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 <arnd@arndb.de> Acked-by: David S. Miller <davem@davemloft.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Andi Kleen <ak@suse.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Vasily Tarasov <vtaras@openvz.org> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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