On Wed, Dec 25, 2013 at 09:15:51AM -0800, H.J. Lu wrote:
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:
- 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.
Signed-off-by: H.J. Lu hjl.tools@gmail.com
arch/x86/include/asm/types.h | 6 ++++++ arch/x86/include/uapi/asm/types.h | 35 ++++++++++++++++++++++++++++++++++- include/uapi/asm-generic/int-ll64.h | 3 +++ 3 files changed, 43 insertions(+), 1 deletion(-) create mode 100644 arch/x86/include/asm/types.h
...
diff --git a/arch/x86/include/uapi/asm/types.h b/arch/x86/include/uapi/asm/types.h index 8e8c23f..7dac28b 100644 --- a/arch/x86/include/uapi/asm/types.h +++ b/arch/x86/include/uapi/asm/types.h
...
+#if defined(__i386__) || defined(__ILP32__) +typedef s64 __attribute__((aligned(4))) __compat_aligned_s64; +typedef u64 __attribute__((aligned(4))) __compat_aligned_u64;
Here are 2 typos. They should be __s64 and __u64.
+#else +typedef __s64 __compat_aligned_s64; +typedef __u64 __compat_aligned_u64; +#endif
Here is the updated patch.
H.J.