From: Sai Praneeth <[email protected]> As part of the preparation for the EFI_MEMORY_RO flag added in the UEFI 2.5 specification, we need the ability to map pages in kernel page tables without _PAGE_RW being set.
Modify kernel_map_pages_in_pgd() to require its callers to pass _PAGE_RW if the pages need to be mapped read/write. Otherwise, we'll map the pages as read-only. Cc: Borislav Petkov <[email protected]> Cc: "Lee, Chun-Yi" <[email protected]> Cc: Ricardo Neri <[email protected]> Cc: Ravi Shankar <[email protected]> Signed-off-by: Sai Praneeth Prakhya <[email protected]> Signed-off-by: Matt Fleming <[email protected]> --- arch/x86/mm/pageattr.c | 3 +++ arch/x86/platform/efi/efi_64.c | 8 ++++---- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index bf312da41a6d..14c38ae80409 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1971,6 +1971,9 @@ int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, if (!(page_flags & _PAGE_NX)) cpa.mask_clr = __pgprot(_PAGE_NX); + if (!(page_flags & _PAGE_RW)) + cpa.mask_clr = __pgprot(_PAGE_RW); + cpa.mask_set = __pgprot(_PAGE_PRESENT | page_flags); retval = __change_page_attr_set_clr(&cpa, 0); diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index b492521503fe..b0965b27e47f 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -233,7 +233,7 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) * phys_efi_set_virtual_address_map(). */ pfn = pa_memmap >> PAGE_SHIFT; - if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, _PAGE_NX)) { + if (kernel_map_pages_in_pgd(pgd, pfn, pa_memmap, num_pages, _PAGE_NX | _PAGE_RW)) { pr_err("Error ident-mapping new memmap (0x%lx)!\n", pa_memmap); return 1; } @@ -262,7 +262,7 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) pfn = md->phys_addr >> PAGE_SHIFT; npages = md->num_pages; - if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, 0)) { + if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, _PAGE_RW)) { pr_err("Failed to map 1:1 memory\n"); return 1; } @@ -279,7 +279,7 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) text = __pa(_text); pfn = text >> PAGE_SHIFT; - if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, 0)) { + if (kernel_map_pages_in_pgd(pgd, pfn, text, npages, _PAGE_RW)) { pr_err("Failed to map kernel text 1:1\n"); return 1; } @@ -294,7 +294,7 @@ void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages) static void __init __map_region(efi_memory_desc_t *md, u64 va) { - unsigned long flags = 0; + unsigned long flags = _PAGE_RW; unsigned long pfn; pgd_t *pgd = efi_pgd; -- 2.6.2
