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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-23 10:59:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-23 10:59:07 -0700
commitec0d7f18ab7b5097d7c0c8f3d909ca1031b9d5cd (patch)
tree7d62c924592145f819ecaa5d60460a05a10dfdbd /arch/x86/kernel/process.c
parent269af9a1a08d368b46d72e74126564d04c354f7e (diff)
parent1dcc8d7ba235a316a056f993e88f0d18b92c60d9 (diff)
downloadblackbird-op-linux-ec0d7f18ab7b5097d7c0c8f3d909ca1031b9d5cd.tar.gz
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Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull fpu state cleanups from Ingo Molnar: "This tree streamlines further aspects of FPU handling by eliminating the prepare_to_copy() complication and moving that logic to arch_dup_task_struct(). It also fixes the FPU dumps in threaded core dumps, removes and old (and now invalid) assumption plus micro-optimizes the exit path by avoiding an FPU save for dead tasks." Fixed up trivial add-add conflict in arch/sh/kernel/process.c that came in because we now do the FPU handling in arch_dup_task_struct() rather than the legacy (and now gone) prepare_to_copy(). * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, fpu: drop the fpu state during thread exit x86, xsave: remove thread_has_fpu() bug check in __sanitize_i387_state() coredump: ensure the fpu state is flushed for proper multi-threaded core dump fork: move the real prepare_to_copy() users to arch_dup_task_struct()
Diffstat (limited to 'arch/x86/kernel/process.c')
-rw-r--r--arch/x86/kernel/process.c25
1 files changed, 19 insertions, 6 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index f2e8c0f951d6..735279e54e59 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -56,10 +56,16 @@ EXPORT_SYMBOL_GPL(idle_notifier_unregister);
struct kmem_cache *task_xstate_cachep;
EXPORT_SYMBOL_GPL(task_xstate_cachep);
+/*
+ * this gets called so that we can store lazy state into memory and copy the
+ * current task into the new thread.
+ */
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
int ret;
+ unlazy_fpu(src);
+
*dst = *src;
if (fpu_allocated(&src->thread.fpu)) {
memset(&dst->thread.fpu, 0, sizeof(dst->thread.fpu));
@@ -89,6 +95,16 @@ void arch_task_cache_init(void)
SLAB_PANIC | SLAB_NOTRACK, NULL);
}
+static inline void drop_fpu(struct task_struct *tsk)
+{
+ /*
+ * Forget coprocessor state..
+ */
+ tsk->fpu_counter = 0;
+ clear_fpu(tsk);
+ clear_used_math();
+}
+
/*
* Free current thread data structures etc..
*/
@@ -111,6 +127,8 @@ void exit_thread(void)
put_cpu();
kfree(bp);
}
+
+ drop_fpu(me);
}
void show_regs_common(void)
@@ -145,12 +163,7 @@ void flush_thread(void)
flush_ptrace_hw_breakpoint(tsk);
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
- /*
- * Forget coprocessor state..
- */
- tsk->fpu_counter = 0;
- clear_fpu(tsk);
- clear_used_math();
+ drop_fpu(tsk);
}
static void hard_disable_TSC(void)
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