linux-toradex.git/arch/x86/include/asm/pgtable_32.h, branch v3.0.44

mm: remove pte_*map_nested()

2010-10-26T23:52:08+00:00

Since we no longer need to provide KM_type, the whole pte_*map_nested()
API is now redundant, remove it.

Signed-off-by: Peter Zijlstra 
Acked-by: Chris Metcalf 
Cc: David Howells 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Steven Rostedt 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: David Miller 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86-32, mm: Add an initial page table for core bootstrapping

2010-10-20T21:23:55+00:00

This patch adds an initial page table with low mappings used exclusively
for booting APs/resuming after ACPI suspend/machine restart. After this,
there's no need to add low mappings to swapper_pg_dir and zap them later
or create own swsusp PGD page solely for ACPI sleep needs - we have
initial_page_table for that.

Signed-off-by: Borislav Petkov 
LKML-Reference: <20101020070526.GA9588@liondog.tnic>
Signed-off-by: H. Peter Anvin

x86-32: Separate 1:1 pagetables from swapper_pg_dir

2010-08-18T16:17:20+00:00

This patch fixes machine crashes which occur when heavily exercising the
CPU hotplug codepaths on a 32-bit kernel. These crashes are caused by
AMD Erratum 383 and result in a fatal machine check exception. Here's
the scenario:

1. On 32-bit, the swapper_pg_dir page table is used as the initial page
table for booting a secondary CPU.

2. To make this work, swapper_pg_dir needs a direct mapping of physical
memory in it (the low mappings). By adding those low, large page (2M)
mappings (PAE kernel), we create the necessary conditions for Erratum
383 to occur.

3. Other CPUs which do not participate in the off- and onlining game may
use swapper_pg_dir while the low mappings are present (when leave_mm is
called). For all steps below, the CPU referred to is a CPU that is using
swapper_pg_dir, and not the CPU which is being onlined.

4. The presence of the low mappings in swapper_pg_dir can result
in TLB entries for addresses below __PAGE_OFFSET to be established
speculatively. These TLB entries are marked global and large.

5. When the CPU with such TLB entry switches to another page table, this
TLB entry remains because it is global.

6. The process then generates an access to an address covered by the
above TLB entry but there is a permission mismatch - the TLB entry
covers a large global page not accessible to userspace.

7. Due to this permission mismatch a new 4kb, user TLB entry gets
established. Further, Erratum 383 provides for a small window of time
where both TLB entries are present. This results in an uncorrectable
machine check exception signalling a TLB multimatch which panics the
machine.

There are two ways to fix this issue:

        1. Always do a global TLB flush when a new cr3 is loaded and the
        old page table was swapper_pg_dir. I consider this a hack hard
        to understand and with performance implications

        2. Do not use swapper_pg_dir to boot secondary CPUs like 64-bit
        does.

This patch implements solution 2. It introduces a trampoline_pg_dir
which has the same layout as swapper_pg_dir with low_mappings. This page
table is used as the initial page table of the booting CPU. Later in the
bringup process, it switches to swapper_pg_dir and does a global TLB
flush. This fixes the crashes in our test cases.

-v2: switch to swapper_pg_dir right after entering start_secondary() so
that we are able to access percpu data which might not be mapped in the
trampoline page table.

Signed-off-by: Joerg Roedel 
LKML-Reference: <20100816123833.GB28147@aftab>
Signed-off-by: Borislav Petkov 
Signed-off-by: H. Peter Anvin

x86: don't include slab.h from arch/x86/include/asm/pgtable_32.h

2010-03-30T13:02:21+00:00

Including slab.h from x86 pgtable_32.h creates a troublesome
dependency chain w/ ftrace enabled.  The following chain leads to
inclusion of pgtable_32.h from define_trace.h.

 trace/define_trace.h
 trace/ftrace.h
 linux/ftrace_event.h
 linux/ring_buffer.h
 linux/mm.h
 asm/pgtable.h
 asm/pgtable_32.h

slab.h itself defines trace hooks via

 linux/sl[aou]b_def.h
 linux/kmemtrace.h
 trace/events/kmem.h

If slab.h is not included before define_trace.h is included, this
leads to duplicate definitions of kmemtrace hooks or other include
dependency problems.

pgtable_32.h doesn't need slab.h to begin with.  Don't include it from
there.

Signed-off-by: Tejun Heo 
Acked-by: Pekka Enberg 
Acked-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: H. Peter Anvin

Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2010-03-03T17:11:02+00:00

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  resource: Fix broken indentation
  resource: Fix generic page_is_ram() for partial RAM pages
  x86, paravirt: Remove kmap_atomic_pte paravirt op.
  x86, vmi: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y
  x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y

x86, paravirt: Remove kmap_atomic_pte paravirt op.

2010-02-27T22:41:35+00:00

Now that both Xen and VMI disable allocations of PTE pages from high
memory this paravirt op serves no further purpose.

This effectively reverts ce6234b5 "add kmap_atomic_pte for mapping
highpte pages".

Signed-off-by: Ian Campbell 
LKML-Reference: <1267204562-11844-3-git-send-email-ian.campbell@citrix.com>
Acked-by: Alok Kataria 
Cc: Jeremy Fitzhardinge 
Cc: Ingo Molnar 
Signed-off-by: H. Peter Anvin

MM: Pass a PTE pointer to update_mmu_cache() rather than the PTE itself

2010-02-20T16:41:46+00:00

On VIVT ARM, when we have multiple shared mappings of the same file
in the same MM, we need to ensure that we have coherency across all
copies.  We do this via make_coherent() by making the pages
uncacheable.

This used to work fine, until we allowed highmem with highpte - we
now have a page table which is mapped as required, and is not available
for modification via update_mmu_cache().

Ralf Beache suggested getting rid of the PTE value passed to
update_mmu_cache():

  On MIPS update_mmu_cache() calls __update_tlb() which walks pagetables
  to construct a pointer to the pte again.  Passing a pte_t * is much
  more elegant.  Maybe we might even replace the pte argument with the
  pte_t?

Ben Herrenschmidt would also like the pte pointer for PowerPC:

  Passing the ptep in there is exactly what I want.  I want that
  -instead- of the PTE value, because I have issue on some ppc cases,
  for I$/D$ coherency, where set_pte_at() may decide to mask out the
  _PAGE_EXEC.

So, pass in the mapped page table pointer into update_mmu_cache(), and
remove the PTE value, updating all implementations and call sites to
suit.

Includes a fix from Stephen Rothwell:

  sparc: fix fallout from update_mmu_cache API change

  Signed-off-by: Stephen Rothwell 

Acked-by: Benjamin Herrenschmidt 
Signed-off-by: Russell King

x86: Add NMI types for kmap_atomic, fix

2009-06-15T15:20:03+00:00

I just realized this has a kmap_atomic bug in...

The below would fix it - but it's complicating this code
some more.

Alternatively I would have to introduce something like
pte_offset_map_irq() which would make the irq/nmi detection and leave
the regular code paths alone, however that would mean either duplicating
the gup_fast() pagewalk or passing down a pte function pointer, which
would only duplicate the gup_pte_range() bit, neither is really
attractive ...

Signed-off-by: Peter Zijlstra 
CC: Nick Piggin 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Arnaldo Carvalho de Melo 
Signed-off-by: Ingo Molnar

x86: Add NMI types for kmap_atomic

2009-06-15T13:57:52+00:00

Two new kmap_atomic slots for NMI context. And teach pte_offset_map()
about NMI context.

Signed-off-by: Peter Zijlstra 
CC: Nick Piggin 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Arnaldo Carvalho de Melo 
Signed-off-by: Ingo Molnar

x86-32: use brk segment for allocating initial kernel pagetable

2009-03-15T00:23:47+00:00

Impact: use new interface instead of previous ad hoc implementation

Rather than having special purpose init_pg_table_start/end variables
to delimit the kernel pagetable built by head_32.S, just use the brk
mechanism to extend the bss for the new pagetable.

This patch removes init_pg_table_start/end and pg0, defines __brk_base
(which is page-aligned and immediately follows _end), initializes
the brk region to start there, and uses it for the 32-bit pagetable.

Signed-off-by: Jeremy Fitzhardinge 
Signed-off-by: H. Peter Anvin