1. 30 Nov, 2015 3 commits
    • Maxim Sheviakov's avatar
      drm/radeon: add quirk for MSI R7 370 · b1bbc748
      Maxim Sheviakov authored
      commit e7865479 upstream.
      
      Just adds the quirk for MSI R7 370 Armor 2X
      Bug:
      https://bugs.freedesktop.org/show_bug.cgi?id=91294Signed-off-by: default avatarMaxim Sheviakov <mrader3940@yandex.ru>
      Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      b1bbc748
    • Krzysztof Mazur's avatar
      x86/setup: Fix low identity map for >= 2GB kernel range · 44f2cfaa
      Krzysztof Mazur authored
      commit 68accac3 upstream.
      
      The commit f5f3497c extended the low identity mapping. However, if
      the kernel uses more than 2 GB (VMSPLIT_2G_OPT or VMSPLIT_1G memory
      split), the normal memory mapping is overwritten by the low identity
      mapping causing a crash. To avoid overwritting, limit the low identity
      map to cover only memory before kernel range (PAGE_OFFSET).
      
      Fixes: f5f3497c "x86/setup: Extend low identity map to cover whole kernel range
      Signed-off-by: default avatarKrzysztof Mazur <krzysiek@podlesie.net>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Laszlo Ersek <lersek@redhat.com>
      Cc: Matt Fleming <matt.fleming@intel.com>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Link: http://lkml.kernel.org/r/1446815916-22105-1-git-send-email-krzysiek@podlesie.netSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      44f2cfaa
    • Paolo Bonzini's avatar
      x86/setup: Extend low identity map to cover whole kernel range · 6693e7ba
      Paolo Bonzini authored
      commit f5f3497c upstream.
      
      On 32-bit systems, the initial_page_table is reused by
      efi_call_phys_prolog as an identity map to call
      SetVirtualAddressMap.  efi_call_phys_prolog takes care of
      converting the current CPU's GDT to a physical address too.
      
      For PAE kernels the identity mapping is achieved by aliasing the
      first PDPE for the kernel memory mapping into the first PDPE
      of initial_page_table.  This makes the EFI stub's trick "just work".
      
      However, for non-PAE kernels there is no guarantee that the identity
      mapping in the initial_page_table extends as far as the GDT; in this
      case, accesses to the GDT will cause a page fault (which quickly becomes
      a triple fault).  Fix this by copying the kernel mappings from
      swapper_pg_dir to initial_page_table twice, both at PAGE_OFFSET and at
      identity mapping.
      
      For some reason, this is only reproducible with QEMU's dynamic translation
      mode, and not for example with KVM.  However, even under KVM one can clearly
      see that the page table is bogus:
      
          $ qemu-system-i386 -pflash OVMF.fd -M q35 vmlinuz0 -s -S -daemonize
          $ gdb
          (gdb) target remote localhost:1234
          (gdb) hb *0x02858f6f
          Hardware assisted breakpoint 1 at 0x2858f6f
          (gdb) c
          Continuing.
      
          Breakpoint 1, 0x02858f6f in ?? ()
          (gdb) monitor info registers
          ...
          GDT=     0724e000 000000ff
          IDT=     fffbb000 000007ff
          CR0=0005003b CR2=ff896000 CR3=032b7000 CR4=00000690
          ...
      
      The page directory is sane:
      
          (gdb) x/4wx 0x32b7000
          0x32b7000:	0x03398063	0x03399063	0x0339a063	0x0339b063
          (gdb) x/4wx 0x3398000
          0x3398000:	0x00000163	0x00001163	0x00002163	0x00003163
          (gdb) x/4wx 0x3399000
          0x3399000:	0x00400003	0x00401003	0x00402003	0x00403003
      
      but our particular page directory entry is empty:
      
          (gdb) x/1wx 0x32b7000 + (0x724e000 >> 22) * 4
          0x32b7070:	0x00000000
      
      [ It appears that you can skate past this issue if you don't receive
        any interrupts while the bogus GDT pointer is loaded, or if you avoid
        reloading the segment registers in general.
      
        Andy Lutomirski provides some additional insight:
      
         "AFAICT it's entirely permissible for the GDTR and/or LDT
          descriptor to point to unmapped memory.  Any attempt to use them
          (segment loads, interrupts, IRET, etc) will try to access that memory
          as if the access came from CPL 0 and, if the access fails, will
          generate a valid page fault with CR2 pointing into the GDT or
          LDT."
      
        Up until commit 23a0d4e8 ("efi: Disable interrupts around EFI
        calls, not in the epilog/prolog calls") interrupts were disabled
        around the prolog and epilog calls, and the functional GDT was
        re-installed before interrupts were re-enabled.
      
        Which explains why no one has hit this issue until now. ]
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Reported-by: default avatarLaszlo Ersek <lersek@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
      [ Updated changelog. ]
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      6693e7ba
  2. 17 Nov, 2015 1 commit
  3. 13 Nov, 2015 36 commits