1. 05 Dec, 2011 6 commits
  2. 04 Dec, 2011 1 commit
    • Linus Torvalds's avatar
      x86: Fix boot failures on older AMD CPU's · 8e8da023
      Linus Torvalds authored
      People with old AMD chips are getting hung boots, because commit
      bcb80e53 ("x86, microcode, AMD: Add microcode revision to
      /proc/cpuinfo") moved the microcode detection too early into
      "early_init_amd()".
      
      At that point we are *so* early in the booth that the exception tables
      haven't even been set up yet, so the whole
      
      	rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);
      
      doesn't actually work: if the rdmsr does a GP fault (due to non-existant
      MSR register on older CPU's), we can't fix it up yet, and the boot fails.
      
      Fix it by simply moving the code to a slightly later point in the boot
      (init_amd() instead of early_init_amd()), since the kernel itself
      doesn't even really care about the microcode patchlevel at this point
      (or really ever: it's made available to user space in /proc/cpuinfo, and
      updated if you do a microcode load).
      Reported-tested-and-bisected-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
      Tested-by: default avatarBob Tracy <rct@gherkin.frus.com>
      Acked-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8e8da023
  3. 03 Dec, 2011 1 commit
    • Konrad Rzeszutek Wilk's avatar
      xen/pm_idle: Make pm_idle be default_idle under Xen. · e5fd47bf
      Konrad Rzeszutek Wilk authored
      The idea behind commit d91ee586 ("cpuidle: replace xen access to x86
      pm_idle and default_idle") was to have one call - disable_cpuidle()
      which would make pm_idle not be molested by other code.  It disallows
      cpuidle_idle_call to be set to pm_idle (which is excellent).
      
      But in the select_idle_routine() and idle_setup(), the pm_idle can still
      be set to either: amd_e400_idle, mwait_idle or default_idle.  This
      depends on some CPU flags (MWAIT) and in AMD case on the type of CPU.
      
      In case of mwait_idle we can hit some instances where the hypervisor
      (Amazon EC2 specifically) sets the MWAIT and we get:
      
        Brought up 2 CPUs
        invalid opcode: 0000 [#1] SMP
      
        Pid: 0, comm: swapper Not tainted 3.1.0-0.rc6.git0.3.fc16.x86_64 #1
        RIP: e030:[<ffffffff81015d1d>]  [<ffffffff81015d1d>] mwait_idle+0x6f/0xb4
        ...
        Call Trace:
         [<ffffffff8100e2ed>] cpu_idle+0xae/0xe8
         [<ffffffff8149ee78>] cpu_bringup_and_idle+0xe/0x10
        RIP  [<ffffffff81015d1d>] mwait_idle+0x6f/0xb4
         RSP <ffff8801d28ddf10>
      
      In the case of amd_e400_idle we don't get so spectacular crashes, but we
      do end up making an MSR which is trapped in the hypervisor, and then
      follow it up with a yield hypercall.  Meaning we end up going to
      hypervisor twice instead of just once.
      
      The previous behavior before v3.0 was that pm_idle was set to
      default_idle regardless of select_idle_routine/idle_setup.
      
      We want to do that, but only for one specific case: Xen.  This patch
      does that.
      
      Fixes RH BZ #739499 and Ubuntu #881076
      Reported-by: default avatarStefan Bader <stefan.bader@canonical.com>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e5fd47bf
  4. 02 Dec, 2011 14 commits
  5. 01 Dec, 2011 18 commits