From: Chen Gang <gang.chen.5i5j@gmail.com>
To: 管雪涛 <gxt@pku.edu.cn>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>,
akpm@linux-foundation.org, liuj97@gmail.com, rientjes@google.com,
dhowells@redhat.com, mhocko@suse.cz, mgorman@suse.de,
linux-kernel@vger.kernel.org
Subject: [PATCH v3] arch:unicore32:mm: add devmem_is_allowed() to support STRICT_DEVMEM
Date: Tue, 15 Apr 2014 09:21:30 +0800 [thread overview]
Message-ID: <534C899A.2020008@gmail.com> (raw)
In-Reply-To: <534C8073.3060607@gmail.com>
unicore32 supports STRICT_DEVMEM, so it needs devmem_is_allowed(), like
some of other architectures have done (e.g. arm, powerpc, x86 ...).
The related error with allmodconfig:
CC drivers/char/mem.o
drivers/char/mem.c: In function ‘range_is_allowed’:
drivers/char/mem.c:69: error: implicit declaration of function ‘devmem_is_allowed’
make[2]: *** [drivers/char/mem.o] Error 1
make[1]: *** [drivers/char] Error 2
make: *** [drivers] Error 2
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
---
arch/unicore32/include/asm/io.h | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/arch/unicore32/include/asm/io.h b/arch/unicore32/include/asm/io.h
index 39decb6..ae327e4 100644
--- a/arch/unicore32/include/asm/io.h
+++ b/arch/unicore32/include/asm/io.h
@@ -44,5 +44,28 @@ extern void __uc32_iounmap(volatile void __iomem *addr);
#define PIO_MASK (unsigned int)(IO_SPACE_LIMIT)
#define PIO_RESERVED (PIO_OFFSET + PIO_MASK + 1)
+#ifdef CONFIG_STRICT_DEVMEM
+
+#include <linux/ioport.h>
+#include <linux/mm.h>
+
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain
+ * address is valid. The argument is a physical page number.
+ * We mimic x86 here by disallowing access to system RAM as well as
+ * device-exclusive MMIO regions. This effectively disable read()/write()
+ * on /dev/mem.
+ */
+static inline int devmem_is_allowed(unsigned long pfn)
+{
+ if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+ return 0;
+ if (!page_is_ram(pfn))
+ return 1;
+ return 0;
+}
+
+#endif /* CONFIG_STRICT_DEVMEM */
+
#endif /* __KERNEL__ */
#endif /* __UNICORE_IO_H__ */
--
1.7.9.5
next prev parent reply other threads:[~2014-04-15 1:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-07 11:28 [PATCH] arch:unicore32:mm: add devmem_is_allowed() to support STRICT_DEVMEM Chen Gang
2014-04-08 3:20 ` 回复: " 管雪涛
2014-04-08 4:54 ` Chen Gang
2014-04-15 0:14 ` Chen Gang
2014-04-15 0:28 ` [PATCH v2] " Chen Gang
2014-04-15 0:42 ` Chen Gang
2014-04-15 1:21 ` Chen Gang [this message]
2014-04-16 5:15 ` 回复: [PATCH v3] " 管雪涛
2014-04-16 5:43 ` Chen Gang
2014-04-16 9:05 ` Michal Hocko
2014-04-16 10:11 ` Chen Gang
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