ARC: [mm] Aliasing VIPT dcache support 4/4

Enforce congruency of userspace shared mappings

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 48af742..d8dd660 100644 (file)
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -32,7 +32,6 @@ generic-y += resource.h
 generic-y += scatterlist.h
 generic-y += sembuf.h
 generic-y += shmbuf.h
-generic-y += shmparam.h
 generic-y += siginfo.h
 generic-y += socket.h
 generic-y += sockios.h

diff --git a/arch/arc/include/asm/cache.h b/arch/arc/include/asm/cache.h
index 6632273..d5555fe 100644 (file)
--- a/arch/arc/include/asm/cache.h
+++ b/arch/arc/include/asm/cache.h
@@ -55,9 +55,6 @@
        : "r"(data), "r"(ptr));         \
 })
 
-/* used to give SHMLBA a value to avoid Cache Aliasing */
-extern unsigned int ARC_shmlba;
-
 #define ARCH_DMA_MINALIGN      L1_CACHE_BYTES
 
 /*

diff --git a/arch/arc/include/asm/cacheflush.h b/arch/arc/include/asm/cacheflush.h
index 14a0fea..9f841af 100644 (file)
--- a/arch/arc/include/asm/cacheflush.h
+++ b/arch/arc/include/asm/cacheflush.h
@@ -19,6 +19,7 @@
 #define _ASM_CACHEFLUSH_H
 
 #include <linux/mm.h>
+#include <asm/shmparam.h>
 
 /*
  * Semantically we need this because icache doesn't snoop dcache/dma.

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index b7e3668..1cc4720 100644 (file)
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -395,6 +395,9 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 
 #include <asm-generic/pgtable.h>
 
+/* to cope with aliasing VIPT cache */
+#define HAVE_ARCH_UNMAPPED_AREA
+
 /*
  * No page table caches to initialise
  */

diff --git a/arch/arc/include/asm/shmparam.h b/arch/arc/include/asm/shmparam.h
new file mode 100644 (file)
index 0000000..fffeecc
--- /dev/null
+++ b/arch/arc/include/asm/shmparam.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ARC_ASM_SHMPARAM_H
+#define __ARC_ASM_SHMPARAM_H
+
+/* Handle upto 2 cache bins */
+#define        SHMLBA  (2 * PAGE_SIZE)
+
+/* Enforce SHMLBA in shmat */
+#define __ARCH_FORCE_SHMLBA
+
+#endif

diff --git a/arch/arc/mm/Makefile b/arch/arc/mm/Makefile
index 168dc14..ac95cc2 100644 (file)
--- a/arch/arc/mm/Makefile
+++ b/arch/arc/mm/Makefile
@@ -7,4 +7,4 @@
 #
 
 obj-y  := extable.o ioremap.o dma.o fault.o init.o
-obj-y  += tlb.o tlbex.o cache_arc700.o
+obj-y  += tlb.o tlbex.o cache_arc700.o mmap.o

diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c
new file mode 100644 (file)
index 0000000..2e06d56
--- /dev/null
+++ b/arch/arc/mm/mmap.c
@@ -0,0 +1,78 @@
+/*
+ * ARC700 mmap
+ *
+ * (started from arm version - for VIPT alias handling)
+ *
+ * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/sched.h>
+#include <asm/cacheflush.h>
+
+#define COLOUR_ALIGN(addr, pgoff)                      \
+       ((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) +      \
+        (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
+
+/*
+ * Ensure that shared mappings are correctly aligned to
+ * avoid aliasing issues with VIPT caches.
+ * We need to ensure that
+ * a specific page of an object is always mapped at a multiple of
+ * SHMLBA bytes.
+ */
+unsigned long
+arch_get_unmapped_area(struct file *filp, unsigned long addr,
+               unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+       struct mm_struct *mm = current->mm;
+       struct vm_area_struct *vma;
+       int do_align = 0;
+       int aliasing = cache_is_vipt_aliasing();
+       struct vm_unmapped_area_info info;
+
+       /*
+        * We only need to do colour alignment if D cache aliases.
+        */
+       if (aliasing)
+               do_align = filp || (flags & MAP_SHARED);
+
+       /*
+        * We enforce the MAP_FIXED case.
+        */
+       if (flags & MAP_FIXED) {
+               if (aliasing && flags & MAP_SHARED &&
+                   (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
+                       return -EINVAL;
+               return addr;
+       }
+
+       if (len > TASK_SIZE)
+               return -ENOMEM;
+
+       if (addr) {
+               if (do_align)
+                       addr = COLOUR_ALIGN(addr, pgoff);
+               else
+                       addr = PAGE_ALIGN(addr);
+
+               vma = find_vma(mm, addr);
+               if (TASK_SIZE - len >= addr &&
+                   (!vma || addr + len <= vma->vm_start))
+                       return addr;
+       }
+
+       info.flags = 0;
+       info.length = len;
+       info.low_limit = mm->mmap_base;
+       info.high_limit = TASK_SIZE;
+       info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+       info.align_offset = pgoff << PAGE_SHIFT;
+       return vm_unmapped_area(&info);
+}