types.h | 51 +++++--- arch/x86/include/asm/pgtable_types.h | 67 +++-------- arch/x86/include/asm/processor.h | 2 +- arch/x86/include/asm/required-features.h | 8 +- arch/x86/include/asm/sparsemem.h | 9 +- arch/x86/kernel/Makefile | 3 +- arch/x86/kernel/head64.c | 71 ++++++++++-- arch/x86/kernel/head_64.S | 35 +++--- arch/x86/kernel/setup.c | 5 +- arch/x86/mm/dump_pagetables.c | 20 ++-- arch/x86/mm/fault.c | 2 +- arch/x86/mm/ident_map.c | 2 +- arch/x86/mm/init_64.c | 32 ++--- arch/x86/mm/kasan_init_64.c | 94 +++++++++++---- arch/x86/mm/kaslr.c | 27 ++--- arch/x86/platform/efi/efi_64.c | 6 +- arch/x86/power/hibernate_64.c | 6 +- arch/x86/xen/Kconfig | 5 - arch/x86/xen/mmu_pv.c | 180 +++++++++++++---------------- include/asm-generic/5level-fixup.h | 1 + include/asm-generic/pgtable-nop4d.h | 1 + include/linux/kasan.h | 2 +- include/linux/mmzone.h | 2 +- mm/kasan/kasan_init.c | 2 +- mm/page_alloc.c | 10 ++ mm/sparse.c | 3 +- 40 files changed, 462 insertions(+), 316 deletions(-) -- 2.13.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
