1. 09 May, 2017 1 commit
  2. 19 Apr, 2017 1 commit
  3. 17 Apr, 2017 1 commit
  4. 30 Mar, 2017 1 commit
    • Josh Poimboeuf's avatar
      x86/build: Mostly disable '-maccumulate-outgoing-args' · 3f135e57
      Josh Poimboeuf authored
      
      
      The GCC '-maccumulate-outgoing-args' flag is enabled for most configs,
      mostly because of issues which are no longer relevant.  For most
      configs, and with most recent versions of GCC, it's no longer needed.
      
      Clarify which cases need it, and only enable it for those cases.  Also
      produce a compile-time error for the ftrace graph + mcount + '-Os' case,
      which will otherwise cause runtime failures.
      
      The main benefit of '-maccumulate-outgoing-args' is that it prevents an
      ugly prologue for functions which have aligned stacks.  But removing the
      option also has some benefits: more readable argument saves, smaller
      text size, and (presumably) slightly improved performance.
      
      Here are the object size savings for 32-bit and 64-bit defconfig
      kernels:
      
            text	   data	    bss	     dec	    hex	filename
        10006710	3543328	1773568	15323606	 e9d1d6	vmlinux.x86-32.before
         9706358	3547424	1773568	15027350	 e54c96	vmlinux.x86-32.after
      
            text	   data	    bss	     dec	    hex	filename
        10652105	4537576	 843776	16033457	 f4a6b1	vmlinux.x86-64.before
        10639629	4537576	 843776	16020981	 f475f5	vmlinux.x86-64.after
      
      That comes out to a 3% text size improvement on x86-32 and a 0.1% text
      size improvement on x86-64.
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Andrew Lutomirski <luto@kernel.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20170316193133.zrj6gug53766m6nn@treble
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      3f135e57
  5. 21 Sep, 2016 1 commit
  6. 26 Jul, 2016 2 commits
    • Kees Cook's avatar
      kbuild: abort build on bad stack protector flag · c965b105
      Kees Cook authored
      Before, the stack protector flag was sanity checked before .config had
      been reprocessed.  This meant the build couldn't be aborted early, and
      only a warning could be emitted followed later by the compiler blowing
      up with an unknown flag.  This has caused a lot of confusion over time,
      so this splits the flag selection from sanity checking and performs the
      sanity checking after the make has been restarted from a reprocessed
      .config, so builds can be aborted as early as possible now.
      
      Additionally moves the x86-specific sanity check to the same location,
      since it suffered from the same warn-then-wait-for-compiler-failure
      problem.
      
      Link: http://lkml.kernel.org/r/20160712223043.GA11664@www.outflux.net
      
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Michal Marek <mmarek@suse.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c965b105
    • Kees Cook's avatar
      kbuild: Abort build on bad stack protector flag · 228d96c6
      Kees Cook authored
      
      
      Before, the stack protector flag was sanity checked before .config had
      been reprocessed. This meant the build couldn't be aborted early, and
      only a warning could be emitted followed later by the compiler blowing
      up with an unknown flag. This has caused a lot of confusion over time,
      so this splits the flag selection from sanity checking and performs the
      sanity checking after the make has been restarted from a reprocessed
      .config, so builds can be aborted as early as possible now.
      
      Additionally moves the x86-specific sanity check to the same location,
      since it suffered from the same warn-then-wait-for-compiler-failure
      problem.
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
      228d96c6
  7. 22 Apr, 2016 2 commits
    • Luis R. Rodriguez's avatar
      x86/init: Rename EBDA code file · f2d85299
      Luis R. Rodriguez authored
      
      
      This makes it clearer what this is.
      Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: andrew.cooper3@citrix.com
      Cc: andriy.shevchenko@linux.intel.com
      Cc: bigeasy@linutronix.de
      Cc: boris.ostrovsky@oracle.com
      Cc: david.vrabel@citrix.com
      Cc: ffainelli@freebox.fr
      Cc: george.dunlap@citrix.com
      Cc: glin@suse.com
      Cc: jgross@suse.com
      Cc: jlee@suse.com
      Cc: josh@joshtriplett.org
      Cc: julien.grall@linaro.org
      Cc: konrad.wilk@oracle.com
      Cc: kozerkov@parallels.com
      Cc: lenb@kernel.org
      Cc: lguest@lists.ozlabs.org
      Cc: linux-acpi@vger.kernel.org
      Cc: lv.zheng@intel.com
      Cc: matt@codeblueprint.co.uk
      Cc: mbizon@freebox.fr
      Cc: rjw@rjwysocki.net
      Cc: robert.moore@intel.com
      Cc: rusty@rustcorp.com.au
      Cc: tiwai@suse.de
      Cc: toshi.kani@hp.com
      Cc: xen-devel@lists.xensource.com
      Link: http://lkml.kernel.org/r/1460592286-300-14-git-send-email-mcgrof@kernel.org
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      f2d85299
    • Luis R. Rodriguez's avatar
      x86/rtc: Replace paravirt rtc check with platform legacy quirk · 8d152e7a
      Luis R. Rodriguez authored
      
      
      We have 4 types of x86 platforms that disable RTC:
      
        * Intel MID
        * Lguest - uses paravirt
        * Xen dom-U - uses paravirt
        * x86 on legacy systems annotated with an ACPI legacy flag
      
      We can consolidate all of these into a platform specific legacy
      quirk set early in boot through i386_start_kernel() and through
      x86_64_start_reservations(). This deals with the RTC quirks which
      we can rely on through the hardware subarch, the ACPI check can
      be dealt with separately.
      
      For Xen things are bit more complex given that the @X86_SUBARCH_XEN
      x86_hardware_subarch is shared on for Xen which uses the PV path for
      both domU and dom0. Since the semantics for differentiating between
      the two are Xen specific we provide a platform helper to help override
      default legacy features -- x86_platform.set_legacy_features(). Use
      of this helper is highly discouraged, its only purpose should be
      to account for the lack of semantics available within your given
      x86_hardware_subarch.
      
      As per 0-day, this bumps the vmlinux size using i386-tinyconfig as
      follows:
      
      TOTAL   TEXT   init.text    x86_early_init_platform_quirks()
      +70     +62    +62          +43
      
      Only 8 bytes overhead total, as the main increase in size is
      all removed via __init.
      Suggested-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
      Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: andrew.cooper3@citrix.com
      Cc: andriy.shevchenko@linux.intel.com
      Cc: bigeasy@linutronix.de
      Cc: boris.ostrovsky@oracle.com
      Cc: david.vrabel@citrix.com
      Cc: ffainelli@freebox.fr
      Cc: george.dunlap@citrix.com
      Cc: glin@suse.com
      Cc: jlee@suse.com
      Cc: josh@joshtriplett.org
      Cc: julien.grall@linaro.org
      Cc: konrad.wilk@oracle.com
      Cc: kozerkov@parallels.com
      Cc: lenb@kernel.org
      Cc: lguest@lists.ozlabs.org
      Cc: linux-acpi@vger.kernel.org
      Cc: lv.zheng@intel.com
      Cc: matt@codeblueprint.co.uk
      Cc: mbizon@freebox.fr
      Cc: rjw@rjwysocki.net
      Cc: robert.moore@intel.com
      Cc: rusty@rustcorp.com.au
      Cc: tiwai@suse.de
      Cc: toshi.kani@hp.com
      Cc: xen-devel@lists.xensource.com
      Link: http://lkml.kernel.org/r/1460592286-300-5-git-send-email-mcgrof@kernel.org
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      8d152e7a
  8. 09 Oct, 2015 1 commit
  9. 21 Sep, 2015 1 commit
  10. 13 Aug, 2015 1 commit
  11. 22 Jul, 2015 1 commit
  12. 04 Jun, 2015 1 commit
    • Ingo Molnar's avatar
      x86/asm/entry: Move the arch/x86/syscalls/ definitions to arch/x86/entry/syscalls/ · 1f57d5d8
      Ingo Molnar authored
      
      
      The build time generated syscall definitions are entry code related, move
      them into the arch/x86/entry/ directory.
      
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      1f57d5d8
  13. 03 Jun, 2015 1 commit
    • Ingo Molnar's avatar
      x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/ · d603c8e1
      Ingo Molnar authored
      
      
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      d603c8e1
  14. 02 Jun, 2015 1 commit
    • Ingo Molnar's avatar
      x86/debug: Remove perpetually broken, unmaintainable dwarf annotations · 131484c8
      Ingo Molnar authored
      
      
      So the dwarf2 annotations in low level assembly code have
      become an increasing hindrance: unreadable, messy macros
      mixed into some of the most security sensitive code paths
      of the Linux kernel.
      
      These debug info annotations don't even buy the upstream
      kernel anything: dwarf driven stack unwinding has caused
      problems in the past so it's out of tree, and the upstream
      kernel only uses the much more robust framepointers based
      stack unwinding method.
      
      In addition to that there's a steady, slow bitrot going
      on with these annotations, requiring frequent fixups.
      There's no tooling and no functionality upstream that
      keeps it correct.
      
      So burn down the sick forest, allowing new, healthier growth:
      
         27 files changed, 350 insertions(+), 1101 deletions(-)
      
      Someone who has the willingness and time to do this
      properly can attempt to reintroduce dwarf debuginfo in x86
      assembly code plus dwarf unwinding from first principles,
      with the following conditions:
      
       - it should be maximally readable, and maximally low-key to
         'ordinary' code reading and maintenance.
      
       - find a build time method to insert dwarf annotations
         automatically in the most common cases, for pop/push
         instructions that manipulate the stack pointer. This could
         be done for example via a preprocessing step that just
         looks for common patterns - plus special annotations for
         the few cases where we want to depart from the default.
         We have hundreds of CFI annotations, so automating most of
         that makes sense.
      
       - it should come with build tooling checks that ensure that
         CFI annotations are sensible. We've seen such efforts from
         the framepointer side, and there's no reason it couldn't be
         done on the dwarf side.
      
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Frédéric Weisbecker <fweisbec@gmail.com
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Jan Beulich <JBeulich@suse.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      131484c8
  15. 17 May, 2015 1 commit
    • Ingo Molnar's avatar
      x86: Pack loops tightly as well · 52648e83
      Ingo Molnar authored
      Packing loops tightly (-falign-loops=1) is beneficial to code size:
      
           text        data    bss     dec              filename
       12566391        1617840 1089536 15273767         vmlinux.align.16-byte
       12224951        1617840 1089536 14932327         vmlinux.align.1-byte
       11976567        1617840 1089536 14683943         vmlinux.align.1-byte.funcs-1-byte
       11903735        1617840 1089536 14611111         vmlinux.align.1-byte.funcs-1-byte.loops-1-byte
      
      Which reduces the size of the kernel by another 0.6%, so the
      the total combined size reduction of the alignment-packing
      patches is ~5.5%.
      
      The x86 decoder bandwidth and caching arguments laid out in:
      
        be6cb027
      
       ("x86: Align jump targets to 1-byte boundaries")
      
      apply to loop alignment as well.
      
      Furtermore, modern CPU uarchs have a loop cache/buffer that
      is a L0 cache before even any uop cache, covering a few
      dozen most recently executed instructions.
      
      This loop cache generally does not have the 16-byte alignment
      restrictions of the uop cache.
      
      Now loop alignment can still be beneficial if:
      
       - a loop is cache-hot and its surroundings are not.
      
       - if the loop is so cache hot that the instruction
         flow becomes x86 decoder bandwidth limited
      
      But loop alignment is harmful if:
      
       - a loop is cache-cold
      
       - a loop's surroundings are cache-hot as well
      
       - two cache-hot loops are close to each other
      
       - if the loop fits into the loop cache
      
       - if the code flow is not decoder bandwidth limited
      
      and I'd argue that the latter five scenarios are much
      more common in the kernel, as our hottest loops are
      typically:
      
       - pointer chasing: this should fit into the loop cache
         in most cases and is typically data cache and address
         generation limited
      
       - generic memory ops (memset, memcpy, etc.): these generally
         fit into the loop cache as well, and are likewise data
         cache limited.
      
      So this patch packs loop addresses tightly as well.
      Acked-by: default avatarDenys Vlasenko <dvlasenk@redhat.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Aswin Chandramouleeswaran <aswin@hp.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Jason Low <jason.low2@hp.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Link: http://lkml.kernel.org/r/20150410123017.GB19918@gmail.com
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      52648e83
  16. 15 May, 2015 1 commit
    • Ingo Molnar's avatar
      x86: Align jump targets to 1-byte boundaries · be6cb027
      Ingo Molnar authored
      
      
      The following NOP in a hot function caught my attention:
      
        >   5a:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
      
      That's a dead NOP that bloats the function a bit, added for the
      default 16-byte alignment that GCC applies for jump targets.
      
      I realize that x86 CPU manufacturers recommend 16-byte jump
      target alignments (it's in the Intel optimization manual),
      to help their relatively narrow decoder prefetch alignment
      and uop cache constraints, but the cost of that is very
      significant:
      
              text           data       bss         dec      filename
          12566391        1617840   1089536    15273767      vmlinux.align.16-byte
          12224951        1617840   1089536    14932327      vmlinux.align.1-byte
      
      By using 1-byte jump target alignment (i.e. no alignment at all)
      we get an almost 3% reduction in kernel size (!) - and a
      probably similar reduction in I$ footprint.
      
      Now, the usual justification for jump target alignment is the
      following:
      
       - modern decoders tend to have 16-byte (effective) decoder
         prefetch windows. (AMD documents it higher but measurements
         suggest the effective prefetch window on curretn uarchs is
         still around 16 bytes)
      
       - on Intel there's also the uop-cache with cachelines that have
         16-byte granularity and limited associativity.
      
       - older x86 uarchs had a penalty for decoder fetches that crossed
         16-byte boundaries. These limits are mostly gone from recent
         uarchs.
      
      So if a forward jump target is aligned to cacheline boundary then
      prefetches will start from a new prefetch-cacheline and there's
      higher chance for decoding in fewer steps and packing tightly.
      
      But I think that argument is flawed for typical optimized kernel
      code flows: forward jumps often go to 'cold' (uncommon) pieces
      of code, and  aligning cold code to cache lines does not bring a
      lot of advantages  (they are uncommon), while it causes
      collateral damage:
      
       - their alignment 'spreads out' the cache footprint, it shifts
         followup hot code further out
      
       - plus it slows down even 'cold' code that immediately follows 'hot'
         code (like in the above case), which could have benefited from the
         partial cacheline that comes off the end of hot code.
      
      But even in the cache-hot case the 16 byte alignment brings
      disadvantages:
      
       - it spreads out the cache footprint, possibly making the code
         fall out of the L1 I$.
      
       - On Intel CPUs, recent microarchitectures have plenty of
         uop cache (typically doubling every 3 years) - while the
         size of the L1 cache grows much less aggressively. So
         workloads are rarely uop cache limited.
      
      The only situation where alignment might matter are tight
      loops that could fit into a single 16 byte chunk - but those
      are pretty rare in the kernel: if they exist they tend
      to be pointer chasing or generic memory ops, which both tend
      to be cache miss (or cache allocation) intensive and are not
      decoder bandwidth limited.
      
      So the balance of arguments strongly favors packing kernel
      instructions tightly versus maximizing for decoder bandwidth:
      this patch changes the jump target alignment from 16 bytes
      to 1 byte (tightly packed, unaligned).
      Acked-by: default avatarDenys Vlasenko <dvlasenk@redhat.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Aswin Chandramouleeswaran <aswin@hp.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Jason Low <jason.low2@hp.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Link: http://lkml.kernel.org/r/20150410120846.GA17101@gmail.com
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      be6cb027
  17. 06 May, 2015 1 commit
    • H.J. Lu's avatar
      x86/asm: Use -mskip-rax-setup if supported · d9ee948d
      H.J. Lu authored
      
      
      GCC 5 added a compiler option, -mskip-rax-setup, for x86-64. It skips
      setting up the RAX register when SSE is disabled and there are no
      variable arguments passed in vector registers. (According to the x86_64
      ABI, %al is used as a hidden register containing the number of vector
      registers used).
      
      Since the kernel doesn't pass vector registers to functions with
      variable arguments, this option can be used to optimize the x86-64
      kernel.
      
      This GCC feature was suggested by Rasmus Villemoes <linux@rasmusvillemoes.dk>.
      This is the corresponding kernel change using it.
      
      For kernel v3.17:
      
            text   data    bss    dec       filename
        11455921 2204048 5853184 19513153   vmlinux #with -mskip-rax-setup
        11480079 2204048 5853184 19537311   vmlinux
      
      For Kernel v4.0+ - custom config:
      
            text   data    bss    dec       filename
        10231778 3479800 16617472 30329050  vmlinux-gcc5+-mskip-rax-setup
        10268797 3547448 16621568 30437813  vmlinux
      Signed-off-by: default avatarH.J. Lu <hjl.tools@gmail.com>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      d9ee948d
  18. 02 Apr, 2015 1 commit
  19. 03 Feb, 2015 1 commit
  20. 16 Sep, 2014 1 commit
  21. 29 Aug, 2014 2 commits
  22. 08 Aug, 2014 2 commits
    • Josh Triplett's avatar
      x86, platform, kconfig: move kvmconfig functionality to a helper · 3aaefce1
      Josh Triplett authored
      
      
      The new mergeconfig helper makes it easier to add other partial
      configurations similar to kvmconfig.  Architecture-independent portions
      of those partial configurations should go in
      kernel/configs/${name}.config, and architecture-dependent portions
      should go in arch/${arch}/configs/${name}.config.
      
      Based on a patch by Luis R. Rodriguez <mcgrof@suse.com>.
      Originally-Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
      
      Modified to make the helper name more general than just virtualization,
      support architecture-dependent and architecture-independent partial
      configurations, move the helper and kvmconfig to
      scripts/kconfig/Makefile, and factor out more of the common file path.
      Signed-off-by: default avatarJosh Triplett <josh@joshtriplett.org>
      3aaefce1
    • Vivek Goyal's avatar
      purgatory: core purgatory functionality · 8fc5b4d4
      Vivek Goyal authored
      
      
      Create a stand alone relocatable object purgatory which runs between two
      kernels.  This name, concept and some code has been taken from
      kexec-tools.  Idea is that this code runs after a crash and it runs in
      minimal environment.  So keep it separate from rest of the kernel and in
      long term we will have to practically do no maintenance of this code.
      
      This code also has the logic to do verify sha256 hashes of various
      segments which have been loaded into memory.  So first we verify that the
      kernel we are jumping to is fine and has not been corrupted and make
      progress only if checsums are verified.
      
      This code also takes care of copying some memory contents to backup region.
      
      [sfr@canb.auug.org.au: run host built programs from objtree]
      Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Eric Biederman <ebiederm@xmission.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Matthew Garrett <mjg59@srcf.ucam.org>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: WANG Chao <chaowang@redhat.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8fc5b4d4
  23. 04 Jun, 2014 1 commit
  24. 07 May, 2014 1 commit
  25. 22 Apr, 2014 1 commit
  26. 14 Apr, 2014 1 commit
  27. 09 Apr, 2014 1 commit
  28. 19 Mar, 2014 1 commit
  29. 05 Feb, 2014 1 commit
    • Borislav Petkov's avatar
      x86: Disable generation of traditional x87 instructions · b399fe35
      Borislav Petkov authored
      
      
      We recently had the case where wrongly used floating-constant 'E' caused
      the generation of traditional x87 instructions in kernel code and
      wreaking all kinds of havoc.
      
      Disable the generation of those too. This will save people a lot of time
      when trying to debug such issues by erroring out of the build instead of
      let them manifest themselves in very spectacular and happy-crappy ways
      at runtime.
      
      We're using -mno-fp-ret-in-387 in addition to -mno-80387 (which is ==
      -msoft-float) because, as the gcc manpage says:
      
        On machines where a function returns floating-point results in the
        80387 register stack, some floating-point opcodes may be emitted even
        if -msoft-float is used.
      
      so we want to turn off *all* non-integer instructions involving any
      architectural FPU state, unless it is absolutely necessary (and those
      cases need special handling anyway).
      
      Cc: Jiri Kosina <jkosina@suse.cz>
      Cc: Michael Matz <matz@suse.de>
      Cc: Michal Hocko <mhocko@suse.cz>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Link: http://lkml.kernel.org/r/1391561711-3023-1-git-send-email-bp@alien8.de
      
      Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      b399fe35
  30. 30 Jan, 2014 1 commit
  31. 22 Jan, 2014 1 commit
  32. 20 Dec, 2013 1 commit
    • Kees Cook's avatar
      stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures · 19952a92
      Kees Cook authored
      
      
      Instead of duplicating the CC_STACKPROTECTOR Kconfig and
      Makefile logic in each architecture, switch to using
      HAVE_CC_STACKPROTECTOR and keep everything in one place. This
      retains the x86-specific bug verification scripts.
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Arjan van de Ven <arjan@linux.intel.com>
      Cc: Michal Marek <mmarek@suse.cz>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: James Hogan <james.hogan@imgtec.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Cc: Shawn Guo <shawn.guo@linaro.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: linux-mips@linux-mips.org
      Cc: linux-arch@vger.kernel.org
      Link: http://lkml.kernel.org/r/1387481759-14535-2-git-send-email-keescook@chromium.org
      
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      19952a92
  33. 09 Dec, 2013 1 commit
    • H. Peter Anvin's avatar
      x86, build: Pass in additional -mno-mmx, -mno-sse options · 8b3b005d
      H. Peter Anvin authored
      In checkin
      
          5551a34e
      
       x86-64, build: Always pass in -mno-sse
      
      we unconditionally added -mno-sse to the main build, to keep newer
      compilers from generating SSE instructions from autovectorization.
      However, this did not extend to the special environments
      (arch/x86/boot, arch/x86/boot/compressed, and arch/x86/realmode/rm).
      Add -mno-sse to the compiler command line for these environments, and
      add -mno-mmx to all the environments as well, as we don't want a
      compiler to generate MMX code either.
      
      This patch also removes a $(cc-option) call for -m32, since we have
      long since stopped supporting compilers too old for the -m32 option,
      and in fact hardcode it in other places in the Makefiles.
      Reported-by: default avatarKevin B. Smith <kevin.b.smith@intel.com>
      Cc: Sunil K. Pandey <sunil.k.pandey@intel.com>
      Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
      Cc: H. J. Lu <hjl.tools@gmail.com>
      Link: http://lkml.kernel.org/n/tip-j21wzqv790q834n7yc6g80j1@git.kernel.org
      Cc: <stable@vger.kernel.org> # build fix only
      8b3b005d
  34. 04 Dec, 2013 1 commit
  35. 08 Aug, 2013 1 commit
  36. 23 Jun, 2013 1 commit