Module: xenomai-forge
Branch: master
Commit: ee00dca4d6f8cd7b9fcf9506e3be0f4af950f232
URL:
http://git.xenomai.org/?p=xenomai-forge.git;a=commit;h=ee00dca4d6f8cd7b9fcf9506e3be0f4af950f232
Author: Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>
Date: Fri Feb 8 17:23:31 2013 +0100
cobalt/x86: fix FPU handling
---
include/asm-x86/thread.h | 2 -
kernel/cobalt/arch/x86/thread.c | 96 ++++-----------------------------------
2 files changed, 10 insertions(+), 88 deletions(-)
diff --git a/include/asm-x86/thread.h b/include/asm-x86/thread.h
index 7ca11cf..af1ff2a 100644
--- a/include/asm-x86/thread.h
+++ b/include/asm-x86/thread.h
@@ -34,8 +34,6 @@ struct xnarchtcb {
unsigned long *ipp;
x86_fpustate *fpup;
unsigned int is_root: 1;
- unsigned int ts_usedfpu: 1;
- unsigned int cr0_ts: 1;
struct {
unsigned long ip;
unsigned long ax;
diff --git a/kernel/cobalt/arch/x86/thread.c b/kernel/cobalt/arch/x86/thread.c
index 7631507..61cb365 100644
--- a/kernel/cobalt/arch/x86/thread.c
+++ b/kernel/cobalt/arch/x86/thread.c
@@ -88,21 +88,11 @@ void xnarch_leave_root(struct xnarchtcb *rootcb)
{
struct task_struct *p = current;
- rootcb->ts_usedfpu = wrap_test_fpu_used(p) != 0;
- rootcb->cr0_ts = (read_cr0() & 8) != 0;
#ifdef CONFIG_X86_64
rootcb->spp = &p->thread.sp;
rootcb->ipp = &p->thread.rip;
#endif
- /* So that xnarch_save_fpu() will operate on the right FPU area. */
- if (rootcb->cr0_ts || rootcb->ts_usedfpu)
- rootcb->fpup = x86_fpustate_ptr(&p->thread);
- else
- /*
- * The kernel is currently using fpu in kernel-space,
- * do not clobber the user-space fpu backup area.
- */
- rootcb->fpup = &rootcb->i387;
+ rootcb->fpup = x86_fpustate_ptr(&p->thread);
}
void xnarch_switch_to(struct xnarchtcb *out_tcb, struct xnarchtcb *in_tcb)
@@ -253,98 +243,32 @@ int xnarch_handle_fpu_fault(struct xnarchtcb *tcb)
void xnarch_save_fpu(struct xnarchtcb *tcb)
{
- struct task_struct *p = tcb->core.host_task;
-
- if (tcb->is_root == 0) {
- /* fpu not used or already saved by __switch_to. */
- if (wrap_test_fpu_used(p) == 0)
- return;
-
- /*
- * Tell Linux that we already saved the state of the
- * FPU hardware of this task.
- */
- wrap_clear_fpu_used(p);
- } else {
- if (tcb->cr0_ts ||
- (tcb->ts_usedfpu && wrap_test_fpu_used(p) == 0))
- return;
-
- wrap_clear_fpu_used(p);
- }
-
- clts();
-
- __do_save_i387(tcb->fpup);
+ /* Already saved by __switch_to */
}
void xnarch_restore_fpu(struct xnarchtcb *tcb)
{
struct task_struct *p = tcb->core.host_task;
- if (tcb->is_root == 0) {
- if (tsk_used_math(p) == 0) {
- stts();
- return; /* Uninit fpu area -- do not restore. */
- }
-
- /*
- * Tell Linux that this task has altered the state of
- * the FPU hardware.
- */
- wrap_set_fpu_used(p);
- } else {
- /*
- * Restore state of FPU only if TS bit in cr0 was
- * clear.
- */
- if (tcb->cr0_ts) {
- wrap_clear_fpu_used(p);
- stts();
- return;
- }
-
- if (tcb->ts_usedfpu && !wrap_test_fpu_used(p)) {
- /*
- * __switch_to saved the fpu context, no need
- * to restore it since we are switching to
- * root, where fpu can be in lazy state.
- */
- stts();
- return;
- }
+ if (tcb->is_root || tsk_used_math(p) == 0) {
+ /* Restore lazy mode */
+ return;
}
+
/*
* Restore the FPU hardware with valid fp registers from a
- * user-space or kernel thread.
+ * RT user-space or kernel thread.
*/
clts();
__do_restore_i387(tcb->fpup);
+ wrap_set_fpu_used(p);
}
void xnarch_enable_fpu(struct xnarchtcb *tcb)
{
- struct task_struct *p = tcb->core.host_task;
-
- if (tcb->is_root == 0) {
- if (tsk_used_math(p) == 0)
- return;
- /*
- * We used to test here if __switch_to had not saved
- * current fpu state, but this can not happen, since
- * xnarch_enable_fpu may only be called when switching
- * back to a user-space task after one or several
- * switches to non-fpu kernel-space real-time tasks,
- * so xnarch_switch_to never uses __switch_to.
- */
- } else if (tcb->cr0_ts)
- return;
-
- /* The comment in the non-root case applies here too. */
-
- clts();
+ xnarch_restore_fpu(tcb);
}
#endif /* CONFIG_XENO_HW_FPU */
@@ -354,8 +278,8 @@ void xnarch_init_root_tcb(struct xnarchtcb *tcb)
tcb->sp = 0;
tcb->spp = &tcb->sp;
tcb->ipp = &tcb->ip;
- tcb->fpup = NULL;
tcb->is_root = 1;
+ tcb->fpup = NULL;
}
void xnarch_init_shadow_tcb(struct xnarchtcb *tcb)
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