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authorPaul Mundt <lethal@linux-sh.org>2008-11-12 12:53:48 +0900
committerPaul Mundt <lethal@linux-sh.org>2008-11-12 12:53:48 +0900
commit185aed75570fb4f78ef283dfa26cd9da5fa06a91 (patch)
treea98cb3f46bf9426f8d4a660d63b8a3ac7d9f369d /arch/sh/mm/mmap.c
parentade7a9b4ccd20ab8159c77a0abd20552f2d6b06c (diff)
sh: Provide a sane valid_phys_addr_range() to prevent TLB reset with PMB.
With the PMB enabled, only P1SEG and up are covered by the PMB mappings, meaning that situations where out-of-bounds physical addresses are read from will lead to TLB reset after the PMB miss, allowing for use cases like dd if=/dev/mem to reset the TLB. Fix this up to make sure the reference is between __MEMORY_START (phys) and __pa(high_memory). This is coherent across all variants of sh/sh64 with and without MMU, though the PMB bug itself is only applicable to SH-4A parts. Reported-by: Hideo Saito <saito@densan.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/mm/mmap.c')
-rw-r--r--arch/sh/mm/mmap.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c
new file mode 100644
index 000000000000..1f3cc3d92d3d
--- /dev/null
+++ b/arch/sh/mm/mmap.c
@@ -0,0 +1,31 @@
+/*
+ * arch/sh/mm/mmap.c
+ *
+ * Copyright (C) 2008 Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <asm/page.h>
+
+/*
+ * You really shouldn't be using read() or write() on /dev/mem. This
+ * might go away in the future.
+ */
+int valid_phys_addr_range(unsigned long addr, size_t count)
+{
+ if (addr < (PAGE_OFFSET + (PFN_START << PAGE_SHIFT)))
+ return 0;
+ if (addr + count > __pa(high_memory))
+ return 0;
+
+ return 1;
+}
+
+int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
+{
+ return 1;
+}