Author: alc Date: Thu Jul 11 02:43:23 2019 New Revision: 349905 URL: https://svnweb.freebsd.org/changeset/base/349905
Log: According to Section D5.10.3 "Maintenance requirements on changing System register values" of the architecture manual, an isb instruction should be executed after updating ttbr0_el1 and before invalidating the TLB. The lack of this instruction in pmap_activate() appears to be the reason why andrew@ and I have observed an unexpected TLB entry for an invalid PTE on entry to pmap_enter_quick_locked(). Thus, we should now be able to revert the workaround committed in r349442. Reviewed by: markj MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D20904 Modified: head/sys/arm64/arm64/efirt_machdep.c head/sys/arm64/arm64/pmap.c Modified: head/sys/arm64/arm64/efirt_machdep.c ============================================================================== --- head/sys/arm64/arm64/efirt_machdep.c Thu Jul 11 02:15:50 2019 (r349904) +++ head/sys/arm64/arm64/efirt_machdep.c Thu Jul 11 02:43:23 2019 (r349905) @@ -239,6 +239,7 @@ efi_arch_enter(void) __asm __volatile( "msr ttbr0_el1, %0 \n" + "isb \n" "dsb ishst \n" "tlbi vmalle1is \n" "dsb ish \n" @@ -266,6 +267,7 @@ efi_arch_leave(void) td = curthread; __asm __volatile( "msr ttbr0_el1, %0 \n" + "isb \n" "dsb ishst \n" "tlbi vmalle1is \n" "dsb ish \n" Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Thu Jul 11 02:15:50 2019 (r349904) +++ head/sys/arm64/arm64/pmap.c Thu Jul 11 02:43:23 2019 (r349905) @@ -5484,8 +5484,10 @@ pmap_activate(struct thread *td) critical_enter(); pmap = vmspace_pmap(td->td_proc->p_vmspace); td->td_proc->p_md.md_l0addr = vtophys(pmap->pm_l0); - __asm __volatile("msr ttbr0_el1, %0" : : - "r"(td->td_proc->p_md.md_l0addr)); + __asm __volatile( + "msr ttbr0_el1, %0 \n" + "isb \n" + : : "r"(td->td_proc->p_md.md_l0addr)); pmap_invalidate_all(pmap); critical_exit(); } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
