Module: xenomai-forge
Branch: next
Commit: ddfec37d9c7d510d174db531cef81c46636fdc4a
URL:
http://git.xenomai.org/?p=xenomai-forge.git;a=commit;h=ddfec37d9c7d510d174db531cef81c46636fdc4a
Author: Jan Kiszka <jan.kis...@siemens.com>
Date: Wed Jan 30 17:00:58 2013 +0100
x86-64: Clean up fxsave/fxrstor
We always work against kernel memory and state here, and we did not
check the returned error code anyway. So downgrade __save_i387_checking/
__restore_i387_checking to non-checking versions and clean up the
corresponding assembly lines.
At this chance, we can pick up the kernel's micro-optimization when
CONFIG_AS_FXSAVEQ is set, i.e. we do not deal with prehistoric gas.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
kernel/cobalt/arch/x86/thread.c | 57 +++++++++++----------------------------
1 files changed, 16 insertions(+), 41 deletions(-)
diff --git a/kernel/cobalt/arch/x86/thread.c b/kernel/cobalt/arch/x86/thread.c
index 61cb365..a75539e 100644
--- a/kernel/cobalt/arch/x86/thread.c
+++ b/kernel/cobalt/arch/x86/thread.c
@@ -157,62 +157,39 @@ void xnarch_switch_to(struct xnarchtcb *out_tcb, struct
xnarchtcb *in_tcb)
#ifdef CONFIG_XENO_HW_FPU
-static inline int __do_save_i387(x86_fpustate *fpup)
+static inline void __do_save_i387(x86_fpustate *fpup)
{
- int err = 0;
-
#ifdef CONFIG_X86_32
if (cpu_has_fxsr)
__asm__ __volatile__("fxsave %0; fnclex":"=m"(*fpup));
else
__asm__ __volatile__("fnsave %0; fwait":"=m"(*fpup));
#else /* CONFIG_X86_64 */
- struct i387_fxsave_struct *fx = &fpup->fxsave;
-
- asm volatile("1: rex64/fxsave (%[fx])\n\t"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- ".section __ex_table,\"a\"\n"
- " .align 8\n"
- " .quad 1b,3b\n"
- ".previous"
- : [err] "=r" (err), "=m" (*fx)
- : [fx] "cdaSDb" (fx), "0" (0));
+#ifdef CONFIG_AS_FXSAVEQ
+ asm volatile("fxsaveq %0" : "=m" (fpup->fxsave));
+#else /* !CONFIG_AS_FXSAVEQ */
+ asm volatile("rex64/fxsave (%[fx])"
+ : "=m" (fpup->fxsave)
+ : [fx] "R" (&fpup->fxsave));
+#endif /* !CONFIG_AS_FXSAVEQ */
#endif /* CONFIG_X86_64 */
-
- return err;
}
-static inline int __do_restore_i387(x86_fpustate *fpup)
+static inline void __do_restore_i387(x86_fpustate *fpup)
{
- int err = 0;
-
#ifdef CONFIG_X86_32
if (cpu_has_fxsr)
__asm__ __volatile__("fxrstor %0": /* no output */ :"m"(*fpup));
else
__asm__ __volatile__("frstor %0": /* no output */ :"m"(*fpup));
#else /* CONFIG_X86_64 */
- struct i387_fxsave_struct *fx = &fpup->fxsave;
-
- asm volatile("1: rex64/fxrstor (%[fx])\n\t"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- ".section __ex_table,\"a\"\n"
- " .align 8\n"
- " .quad 1b,3b\n"
- ".previous"
- : [err] "=r" (err)
- : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));
+#ifdef CONFIG_AS_FXSAVEQ
+ asm volatile("fxrstorq %0" : : "m" (fpup->fxsave));
+#else /* !CONFIG_AS_FXSAVEQ */
+ asm volatile("rex64/fxrstor (%0)"
+ : : "R" (&fpup->fxsave), "m" (fpup->fxsave));
+#endif /* !CONFIG_AS_FXSAVEQ */
#endif /* CONFIG_X86_64 */
-
- return err;
}
int xnarch_handle_fpu_fault(struct xnarchtcb *tcb)
@@ -250,11 +227,9 @@ void xnarch_restore_fpu(struct xnarchtcb *tcb)
{
struct task_struct *p = tcb->core.host_task;
- if (tcb->is_root || tsk_used_math(p) == 0) {
+ if (tcb->is_root || tsk_used_math(p) == 0)
/* Restore lazy mode */
return;
- }
-
/*
* Restore the FPU hardware with valid fp registers from a
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