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authorArnd Bergmann <arnd@arndb.de>2012-02-28 12:42:14 +0000
committerArnd Bergmann <arnd@arndb.de>2012-02-28 12:42:21 +0000
commitfb0b82b32ce17564bc64cede50bf4a3204eecc60 (patch)
tree00b5e466074c6fb373d64c493b3341186024acc7 /arch/x86/kernel/process_64.c
parenta173fc693b25216c5c834978f4fafd731fd4ff94 (diff)
parent43de6a7dda6e9a7345e218e688f2092f991126f0 (diff)
Merge branch 'board-specific' of git://github.com/hzhuang1/linux into next/boards
* 'board-specific' of git://github.com/hzhuang1/linux: (5 commits) ARM: pxa: add dummy clock for pxa25x and pxa27x ARM: mmp: append irq name of gpio device pxa/hx4700: Fix PXA_GPIO_IRQ_BASE/IRQ_NUM values pxa/hx4700: Add ASIC3 LED support pxa/hx4700: Correct StrataFlash block size discovery (update to v3.3-rc5)
Diffstat (limited to 'arch/x86/kernel/process_64.c')
-rw-r--r--arch/x86/kernel/process_64.c30
1 files changed, 5 insertions, 25 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9b9fe4a85c8..cfa5c90c01d 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -286,6 +286,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
set_tsk_thread_flag(p, TIF_FORK);
+ p->fpu_counter = 0;
p->thread.io_bitmap_ptr = NULL;
savesegment(gs, p->thread.gsindex);
@@ -386,18 +387,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
int cpu = smp_processor_id();
struct tss_struct *tss = &per_cpu(init_tss, cpu);
unsigned fsindex, gsindex;
- bool preload_fpu;
+ fpu_switch_t fpu;
- /*
- * If the task has used fpu the last 5 timeslices, just do a full
- * restore of the math state immediately to avoid the trap; the
- * chances of needing FPU soon are obviously high now
- */
- preload_fpu = tsk_used_math(next_p) && next_p->fpu_counter > 5;
-
- /* we're going to use this soon, after a few expensive things */
- if (preload_fpu)
- prefetch(next->fpu.state);
+ fpu = switch_fpu_prepare(prev_p, next_p, cpu);
/*
* Reload esp0, LDT and the page table pointer:
@@ -427,13 +419,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
load_TLS(next, cpu);
- /* Must be after DS reload */
- __unlazy_fpu(prev_p);
-
- /* Make sure cpu is ready for new context */
- if (preload_fpu)
- clts();
-
/*
* Leave lazy mode, flushing any hypercalls made here.
* This must be done before restoring TLS segments so
@@ -474,6 +459,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
prev->gsindex = gsindex;
+ switch_fpu_finish(next_p, fpu);
+
/*
* Switch the PDA and FPU contexts.
*/
@@ -492,13 +479,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
__switch_to_xtra(prev_p, next_p, tss);
- /*
- * Preload the FPU context, now that we've determined that the
- * task is likely to be using it.
- */
- if (preload_fpu)
- __math_state_restore();
-
return prev_p;
}