diff options
| author | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-30 15:35:11 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-11-07 12:31:51 -0800 |
| commit | 570bd39ac8505e57b1d62e56b84eea9de8473c15 (patch) | |
| tree | 20fcb338c29222b130228294893ab186df77732f /arch/x86/include | |
| parent | 71c6bd5af2d984fadd81611ad643bda52e82ad79 (diff) | |
Revert "x86, hotplug: Use mwait to offline a processor, fix the legacy case"
This reverts commit 226917b0735f31cf5c704e07fdd590d99bbfae58 (upstream
ea53069231f9317062910d6e772cca4ce93de8c8 and
a68e5c94f7d3dd64fef34dd5d97e365cae4bb42a and
ce5f68246bf2385d6174856708d0b746dc378f20 all mushed together) as
Jonathan Nieder reports that this causes a regression on some hardware.
More details can be found at http://bugs.debian.org/622259
Cc: Jonathan Nieder <jrnieder@gmail.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/processor.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index da35a70f6129..fa04deade0a6 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -765,6 +765,29 @@ extern unsigned long boot_option_idle_override; extern unsigned long idle_halt; extern unsigned long idle_nomwait; +/* + * on systems with caches, caches must be flashed as the absolute + * last instruction before going into a suspended halt. Otherwise, + * dirty data can linger in the cache and become stale on resume, + * leading to strange errors. + * + * perform a variety of operations to guarantee that the compiler + * will not reorder instructions. wbinvd itself is serializing + * so the processor will not reorder. + * + * Systems without cache can just go into halt. + */ +static inline void wbinvd_halt(void) +{ + mb(); + /* check for clflush to determine if wbinvd is legal */ + if (cpu_has_clflush) + asm volatile("cli; wbinvd; 1: hlt; jmp 1b" : : : "memory"); + else + while (1) + halt(); +} + extern void enable_sep_cpu(void); extern int sysenter_setup(void); |