Introduce compat_u64 and compat_s64 types

One common problem with 32 bit system call and ioctl emulation is the
different alignment rules between i386 and 64 bit machines.  A number of
drivers work around this by marking the compat structures as
'attribute((packed))', which is not the right solution because it breaks
all the non-x86 architectures that want to use the same compat code.

Hopefully, this patch improves the situation, it introduces two new types,
compat_u64 and compat_s64.  These are defined on all architectures to have
the same size and alignment as the 32 bit version of u64 and s64.

Signed-off-by: Arnd Bergmann <[email protected]>
Acked-by: David S. Miller <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Vasily Tarasov <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Arnd Bergmann 2007-07-15 23:41:11 -07:00 • committed by Linus Torvalds
commit 4b7775870b
7 changed files with 14 additions and 0 deletions

View file

@ -31,8 +31,10 @@ typedef s32 compat_timer_t;
typedef s32 compat_int_t;
typedef s32 compat_long_t;
typedef s64 compat_s64;
typedef u32 compat_uint_t;
typedef u32 compat_ulong_t;
typedef u64 compat_u64;
struct compat_timespec {
compat_time_t tv_sec;