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
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -32,7 +32,6 @@
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
--- 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
--- 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 b7e36684..1cc4720 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -395,6 +395,9 @@
#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
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
--- 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
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);
+}
