1. 08 5月, 2015 1 次提交
  2. 18 4月, 2015 1 次提交
  3. 15 4月, 2015 5 次提交
    • V
      mm: move memtest under mm · 4a20799d
      Vladimir Murzin 提交于
      Memtest is a simple feature which fills the memory with a given set of
      patterns and validates memory contents, if bad memory regions is detected
      it reserves them via memblock API.  Since memblock API is widely used by
      other architectures this feature can be enabled outside of x86 world.
      
      This patch set promotes memtest to live under generic mm umbrella and
      enables memtest feature for arm/arm64.
      
      It was reported that this patch set was useful for tracking down an issue
      with some errant DMA on an arm64 platform.
      
      This patch (of 6):
      
      There is nothing platform dependent in the core memtest code, so other
      platforms might benefit from this feature too.
      
      [linux@roeck-us.net: MEMTEST depends on MEMBLOCK]
      Signed-off-by: NVladimir Murzin <vladimir.murzin@arm.com>
      Acked-by: NWill Deacon <will.deacon@arm.com>
      Tested-by: NMark Rutland <mark.rutland@arm.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Paul Bolle <pebolle@tiscali.nl>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4a20799d
    • K
      mm: split ET_DYN ASLR from mmap ASLR · d1fd836d
      Kees Cook 提交于
      This fixes the "offset2lib" weakness in ASLR for arm, arm64, mips,
      powerpc, and x86.  The problem is that if there is a leak of ASLR from
      the executable (ET_DYN), it means a leak of shared library offset as
      well (mmap), and vice versa.  Further details and a PoC of this attack
      is available here:
      
        http://cybersecurity.upv.es/attacks/offset2lib/offset2lib.html
      
      With this patch, a PIE linked executable (ET_DYN) has its own ASLR
      region:
      
        $ ./show_mmaps_pie
        54859ccd6000-54859ccd7000 r-xp  ...  /tmp/show_mmaps_pie
        54859ced6000-54859ced7000 r--p  ...  /tmp/show_mmaps_pie
        54859ced7000-54859ced8000 rw-p  ...  /tmp/show_mmaps_pie
        7f75be764000-7f75be91f000 r-xp  ...  /lib/x86_64-linux-gnu/libc.so.6
        7f75be91f000-7f75beb1f000 ---p  ...  /lib/x86_64-linux-gnu/libc.so.6
        7f75beb1f000-7f75beb23000 r--p  ...  /lib/x86_64-linux-gnu/libc.so.6
        7f75beb23000-7f75beb25000 rw-p  ...  /lib/x86_64-linux-gnu/libc.so.6
        7f75beb25000-7f75beb2a000 rw-p  ...
        7f75beb2a000-7f75beb4d000 r-xp  ...  /lib64/ld-linux-x86-64.so.2
        7f75bed45000-7f75bed46000 rw-p  ...
        7f75bed46000-7f75bed47000 r-xp  ...
        7f75bed47000-7f75bed4c000 rw-p  ...
        7f75bed4c000-7f75bed4d000 r--p  ...  /lib64/ld-linux-x86-64.so.2
        7f75bed4d000-7f75bed4e000 rw-p  ...  /lib64/ld-linux-x86-64.so.2
        7f75bed4e000-7f75bed4f000 rw-p  ...
        7fffb3741000-7fffb3762000 rw-p  ...  [stack]
        7fffb377b000-7fffb377d000 r--p  ...  [vvar]
        7fffb377d000-7fffb377f000 r-xp  ...  [vdso]
      
      The change is to add a call the newly created arch_mmap_rnd() into the
      ELF loader for handling ET_DYN ASLR in a separate region from mmap ASLR,
      as was already done on s390.  Removes CONFIG_BINFMT_ELF_RANDOMIZE_PIE,
      which is no longer needed.
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Reported-by: NHector Marco-Gisbert <hecmargi@upv.es>
      Cc: Russell King <linux@arm.linux.org.uk>
      Reviewed-by: NIngo Molnar <mingo@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: "David A. Long" <dave.long@linaro.org>
      Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
      Cc: Arun Chandran <achandran@mvista.com>
      Cc: Yann Droneaud <ydroneaud@opteya.com>
      Cc: Min-Hua Chen <orca.chen@gmail.com>
      Cc: Paul Burton <paul.burton@imgtec.com>
      Cc: Alex Smith <alex@alex-smith.me.uk>
      Cc: Markos Chandras <markos.chandras@imgtec.com>
      Cc: Vineeth Vijayan <vvijayan@mvista.com>
      Cc: Jeff Bailey <jeffbailey@google.com>
      Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
      Cc: Ben Hutchings <ben@decadent.org.uk>
      Cc: Behan Webster <behanw@converseincode.com>
      Cc: Ismael Ripoll <iripoll@upv.es>
      Cc: Jan-Simon Mller <dl9pf@gmx.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d1fd836d
    • K
      mm: expose arch_mmap_rnd when available · 2b68f6ca
      Kees Cook 提交于
      When an architecture fully supports randomizing the ELF load location,
      a per-arch mmap_rnd() function is used to find a randomized mmap base.
      In preparation for randomizing the location of ET_DYN binaries
      separately from mmap, this renames and exports these functions as
      arch_mmap_rnd(). Additionally introduces CONFIG_ARCH_HAS_ELF_RANDOMIZE
      for describing this feature on architectures that support it
      (which is a superset of ARCH_BINFMT_ELF_RANDOMIZE_PIE, since s390
      already supports a separated ET_DYN ASLR from mmap ASLR without the
      ARCH_BINFMT_ELF_RANDOMIZE_PIE logic).
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Cc: Hector Marco-Gisbert <hecmargi@upv.es>
      Cc: Russell King <linux@arm.linux.org.uk>
      Reviewed-by: NIngo Molnar <mingo@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: "David A. Long" <dave.long@linaro.org>
      Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
      Cc: Arun Chandran <achandran@mvista.com>
      Cc: Yann Droneaud <ydroneaud@opteya.com>
      Cc: Min-Hua Chen <orca.chen@gmail.com>
      Cc: Paul Burton <paul.burton@imgtec.com>
      Cc: Alex Smith <alex@alex-smith.me.uk>
      Cc: Markos Chandras <markos.chandras@imgtec.com>
      Cc: Vineeth Vijayan <vvijayan@mvista.com>
      Cc: Jeff Bailey <jeffbailey@google.com>
      Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
      Cc: Ben Hutchings <ben@decadent.org.uk>
      Cc: Behan Webster <behanw@converseincode.com>
      Cc: Ismael Ripoll <iripoll@upv.es>
      Cc: Jan-Simon Mller <dl9pf@gmx.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2b68f6ca
    • T
      x86, mm: support huge KVA mappings on x86 · 6b637835
      Toshi Kani 提交于
      Implement huge KVA mapping interfaces on x86.
      
      On x86, MTRRs can override PAT memory types with a 4KB granularity.  When
      using a huge page, MTRRs can override the memory type of the huge page,
      which may lead a performance penalty.  The processor can also behave in an
      undefined manner if a huge page is mapped to a memory range that MTRRs
      have mapped with multiple different memory types.  Therefore, the mapping
      code falls back to use a smaller page size toward 4KB when a mapping range
      is covered by non-WB type of MTRRs.  The WB type of MTRRs has no affect on
      the PAT memory types.
      
      pud_set_huge() and pmd_set_huge() call mtrr_type_lookup() to see if a
      given range is covered by MTRRs.  MTRR_TYPE_WRBACK indicates that the
      range is either covered by WB or not covered and the MTRR default value is
      set to WB.  0xFF indicates that MTRRs are disabled.
      
      HAVE_ARCH_HUGE_VMAP is selected when X86_64 or X86_32 with X86_PAE is set.
       X86_32 without X86_PAE is not supported since such config can unlikey be
      benefited from this feature, and there was an issue found in testing.
      
      [fengguang.wu@intel.com: ioremap_pud_capable can be static]
      Signed-off-by: NToshi Kani <toshi.kani@hp.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Robert Elliott <Elliott@hp.com>
      Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6b637835
    • K
      x86: expose number of page table levels on Kconfig level · 98233368
      Kirill A. Shutemov 提交于
      We would want to use number of page table level to define mm_struct.
      Let's expose it as CONFIG_PGTABLE_LEVELS.
      Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Tested-by: NGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      98233368
  4. 01 4月, 2015 1 次提交
  5. 25 3月, 2015 1 次提交
  6. 13 3月, 2015 1 次提交
  7. 06 3月, 2015 1 次提交
  8. 05 3月, 2015 2 次提交
    • I
      x86/mm: Further simplify 1 GB kernel linear mappings handling · 10971ab2
      Ingo Molnar 提交于
      It's a bit pointless to allow Kconfig configuration for 1GB kernel
      mappings, it's already hidden behind a 'default y' and CONFIG_EXPERT.
      
      Remove this complication and simplify the code by renaming
      CONFIG_ENABLE_DIRECT_GBPAGES to CONFIG_X86_DIRECT_GBPAGES and
      document the DEBUG_PAGE_ALLOC and KMEMCHECK quirks.
      
      Cc: Luis R. Rodriguez <mcgrof@suse.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: David Vrabel <david.vrabel@citrix.com>
      Cc: Dexuan Cui <decui@microsoft.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: JBeulich@suse.com
      Cc: Jan Beulich <JBeulich@suse.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Juergen Gross <jgross@suse.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tony Lindgren <tony@atomide.com>
      Cc: Toshi Kani <toshi.kani@hp.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Xishi Qiu <qiuxishi@huawei.com>
      Cc: julia.lawall@lip6.fr
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      10971ab2
    • L
      x86/mm: Simplify enabling direct_gbpages · e5008abe
      Luis R. Rodriguez 提交于
      direct_gbpages can be force enabled as an early parameter
      but not really have taken effect when DEBUG_PAGEALLOC
      or KMEMCHECK is enabled. You can also enable direct_gbpages
      right now if you have an x86_64 architecture but your CPU
      doesn't really have support for this feature. In both cases
      PG_LEVEL_1G won't actually be enabled but direct_gbpages is used
      in other areas under the assumptions that PG_LEVEL_1G
      was set. Fix this by putting together all requirements
      which make this feature sensible to enable under, and only
      enable both finally flipping on PG_LEVEL_1G and leaving
      PG_LEVEL_1G set when this is true.
      
      We only enable this feature then to be possible on sensible
      builds defined by the new ENABLE_DIRECT_GBPAGES. If the
      CPU has support for it you can either enable this by using
      the DIRECT_GBPAGES option or using the early kernel parameter.
      If a platform had support for this you can always force disable
      it as well.
      Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: David Vrabel <david.vrabel@citrix.com>
      Cc: Dexuan Cui <decui@microsoft.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: JBeulich@suse.com
      Cc: Jan Beulich <JBeulich@suse.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Juergen Gross <jgross@suse.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tony Lindgren <tony@atomide.com>
      Cc: Toshi Kani <toshi.kani@hp.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Xishi Qiu <qiuxishi@huawei.com>
      Cc: julia.lawall@lip6.fr
      Link: http://lkml.kernel.org/r/1425518654-3403-3-git-send-email-mcgrof@do-not-panic.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      e5008abe
  9. 19 2月, 2015 4 次提交
  10. 14 2月, 2015 1 次提交
    • A
      x86_64: add KASan support · ef7f0d6a
      Andrey Ryabinin 提交于
      This patch adds arch specific code for kernel address sanitizer.
      
      16TB of virtual addressed used for shadow memory.  It's located in range
      [ffffec0000000000 - fffffc0000000000] between vmemmap and %esp fixup
      stacks.
      
      At early stage we map whole shadow region with zero page.  Latter, after
      pages mapped to direct mapping address range we unmap zero pages from
      corresponding shadow (see kasan_map_shadow()) and allocate and map a real
      shadow memory reusing vmemmap_populate() function.
      
      Also replace __pa with __pa_nodebug before shadow initialized.  __pa with
      CONFIG_DEBUG_VIRTUAL=y make external function call (__phys_addr)
      __phys_addr is instrumented, so __asan_load could be called before shadow
      area initialized.
      Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Konstantin Serebryany <kcc@google.com>
      Cc: Dmitry Chernenkov <dmitryc@google.com>
      Signed-off-by: NAndrey Konovalov <adech.fo@gmail.com>
      Cc: Yuri Gribov <tetra2005@gmail.com>
      Cc: Konstantin Khlebnikov <koct9i@gmail.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Jim Davis <jim.epost@gmail.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ef7f0d6a
  11. 06 2月, 2015 1 次提交
  12. 04 2月, 2015 1 次提交
  13. 24 1月, 2015 1 次提交
  14. 23 1月, 2015 1 次提交
  15. 22 1月, 2015 1 次提交
  16. 20 1月, 2015 1 次提交
  17. 07 1月, 2015 1 次提交
    • P
      rcu: Make SRCU optional by using CONFIG_SRCU · 83fe27ea
      Pranith Kumar 提交于
      SRCU is not necessary to be compiled by default in all cases. For tinification
      efforts not compiling SRCU unless necessary is desirable.
      
      The current patch tries to make compiling SRCU optional by introducing a new
      Kconfig option CONFIG_SRCU which is selected when any of the components making
      use of SRCU are selected.
      
      If we do not select CONFIG_SRCU, srcu.o will not be compiled at all.
      
         text    data     bss     dec     hex filename
         2007       0       0    2007     7d7 kernel/rcu/srcu.o
      
      Size of arch/powerpc/boot/zImage changes from
      
         text    data     bss     dec     hex filename
       831552   64180   23944  919676   e087c arch/powerpc/boot/zImage : before
       829504   64180   23952  917636   e0084 arch/powerpc/boot/zImage : after
      
      so the savings are about ~2000 bytes.
      Signed-off-by: NPranith Kumar <bobby.prani@gmail.com>
      CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      CC: Josh Triplett <josh@joshtriplett.org>
      CC: Lai Jiangshan <laijs@cn.fujitsu.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      [ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
      83fe27ea
  18. 22 12月, 2014 1 次提交
  19. 16 12月, 2014 2 次提交
  20. 15 12月, 2014 1 次提交
  21. 14 12月, 2014 1 次提交
  22. 18 11月, 2014 1 次提交
    • Q
      x86, mpx: Add MPX-specific mmap interface · 57319d80
      Qiaowei Ren 提交于
      We have chosen to perform the allocation of bounds tables in
      kernel (See the patch "on-demand kernel allocation of bounds
      tables") and to mark these VMAs with VM_MPX.
      
      However, there is currently no suitable interface to actually do
      this.  Existing interfaces, like do_mmap_pgoff(), have no way to
      set a modified ->vm_ops or ->vm_flags and don't hold mmap_sem
      long enough to let a caller do it.
      
      This patch wraps mmap_region() and hold mmap_sem long enough to
      make the modifications to the VMA which we need.
      
      Also note the 32/64-bit #ifdef in the header.  We actually need
      to do this at runtime eventually.  But, for now, we don't support
      running 32-bit binaries on 64-bit kernels.  Support for this will
      come in later patches.
      Signed-off-by: NQiaowei Ren <qiaowei.ren@intel.com>
      Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
      Cc: linux-mm@kvack.org
      Cc: linux-mips@linux-mips.org
      Cc: Dave Hansen <dave@sr71.net>
      Link: http://lkml.kernel.org/r/20141114151827.CE440F67@viggo.jf.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      57319d80
  23. 04 11月, 2014 2 次提交
  24. 28 10月, 2014 1 次提交
  25. 10 10月, 2014 1 次提交
    • M
      mm: remove misleading ARCH_USES_NUMA_PROT_NONE · 6a33979d
      Mel Gorman 提交于
      ARCH_USES_NUMA_PROT_NONE was defined for architectures that implemented
      _PAGE_NUMA using _PROT_NONE.  This saved using an additional PTE bit and
      relied on the fact that PROT_NONE vmas were skipped by the NUMA hinting
      fault scanner.  This was found to be conceptually confusing with a lot of
      implicit assumptions and it was asked that an alternative be found.
      
      Commit c46a7c81 "x86: define _PAGE_NUMA by reusing software bits on the
      PMD and PTE levels" redefined _PAGE_NUMA on x86 to be one of the swap PTE
      bits and shrunk the maximum possible swap size but it did not go far
      enough.  There are no architectures that reuse _PROT_NONE as _PROT_NUMA
      but the relics still exist.
      
      This patch removes ARCH_USES_NUMA_PROT_NONE and removes some unnecessary
      duplication in powerpc vs the generic implementation by defining the types
      the core NUMA helpers expected to exist from x86 with their ppc64
      equivalent.  This necessitated that a PTE bit mask be created that
      identified the bits that distinguish present from NUMA pte entries but it
      is expected this will only differ between arches based on _PAGE_PROTNONE.
      The naming for the generic helpers was taken from x86 originally but ppc64
      has types that are equivalent for the purposes of the helper so they are
      mapped instead of duplicating code.
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6a33979d
  26. 19 9月, 2014 2 次提交
  27. 14 9月, 2014 1 次提交
    • L
      Make ARCH_HAS_FAST_MULTIPLIER a real config variable · 72d93104
      Linus Torvalds 提交于
      It used to be an ad-hoc hack defined by the x86 version of
      <asm/bitops.h> that enabled a couple of library routines to know whether
      an integer multiply is faster than repeated shifts and additions.
      
      This just makes it use the real Kconfig system instead, and makes x86
      (which was the only architecture that did this) select the option.
      
      NOTE! Even for x86, this really is kind of wrong.  If we cared, we would
      probably not enable this for builds optimized for netburst (P4), where
      shifts-and-adds are generally faster than multiplies.  This patch does
      *not* change that kind of logic, though, it is purely a syntactic change
      with no code changes.
      
      This was triggered by the fact that we have other places that really
      want to know "do I want to expand multiples by constants by hand or
      not", particularly the hash generation code.
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      72d93104
  28. 30 8月, 2014 1 次提交
    • V
      kexec: create a new config option CONFIG_KEXEC_FILE for new syscall · 74ca317c
      Vivek Goyal 提交于
      Currently new system call kexec_file_load() and all the associated code
      compiles if CONFIG_KEXEC=y.  But new syscall also compiles purgatory
      code which currently uses gcc option -mcmodel=large.  This option seems
      to be available only gcc 4.4 onwards.
      
      Hiding new functionality behind a new config option will not break
      existing users of old gcc.  Those who wish to enable new functionality
      will require new gcc.  Having said that, I am trying to figure out how
      can I move away from using -mcmodel=large but that can take a while.
      
      I think there are other advantages of introducing this new config
      option.  As this option will be enabled only on x86_64, other arches
      don't have to compile generic kexec code which will never be used.  This
      new code selects CRYPTO=y and CRYPTO_SHA256=y.  And all other arches had
      to do this for CONFIG_KEXEC.  Now with introduction of new config
      option, we can remove crypto dependency from other arches.
      
      Now CONFIG_KEXEC_FILE is available only on x86_64.  So whereever I had
      CONFIG_X86_64 defined, I got rid of that.
      
      For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to
      "depends on CRYPTO=y".  This should be safer as "select" is not
      recursive.
      Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
      Cc: Eric Biederman <ebiederm@xmission.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Tested-by: NShaun Ruffell <sruffell@digium.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      74ca317c
  29. 28 8月, 2014 1 次提交