dtc/libfdt: introduce fdt types for annotation by endian checkers

Projects such as linux and u-boot run sparse on libfdt.  libfdt
contains the notion of endianness via usage of endian conversion
functions such as fdt32_to_cpu.  As such, in order to pass endian
checks, libfdt has to annotate its fdt variables such that sparse
can warn when mixing bitwise and regular integers.  This patch adds
these new fdtXX_t types and, ifdef __CHECKER__ (a symbol sparse
defines), includes the bitwise annotation.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 42 insertions, 11 deletions

diff --git a/libfdt/libfdt_env.h b/libfdt/libfdt_env.h
index 213d7fb..956b4ae 100644
--- a/libfdt/libfdt_env.h
+++ b/libfdt/libfdt_env.h
@@ -5,25 +5,56 @@
 #include <stdint.h>
 #include <string.h>
 
-#define EXTRACT_BYTE(n)	((unsigned long long)((uint8_t *)&x)[n])
-static inline uint16_t fdt16_to_cpu(uint16_t x)
+#ifdef __CHECKER__
+#define __force __attribute__((force))
+#define __bitwise __attribute__((bitwise))
+#else
+#define __force
+#define __bitwise
+#endif
+
+typedef uint16_t __bitwise fdt16_t;
+typedef uint32_t __bitwise fdt32_t;
+typedef uint64_t __bitwise fdt64_t;
+
+#define EXTRACT_BYTE(x, n)	((unsigned long long)((uint8_t *)&x)[n])
+#define CPU_TO_FDT16(x) ((EXTRACT_BYTE(x, 0) << 8) | EXTRACT_BYTE(x, 1))
+#define CPU_TO_FDT32(x) ((EXTRACT_BYTE(x, 0) << 24) | (EXTRACT_BYTE(x, 1) << 16) | \
+			 (EXTRACT_BYTE(x, 2) << 8) | EXTRACT_BYTE(x, 3))
+#define CPU_TO_FDT64(x) ((EXTRACT_BYTE(x, 0) << 56) | (EXTRACT_BYTE(x, 1) << 48) | \
+			 (EXTRACT_BYTE(x, 2) << 40) | (EXTRACT_BYTE(x, 3) << 32) | \
+			 (EXTRACT_BYTE(x, 4) << 24) | (EXTRACT_BYTE(x, 5) << 16) | \
+			 (EXTRACT_BYTE(x, 6) << 8) | EXTRACT_BYTE(x, 7))
+
+static inline uint16_t fdt16_to_cpu(fdt16_t x)
+{
+	return (__force uint16_t)CPU_TO_FDT16(x);
+}
+static inline fdt16_t cpu_to_fdt16(uint16_t x)
 {
-	return (EXTRACT_BYTE(0) << 8) | EXTRACT_BYTE(1);
+	return (__force fdt16_t)CPU_TO_FDT16(x);
 }
-#define cpu_to_fdt16(x) fdt16_to_cpu(x)
 
-static inline uint32_t fdt32_to_cpu(uint32_t x)
+static inline uint32_t fdt32_to_cpu(fdt32_t x)
 {
-	return (EXTRACT_BYTE(0) << 24) | (EXTRACT_BYTE(1) << 16) | (EXTRACT_BYTE(2) << 8) | EXTRACT_BYTE(3);
+	return (__force uint32_t)CPU_TO_FDT32(x);
+}
+static inline fdt32_t cpu_to_fdt32(uint32_t x)
+{
+	return (__force fdt32_t)CPU_TO_FDT32(x);
 }
-#define cpu_to_fdt32(x) fdt32_to_cpu(x)
 
-static inline uint64_t fdt64_to_cpu(uint64_t x)
+static inline uint64_t fdt64_to_cpu(fdt64_t x)
+{
+	return (__force uint64_t)CPU_TO_FDT64(x);
+}
+static inline fdt64_t cpu_to_fdt64(uint64_t x)
 {
-	return (EXTRACT_BYTE(0) << 56) | (EXTRACT_BYTE(1) << 48) | (EXTRACT_BYTE(2) << 40) | (EXTRACT_BYTE(3) << 32)
-		| (EXTRACT_BYTE(4) << 24) | (EXTRACT_BYTE(5) << 16) | (EXTRACT_BYTE(6) << 8) | EXTRACT_BYTE(7);
+	return (__force fdt64_t)CPU_TO_FDT64(x);
 }
-#define cpu_to_fdt64(x) fdt64_to_cpu(x)
+#undef CPU_TO_FDT64
+#undef CPU_TO_FDT32
+#undef CPU_TO_FDT16
 #undef EXTRACT_BYTE
 
 #endif /* _LIBFDT_ENV_H */