Commit 5d6ad668 authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

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@kernel.org


Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2abf962a

arch/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -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"

arch/arm64/Kconfig

+1 −3
Original line number Diff line number Diff line
@@ -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

arch/arm64/mm/pageattr.c

+6 −2
Original line number Diff line number Diff line
@@ -155,7 +155,7 @@ int set_direct_map_invalid_noflush(struct page *page) 
		.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(struct page *page) 
		.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(struct page *page) 
				   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 *page, int numpages, int enable) 
	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 *page) 
	ptep = pte_offset_kernel(pmdp, addr);

	return pte_valid(READ_ONCE(*ptep));

}

#endif /* CONFIG_HIBERNATION */

#endif /* CONFIG_DEBUG_PAGEALLOC */

arch/powerpc/Kconfig

+1 −4
Original line number Diff line number Diff line
@@ -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

arch/riscv/Kconfig

+1 −3
Original line number Diff line number Diff line
@@ -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