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Groups > linux.kernel > #1593381

[PATCHv4 15/33] x86/efi: handle p4d in EFI pagetables

From "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCHv4 15/33] x86/efi: handle p4d in EFI pagetables
Date 2017-03-06 15:10 +0100
Message-ID <ti1uP-Rx-63@gated-at.bofh.it> (permalink)
References <ti1l7-yB-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Allocate additional page table level and change efi_sync_low_kernel_mappings()
to make syncing logic work with additional page table level.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
---
 arch/x86/platform/efi/efi_64.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 8544dae3d1b4..34d019f75239 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -135,6 +135,7 @@ static pgd_t *efi_pgd;
 int __init efi_alloc_page_tables(void)
 {
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	gfp_t gfp_mask;
 
@@ -147,15 +148,20 @@ int __init efi_alloc_page_tables(void)
 		return -ENOMEM;
 
 	pgd = efi_pgd + pgd_index(EFI_VA_END);
+	p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
+	if (!p4d) {
+		free_page((unsigned long)efi_pgd);
+		return -ENOMEM;
+	}
 
-	pud = pud_alloc_one(NULL, 0);
+	pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
 	if (!pud) {
+		if (CONFIG_PGTABLE_LEVELS > 4)
+			free_page((unsigned long) pgd_page_vaddr(*pgd));
 		free_page((unsigned long)efi_pgd);
 		return -ENOMEM;
 	}
 
-	pgd_populate(NULL, pgd, pud);
-
 	return 0;
 }
 
@@ -190,6 +196,18 @@ void efi_sync_low_kernel_mappings(void)
 	num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET);
 	memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries);
 
+	/* The same story as with PGD entries */
+	BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END));
+	BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK));
+
+	pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
+	pgd_k = pgd_offset_k(EFI_VA_END);
+	p4d_efi = p4d_offset(pgd_efi, 0);
+	p4d_k = p4d_offset(pgd_k, 0);
+
+	num_entries = p4d_index(EFI_VA_END);
+	memcpy(p4d_efi, p4d_k, sizeof(p4d_t) * num_entries);
+
 	/*
 	 * We share all the PUD entries apart from those that map the
 	 * EFI regions. Copy around them.
@@ -197,20 +215,15 @@ void efi_sync_low_kernel_mappings(void)
 	BUILD_BUG_ON((EFI_VA_START & ~PUD_MASK) != 0);
 	BUILD_BUG_ON((EFI_VA_END & ~PUD_MASK) != 0);
 
-	pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
-	p4d_efi = p4d_offset(pgd_efi, 0);
+	p4d_efi = p4d_offset(pgd_efi, EFI_VA_END);
+	p4d_k = p4d_offset(pgd_k, EFI_VA_END);
 	pud_efi = pud_offset(p4d_efi, 0);
-
-	pgd_k = pgd_offset_k(EFI_VA_END);
-	p4d_k = p4d_offset(pgd_k, 0);
 	pud_k = pud_offset(p4d_k, 0);
 
 	num_entries = pud_index(EFI_VA_END);
 	memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries);
 
-	p4d_efi = p4d_offset(pgd_efi, EFI_VA_START);
 	pud_efi = pud_offset(p4d_efi, EFI_VA_START);
-	p4d_k = p4d_offset(pgd_k, EFI_VA_START);
 	pud_k = pud_offset(p4d_k, EFI_VA_START);
 
 	num_entries = PTRS_PER_PUD - pud_index(EFI_VA_START);
-- 
2.11.0

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[PATCHv4 00/33] 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 01/33] x86/cpufeature: Add 5-level paging detection "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 14/33] x86/kexec: support p4d_t "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and xen_cleanmfnmap() to support p4d "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
    Re: [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-06 21:50 +0100
      Re: [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-03-07 14:10 +0100
        Re: [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-07 19:20 +0100
          Re: [Xen-devel] [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Andrew Cooper <andrew.cooper3@citrix.com> - 2017-03-07 19:30 +0100
            Re: [Xen-devel] [PATCHv4 18/33] x86/xen: convert __xen_pgd_walk() and  xen_cleanmfnmap() to support p4d Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-07 20:30 +0100
  [PATCHv4 30/33] x86/mm: make kernel_physical_mapping_init() support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 21/33] x86/asm: remove __VIRTUAL_MASK_SHIFT==47 assert "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 08/33] x86: basic changes into headers for 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 16/33] x86/mm/pat: handle additional page table "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 05/33] asm-generic: introduce <asm-generic/pgtable-nop4d.h> "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 15/33] x86/efi: handle p4d in EFI pagetables "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 19/33] x86: convert the rest of the code to support p4d_t "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 20/33] x86: detect 5-level paging support "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 07/33] mm: introduce __p4d_alloc() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 27/33] x86/espfix: support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 13/33] x86/power: support p4d_t in hibernate code "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:10 +0100
  [PATCHv4 02/33] asm-generic: introduce 5level-fixup.h "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-03-06 15:20 +0100
  Re: [PATCHv4 00/33] 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-06 19:40 +0100
    Re: [PATCHv4 00/33] 5-level paging Thomas Gleixner <tglx@linutronix.de> - 2017-03-06 19:50 +0100
      Re: [PATCHv4 00/33] 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-06 20:10 +0100
        Re: [PATCHv4 00/33] 5-level paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-03-06 20:10 +0100
          Re: [PATCHv4 00/33] 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-06 20:50 +0100
      Re: [PATCHv4 00/33] 5-level paging Stephen Rothwell <sfr@canb.auug.org.au> - 2017-03-07 02:30 +0100
        Re: [PATCHv4 00/33] 5-level paging Thomas Gleixner <tglx@linutronix.de> - 2017-03-07 11:20 +0100

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