Re: [PATCH 1/2] Add __compat_aligned_s64 and __compat_aligned_u64
From: H.J. Lu
Date: Wed Dec 25 2013 - 13:15:48 EST
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
> 1. Add default __compat_aligned_s64/__compat_aligned_u64 to
> 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@xxxxxxxxx>
> 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.
> +typedef __s64 __compat_aligned_s64;
> +typedef __u64 __compat_aligned_u64;
Here is the updated patch.