From 54cb3dbb4a1cccd6b1bffc169ff638f8e74daf44 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 6 Feb 2010 11:27:45 +0000 Subject: [PATCH] ARM: vfp: fix vfp_sync_state() The more I look at vfp_sync_state(), the more I believe it's trying to do its job in a really obscure way. Essentially, last_VFP_context[] tracks who owns the state in the VFP hardware. If last_VFP_context[] is the context for the thread which we're interested in, then the VFP hardware has context which is not saved in the software state - so we need to bring the software state up to date. If last_VFP_context[] is for some other thread, we really don't care what state the VFP hardware is in; it doesn't contain any information pertinent to the thread we're trying to deal with - so don't touch the hardware. Signed-off-by: Russell King --- arch/arm/vfp/vfpmodule.c | 36 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 20 deletions(-) diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c index f60a5400a25b..86a57aeeda4a 100644 --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -444,32 +444,28 @@ void vfp_sync_state(struct thread_info *thread) 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. + * If the thread we're interested in is the current owner of the + * hardware VFP state, then we need to save its state. */ - if (fpexc & FPEXC_EN) - goto out; + if (last_VFP_context[cpu] == &thread->vfpstate) { + u32 fpexc = fmrx(FPEXC); - if (!last_VFP_context[cpu]) - goto out; + /* + * Save the last VFP state on this CPU. + */ + fmxr(FPEXC, fpexc | FPEXC_EN); + vfp_save_state(&thread->vfpstate, fpexc | FPEXC_EN); + fmxr(FPEXC, fpexc & ~FPEXC_EN); - /* - * Save the last VFP state on this CPU. - */ - fmxr(FPEXC, fpexc | FPEXC_EN); - vfp_save_state(last_VFP_context[cpu], fpexc); - fmxr(FPEXC, fpexc); + /* + * Set the context to NULL to force a reload the next time + * the thread uses the VFP. + */ + last_VFP_context[cpu] = NULL; + } - /* - * Set the context to NULL to force a reload the next time the thread - * uses the VFP. - */ - last_VFP_context[cpu] = NULL; - -out: put_cpu(); } #endif