Attachment 199259 Details for Bug 233088 – proposed patch

[patch] proposed patch

pmap_remove_l2.diff (text/plain), 2.45 KB, created by Mark Johnston on 2018-11-15 17:29:17 UTC

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Creator: Mark Johnston

Created: 2018-11-15 17:29:17 UTC

Size: 2.45 KB

patch

obsolete

>commit 585ddfd05a7b01cac0a86f21e997a5e2b3f721fd
>Author: Mark Johnston <markjdb@gmail.com>
>Date:   Tue Nov 13 11:36:37 2018 -0500
>
>    arm64 pmap: Handle kernel mappings in pmap_remove_l2().
>
>diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
>index 1e8f61fa1a5e..3c8bf9b48b1b 100644
>--- a/sys/arm64/arm64/pmap.c
>+++ b/sys/arm64/arm64/pmap.c
>@@ -2382,8 +2382,40 @@ pmap_pv_insert_l2(pmap_t pmap, vm_offset_t va, pd_entry_t l2e, u_int flags,
> 	return (true);
> }
> 
>+static void
>+pmap_remove_kernel_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_t va)
>+{
>+	pt_entry_t newl2, oldl2;
>+	vm_page_t ml3;
>+	vm_paddr_t ml3pa;
>+
>+	KASSERT(!VIRT_IN_DMAP(va), ("removing direct mapping of %#lx", va));
>+	KASSERT(pmap == kernel_pmap, ("pmap %p is not kernel_pmap", pmap));
>+	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
>+
>+	ml3 = pmap_remove_pt_page(pmap, va);
>+	if (ml3 == NULL)
>+		panic("pmap_remove_kernel_l2: Missing pt page");
>+
>+	ml3pa = VM_PAGE_TO_PHYS(ml3);
>+	newl2 = ml3pa | L2_TABLE;
>+
>+	/*
>+	 * Initialize the page table page.
>+	 */
>+	pagezero((void *)PHYS_TO_DMAP(ml3pa));
>+
>+	/*
>+	 * Demote the mapping.  The caller must have already invalidated the
>+	 * mapping (i.e., the "break" in break-before-make).
>+	 */
>+	oldl2 = pmap_load_store(l2, newl2);
>+	KASSERT(oldl2 == 0, ("%s: found existing mapping at %p: %#lx",
>+	    __func__, l2, oldl2));
>+}
>+
> /*
>- * pmap_remove_l2: do the things to unmap a level 2 superpage in a process
>+ * pmap_remove_l2: Do the things to unmap a level 2 superpage.
>  */
> static int
> pmap_remove_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_t sva,
>@@ -2419,16 +2451,18 @@ pmap_remove_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_t sva,
> 				vm_page_aflag_clear(m, PGA_WRITEABLE);
> 		}
> 	}
>-	KASSERT(pmap != kernel_pmap,
>-	    ("Attempting to remove an l2 kernel page"));
>-	ml3 = pmap_remove_pt_page(pmap, sva);
>-	if (ml3 != NULL) {
>-		pmap_resident_count_dec(pmap, 1);
>-		KASSERT(ml3->wire_count == NL3PG,
>-		    ("pmap_remove_l2: l3 page wire count error"));
>-		ml3->wire_count = 1;
>-		vm_page_unwire_noq(ml3);
>-		pmap_add_delayed_free_list(ml3, free, FALSE);
>+	if (pmap == kernel_pmap) {
>+		pmap_remove_kernel_l2(pmap, l2, sva);
>+	} else {
>+		ml3 = pmap_remove_pt_page(pmap, sva);
>+		if (ml3 != NULL) {
>+			pmap_resident_count_dec(pmap, 1);
>+			KASSERT(ml3->wire_count == NL3PG,
>+			    ("pmap_remove_l2: l3 page wire count error"));
>+			ml3->wire_count = 1;
>+			vm_page_unwire_noq(ml3);
>+			pmap_add_delayed_free_list(ml3, free, FALSE);
>+		}
> 	}
> 	return (pmap_unuse_pt(pmap, sva, l1e, free));
> }

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Attachments on bug 233088: 199094 | 199188 | 199259