From: Mike Rapoport <rppt@xxxxxxxxxxxxx> Subject: arch, mm: restore dependency of __kernel_map_pages() on DEBUG_PAGEALLOC The design of DEBUG_PAGEALLOC presumes that __kernel_map_pages() must never fail. With this assumption is wouldn't be safe to allow general usage of this function. Moreover, some architectures that implement __kernel_map_pages() have this function guarded by #ifdef DEBUG_PAGEALLOC and some refuse to map/unmap pages when page allocation debugging is disabled at runtime. As all the users of __kernel_map_pages() were converted to use debug_pagealloc_map_pages() it is safe to make it available only when DEBUG_PAGEALLOC is set. Link: https://lkml.kernel.org/r/20201109192128.960-4-rppt@xxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> Acked-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@xxxxxxxxx> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Len Brown <len.brown@xxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> Cc: Pavel Machek <pavel@xxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/Kconfig | 3 +++ arch/arm64/Kconfig | 4 +--- arch/arm64/mm/pageattr.c | 8 ++++++-- arch/powerpc/Kconfig | 5 +---- arch/riscv/Kconfig | 4 +--- arch/riscv/include/asm/pgtable.h | 2 -- arch/riscv/mm/pageattr.c | 2 ++ arch/s390/Kconfig | 4 +--- arch/sparc/Kconfig | 4 +--- arch/x86/Kconfig | 4 +--- arch/x86/mm/pat/set_memory.c | 2 ++ include/linux/mm.h | 10 +++++++--- 12 files changed, 26 insertions(+), 26 deletions(-) --- a/arch/arm64/Kconfig~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/arm64/Kconfig @@ -71,6 +71,7 @@ config ARM64 select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS select ARCH_USE_SYM_ANNOTATIONS + select ARCH_SUPPORTS_DEBUG_PAGEALLOC select ARCH_SUPPORTS_MEMORY_FAILURE select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK select ARCH_SUPPORTS_ATOMIC_RMW @@ -1028,9 +1029,6 @@ config HOLES_IN_ZONE source "kernel/Kconfig.hz" -config ARCH_SUPPORTS_DEBUG_PAGEALLOC - def_bool y - config ARCH_SPARSEMEM_ENABLE def_bool y select SPARSEMEM_VMEMMAP_ENABLE --- a/arch/arm64/mm/pageattr.c~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/arm64/mm/pageattr.c @@ -155,7 +155,7 @@ int set_direct_map_invalid_noflush(struc .clear_mask = __pgprot(PTE_VALID), }; - if (!rodata_full) + if (!debug_pagealloc_enabled() && !rodata_full) return 0; return apply_to_page_range(&init_mm, @@ -170,7 +170,7 @@ int set_direct_map_default_noflush(struc .clear_mask = __pgprot(PTE_RDONLY), }; - if (!rodata_full) + if (!debug_pagealloc_enabled() && !rodata_full) return 0; return apply_to_page_range(&init_mm, @@ -178,6 +178,7 @@ int set_direct_map_default_noflush(struc PAGE_SIZE, change_page_range, &data); } +#ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { if (!debug_pagealloc_enabled() && !rodata_full) @@ -186,6 +187,7 @@ void __kernel_map_pages(struct page *pag set_memory_valid((unsigned long)page_address(page), numpages, enable); } +#ifdef CONFIG_HIBERNATION /* * This function is used to determine if a linear map page has been marked as * not-valid. Walk the page table and check the PTE_VALID bit. This is based @@ -232,3 +234,5 @@ bool kernel_page_present(struct page *pa ptep = pte_offset_kernel(pmdp, addr); return pte_valid(READ_ONCE(*ptep)); } +#endif /* CONFIG_HIBERNATION */ +#endif /* CONFIG_DEBUG_PAGEALLOC */ --- a/arch/Kconfig~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/Kconfig @@ -1047,6 +1047,9 @@ config ARCH_WANT_LD_ORPHAN_WARN config HAVE_ARCH_PFN_VALID bool +config ARCH_SUPPORTS_DEBUG_PAGEALLOC + bool + source "kernel/gcov/Kconfig" source "scripts/gcc-plugins/Kconfig" --- a/arch/powerpc/Kconfig~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/powerpc/Kconfig @@ -146,6 +146,7 @@ config PPC select ARCH_MIGHT_HAVE_PC_SERIO select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_DEBUG_PAGEALLOC if PPC32 || PPC_BOOK3S_64 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if PPC64 select ARCH_USE_QUEUED_RWLOCKS if PPC_QUEUED_SPINLOCKS @@ -356,10 +357,6 @@ config PPC_OF_PLATFORM_PCI depends on PCI depends on PPC64 # not supported on 32 bits yet -config ARCH_SUPPORTS_DEBUG_PAGEALLOC - depends on PPC32 || PPC_BOOK3S_64 - def_bool y - config ARCH_SUPPORTS_UPROBES def_bool y --- a/arch/riscv/include/asm/pgtable.h~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/riscv/include/asm/pgtable.h @@ -461,8 +461,6 @@ static inline int ptep_clear_flush_young #define VMALLOC_START 0 #define VMALLOC_END TASK_SIZE -static inline void __kernel_map_pages(struct page *page, int numpages, int enable) {} - #endif /* !CONFIG_MMU */ #define kern_addr_valid(addr) (1) /* FIXME */ --- a/arch/riscv/Kconfig~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/riscv/Kconfig @@ -14,6 +14,7 @@ config RISCV def_bool y select ARCH_CLOCKSOURCE_INIT select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU select ARCH_HAS_BINFMT_FLAT select ARCH_HAS_DEBUG_VM_PGTABLE select ARCH_HAS_DEBUG_VIRTUAL if MMU @@ -153,9 +154,6 @@ config ARCH_SELECT_MEMORY_MODEL config ARCH_WANT_GENERAL_HUGETLB def_bool y -config ARCH_SUPPORTS_DEBUG_PAGEALLOC - def_bool y - config SYS_SUPPORTS_HUGETLBFS depends on MMU def_bool y --- a/arch/riscv/mm/pageattr.c~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/riscv/mm/pageattr.c @@ -184,6 +184,7 @@ int set_direct_map_default_noflush(struc return ret; } +#ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { if (!debug_pagealloc_enabled()) @@ -196,3 +197,4 @@ void __kernel_map_pages(struct page *pag __set_memory((unsigned long)page_address(page), numpages, __pgprot(0), __pgprot(_PAGE_PRESENT)); } +#endif --- a/arch/s390/Kconfig~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/s390/Kconfig @@ -35,9 +35,6 @@ config GENERIC_LOCKBREAK config PGSTE def_bool y if KVM -config ARCH_SUPPORTS_DEBUG_PAGEALLOC - def_bool y - config AUDIT_ARCH def_bool y @@ -106,6 +103,7 @@ config S390 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE select ARCH_STACKWALK select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_DEBUG_PAGEALLOC select ARCH_SUPPORTS_NUMA_BALANCING select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF --- a/arch/sparc/Kconfig~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/sparc/Kconfig @@ -88,6 +88,7 @@ config SPARC64 select HAVE_C_RECORDMCOUNT select HAVE_ARCH_AUDITSYSCALL select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_DEBUG_PAGEALLOC select HAVE_NMI select HAVE_REGS_AND_STACK_ACCESS_API select ARCH_USE_QUEUED_RWLOCKS @@ -148,9 +149,6 @@ config GENERIC_ISA_DMA bool default y if SPARC32 -config ARCH_SUPPORTS_DEBUG_PAGEALLOC - def_bool y if SPARC64 - config PGTABLE_LEVELS default 4 if 64BIT default 3 --- a/arch/x86/Kconfig~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/x86/Kconfig @@ -91,6 +91,7 @@ config X86 select ARCH_STACKWALK select ARCH_SUPPORTS_ACPI select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_DEBUG_PAGEALLOC select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_QUEUED_RWLOCKS @@ -331,9 +332,6 @@ config ZONE_DMA32 config AUDIT_ARCH def_bool y if X86_64 -config ARCH_SUPPORTS_DEBUG_PAGEALLOC - def_bool y - config KASAN_SHADOW_OFFSET hex depends on KASAN --- a/arch/x86/mm/pat/set_memory.c~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/arch/x86/mm/pat/set_memory.c @@ -2194,6 +2194,7 @@ int set_direct_map_default_noflush(struc return __set_pages_p(page, 1); } +#ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { if (PageHighMem(page)) @@ -2239,6 +2240,7 @@ bool kernel_page_present(struct page *pa return (pte_val(*pte) & _PAGE_PRESENT); } #endif /* CONFIG_HIBERNATION */ +#endif /* CONFIG_DEBUG_PAGEALLOC */ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, unsigned numpages, unsigned long page_flags) --- a/include/linux/mm.h~arch-mm-restore-dependency-of-__kernel_map_pages-on-debug_pagealloc +++ a/include/linux/mm.h @@ -2931,7 +2931,11 @@ static inline bool debug_pagealloc_enabl return static_branch_unlikely(&_debug_pagealloc_enabled); } -#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) +#ifdef CONFIG_DEBUG_PAGEALLOC +/* + * To support DEBUG_PAGEALLOC architecture must ensure that + * __kernel_map_pages() never fails + */ extern void __kernel_map_pages(struct page *page, int numpages, int enable); static inline void debug_pagealloc_map_pages(struct page *page, int numpages) @@ -2949,13 +2953,13 @@ static inline void debug_pagealloc_unmap #ifdef CONFIG_HIBERNATION extern bool kernel_page_present(struct page *page); #endif /* CONFIG_HIBERNATION */ -#else /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */ +#else /* CONFIG_DEBUG_PAGEALLOC */ static inline void debug_pagealloc_map_pages(struct page *page, int numpages) {} static inline void debug_pagealloc_unmap_pages(struct page *page, int numpages) {} #ifdef CONFIG_HIBERNATION static inline bool kernel_page_present(struct page *page) { return true; } #endif /* CONFIG_HIBERNATION */ -#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */ +#endif /* CONFIG_DEBUG_PAGEALLOC */ #ifdef __HAVE_ARCH_GATE_AREA extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm); _
