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

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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: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Borislav 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2016-07-14 13:22:51 -07:00 committed by Ingo Molnar
parent 360cb4d155
commit d92fc69cca
6 changed files with 0 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/efi.h
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@ -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);

2
arch/x86/include/asm/pgtable_types.h
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@ -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 */

28
arch/x86/mm/pageattr.c
View File

@ -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 @@ out:
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.

2
arch/x86/platform/efi/efi.c
View File

@ -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);

3
arch/x86/platform/efi/efi_32.c
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@ -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)
{

5
arch/x86/platform/efi/efi_64.c
View File

@ -285,11 +285,6 @@ 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)
{
kernel_unmap_pages_in_pgd(efi_pgd, pa_memmap, num_pages);
}
static void __init __map_region(efi_memory_desc_t *md, u64 va)
{
unsigned long flags = _PAGE_RW;