X32 uses the 32-bit compat layer for 32-bit kernel interface, which is also used by ia32. But long long is 4-byte aligned for ia32 and 8-byte aligned for x32. When the long long field in a system call struct has different offsets between ia32 and x32 due to alignment padding, like struct snd_ctl_elem_value in include/uapi/sound/asound.h, we need to either add a special case for x32 or we can use 4-byte aligned long long in the system call struct so that x32 can share the same compat system cal with ia32. This patch adds __compat_aligned_s64 and __compat_aligned_u64 to include/uapi/asm-generic/int-ll64.h. By default, they are the same as __s64/__u64. It does the following things:
1. Add default __compat_aligned_s64/__compat_aligned_u64 to include/uapi/asm-generic/int-ll64.h. 2. Add arch/x86/include/asm/types.h for kernel internal use, which is the same as before, i.e., <asm-generic/types.h>. 3. Change arch/x86/include/uapi/asm/types.h not to use the default include/uapi/asm-generic/int-ll64.h. Instead, it has a modified copy of include/uapi/asm-generic/int-ll64.h with 4-byte aligned __compat_aligned_s64 and __compat_aligned_u64 for x32 and ia32. When building x86 kernel, nothing is changed. The difference is x32 can use 4-byte aligned long long for system calls so that it can share the same 32-bit compat system call with ia32. -- H.J.
0001-Add-__compat_aligned_s64-and-__compat_aligned_u64.patch
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