linux-stable.git/arch/x86/kernel/setup.c, branch linux-4.7.y

ACPI / x86: Cleanup initrd related code

2016-04-18T21:59:09+00:00

In arch/x86/kernel/setup.c, the #ifdef kept for CONFIG_ACPI actually is
related to the accessibility of initrd_start/initrd_end, so the stub should
be provided from this source file and should only be dependent on
CONFIG_BLK_DEV_INITRD.

Note that when ACPI=n and BLK_DEV_INITRD=y, early_initrd_acpi_init() is
still a stub because of the stub prepared for early_acpi_table_init().

Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / tables: Move table override mechanisms to tables.c

2016-04-18T21:59:08+00:00

This patch moves acpi_os_table_override() and
acpi_os_physical_table_override() to tables.c.

Along with the mechanisms, acpi_initrd_initialize_tables() is also moved to
tables.c to form a static function. The following functions are renamed
according to this change:
 1. acpi_initrd_override() -> renamed to early_acpi_table_init(), which
    invokes acpi_table_initrd_init()
 2. acpi_os_physical_table_override() -> which invokes
    acpi_table_initrd_override()
 3. acpi_initialize_initrd_tables() -> renamed to acpi_table_initrd_scan()

Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

Revert "x86: remove the kernel code/data/bss resources from /proc/iomem"

2016-04-14T19:55:32+00:00

This reverts commit c4004b02f8e5b9ce357a0bb1641756cc86962664.

Sadly, my hope that nobody would actually use the special kernel entries
in /proc/iomem were dashed by kexec.  Which reads /proc/iomem explicitly
to find the kernel base address.  Nasty.

Anyway, that means we can't do the sane and simple thing and just remove
the entries, and we'll instead have to mask them out based on permissions.

Reported-by: Zhengyu Zhang 
Reported-by: Dave Young 
Reported-by: Freeman Zhang 
Reported-by: Emrah Demir 
Reported-by: Baoquan He 
Signed-off-by: Linus Torvalds

x86: remove the kernel code/data/bss resources from /proc/iomem

2016-04-06T20:45:07+00:00

Let's see if anybody even notices.  I doubt anybody uses this, and it
does expose addresses that should be randomized, so let's just remove
the code.  It's old and traditional, and it used to be cute, but we
should have removed this long ago.

If it turns out anybody notices and this breaks something, we'll have to
revert this, and maybe we'll end up using other approaches instead
(using %pK or similar).  But removing unnecessary code is always the
preferred option.

Noted-by: Emrah Demir 
Signed-off-by: Linus Torvalds

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

2016-03-21T02:08:56+00:00

Pull x86 protection key support from Ingo Molnar:
 "This tree adds support for a new memory protection hardware feature
  that is available in upcoming Intel CPUs: 'protection keys' (pkeys).

  There's a background article at LWN.net:

      https://lwn.net/Articles/643797/

  The gist is that protection keys allow the encoding of
  user-controllable permission masks in the pte.  So instead of having a
  fixed protection mask in the pte (which needs a system call to change
  and works on a per page basis), the user can map a (handful of)
  protection mask variants and can change the masks runtime relatively
  cheaply, without having to change every single page in the affected
  virtual memory range.

  This allows the dynamic switching of the protection bits of large
  amounts of virtual memory, via user-space instructions.  It also
  allows more precise control of MMU permission bits: for example the
  executable bit is separate from the read bit (see more about that
  below).

  This tree adds the MM infrastructure and low level x86 glue needed for
  that, plus it adds a high level API to make use of protection keys -
  if a user-space application calls:

        mmap(..., PROT_EXEC);

  or

        mprotect(ptr, sz, PROT_EXEC);

  (note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice
  this special case, and will set a special protection key on this
  memory range.  It also sets the appropriate bits in the Protection
  Keys User Rights (PKRU) register so that the memory becomes unreadable
  and unwritable.

  So using protection keys the kernel is able to implement 'true'
  PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies
  PROT_READ as well.  Unreadable executable mappings have security
  advantages: they cannot be read via information leaks to figure out
  ASLR details, nor can they be scanned for ROP gadgets - and they
  cannot be used by exploits for data purposes either.

  We know about no user-space code that relies on pure PROT_EXEC
  mappings today, but binary loaders could start making use of this new
  feature to map binaries and libraries in a more secure fashion.

  There is other pending pkeys work that offers more high level system
  call APIs to manage protection keys - but those are not part of this
  pull request.

  Right now there's a Kconfig that controls this feature
  (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled
  (like most x86 CPU feature enablement code that has no runtime
  overhead), but it's not user-configurable at the moment.  If there's
  any serious problem with this then we can make it configurable and/or
  flip the default"

* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
  x86/mm/pkeys: Fix mismerge of protection keys CPUID bits
  mm/pkeys: Fix siginfo ABI breakage caused by new u64 field
  x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA
  mm/core, x86/mm/pkeys: Add execute-only protection keys support
  x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags
  x86/mm/pkeys: Allow kernel to modify user pkey rights register
  x86/fpu: Allow setting of XSAVE state
  x86/mm: Factor out LDT init from context init
  mm/core, x86/mm/pkeys: Add arch_validate_pkey()
  mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits()
  x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU
  x86/mm/pkeys: Add Kconfig prompt to existing config option
  x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps
  x86/mm/pkeys: Dump PKRU with other kernel registers
  mm/core, x86/mm/pkeys: Differentiate instruction fetches
  x86/mm/pkeys: Optimize fault handling in access_error()
  mm/core: Do not enforce PKEY permissions on remote mm access
  um, pkeys: Add UML arch_*_access_permitted() methods
  mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys
  x86/mm/gup: Simplify get_user_pages() PTE bit handling
  ...

x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps

2016-02-18T18:46:29+00:00

The protection key can now be just as important as read/write
permissions on a VMA.  We need some debug mechanism to help
figure out if it is in play.  smaps seems like a logical
place to expose it.

arch/x86/kernel/setup.c is a bit of a weirdo place to put
this code, but it already had seq_file.h and there was not
a much better existing place to put it.

We also use no #ifdef.  If protection keys is .config'd out we
will effectively get the same function as if we used the weak
generic function.

Signed-off-by: Dave Hansen 
Reviewed-by: Thomas Gleixner 
Cc: Al Viro 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Baoquan He 
Cc: Borislav Petkov 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Dave Young 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Jerome Marchand 
Cc: Jiri Kosina 
Cc: Joerg Roedel 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Konstantin Khlebnikov 
Cc: Laurent Dufour 
Cc: Linus Torvalds 
Cc: Mark Salter 
Cc: Mark Williamson 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Vlastimil Babka 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210227.4F8EB3F8@viggo.jf.intel.com
Signed-off-by: Ingo Molnar

x86/e820: Set System RAM type and descriptor

2016-01-30T08:49:57+00:00

Change e820_reserve_resources() to set 'flags' and 'desc' from
e820 types.

Set E820_RESERVED_KERN and E820_RAM's (System RAM) io resource
type to IORESOURCE_SYSTEM_RAM.

Do the same for "Kernel data", "Kernel code", and "Kernel bss",
which are child nodes of System RAM.

I/O resource descriptor is set to 'desc' for entries that are
(and will be) target ranges of walk_iomem_res() and
region_intersects().

Signed-off-by: Toshi Kani 
Signed-off-by: Borislav Petkov 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Baoquan He 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dan Williams 
Cc: Dave Young 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Jiri Kosina 
Cc: Joerg Roedel 
Cc: Juergen Gross 
Cc: Linus Torvalds 
Cc: Luis R. Rodriguez 
Cc: Mark Salter 
Cc: Paolo Bonzini 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: Toshi Kani 
Cc: WANG Chao 
Cc: linux-arch@vger.kernel.org
Cc: linux-mm 
Link: http://lkml.kernel.org/r/1453841853-11383-5-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar

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

2016-01-12T01:16:01+00:00

Pull x86 mm updates from Ingo Molnar:
 "The main changes in this cycle were:

   - make the debugfs 'kernel_page_tables' file read-only, as it only
     has read ops.  (Borislav Petkov)

   - micro-optimize clflush_cache_range() (Chris Wilson)

   - swiotlb enhancements, which fixes certain KVM emulated devices
     (Igor Mammedov)

   - fix an LDT related debug message (Jan Beulich)

   - modularize CONFIG_X86_PTDUMP (Kees Cook)

   - tone down an overly alarming warning (Laura Abbott)

   - Mark variable __initdata (Rasmus Villemoes)

   - PAT additions (Toshi Kani)"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Micro-optimise clflush_cache_range()
  x86/mm/pat: Change free_memtype() to support shrinking case
  x86/mm/pat: Add untrack_pfn_moved for mremap
  x86/mm: Drop WARN from multi-BAR check
  x86/LDT: Print the real LDT base address
  x86/mm/64: Enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN
  x86/mm: Introduce max_possible_pfn
  x86/mm/ptdump: Make (debugfs)/kernel_page_tables read-only
  x86/mm/mtrr: Mark the 'range_new' static variable in mtrr_calc_range_state() as __initdata
  x86/mm: Turn CONFIG_X86_PTDUMP into a module

x86/mm: Introduce max_possible_pfn

2015-12-06T11:46:31+00:00

max_possible_pfn will be used for tracking max possible
PFN for memory that isn't present in E820 table and
could be hotplugged later.

By default max_possible_pfn is initialized with max_pfn,
but later it could be updated with highest PFN of
hotpluggable memory ranges declared in ACPI SRAT table
if any present.

Signed-off-by: Igor Mammedov 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: akataria@vmware.com
Cc: fujita.tomonori@lab.ntt.co.jp
Cc: konrad.wilk@oracle.com
Cc: pbonzini@redhat.com
Cc: revers@redhat.com
Cc: riel@redhat.com
Link: http://lkml.kernel.org/r/1449234426-273049-2-git-send-email-imammedo@redhat.com
Signed-off-by: Ingo Molnar

x86/microcode: Initialize the driver late when facilities are up

2015-11-23T09:39:49+00:00

Running microcode_init() from setup_arch() is a bad idea because
not even kmalloc() is ready at that point and the loader does
all kinds of allocations and init/registration with various
subsystems.

Make it a late initcall when required facilities are initialized
so that the microcode driver initialization can succeed too.

Reported-and-tested-by: Markus Trippelsdorf 
Signed-off-by: Borislav Petkov 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20151120112400.GC4028@pd.tnic
Signed-off-by: Ingo Molnar