lkml.org 
[lkml]   [2014]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH v2] arch:unicore32:mm: add devmem_is_allowed() to support STRICT_DEVMEM
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 | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/arch/unicore32/include/asm/io.h b/arch/unicore32/include/asm/io.h
index 39decb6..839c2ea 100644
--- a/arch/unicore32/include/asm/io.h
+++ b/arch/unicore32/include/asm/io.h
@@ -44,5 +44,23 @@ 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
+/*
+ * 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2014-04-15 02:41    [W:1.090 / U:0.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site