diff options
Diffstat (limited to 'recipes/linux/linux-omap-2.6.29/vfp/04-vfp-threads.patch')
| -rw-r--r-- | recipes/linux/linux-omap-2.6.29/vfp/04-vfp-threads.patch | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/recipes/linux/linux-omap-2.6.29/vfp/04-vfp-threads.patch b/recipes/linux/linux-omap-2.6.29/vfp/04-vfp-threads.patch new file mode 100644 index 0000000000..221b2774a1 --- /dev/null +++ b/recipes/linux/linux-omap-2.6.29/vfp/04-vfp-threads.patch @@ -0,0 +1,98 @@ +From: Imre Deak <imre.deak@nokia.com> +Date: Wed, 1 Jul 2009 21:20:59 +0000 (+0300) +Subject: So far vfp_sync_state worked only for threads other than the current one. This worked... +X-Git-Url: http://siarhei.siamashka.name/gitweb/?p=linux-omap-2.6.git;a=commitdiff_plain;h=23671113997664ae55c8132fc4a56e676d5b46c7 + +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> +--- + +diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c +index 01599c4..969b77a 100644 +--- a/arch/arm/vfp/vfpmodule.c ++++ b/arch/arm/vfp/vfpmodule.c +@@ -380,12 +380,19 @@ 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 +@@ -393,18 +400,22 @@ 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]) +@@ -413,8 +424,14 @@ 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); + + /* +@@ -426,7 +443,6 @@ void vfp_sync_state(struct thread_info *thread) + out: + put_cpu(); + } +-#endif + + #include <linux/smp.h> + |