ARM: vfp ptrace: no point flushing hw context for PTRACE_GETVFPREGS
If we're only reading the VFP context via the ptrace call, there's
no need to invalidate the hardware context - we only need to do that
on PTRACE_SETVFPREGS. This allows more efficient monitoring of a
traced task.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 2dfb7d7..b74970e 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -115,7 +115,8 @@
extern void iwmmxt_task_release(struct thread_info *);
extern void iwmmxt_task_switch(struct thread_info *);
-extern void vfp_sync_state(struct thread_info *thread);
+extern void vfp_sync_hwstate(struct thread_info *);
+extern void vfp_flush_hwstate(struct thread_info *);
#endif
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index bdf002b..08f899f 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -700,7 +700,7 @@
union vfp_state *vfp = &thread->vfpstate;
struct user_vfp __user *ufp = data;
- vfp_sync_state(thread);
+ vfp_sync_hwstate(thread);
/* copy the floating point registers */
if (copy_to_user(&ufp->fpregs, &vfp->hard.fpregs,
@@ -723,7 +723,7 @@
union vfp_state *vfp = &thread->vfpstate;
struct user_vfp __user *ufp = data;
- vfp_sync_state(thread);
+ vfp_sync_hwstate(thread);
/* copy the floating point registers */
if (copy_from_user(&vfp->hard.fpregs, &ufp->fpregs,
@@ -734,6 +734,8 @@
if (get_user(vfp->hard.fpscr, &ufp->fpscr))
return -EFAULT;
+ vfp_flush_hwstate(thread);
+
return 0;
}
#endif
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 86a57ae..def19f8 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -430,7 +430,11 @@
* saved one. This function is used by the ptrace mechanism.
*/
#ifdef CONFIG_SMP
-void vfp_sync_state(struct thread_info *thread)
+void vfp_sync_hwstate(struct thread_info *thread)
+{
+}
+
+void vfp_flush_hwstate(struct thread_info *thread)
{
/*
* On SMP systems, the VFP state is automatically saved at every
@@ -441,7 +445,7 @@
thread->vfpstate.hard.cpu = NR_CPUS;
}
#else
-void vfp_sync_state(struct thread_info *thread)
+void vfp_sync_hwstate(struct thread_info *thread)
{
unsigned int cpu = get_cpu();
@@ -457,6 +461,23 @@
*/
fmxr(FPEXC, fpexc | FPEXC_EN);
vfp_save_state(&thread->vfpstate, fpexc | FPEXC_EN);
+ fmxr(FPEXC, fpexc);
+ }
+
+ put_cpu();
+}
+
+void vfp_flush_hwstate(struct thread_info *thread)
+{
+ unsigned int cpu = get_cpu();
+
+ /*
+ * If the thread we're interested in is the current owner of the
+ * hardware VFP state, then we need to save its state.
+ */
+ if (last_VFP_context[cpu] == &thread->vfpstate) {
+ u32 fpexc = fmrx(FPEXC);
+
fmxr(FPEXC, fpexc & ~FPEXC_EN);
/*
