From faa379332f3cb3375db1849e27386f8bc9b97da4 Mon Sep 17 00:00:00 2001 From: Thomas Garnier Date: Tue, 21 Jun 2016 17:47:00 -0700 Subject: [PATCH] x86/mm: Add PUD VA support for physical mapping Minor change that allows early boot physical mapping of PUD level virtual addresses. The current implementation expects the virtual address to be PUD aligned. For KASLR memory randomization, we need to be able to randomize the offset used on the PUD table. It has no impact on current usage. Signed-off-by: Thomas Garnier Signed-off-by: Kees Cook Cc: Alexander Kuleshov Cc: Alexander Popov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Aneesh Kumar K.V Cc: Baoquan He Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Christian Borntraeger Cc: Dan Williams Cc: Dave Hansen Cc: Dave Young Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: Jan Beulich Cc: Joerg Roedel Cc: Jonathan Corbet Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Lv Zheng Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Fleming Cc: Peter Zijlstra Cc: Stephen Smalley Cc: Thomas Gleixner Cc: Toshi Kani Cc: Xiao Guangrong Cc: Yinghai Lu Cc: kernel-hardening@lists.openwall.com Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/1466556426-32664-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar --- arch/x86/mm/init_64.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 6714712bd5da..7bf1ddb54537 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -465,7 +465,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end, /* * Create PUD level page table mapping for physical addresses. The virtual - * and physical address have to be aligned at this level. + * and physical address do not have to be aligned at this level. KASLR can + * randomize virtual addresses up to this level. * It returns the last physical address mapped. */ static unsigned long __meminit @@ -474,14 +475,18 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, { unsigned long pages = 0, paddr_next; unsigned long paddr_last = paddr_end; - int i = pud_index(paddr); + unsigned long vaddr = (unsigned long)__va(paddr); + int i = pud_index(vaddr); for (; i < PTRS_PER_PUD; i++, paddr = paddr_next) { - pud_t *pud = pud_page + pud_index(paddr); + pud_t *pud; pmd_t *pmd; pgprot_t prot = PAGE_KERNEL; + vaddr = (unsigned long)__va(paddr); + pud = pud_page + pud_index(vaddr); paddr_next = (paddr & PUD_MASK) + PUD_SIZE; + if (paddr >= paddr_end) { if (!after_bootmem && !e820_any_mapped(paddr & PUD_MASK, paddr_next, @@ -551,7 +556,7 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, /* * Create page table mapping for the physical memory for specific physical - * addresses. The virtual and physical addresses have to be aligned on PUD level + * addresses. The virtual and physical addresses have to be aligned on PMD level * down. It returns the last physical address mapped. */ unsigned long __meminit -- 2.20.1