diff options
Diffstat (limited to 'extras/recipes-kernel/linux/linux-omap-psp-2.6.32/0031-ARM-VFP-add-support-to-sync-the-VFP-state-of-the-cur.patch')
| -rw-r--r-- | extras/recipes-kernel/linux/linux-omap-psp-2.6.32/0031-ARM-VFP-add-support-to-sync-the-VFP-state-of-the-cur.patch | 109 |
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 + |