[XTENSA] Add support for cache-aliasing
Add support for processors that have cache-aliasing issues, such as
the Stretch S5000 processor. Cache-aliasing means that the size of
the cache (for one way) is larger than the page size, thus, a page
can end up in several places in cache depending on the virtual to
physical translation. The method used here is to map a user page
temporarily through the auto-refill way 0 and of of the DTLB.
We probably will want to revisit this issue and use a better
approach with kmap/kunmap.
Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/arch/xtensa/mm/misc.S b/arch/xtensa/mm/misc.S
index ae08533..e1f8803 100644
--- a/arch/xtensa/mm/misc.S
+++ b/arch/xtensa/mm/misc.S
@@ -7,29 +7,33 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
- * Copyright (C) 2001 - 2005 Tensilica Inc.
+ * Copyright (C) 2001 - 2007 Tensilica Inc.
*
* Chris Zankel <chris@zankel.net>
*/
-/* Note: we might want to implement some of the loops as zero-overhead-loops,
- * where applicable and if supported by the processor.
- */
#include <linux/linkage.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/asmmacro.h>
#include <asm/cacheasm.h>
+#include <asm/tlbflush.h>
-/* clear_page (page) */
+
+/*
+ * clear_page and clear_user_page are the same for non-cache-aliased configs.
+ *
+ * clear_page (unsigned long page)
+ * a2
+ */
ENTRY(clear_page)
entry a1, 16
- addi a4, a2, PAGE_SIZE
- movi a3, 0
-1: s32i a3, a2, 0
+ movi a3, 0
+ __loopi a2, a7, PAGE_SIZE, 32
+ s32i a3, a2, 0
s32i a3, a2, 4
s32i a3, a2, 8
s32i a3, a2, 12
@@ -37,43 +41,278 @@
s32i a3, a2, 20
s32i a3, a2, 24
s32i a3, a2, 28
- addi a2, a2, 32
- blt a2, a4, 1b
+ __endla a2, a7, 32
retw
/*
+ * copy_page and copy_user_page are the same for non-cache-aliased configs.
+ *
* copy_page (void *to, void *from)
- * a2 a3
+ * a2 a3
*/
ENTRY(copy_page)
entry a1, 16
- addi a4, a2, PAGE_SIZE
-1: l32i a5, a3, 0
- l32i a6, a3, 4
- l32i a7, a3, 8
- s32i a5, a2, 0
- s32i a6, a2, 4
- s32i a7, a2, 8
- l32i a5, a3, 12
- l32i a6, a3, 16
- l32i a7, a3, 20
- s32i a5, a2, 12
- s32i a6, a2, 16
- s32i a7, a2, 20
- l32i a5, a3, 24
- l32i a6, a3, 28
- s32i a5, a2, 24
- s32i a6, a2, 28
- addi a2, a2, 32
- addi a3, a3, 32
- blt a2, a4, 1b
+ __loopi a2, a4, PAGE_SIZE, 32
+
+ l32i a8, a3, 0
+ l32i a9, a3, 4
+ s32i a8, a2, 0
+ s32i a9, a2, 4
+
+ l32i a8, a3, 8
+ l32i a9, a3, 12
+ s32i a8, a2, 8
+ s32i a9, a2, 12
+
+ l32i a8, a3, 16
+ l32i a9, a3, 20
+ s32i a8, a2, 16
+ s32i a9, a2, 20
+
+ l32i a8, a3, 24
+ l32i a9, a3, 28
+ s32i a8, a2, 24
+ s32i a9, a2, 28
+
+ addi a2, a2, 32
+ addi a3, a3, 32
+
+ __endl a2, a4
retw
/*
+ * If we have to deal with cache aliasing, we use temporary memory mappings
+ * to ensure that the source and destination pages have the same color as
+ * the virtual address. We use way 0 and 1 for temporary mappings in such cases.
+ *
+ * The temporary DTLB entries shouldn't be flushed by interrupts, but are
+ * flushed by preemptive task switches. Special code in the
+ * fast_second_level_miss handler re-established the temporary mapping.
+ * It requires that the PPNs for the destination and source addresses are
+ * in a6, and a7, respectively.
+ */
+
+/* TLB miss exceptions are treated special in the following region */
+
+ENTRY(__tlbtemp_mapping_start)
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+
+/*
+ * clear_user_page (void *addr, unsigned long vaddr, struct page *page)
+ * a2 a3 a4
+ */
+
+ENTRY(clear_user_page)
+ entry a1, 32
+
+ /* Mark page dirty and determine alias. */
+
+ movi a7, (1 << PG_ARCH_1)
+ l32i a5, a4, PAGE_FLAGS
+ xor a6, a2, a3
+ extui a3, a3, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+ extui a6, a6, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+ or a5, a5, a7
+ slli a3, a3, PAGE_SHIFT
+ s32i a5, a4, PAGE_FLAGS
+
+ /* Skip setting up a temporary DTLB if not aliased. */
+
+ beqz a6, 1f
+
+ /* Invalidate kernel page. */
+
+ mov a10, a2
+ call8 __invalidate_dcache_page
+
+ /* Setup a temporary DTLB with the color of the VPN */
+
+ movi a4, -PAGE_OFFSET + (PAGE_KERNEL | _PAGE_HW_WRITE)
+ movi a5, TLBTEMP_BASE_1 # virt
+ add a6, a2, a4 # ppn
+ add a2, a5, a3 # add 'color'
+
+ wdtlb a6, a2
+ dsync
+
+1: movi a3, 0
+ __loopi a2, a7, PAGE_SIZE, 32
+ s32i a3, a2, 0
+ s32i a3, a2, 4
+ s32i a3, a2, 8
+ s32i a3, a2, 12
+ s32i a3, a2, 16
+ s32i a3, a2, 20
+ s32i a3, a2, 24
+ s32i a3, a2, 28
+ __endla a2, a7, 32
+
+ bnez a6, 1f
+ retw
+
+ /* We need to invalidate the temporary idtlb entry, if any. */
+
+1: addi a2, a2, -PAGE_SIZE
+ idtlb a2
+ dsync
+
+ retw
+
+/*
+ * copy_page_user (void *to, void *from, unsigned long vaddr, struct page *page)
+ * a2 a3 a4 a5
+ */
+
+ENTRY(copy_user_page)
+
+ entry a1, 32
+
+ /* Mark page dirty and determine alias for destination. */
+
+ movi a8, (1 << PG_ARCH_1)
+ l32i a9, a5, PAGE_FLAGS
+ xor a6, a2, a4
+ xor a7, a3, a4
+ extui a4, a4, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+ extui a6, a6, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+ extui a7, a7, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+ or a9, a9, a8
+ slli a4, a4, PAGE_SHIFT
+ s32i a9, a5, PAGE_FLAGS
+ movi a5, -PAGE_OFFSET + (PAGE_KERNEL | _PAGE_HW_WRITE)
+
+ beqz a6, 1f
+
+ /* Invalidate dcache */
+
+ mov a10, a2
+ call8 __invalidate_dcache_page
+
+ /* Setup a temporary DTLB with a matching color. */
+
+ movi a8, TLBTEMP_BASE_1 # base
+ add a6, a2, a5 # ppn
+ add a2, a8, a4 # add 'color'
+
+ wdtlb a6, a2
+ dsync
+
+ /* Skip setting up a temporary DTLB for destination if not aliased. */
+
+1: beqz a7, 1f
+
+ /* Setup a temporary DTLB with a matching color. */
+
+ movi a8, TLBTEMP_BASE_2 # base
+ add a7, a3, a5 # ppn
+ add a3, a8, a4
+ addi a8, a3, 1 # way1
+
+ wdtlb a7, a8
+ dsync
+
+1: __loopi a2, a4, PAGE_SIZE, 32
+
+ l32i a8, a3, 0
+ l32i a9, a3, 4
+ s32i a8, a2, 0
+ s32i a9, a2, 4
+
+ l32i a8, a3, 8
+ l32i a9, a3, 12
+ s32i a8, a2, 8
+ s32i a9, a2, 12
+
+ l32i a8, a3, 16
+ l32i a9, a3, 20
+ s32i a8, a2, 16
+ s32i a9, a2, 20
+
+ l32i a8, a3, 24
+ l32i a9, a3, 28
+ s32i a8, a2, 24
+ s32i a9, a2, 28
+
+ addi a2, a2, 32
+ addi a3, a3, 32
+
+ __endl a2, a4
+
+ /* We need to invalidate any temporary mapping! */
+
+ bnez a6, 1f
+ bnez a7, 2f
+ retw
+
+1: addi a2, a2, -PAGE_SIZE
+ idtlb a2
+ dsync
+ bnez a7, 2f
+ retw
+
+2: addi a3, a3, -PAGE_SIZE+1
+ idtlb a3
+ dsync
+
+ retw
+
+#endif
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+
+/*
+ * void __flush_invalidate_dcache_page_alias (addr, phys)
+ * a2 a3
+ */
+
+ENTRY(__flush_invalidate_dcache_page_alias)
+ entry sp, 16
+
+ movi a7, 0 # required for exception handler
+ addi a6, a3, (PAGE_KERNEL | _PAGE_HW_WRITE)
+ mov a4, a2
+ wdtlb a6, a2
+ dsync
+
+ ___flush_invalidate_dcache_page a2 a3
+
+ idtlb a4
+ dsync
+
+ retw
+
+#endif
+
+ENTRY(__tlbtemp_mapping_itlb)
+
+#if (ICACHE_WAY_SIZE > PAGE_SIZE)
+
+ENTRY(__invalidate_icache_page_alias)
+ entry sp, 16
+
+ addi a6, a3, (PAGE_KERNEL | _PAGE_HW_WRITE)
+ mov a4, a2
+ witlb a6, a2
+ isync
+
+ ___invalidate_icache_page a2 a3
+
+ iitlb a4
+ isync
+ retw
+
+#endif
+
+/* End of special treatment in tlb miss exception */
+
+ENTRY(__tlbtemp_mapping_end)
+
+/*
* void __invalidate_icache_page(ulong start)
*/
@@ -121,8 +360,6 @@
dsync
retw
-
-
/*
* void __invalidate_icache_range(ulong start, ulong size)
*/
@@ -168,7 +405,6 @@
___invalidate_dcache_range a2 a3 a4
-
retw
/*