Date: Mon, 8 Jan 2018 11:08:45 +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: r327691 - head/sys/arm64/arm64 Message-ID: <201801081108.w08B8jN5014903@repo.freebsd.org>
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Author: andrew Date: Mon Jan 8 11:08:45 2018 New Revision: 327691 URL: https://svnweb.freebsd.org/changeset/base/327691 Log: Only install the new pagetable pointer into ttbr0_el1 when it differs from the existing value. MFC after: 1 week Sponsored by: DARPA, AFRL Modified: head/sys/arm64/arm64/pmap.c Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Mon Jan 8 10:23:31 2018 (r327690) +++ head/sys/arm64/arm64/pmap.c Mon Jan 8 11:08:45 2018 (r327691) @@ -4677,17 +4677,20 @@ pmap_switch(struct thread *old, struct thread *new) * to a user process. */ - __asm __volatile( - /* Switch to the new pmap */ - "msr ttbr0_el1, %0 \n" - "isb \n" + if (old == NULL || + old->td_proc->p_md.md_l0addr != new->td_proc->p_md.md_l0addr) { + __asm __volatile( + /* Switch to the new pmap */ + "msr ttbr0_el1, %0 \n" + "isb \n" - /* Invalidate the TLB */ - "dsb ishst \n" - "tlbi vmalle1is \n" - "dsb ish \n" - "isb \n" - : : "r"(new->td_proc->p_md.md_l0addr)); + /* Invalidate the TLB */ + "dsb ishst \n" + "tlbi vmalle1is \n" + "dsb ish \n" + "isb \n" + : : "r"(new->td_proc->p_md.md_l0addr)); + } return (pcb); }
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