x86/mm/pat: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd() (15f003d2) · Commits · 戴 / test

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. Signed-off-by:

Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Signed-off-by:

Matt Fleming <matt@codeblueprint.co.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> 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: Hugh Dickins <hughd@google.com> Cc: Lee, Chun-Yi <jlee@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Shankar <ravi.v.shankar@intel.com> Cc: Ricardo Neri <ricardo.neri@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1455712566-16727-12-git-send-email-matt@codeblueprint.co.uk Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/mm/pageattr.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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);

arch/x86/platform/efi/efi_64.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -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;

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