From d92fc69ccac4c0a20679fdbdc81b2010685a6f33 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 14 Jul 2016 13:22:51 -0700 Subject: 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: Andy Lutomirski Reviewed-by: Matt Fleming Acked-by: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/77ff20fdde3b75cd393be5559ad8218870520248.1468527351.git.luto@kernel.org Signed-off-by: Ingo Molnar diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 78d1e74..45ea38d 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -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); diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index d14d0a5..f1218f5 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -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 */ diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 26aa487..26c93c6 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -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. diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index f93545e..62986e5 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -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); diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c index 338402b..cef39b0 100644 --- a/arch/x86/platform/efi/efi_32.c +++ b/arch/x86/platform/efi/efi_32.c @@ -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) { diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index b226b3f..d288dce 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -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; -- cgit v0.10.2