Date: Tue, 21 Nov 2017 13:19:38 +0000 (UTC) From: Andrew Turner <andrew@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r326056 - head/sys/arm64/arm64 Message-ID: <201711211319.vALDJcNt074076@repo.freebsd.org>
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Author: andrew Date: Tue Nov 21 13:19:38 2017 New Revision: 326056 URL: https://svnweb.freebsd.org/changeset/base/326056 Log: When fpcurthread is not the current thread it may be non-NULL. In this case another thread has had the VFP unit enabled and will have its state in the VFP registers along with it stored in memory. As such we don't need to store the state, but do need to zero the fpcurthread pointer to stop the VFP driver from using the enable fast path. Reported by: emaste Sponsored by: DARPA, AFRL Modified: head/sys/arm64/arm64/vfp.c Modified: head/sys/arm64/arm64/vfp.c ============================================================================== --- head/sys/arm64/arm64/vfp.c Tue Nov 21 13:17:40 2017 (r326055) +++ head/sys/arm64/arm64/vfp.c Tue Nov 21 13:19:38 2017 (r326056) @@ -273,11 +273,8 @@ fpu_kern_enter(struct thread *td, struct fpu_kern_ctx critical_enter(); if (curthread == PCPU_GET(fpcurthread)) { vfp_save_state(curthread, pcb); - PCPU_SET(fpcurthread, NULL); - } else { - KASSERT(PCPU_GET(fpcurthread) == NULL, - ("invalid fpcurthread")); } + PCPU_SET(fpcurthread, NULL); vfp_enable(); pcb->pcb_fpflags |= PCB_FP_KERN | PCB_FP_NOSAVE |
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