1 files changed, 109 insertions, 0 deletions

diff --git a/extras/recipes-kernel/linux/linux-omap-psp-2.6.32/0031-ARM-VFP-add-support-to-sync-the-VFP-state-of-the-cur.patch b/extras/recipes-kernel/linux/linux-omap-psp-2.6.32/0031-ARM-VFP-add-support-to-sync-the-VFP-state-of-the-cur.patch
new file mode 100644
index 00000000..28d9f376
--- /dev/null
+++ b/extras/recipes-kernel/linux/linux-omap-psp-2.6.32/0031-ARM-VFP-add-support-to-sync-the-VFP-state-of-the-cur.patch
@@ -0,0 +1,109 @@
+From b366c2810c736d8d544cf261f3354eebaf5e5655 Mon Sep 17 00:00:00 2001
+From: Imre Deak <imre.deak@nokia.com>
+Date: Thu, 4 Feb 2010 21:38:02 +0200
+Subject: [PATCH 31/45] ARM: VFP: add support to sync the VFP state of the current thread
+
+ARM: VFP: add support to sync the VFP state of the current thread
+
+So far vfp_sync_state worked only for threads other than the current
+one. This worked for tracing other threads, but not for PTRACE_TRACEME.
+Syncing for the current thread will also be needed by an upcoming patch
+adding support for VFP context save / restore around signal handlers.
+
+For SMP we need get_cpu now, since we have to protect the FPEXC
+register, other than this things remained the same for threads other
+than the current.
+
+Signed-off-by: Imre Deak <imre.deak@nokia.com>
+Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
+---
+ arch/arm/vfp/vfpmodule.c |   46 +++++++++++++++++++++++++++++++---------------
+ 1 files changed, 31 insertions(+), 15 deletions(-)
+
+diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
+index aed05bc..f28f45b 100644
+--- a/arch/arm/vfp/vfpmodule.c
++++ b/arch/arm/vfp/vfpmodule.c
+@@ -423,12 +423,19 @@ static inline void vfp_pm_init(void) { }
+ #endif /* CONFIG_PM */
+ 
+ /*
+- * Synchronise the hardware VFP state of a thread other than current with the
+- * saved one. This function is used by the ptrace mechanism.
++ * Synchronise the hardware VFP state of a thread with the saved one.
++ * This function is used by the ptrace mechanism and the signal handler path.
+  */
+-#ifdef CONFIG_SMP
+ void vfp_sync_state(struct thread_info *thread)
+ {
++       unsigned int cpu = get_cpu();
++       u32 fpexc = fmrx(FPEXC);
++       int vfp_enabled;
++       int self;
++
++       vfp_enabled = fpexc & FPEXC_EN;
++       self = thread == current_thread_info();
++#ifdef CONFIG_SMP
+        /*
+         * On SMP systems, the VFP state is automatically saved at every
+         * context switch. We mark the thread VFP state as belonging to a
+@@ -436,18 +443,22 @@ void vfp_sync_state(struct thread_info *thread)
+         * needed.
+         */
+        thread->vfpstate.hard.cpu = NR_CPUS;
+-}
+-#else
+-void vfp_sync_state(struct thread_info *thread)
+-{
+-       unsigned int cpu = get_cpu();
+-       u32 fpexc = fmrx(FPEXC);
+-
+        /*
+-        * If VFP is enabled, the previous state was already saved and
+-        * last_VFP_context updated.
++        * Only the current thread's saved VFP context can be out-of-date.
++        * For others there is nothing else to do, since we already ensured
++        * force loading above.
+         */
+-       if (fpexc & FPEXC_EN)
++       if (!self)
++               goto out;
++#endif
++       /*
++        * If the VFP is enabled only the current thread's saved VFP
++        * context can get out-of-date. For other threads the context
++        * was updated when the current thread started to use the VFP.
++        * This also means that the context will be reloaded next time
++        * the thread uses the VFP, so no need to enforce it.
++        */
++       if (vfp_enabled && !self)
+                goto out;
+ 
+        if (!last_VFP_context[cpu])
+@@ -456,8 +467,14 @@ void vfp_sync_state(struct thread_info *thread)
+        /*
+         * Save the last VFP state on this CPU.
+         */
+-       fmxr(FPEXC, fpexc | FPEXC_EN);
++       if (!vfp_enabled)
++               fmxr(FPEXC, fpexc | FPEXC_EN);
+        vfp_save_state(last_VFP_context[cpu], fpexc);
++       /*
++        * Disable VFP in case it was enabled so that the force reload
++        * can happen.
++        */
++       fpexc &= ~FPEXC_EN;
+        fmxr(FPEXC, fpexc);
+ 
+        /*
+@@ -469,7 +486,6 @@ void vfp_sync_state(struct thread_info *thread)
+ out:
+        put_cpu();
+ }
+-#endif
+ 
+ #include <linux/smp.h>
+ 
+-- 
+1.6.6.1
+