From f63375759eb2d49eda5984ac62b5abc7ca2e2b3b Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Sun, 2 Sep 2018 22:38:41 +0200 Subject: dmidecode: SMBIOS data is little-endian 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 --- types.h | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) (limited to 'types.h') diff --git a/types.h b/types.h index 19d803d..51c32d7 100644 --- a/types.h +++ b/types.h @@ -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 -- cgit v1.2.1