1. 08 May, 2017 1 commit
    • Xunlei Pang's avatar
      x86/mm: Add support for gbpages to kernel_ident_mapping_init() · 66aad4fd
      Xunlei Pang authored
      
      
      Kernel identity mappings on x86-64 kernels are created in two
      ways: by the early x86 boot code, or by kernel_ident_mapping_init().
      
      Native kernels (which is the dominant usecase) use the former,
      but the kexec and the hibernation code uses kernel_ident_mapping_init().
      
      There's a subtle difference between these two ways of how identity
      mappings are created, the current kernel_ident_mapping_init() code
      creates identity mappings always using 2MB page(PMD level) - while
      the native kernel boot path also utilizes gbpages where available.
      
      This difference is suboptimal both for performance and for memory
      usage: kernel_ident_mapping_init() needs to allocate pages for the
      page tables when creating the new identity mappings.
      
      This patch adds 1GB page(PUD level) support to kernel_ident_mapping_init()
      to address these concerns.
      
      The primary advantage would be better TLB coverage/performance,
      because we'd utilize 1GB TLBs instead of 2MB ones.
      
      It is also useful for machines with large number of memory to
      save paging structure allocations(around 4MB/TB using 2MB page)
      when setting identity mappings for all the memory, after using
      1GB page it will consume only 8KB/TB.
      
      ( Note that this change alone does not activate gbpages in kexec,
        we are doing that in a separate patch. )
      Signed-off-by: default avatarXunlei Pang <xlpang@redhat.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Eric Biederman <ebiederm@xmission.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: akpm@linux-foundation.org
      Cc: kexec@lists.infradead.org
      Link: http://lkml.kernel.org/r/1493862171-8799-1-git-send-email-xlpang@redhat.com
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      66aad4fd
  2. 14 Mar, 2017 1 commit
    • Kirill A. Shutemov's avatar
      x86/mm/ident_map: Add 5-level paging support · ea3b5e60
      Kirill A. Shutemov authored
      
      
      Add additional page table level handing. It's mostly mechanical.
      
      The only quirk is that with p4d folded, 'pgd' is equal to 'p4d' in
      kernel_ident_mapping_init(). The pgd entry has to point to the pud
      page table in this case.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-arch@vger.kernel.org
      Cc: linux-mm@kvack.org
      Link: http://lkml.kernel.org/r/20170313143309.16020-5-kirill.shutemov@linux.intel.com
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      ea3b5e60
  3. 08 Aug, 2016 1 commit
  4. 10 May, 2016 1 commit
    • Kees Cook's avatar
      x86/boot: Add missing file header comments · cb18ef0d
      Kees Cook authored
      
      
      There were some files with missing header comments. Since they are
      included from both compressed and regular kernels, make note of that.
      Also corrects a typo in the mem_avoid comments.
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: kernel-hardening@lists.openwall.com
      Cc: lasse.collin@tukaani.org
      Link: http://lkml.kernel.org/r/1462825332-10505-3-git-send-email-keescook@chromium.org
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      cb18ef0d
  5. 07 May, 2016 1 commit
    • Yinghai Lu's avatar
      x86/boot: Split out kernel_ident_mapping_init() · cf4fb15b
      Yinghai Lu authored
      
      
      In order to support on-demand page table creation when moving the
      kernel for KASLR, we need to use kernel_ident_mapping_init() in the
      decompression code.
      
      This splits it out into its own file for use outside of init_64.c.
      Additionally, checking for __pa/__va defines is added since they
      need to be overridden in the decompression code.
      
      [kees: rewrote changelog]
      Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: kernel-hardening@lists.openwall.com
      Cc: lasse.collin@tukaani.org
      Link: http://lkml.kernel.org/r/1462572095-11754-3-git-send-email-keescook@chromium.org
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      cf4fb15b