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x86: improvements to build-time pagetable generation
* Additional comments, including size and runtime use. * Consistent use of .quad, rather than a mix including .long. No change in runtime behaviour. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
This commit is contained in:
Andrew Cooper authored and Jan Beulich committed
1 parent
aaa511d217
commit
0c15c49d42
1 file changed
+18
-7
@@ -86,32 +86,40 @@ GLOBAL(__page_tables_start)
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* Mapping of first 2 megabytes of memory. This is mapped with 4kB mappings
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* to avoid type conflicts with fixed-range MTRRs covering the lowest megabyte
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* of physical memory. In any case the VGA hole should be mapped with type UC.
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* Uses 1x 4k page.
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*/
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GLOBAL(l1_identmap)
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pfn = 0
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.rept L1_PAGETABLE_ENTRIES
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/* VGA hole (0xa0000-0xc0000) should be mapped UC. */
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.if pfn >= 0xa0 && pfn < 0xc0
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.long (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR_NOCACHE | MAP_SMALL_PAGES
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.quad (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR_NOCACHE | MAP_SMALL_PAGES
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.else
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.long (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR | MAP_SMALL_PAGES
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.quad (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR | MAP_SMALL_PAGES
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.endif
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.long 0
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pfn = pfn + 1
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.endr
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.size l1_identmap, . - l1_identmap
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/* Mapping of first 16 megabytes of memory. */
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/*
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* Space for mapping the first 4GB of memory, with the first 16 megabytes
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* actualy mapped (mostly using superpages). Uses 4x 4k pages.
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*/
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GLOBAL(l2_identmap)
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.quad sym_phys(l1_identmap) + __PAGE_HYPERVISOR
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pfn = 0
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idx = 1
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.rept 7
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pfn = pfn + (1 << PAGETABLE_ORDER)
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.quad (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR | _PAGE_PSE
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.quad (idx << L2_PAGETABLE_SHIFT) | PAGE_HYPERVISOR | _PAGE_PSE
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idx = idx + 1
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.endr
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.fill 4 * L2_PAGETABLE_ENTRIES - 8, 8, 0
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.size l2_identmap, . - l2_identmap
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/*
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* L2 mapping the 1GB Xen text/data/bss region. At boot it maps 16MB from
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* __image_base__, and is modified when Xen relocates itself. Uses 1x 4k
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* page.
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*/
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GLOBAL(l2_xenmap)
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idx = 0
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.rept 8
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@@ -121,6 +129,7 @@ GLOBAL(l2_xenmap)
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.fill L2_PAGETABLE_ENTRIES - 8, 8, 0
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.size l2_xenmap, . - l2_xenmap
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/* L2 mapping the fixmap. Uses 1x 4k page. */
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l2_fixmap:
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idx = 0
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.rept L2_PAGETABLE_ENTRIES
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@@ -133,6 +142,7 @@ l2_fixmap:
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.endr
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.size l2_fixmap, . - l2_fixmap
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/* Identity map, covering the 4 l2_identmap tables. Uses 1x 4k page. */
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GLOBAL(l3_identmap)
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idx = 0
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.rept 4
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@@ -142,6 +152,7 @@ GLOBAL(l3_identmap)
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.fill L3_PAGETABLE_ENTRIES - 4, 8, 0
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.size l3_identmap, . - l3_identmap
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/* L3 mapping the fixmap. Uses 1x 4k page. */
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l3_xenmap:
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idx = 0
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.rept L3_PAGETABLE_ENTRIES
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