linux-stable.git/arch/x86/kernel/process.c, branch linux-3.1.y Linux kernel stable tree xen/pm_idle: Make pm_idle be default_idle under Xen. 2011-12-21T20:58:31+00:00 Konrad Rzeszutek Wilk konrad.wilk@oracle.com 2011-11-21T23:02:02+00:00 dc43883928066a7fc474755c6e96f8fae348fe59 commit e5fd47bfab2df0c2184cc0bf4245d8e1bb7724fb upstream. The idea behind commit d91ee5863b71 ("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: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
commit e5fd47bfab2df0c2184cc0bf4245d8e1bb7724fb upstream.

The idea behind commit d91ee5863b71 ("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: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
x86 idle: move mwait_idle_with_hints() to where it is used 2011-08-03T23:06:36+00:00 Len Brown len.brown@intel.com 2011-03-31T03:52:29+00:00 4bfc8288bc4a64529c5547d17349a2a1f4675507 ...and make it static no functional change cc: x86@kernel.org Acked-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Len Brown <len.brown@intel.com> 
...and make it static

no functional change

cc: x86@kernel.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
x86 idle: APM requires pm_idle/default_idle unconditionally when a module 2011-06-14T20:42:20+00:00 Andy Whitcroft apw@canonical.com 2011-06-14T19:45:10+00:00 60b8b1de0dd2bf246f0e074d287bb3f0bc42a755 [ Also from Ben Hutchings <ben@decadent.org.uk> and Vitaliy Ivanov <vitalivanov@gmail.com> ] Commit 06ae40ce073d ("x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it") removed the export for pm_idle/default_idle unless the apm module was modularised and CONFIG_APM_CPU_IDLE was set. But the apm module uses pm_idle/default_idle unconditionally, CONFIG_APM_CPU_IDLE only affects the bios idle threshold. Adjust the export accordingly. [ Used #ifdef instead of #if defined() as it's shorter, and what both Ben and Vitaliy used.. Andy, you're out-voted ;) - Linus ] Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Len Brown <len.brown@intel.com> Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
[ Also from Ben Hutchings <ben@decadent.org.uk> and Vitaliy Ivanov
  <vitalivanov@gmail.com> ]

Commit 06ae40ce073d ("x86 idle: EXPORT_SYMBOL(default_idle, pm_idle)
only when APM demands it") removed the export for pm_idle/default_idle
unless the apm module was modularised and CONFIG_APM_CPU_IDLE was set.

But the apm module uses pm_idle/default_idle unconditionally,
CONFIG_APM_CPU_IDLE only affects the bios idle threshold.  Adjust the
export accordingly.

[ Used #ifdef instead of #if defined() as it's shorter, and what both
  Ben and Vitaliy used.. Andy, you're out-voted ;)    - Linus ]

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-05-31T17:07:22+00:00 Linus Torvalds torvalds@linux-foundation.org 2011-05-31T17:07:22+00:00 af0d6a0a3a30946f7df69c764791f1b0643f7cd6 * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix mwait_play_dead() faulting on mwait-incapable cpus x86 idle: Fix mwait deprecation warning message Evil merge to remove extra quote noticed by Joe Perches 
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix mwait_play_dead() faulting on mwait-incapable cpus
  x86 idle: Fix mwait deprecation warning message

Evil merge to remove extra quote noticed by Joe Perches
x86 idle: Fix mwait deprecation warning message 2011-05-30T11:02:04+00:00 Borislav Petkov bp@alien8.de 2011-05-30T09:38:06+00:00 598e887d8b01655780c81cc86a9e7820ed091580 Fix: arch/x86/kernel/process.c:645:1: warning: unknown escape sequence '\i' due to missing escape backslash, introduced by this commit: 5d4c47e0195b: x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param Signed-off-by: Borislav Petkov <bp@alien8.de> Cc: Len Brown <len.brown@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1306748286-24701-1-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@elte.hu> 
Fix:

  arch/x86/kernel/process.c:645:1: warning: unknown escape sequence '\i'

due to missing escape backslash, introduced by this commit:

  5d4c47e0195b: x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param

Signed-off-by: Borislav Petkov <bp@alien8.de>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1306748286-24701-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6 2011-05-29T18:18:09+00:00 Linus Torvalds torvalds@linux-foundation.org 2011-05-29T18:18:09+00:00 f310642123e0d32d919c60ca3fab5acd130c4ba3 * 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6: x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param x86 idle: deprecate "no-hlt" cmdline param x86 idle APM: deprecate CONFIG_APM_CPU_IDLE x86 idle floppy: deprecate disable_hlt() x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it x86 idle: clarify AMD erratum 400 workaround idle governor: Avoid lock acquisition to read pm_qos before entering idle cpuidle: menu: fixed wrapping timers at 4.294 seconds 
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6:
  x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param
  x86 idle: deprecate "no-hlt" cmdline param
  x86 idle APM: deprecate CONFIG_APM_CPU_IDLE
  x86 idle floppy: deprecate disable_hlt()
  x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it
  x86 idle: clarify AMD erratum 400 workaround
  idle governor: Avoid lock acquisition to read pm_qos before entering idle
  cpuidle: menu: fixed wrapping timers at 4.294 seconds
x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param 2011-05-29T07:39:17+00:00 Len Brown len.brown@intel.com 2011-04-01T19:46:09+00:00 5d4c47e0195b989f284907358bd5c268a44b91c7 mwait_idle() is a C1-only idle loop intended to be more efficient than HLT on SMP hardware that supports it. But mwait_idle() has been replaced by the more general mwait_idle_with_hints(), which handles both C1 and deeper C-states. ACPI uses only mwait_idle_with_hints(), and never uses mwait_idle(). Deprecate mwait_idle() and the "idle=mwait" cmdline param to simplify the x86 idle code. After this change, kernels configured with (!CONFIG_ACPI=n && !CONFIG_INTEL_IDLE=n) when run on hardware that support MWAIT will simply use HLT. If MWAIT is desired on those systems, cpuidle and the cpuidle drivers above can be used. cc: x86@kernel.org cc: stable@kernel.org # .39.x Signed-off-by: Len Brown <len.brown@intel.com> 
mwait_idle() is a C1-only idle loop intended to be more efficient
than HLT on SMP hardware that supports it.

But mwait_idle() has been replaced by the more general
mwait_idle_with_hints(), which handles both C1 and deeper C-states.
ACPI uses only mwait_idle_with_hints(), and never uses mwait_idle().

Deprecate mwait_idle() and the "idle=mwait" cmdline param
to simplify the x86 idle code.

After this change, kernels configured with
(!CONFIG_ACPI=n && !CONFIG_INTEL_IDLE=n) when run on hardware
that support MWAIT will simply use HLT.  If MWAIT is desired
on those systems, cpuidle and the cpuidle drivers above
can be used.

cc: x86@kernel.org
cc: stable@kernel.org # .39.x
Signed-off-by: Len Brown <len.brown@intel.com>
x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it 2011-05-29T07:39:14+00:00 Len Brown len.brown@intel.com 2011-04-01T19:28:09+00:00 06ae40ce073daf233607a3c54a489f2c1e44683e In the long run, we don't want default_idle() or (pm_idle)() to be exported outside of process.c. Start by not exporting them to modules, unless the APM build demands it. cc: x86@kernel.org cc: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Len Brown <len.brown@intel.com> 
In the long run, we don't want default_idle() or (pm_idle)() to
be exported outside of process.c.  Start by not exporting them
to modules, unless the APM build demands it.

cc: x86@kernel.org
cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
x86 idle: clarify AMD erratum 400 workaround 2011-05-29T07:38:57+00:00 Len Brown len.brown@intel.com 2011-04-01T20:59:53+00:00 02c68a02018669d1817c43c42de800975cbec467 The workaround for AMD erratum 400 uses the term "c1e" falsely suggesting: 1. Intel C1E is somehow involved 2. All AMD processors with C1E are involved Use the string "amd_c1e" instead of simply "c1e" to clarify that this workaround is specific to AMD's version of C1E. Use the string "e400" to clarify that the workaround is specific to AMD processors with Erratum 400. This patch is text-substitution only, with no functional change. cc: x86@kernel.org Acked-by: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: Len Brown <len.brown@intel.com> 
The workaround for AMD erratum 400 uses the term "c1e" falsely suggesting:
1. Intel C1E is somehow involved
2. All AMD processors with C1E are involved

Use the string "amd_c1e" instead of simply "c1e" to clarify that
this workaround is specific to AMD's version of C1E.
Use the string "e400" to clarify that the workaround is specific
to AMD processors with Erratum 400.

This patch is text-substitution only, with no functional change.

cc: x86@kernel.org
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>
x86: A fast way to check capabilities of the current cpu 2011-03-29T08:18:30+00:00 Christoph Lameter cl@linux.com 2011-03-12T11:50:10+00:00 349c004e3d31fda23ad225b61861be38047fff16 Add this_cpu_has() which determines if the current cpu has a certain ability using a segment prefix and a bit test operation. For that we need to add bit operations to x86s percpu.h. Many uses of cpu_has use a pointer passed to a function to determine the current flags. That is no longer necessary after this patch. However, this patch only converts the straightforward cases where cpu_has is used with this_cpu_ptr. The rest is work for later. -tj: Rolled up patch to add x86_ prefix and use percpu_read() instead of percpu_read_stable(). Signed-off-by: Christoph Lameter <cl@linux.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org> 
Add this_cpu_has() which determines if the current cpu has a certain
ability using a segment prefix and a bit test operation.

For that we need to add bit operations to x86s percpu.h.

Many uses of cpu_has use a pointer passed to a function to determine
the current flags. That is no longer necessary after this patch.

However, this patch only converts the straightforward cases where
cpu_has is used with this_cpu_ptr. The rest is work for later.

-tj: Rolled up patch to add x86_ prefix and use percpu_read() instead
     of percpu_read_stable().

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>