1. 12 May, 2011 3 commits
    • Sedat Dilek's avatar
      x86/mm: Fix section mismatch derived from native_pagetable_reserve() · 53f8023f
      Sedat Dilek authored
      With CONFIG_DEBUG_SECTION_MISMATCH=y I see these warnings in next-20110415:
      
        LD      vmlinux.o
        MODPOST vmlinux.o
      WARNING: vmlinux.o(.text+0x1ba48): Section mismatch in reference from the function native_pagetable_reserve() to the function .init.text:memblock_x86_reserve_range()
      The function native_pagetable_reserve() references
      the function __init memblock_x86_reserve_range().
      This is often because native_pagetable_reserve lacks a __init
      annotation or the annotation of memblock_x86_reserve_range is wrong.
      
      This patch fixes the issue.
      Thanks to pipacs from PaX project for help on IRC.
      Acked-by: default avatar"H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      53f8023f
    • Stefano Stabellini's avatar
      x86,xen: introduce x86_init.mapping.pagetable_reserve · 279b706b
      Stefano Stabellini authored
      Introduce a new x86_init hook called pagetable_reserve that at the end
      of init_memory_mapping is used to reserve a range of memory addresses for
      the kernel pagetable pages we used and free the other ones.
      
      On native it just calls memblock_x86_reserve_range while on xen it also
      takes care of setting the spare memory previously allocated
      for kernel pagetable pages from RO to RW, so that it can be used for
      other purposes.
      
      A detailed explanation of the reason why this hook is needed follows.
      
      As a consequence of the commit:
      
      commit 4b239f45
      Author: Yinghai Lu <yinghai@kernel.org>
      Date:   Fri Dec 17 16:58:28 2010 -0800
      
          x86-64, mm: Put early page table high
      
      at some point init_memory_mapping is going to reach the pagetable pages
      area and map those pages too (mapping them as normal memory that falls
      in the range of addresses passed to init_memory_mapping as argument).
      Some of those pages are already pagetable pages (they are in the range
      pgt_buf_start-pgt_buf_end) therefore they are going to be mapped RO and
      everything is fine.
      Some of these pages are not pagetable pages yet (they fall in the range
      pgt_buf_end-pgt_buf_top; for example the page at pgt_buf_end) so they
      are going to be mapped RW.  When these pages become pagetable pages and
      are hooked into the pagetable, xen will find that the guest has already
      a RW mapping of them somewhere and fail the operation.
      The reason Xen requires pagetables to be RO is that the hypervisor needs
      to verify that the pagetables are valid before using them. The validation
      operations are called "pinning" (more details in arch/x86/xen/mmu.c).
      
      In order to fix the issue we mark all the pages in the entire range
      pgt_buf_start-pgt_buf_top as RO, however when the pagetable allocation
      is completed only the range pgt_buf_start-pgt_buf_end is reserved by
      init_memory_mapping. Hence the kernel is going to crash as soon as one
      of the pages in the range pgt_buf_end-pgt_buf_top is reused (b/c those
      ranges are RO).
      
      For this reason we need a hook to reserve the kernel pagetable pages we
      used and free the other ones so that they can be reused for other
      purposes.
      On native it just means calling memblock_x86_reserve_range, on Xen it
      also means marking RW the pagetable pages that we allocated before but
      that haven't been used before.
      
      Another way to fix this is without using the hook is by adding a 'if
      (xen_pv_domain)' in the 'init_memory_mapping' code and calling the Xen
      counterpart, but that is just nasty.
      Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      Acked-by: default avatarYinghai Lu <yinghai@kernel.org>
      Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      279b706b
    • Konrad Rzeszutek Wilk's avatar
      Revert "xen/mmu: Add workaround "x86-64, mm: Put early page table high"" · 92bdaef7
      Konrad Rzeszutek Wilk authored
      This reverts commit a3864783.
      
      It does not work with certain AMD machines.
      
      last_pfn = 0x100000 max_arch_pfn = 0x400000000
      initial memory mapped : 0 - 02c3a000
      Base memory trampoline at [ffff88000009b000] 9b000 size 20480
      init_memory_mapping: 0000000000000000-0000000100000000
       0000000000 - 0100000000 page 4k
      kernel direct mapping tables up to 100000000 @ ff7fb000-100000000
      init_memory_mapping: 0000000100000000-00000001e0800000
       0100000000 - 01e0800000 page 4k
      kernel direct mapping tables up to 1e0800000 @ 1df0f3000-1e0000000
      xen: setting RW the range fffdc000 - 100000000
      RAMDISK: 0203b000 - 02c3a000
      No NUMA configuration found
      Faking a node at 0000000000000000-00000001e0800000
      NUMA: Using 63 for the hash shift.
      Initmem setup node 0 0000000000000000-00000001e0800000
        NODE_DATA [00000001dfffb000 - 00000001dfffffff]
      BUG: unable to handle kernel NULL pointer dereference at           (null)
      IP: [<ffffffff81cf6a75>] setup_node_bootmem+0x18a/0x1ea
      PGD 0
      Oops: 0003 [#1] SMP
      last sysfs file:
      CPU 0
      Modules linked in:
      
      Pid: 0, comm: swapper Not tainted 2.6.39-0-virtual #6~smb1
      RIP: e030:[<ffffffff81cf6a75>]  [<ffffffff81cf6a75>] setup_node_bootmem+0x18a/0x1ea
      RSP: e02b:ffffffff81c01e38  EFLAGS: 00010046
      RAX: 0000000000000000 RBX: 00000001e0800000 RCX: 0000000000001040
      RDX: 0000000000004100 RSI: 0000000000000000 RDI: ffff8801dfffb000
      RBP: ffffffff81c01e58 R08: 0000000000000020 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
      R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000bfe400
      FS:  0000000000000000(0000) GS:ffffffff81cca000(0000) knlGS:0000000000000000
      CS:  e033 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 0000000000000000 CR3: 0000000001c03000 CR4: 0000000000000660
      DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
      Process swapper (pid: 0, threadinfo ffffffff81c00000, task ffffffff81c0b020)
      Stack:
       0000000000000040 0000000000000001 0000000000000000 ffffffffffffffff
       ffffffff81c01e88 ffffffff81cf6c25 0000000000000000 0000000000000000
       ffffffff81cf687f 0000000000000000 ffffffff81c01ea8 ffffffff81cf6e45
      Call Trace:
       [<ffffffff81cf6c25>] numa_register_memblks.constprop.3+0x150/0x181
       [<ffffffff81cf687f>] ? numa_add_memblk+0x7c/0x7c
       [<ffffffff81cf6e45>] numa_init.part.2+0x1c/0x7c
       [<ffffffff81cf687f>] ? numa_add_memblk+0x7c/0x7c
       [<ffffffff81cf6f67>] numa_init+0x6c/0x70
       [<ffffffff81cf7057>] initmem_init+0x39/0x3b
       [<ffffffff81ce5865>] setup_arch+0x64e/0x769
       [<ffffffff815e43c1>] ? printk+0x51/0x53
       [<ffffffff81cdf92b>] start_kernel+0xd4/0x3f3
       [<ffffffff81cdf388>] x86_64_start_reservations+0x132/0x136
       [<ffffffff81ce2ed4>] xen_start_kernel+0x588/0x58f
      Code: 41 00 00 48 8b 3c c5 a0 24 cc 81 31 c0 40 f6 c7 01 74 05 aa 66 ba ff 40 40 f6 c7 02 74 05 66 ab 83 ea 02 89 d1 c1 e9 02 f6 c2 02 <f3> ab 74 02 66 ab 80 e2 01 74 01 aa 49 63 c4 48 c1 eb 0c 44 89
      RIP  [<ffffffff81cf6a75>] setup_node_bootmem+0x18a/0x1ea
       RSP <ffffffff81c01e38>
      CR2: 0000000000000000
      ---[ end trace a7919e7f17c0a725 ]---
      Kernel panic - not syncing: Attempted to kill the idle task!
      Pid: 0, comm: swapper Tainted: G      D     2.6.39-0-virtual #6~smb1
      Reported-by: default avatarStefan Bader <stefan.bader@canonical.com>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      92bdaef7
  2. 04 May, 2011 4 commits
  3. 03 May, 2011 8 commits
  4. 02 May, 2011 24 commits
  5. 01 May, 2011 1 commit
    • Yinghai Lu's avatar
      x86, NUMA: Fix empty memblk detection in numa_cleanup_meminfo() · 2be19102
      Yinghai Lu authored
      numa_cleanup_meminfo() trims each memblk between low (0) and
      high (max_pfn) limits and discards empty ones.  However, the
      emptiness detection incorrectly used equality test.  If the
      start of a memblk is higher than max_pfn, it is empty but fails
      the equality test and doesn't get discarded.
      
      The condition triggers when max_pfn is lower than start of a
      NUMA node and results in memory misconfiguration - leading to
      WARN_ON()s and other funnies.  The bug was discovered in devel
      branch where 32bit too uses this code path for NUMA init.  If a
      node is above the addressing limit, max_pfn ends up lower than
      the node triggering this problem.
      
      The failure hasn't been observed on x86-64 but is still possible
      with broken hardware e820/NUMA info.  As the fix is very low
      risk, it would be better to apply it even for 64bit.
      
      Fix it by using >= instead of ==.
      Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
      [ Extracted the actual fix from the original patch and rewrote patch description. ]
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Link: http://lkml.kernel.org/r/20110501171204.GO29280@htj.dyndns.orgSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      2be19102