summaryrefslogtreecommitdiff
path: root/arch/x86/include/asm/i387.h
diff options
context:
space:
mode:
authorBrian Gerst <brgerst@gmail.com>2010-09-03 21:17:12 -0400
committerH. Peter Anvin <hpa@linux.intel.com>2010-09-09 14:16:45 -0700
commita4d4fbc7735bba6654b20f859135f9d3f8fe7f76 (patch)
tree4b501fbfbce08e3222f137a284b354425162f873 /arch/x86/include/asm/i387.h
parentbfd946cb891800d408decaae268a3480775178a3 (diff)
x86-64, fpu: Disable preemption when using TS_USEDFPU
Consolidates code and fixes the below race for 64-bit. commit 9fa2f37bfeb798728241cc4a19578ce6e4258f25 Author: torvalds <torvalds> Date: Tue Sep 2 07:37:25 2003 +0000 Be a lot more careful about TS_USEDFPU and preemption We had some races where we testecd (or set) TS_USEDFPU together with sequences that depended on the setting (like clearing or setting the TS flag in %cr0) and we could be preempted in between, which screws up the FPU state, since preemption will itself change USEDFPU and the TS flag. This makes it a lot more explicit: the "internal" low-level FPU functions ("__xxxx_fpu()") all require preemption to be disabled, and the exported "real" functions will make sure that is the case. One case - in __switch_to() - was switched to the non-preempt-safe internal version, since the scheduler itself has already disabled preemption. BKrev: 3f5448b5WRiQuyzAlbajs3qoQjSobw Signed-off-by: Brian Gerst <brgerst@gmail.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <1283563039-3466-6-git-send-email-brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/i387.h')
-rw-r--r--arch/x86/include/asm/i387.h15
1 files changed, 0 insertions, 15 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 88065e3a03c0..8b40a8379cc2 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -387,19 +387,6 @@ static inline void irq_ts_restore(int TS_state)
stts();
}
-#ifdef CONFIG_X86_64
-
-static inline void save_init_fpu(struct task_struct *tsk)
-{
- __save_init_fpu(tsk);
- stts();
-}
-
-#define unlazy_fpu __unlazy_fpu
-#define clear_fpu __clear_fpu
-
-#else /* CONFIG_X86_32 */
-
/*
* These disable preemption on their own and are safe
*/
@@ -425,8 +412,6 @@ static inline void clear_fpu(struct task_struct *tsk)
preempt_enable();
}
-#endif /* CONFIG_X86_64 */
-
/*
* i387 state interaction
*/