user/sven/linux.git/arch/x86/kernel/process.c, branch v3.2.58

x86: Remove the ancient and deprecated disable_hlt() and enable_hlt() facility

2012-11-16T16:46:46Z

commit f6365201d8a21fb347260f89d6e9b3e718d63c70 upstream. The X86_32-only disable_hlt/enable_hlt mechanism was used by the 32-bit floppy driver. Its effect was to replace the use of the HLT instruction inside default_idle() with cpu_relax() - essentially it turned off the use of HLT. This workaround was commented in the code as: "disable hlt during certain critical i/o operations" "This halt magic was a workaround for ancient floppy DMA wreckage. It should be safe to remove." H. Peter Anvin additionally adds: "To the best of my knowledge, no-hlt only existed because of flaky power distributions on 386/486 systems which were sold to run DOS. Since DOS did no power management of any kind, including HLT, the power draw was fairly uniform; when exposed to the much hhigher noise levels you got when Linux used HLT caused some of these systems to fail. They were by far in the minority even back then." Alan Cox further says: "Also for the Cyrix 5510 which tended to go castors up if a HLT occurred during a DMA cycle and on a few other boxes HLT during DMA tended to go astray. Do we care ? I doubt it. The 5510 was pretty obscure, the 5520 fixed it, the 5530 is probably the oldest still in any kind of use." So, let's finally drop this. Signed-off-by: Len Brown Signed-off-by: Josh Boyer Signed-off-by: Andrew Morton Acked-by: "H. Peter Anvin" Acked-by: Alan Cox Cc: Stephen Hemminger Link: http://lkml.kernel.org/n/tip-3rhk9bzf0x9rljkv488tloib@git.kernel.org [ If anyone cares then alternative instruction patching could be used to replace HLT with a one-byte NOP instruction. Much simpler. ] Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings

xen/pm_idle: Make pm_idle be default_idle under Xen.

2011-12-03T18:49:58Z

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:[] [] mwait_idle+0x6f/0xb4 ... Call Trace: [] cpu_idle+0xae/0xe8 [] cpu_bringup_and_idle+0xe/0x10 RIP [] mwait_idle+0x6f/0xb4 RSP 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 Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Linus Torvalds

x86, mm, trivial: Remove unnecessary get_order() in free_thread_info()

2011-08-23T19:49:35Z

Because THREAD_SIZE is defined as PAGE_SIZE << THREAD_ORDER on x86, the call of get_order(THREAD_SIZE) can be replaced with THREAD_ORDER. Signed-off-by: Zhao Jin Link: http://lkml.kernel.org/r/4E4FB5A9.700@gmail.com Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar

x86 idle: move mwait_idle_with_hints() to where it is used

2011-08-03T23:06:36Z

...and make it static no functional change cc: x86@kernel.org Acked-by: H. Peter Anvin Signed-off-by: Len Brown

x86 idle: APM requires pm_idle/default_idle unconditionally when a module

2011-06-14T20:42:20Z

[ Also from Ben Hutchings and Vitaliy Ivanov ] 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 Acked-by: Jiri Kosina Acked-by: Ingo Molnar Acked-by: Len Brown Signed-off-by: Andy Whitcroft Signed-off-by: Vitaliy Ivanov Signed-off-by: Ben Hutchings Signed-off-by: Linus Torvalds

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-05-31T17:07:22Z

* '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

2011-05-30T11:02:04Z

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 Cc: Len Brown Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1306748286-24701-1-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar

Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6

2011-05-29T18:18:09Z

* '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

2011-05-29T07:39:17Z

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

x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it

2011-05-29T07:39:14Z

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 Signed-off-by: Len Brown