Author: andrew Date: Wed Nov 4 10:21:30 2020 New Revision: 367320 URL: https://svnweb.freebsd.org/changeset/base/367320
Log: Allow the creation of 3 level page tables on arm64 The stage 2 arm64 page tables may need to start at a lower level. This is because we may only be able to map a limited IPA range and trying to use a full 4 levels will cause the CPU to fault in an unrecoverable way. To simplify the code we still allocate the full 4 levels, however level 0 will only ever be used to find the level 1 table used as the base. Handle this by creating a dummy entry in the level 0 table to point to the level 1 table. Sponsored by: Innovate UK Differential Revision: https://reviews.freebsd.org/D26066 Modified: head/sys/arm64/arm64/pmap.c Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Wed Nov 4 07:54:07 2020 (r367319) +++ head/sys/arm64/arm64/pmap.c Wed Nov 4 10:21:30 2020 (r367320) @@ -970,6 +970,8 @@ pmap_bootstrap(vm_offset_t l0pt, vm_offset_t l1pt, vm_ kernel_pmap->pm_l0_paddr = l0pt - kern_delta; kernel_pmap->pm_cookie = COOKIE_FROM(-1, INT_MIN); kernel_pmap->pm_stage = PM_STAGE1; + kernel_pmap->pm_levels = 4; + kernel_pmap->pm_ttbr = kernel_pmap->pm_l0_paddr; kernel_pmap->pm_asid_set = &asids; /* Assume the address we were loaded to is a valid physical address */ @@ -1714,33 +1716,37 @@ pmap_pinit0(pmap_t pmap) pmap->pm_root.rt_root = 0; pmap->pm_cookie = COOKIE_FROM(ASID_RESERVED_FOR_PID_0, INT_MIN); pmap->pm_stage = PM_STAGE1; + pmap->pm_levels = 4; + pmap->pm_ttbr = pmap->pm_l0_paddr; pmap->pm_asid_set = &asids; PCPU_SET(curpmap, pmap); } int -pmap_pinit_stage(pmap_t pmap, enum pmap_stage stage) +pmap_pinit_stage(pmap_t pmap, enum pmap_stage stage, int levels) { - vm_page_t l0pt; + vm_page_t m; /* * allocate the l0 page */ - while ((l0pt = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | + while ((m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO)) == NULL) vm_wait(NULL); - pmap->pm_l0_paddr = VM_PAGE_TO_PHYS(l0pt); + pmap->pm_l0_paddr = VM_PAGE_TO_PHYS(m); pmap->pm_l0 = (pd_entry_t *)PHYS_TO_DMAP(pmap->pm_l0_paddr); - if ((l0pt->flags & PG_ZERO) == 0) + if ((m->flags & PG_ZERO) == 0) pagezero(pmap->pm_l0); pmap->pm_root.rt_root = 0; bzero(&pmap->pm_stats, sizeof(pmap->pm_stats)); pmap->pm_cookie = COOKIE_FROM(-1, INT_MAX); + MPASS(levels == 3 || levels == 4); + pmap->pm_levels = levels; pmap->pm_stage = stage; switch (stage) { case PM_STAGE1: @@ -1757,6 +1763,18 @@ pmap_pinit_stage(pmap_t pmap, enum pmap_stage stage) /* XXX Temporarily disable deferred ASID allocation. */ pmap_alloc_asid(pmap); + /* + * Allocate the level 1 entry to use as the root. This will increase + * the refcount on the level 1 page so it won't be removed until + * pmap_release() is called. + */ + if (pmap->pm_levels == 3) { + PMAP_LOCK(pmap); + m = _pmap_alloc_l3(pmap, NUL2E + NUL1E, NULL); + PMAP_UNLOCK(pmap); + } + pmap->pm_ttbr = VM_PAGE_TO_PHYS(m); + return (1); } @@ -1764,7 +1782,7 @@ int pmap_pinit(pmap_t pmap) { - return (pmap_pinit_stage(pmap, PM_STAGE1)); + return (pmap_pinit_stage(pmap, PM_STAGE1, 4)); } /* @@ -2017,10 +2035,29 @@ retry: void pmap_release(pmap_t pmap) { + boolean_t rv; + struct spglist free; struct asid_set *set; vm_page_t m; int asid; + if (pmap->pm_levels != 4) { + PMAP_ASSERT_STAGE2(pmap); + KASSERT(pmap->pm_stats.resident_count == 1, + ("pmap_release: pmap resident count %ld != 0", + pmap->pm_stats.resident_count)); + KASSERT((pmap->pm_l0[0] & ATTR_DESCR_VALID) == ATTR_DESCR_VALID, + ("pmap_release: Invalid l0 entry: %lx", pmap->pm_l0[0])); + + SLIST_INIT(&free); + m = PHYS_TO_VM_PAGE(pmap->pm_ttbr); + PMAP_LOCK(pmap); + rv = pmap_unwire_l3(pmap, 0, m, &free); + PMAP_UNLOCK(pmap); + MPASS(rv == TRUE); + vm_page_free_pages_toq(&free, true); + } + KASSERT(pmap->pm_stats.resident_count == 0, ("pmap_release: pmap resident count %ld != 0", pmap->pm_stats.resident_count)); @@ -6514,7 +6551,7 @@ pmap_to_ttbr0(pmap_t pmap) { return (ASID_TO_OPERAND(COOKIE_TO_ASID(pmap->pm_cookie)) | - pmap->pm_l0_paddr); + pmap->pm_ttbr); } static bool _______________________________________________ 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"
