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 <[email protected]>
---
arch/unicore32/include/asm/page.h | 4 ++++
arch/unicore32/mm/init.c | 18 ++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/arch/unicore32/include/asm/page.h
b/arch/unicore32/include/asm/page.h
index 594b322..231cb89 100644
--- a/arch/unicore32/include/asm/page.h
+++ b/arch/unicore32/include/asm/page.h
@@ -68,6 +68,10 @@ typedef struct page *pgtable_t;
extern int pfn_valid(unsigned long);
+#ifdef CONFIG_STRICT_DEVMEM
+extern int devmem_is_allowed(unsigned long pfn);
+#endif /* CONFIG_STRICT_DEVMEM */
+
#include <asm/memory.h>
#endif /* !__ASSEMBLY__ */
diff --git a/arch/unicore32/mm/init.c b/arch/unicore32/mm/init.c
index be2bde9..3bc3a59 100644
--- a/arch/unicore32/mm/init.c
+++ b/arch/unicore32/mm/init.c
@@ -449,3 +449,21 @@ static int __init keepinitrd_setup(char *__unused)
__setup("keepinitrd", keepinitrd_setup);
#endif
+
+#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.
+ */
+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 */
--
1.7.9.5
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