[dmidecode] [PATCH] dmidecode: SMBIOS data is little-endian

[Jean Delvare]

I originally assumed that the SMBIOS data would use the byte ordering
of the host, however since v2.8.0 the SMBIOS specification clarified
that the SMBIOS data is always little-endian. So change the access
helpers accordingly.

This is good news as far as portability is concerned: we can dump the
table of one host and decode it on another.

Signed-off-by: Jean Delvare <address@hidden>
---
 types.h |   27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

--- dmidecode.orig/types.h      2018-08-06 16:09:54.272472516 +0200
+++ dmidecode/types.h   2018-08-06 16:14:01.015885077 +0200
@@ -11,8 +11,7 @@ typedef unsigned int u32;
 /*
  * You may use the following defines to adjust the type definitions
  * depending on the architecture:
- * - Define BIGENDIAN on big-endian systems. Untested, as all target
- *   systems to date are little-endian.
+ * - Define BIGENDIAN on big-endian systems.
  * - Define ALIGNMENT_WORKAROUND if your system doesn't support
  *   non-aligned memory access. In this case, we use a slower, but safer,
  *   memory access method. This should be done automatically in config.h
@@ -31,7 +30,7 @@ typedef struct {
 } u64;
 #endif
 
-#ifdef ALIGNMENT_WORKAROUND
+#if defined(ALIGNMENT_WORKAROUND) || defined(BIGENDIAN)
 static inline u64 U64(u32 low, u32 high)
 {
        u64 self;
@@ -43,20 +42,18 @@ static inline u64 U64(u32 low, u32 high)
 }
 #endif
 
-#ifdef ALIGNMENT_WORKAROUND
-#      ifdef BIGENDIAN
-#      define WORD(x) (u16)((x)[1] + ((x)[0] << 8))
-#      define DWORD(x) (u32)((x)[3] + ((x)[2] << 8) + ((x)[1] << 16) + ((x)[0] 
<< 24))
-#      define QWORD(x) (U64(DWORD(x + 4), DWORD(x)))
-#      else /* BIGENDIAN */
-#      define WORD(x) (u16)((x)[0] + ((x)[1] << 8))
-#      define DWORD(x) (u32)((x)[0] + ((x)[1] << 8) + ((x)[2] << 16) + ((x)[3] 
<< 24))
-#      define QWORD(x) (U64(DWORD(x), DWORD(x + 4)))
-#      endif /* BIGENDIAN */
-#else /* ALIGNMENT_WORKAROUND */
+/*
+ * Per SMBIOS v2.8.0 and later, all structures assume a little-endian
+ * ordering convention.
+ */
+#if defined(ALIGNMENT_WORKAROUND) || defined(BIGENDIAN)
+#define WORD(x) (u16)((x)[0] + ((x)[1] << 8))
+#define DWORD(x) (u32)((x)[0] + ((x)[1] << 8) + ((x)[2] << 16) + ((x)[3] << 
24))
+#define QWORD(x) (U64(DWORD(x), DWORD(x + 4)))
+#else /* ALIGNMENT_WORKAROUND || BIGENDIAN */
 #define WORD(x) (u16)(*(const u16 *)(x))
 #define DWORD(x) (u32)(*(const u32 *)(x))
 #define QWORD(x) (*(const u64 *)(x))
-#endif /* ALIGNMENT_WORKAROUND */
+#endif /* ALIGNMENT_WORKAROUND || BIGENDIAN */
 
 #endif


-- 
Jean Delvare
SUSE L3 Support