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Commit d92fc69c authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() 



kernel_unmap_pages_in_pgd() is dangerous: if a PGD entry in
init_mm.pgd were to be cleared, callers would need to ensure that
the pgd entry hadn't been propagated to any other pgd.

Its only caller was efi_cleanup_page_tables(), and that, in turn,
was unused, so just delete both functions.  This leaves a couple of
other helpers unused, so delete them, too.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>
Acked-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/77ff20fdde3b75cd393be5559ad8218870520248.1468527351.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 360cb4d1

arch/x86/include/asm/efi.h

+0 −1
Original line number Diff line number Diff line
@@ -125,7 +125,6 @@ extern void __init efi_map_region_fixed(efi_memory_desc_t *md); 
extern void efi_sync_low_kernel_mappings(void);

extern int __init efi_alloc_page_tables(void);

extern int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages);

extern void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages);

extern void __init old_map_region(efi_memory_desc_t *md);

extern void __init runtime_code_page_mkexec(void);

extern void __init efi_runtime_update_mappings(void);

arch/x86/include/asm/pgtable_types.h

+0 −2
Original line number Diff line number Diff line
@@ -481,8 +481,6 @@ extern pmd_t *lookup_pmd_address(unsigned long address); 
extern phys_addr_t slow_virt_to_phys(void *__address);

extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,

				   unsigned numpages, unsigned long page_flags);

void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address,

			       unsigned numpages);

#endif	/* !__ASSEMBLY__ */



#endif /* _ASM_X86_PGTABLE_DEFS_H */

arch/x86/mm/pageattr.c

+0 −28
Original line number Diff line number Diff line
@@ -746,18 +746,6 @@ static bool try_to_free_pmd_page(pmd_t *pmd) 
	return true;

}



static bool try_to_free_pud_page(pud_t *pud)

{

	int i;



	for (i = 0; i < PTRS_PER_PUD; i++)

		if (!pud_none(pud[i]))

			return false;



	free_page((unsigned long)pud);

	return true;

}



static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end)

{

	pte_t *pte = pte_offset_kernel(pmd, start);
@@ -871,16 +859,6 @@ static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) 
	 */

}



static void unmap_pgd_range(pgd_t *root, unsigned long addr, unsigned long end)

{

	pgd_t *pgd_entry = root + pgd_index(addr);



	unmap_pud_range(pgd_entry, addr, end);



	if (try_to_free_pud_page((pud_t *)pgd_page_vaddr(*pgd_entry)))

		pgd_clear(pgd_entry);

}



static int alloc_pte_page(pmd_t *pmd)

{

	pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
@@ -1994,12 +1972,6 @@ int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, 
	return retval;

}



void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address,

			       unsigned numpages)

{

	unmap_pgd_range(root, address, address + (numpages << PAGE_SHIFT));

}



/*

 * The testcases use internal knowledge of the implementation that shouldn't

 * be exposed to the rest of the kernel. Include these directly here.

arch/x86/platform/efi/efi.c

+0 −2
Original line number Diff line number Diff line
@@ -978,8 +978,6 @@ static void __init __efi_enter_virtual_mode(void) 
	 * EFI mixed mode we need all of memory to be accessible when

	 * we pass parameters to the EFI runtime services in the

	 * thunking code.

	 *

	 * efi_cleanup_page_tables(__pa(new_memmap), 1 << pg_shift);

	 */

	free_pages((unsigned long)new_memmap, pg_shift);

arch/x86/platform/efi/efi_32.c

+0 −3
Original line number Diff line number Diff line
@@ -49,9 +49,6 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) 
{

	return 0;

}

void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages)

{

}



void __init efi_map_region(efi_memory_desc_t *md)

{