ARC: [mm] Aliasing VIPT dcache support 2/4
This is the meat of the series which prevents any dcache alias creation
by always keeping the U and K mapping of a page congruent.
If a mapping already exists, and other tries to access the page, prev
one is flushed to physical page (wback+inv)
Essentially flush_dcache_page()/copy_user_highpage() create K-mapping
of a page, but try to defer flushing, unless U-mapping exist.
When page is actually mapped to userspace, update_mmu_cache() flushes
the K-mapping (in certain cases this can be optimised out)
Additonally flush_cache_mm(), flush_cache_range(), flush_cache_page()
handle the puring of stale userspace mappings on exit/munmap...
flush_anon_page() handles the existing U-mapping for anon page before
kernel reads it via the GUP path.
Note that while not complete, this is enough to boot a simple
dynamically linked Busybox based rootfs
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/include/asm/cacheflush.h b/arch/arc/include/asm/cacheflush.h
index ed820bcb..d692fbb 100644
--- a/arch/arc/include/asm/cacheflush.h
+++ b/arch/arc/include/asm/cacheflush.h
@@ -50,18 +50,55 @@
#define flush_cache_vmap(start, end) flush_cache_all()
#define flush_cache_vunmap(start, end) flush_cache_all()
-/*
- * VM callbacks when entire/range of user-space V-P mappings are
- * torn-down/get-invalidated
- *
- * Currently we don't support D$ aliasing configs for our VIPT caches
- * NOPS for VIPT Cache with non-aliasing D$ configurations only
- */
-#define flush_cache_dup_mm(mm) /* called on fork */
+#define flush_cache_dup_mm(mm) /* called on fork (VIVT only) */
+
+#ifndef CONFIG_ARC_CACHE_VIPT_ALIASING
+
#define flush_cache_mm(mm) /* called on munmap/exit */
#define flush_cache_range(mm, u_vstart, u_vend)
#define flush_cache_page(vma, u_vaddr, pfn) /* PF handling/COW-break */
+#else /* VIPT aliasing dcache */
+
+/* To clear out stale userspace mappings */
+void flush_cache_mm(struct mm_struct *mm);
+void flush_cache_range(struct vm_area_struct *vma,
+ unsigned long start,unsigned long end);
+void flush_cache_page(struct vm_area_struct *vma,
+ unsigned long user_addr, unsigned long page);
+
+/*
+ * To make sure that userspace mapping is flushed to memory before
+ * get_user_pages() uses a kernel mapping to access the page
+ */
+#define ARCH_HAS_FLUSH_ANON_PAGE
+void flush_anon_page(struct vm_area_struct *vma,
+ struct page *page, unsigned long u_vaddr);
+
+#endif /* CONFIG_ARC_CACHE_VIPT_ALIASING */
+
+/*
+ * Simple wrapper over config option
+ * Bootup code ensures that hardware matches kernel configuration
+ */
+static inline int cache_is_vipt_aliasing(void)
+{
+#ifdef CONFIG_ARC_CACHE_VIPT_ALIASING
+ return 1;
+#else
+ return 0;
+#endif
+}
+
+#define CACHE_COLOR(addr) (((unsigned long)(addr) >> (PAGE_SHIFT)) & 3)
+
+/*
+ * checks if two addresses (after page aligning) index into same cache set
+ */
+#define addr_not_cache_congruent(addr1, addr2) \
+ cache_is_vipt_aliasing() ? \
+ (CACHE_COLOR(addr1) != CACHE_COLOR(addr2)) : 0 \
+
#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
do { \
memcpy(dst, src, len); \
diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index bdf5461..374a355 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -16,13 +16,27 @@
#define get_user_page(vaddr) __get_free_page(GFP_KERNEL)
#define free_user_page(page, addr) free_page(addr)
-/* TBD: for now don't worry about VIPT D$ aliasing */
#define clear_page(paddr) memset((paddr), 0, PAGE_SIZE)
#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
+#ifndef CONFIG_ARC_CACHE_VIPT_ALIASING
+
#define clear_user_page(addr, vaddr, pg) clear_page(addr)
#define copy_user_page(vto, vfrom, vaddr, pg) copy_page(vto, vfrom)
+#else /* VIPT aliasing dcache */
+
+struct vm_area_struct;
+struct page;
+
+#define __HAVE_ARCH_COPY_USER_HIGHPAGE
+
+void copy_user_highpage(struct page *to, struct page *from,
+ unsigned long u_vaddr, struct vm_area_struct *vma);
+void clear_user_page(void *to, unsigned long u_vaddr, struct page *page);
+
+#endif /* CONFIG_ARC_CACHE_VIPT_ALIASING */
+
#undef STRICT_MM_TYPECHECKS
#ifdef STRICT_MM_TYPECHECKS
diff --git a/arch/arc/include/asm/tlb.h b/arch/arc/include/asm/tlb.h
index fe91719..85b6df8 100644
--- a/arch/arc/include/asm/tlb.h
+++ b/arch/arc/include/asm/tlb.h
@@ -30,13 +30,20 @@
/*
* This pair is called at time of munmap/exit to flush cache and TLB entries
* for mappings being torn down.
- * 1) cache-flush part -implemented via tlb_start_vma( ) can be NOP (for now)
- * as we don't support aliasing configs in our VIPT D$.
+ * 1) cache-flush part -implemented via tlb_start_vma( ) for VIPT aliasing D$
* 2) tlb-flush part - implemted via tlb_end_vma( ) flushes the TLB range
*
* Note, read http://lkml.org/lkml/2004/1/15/6
*/
+#ifndef CONFIG_ARC_CACHE_VIPT_ALIASING
#define tlb_start_vma(tlb, vma)
+#else
+#define tlb_start_vma(tlb, vma) \
+do { \
+ if (!tlb->fullmm) \
+ flush_cache_range(vma, vma->vm_start, vma->vm_end); \
+} while(0)
+#endif
#define tlb_end_vma(tlb, vma) \
do { \