linux-kernel - [PATCH 1/2] Add __compat_aligned_s64 and __compat_aligned

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Date:	Wed, 25 Dec 2013 09:15:51 -0800
From:	"H.J. Lu" <hjl.tools@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	"alan.cox@...el.com Thomas Gleixner" <tglx@...utronix.de>,
	tiwai@...e.de, perex@...ex.cz, alsa-devel@...a-project.org
Subject: [PATCH 1/2] Add __compat_aligned_s64 and __compat_aligned_u64

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.

Signed-off-by: H.J. Lu <hjl.tools@...il.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/asm/types.h b/arch/x86/include/asm/types.h
new file mode 100644
index 0000000..8e8c23f
--- /dev/null
+++ b/arch/x86/include/asm/types.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_X86_TYPES_H
+#define _ASM_X86_TYPES_H
+
+#include <asm-generic/types.h>
+
+#endif /* _ASM_X86_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
@@ -1,6 +1,39 @@
 #ifndef _ASM_X86_TYPES_H
 #define _ASM_X86_TYPES_H

-#include <asm-generic/types.h>
+#include <asm/bitsperlong.h>
+
+#ifndef __ASSEMBLY__
+/*
+ * __xx is ok: it doesn't pollute the POSIX namespace. Use these in the
+ * header files exported to user space
+ */
+
+typedef __signed__ char __s8;
+typedef unsigned char __u8;
+
+typedef __signed__ short __s16;
+typedef unsigned short __u16;
+
+typedef __signed__ int __s32;
+typedef unsigned int __u32;
+
+#ifdef __GNUC__
+__extension__ typedef __signed__ long long __s64;
+__extension__ typedef unsigned long long __u64;
+#else
+typedef __signed__ long long __s64;
+typedef unsigned long long __u64;
+#endif
+
+#if defined(__i386__) || defined(__ILP32__)
+typedef s64 __attribute__((aligned(4))) __compat_aligned_s64;
+typedef u64 __attribute__((aligned(4))) __compat_aligned_u64;
+#else
+typedef __s64 __compat_aligned_s64;
+typedef __u64 __compat_aligned_u64;
+#endif
+
+#endif /* __ASSEMBLY__ */

 #endif /* _ASM_X86_TYPES_H */
diff --git a/include/uapi/asm-generic/int-ll64.h b/include/uapi/asm-generic/int-ll64.h
index a8658b2..3306917 100644
--- a/include/uapi/asm-generic/int-ll64.h
+++ b/include/uapi/asm-generic/int-ll64.h
@@ -33,6 +33,9 @@ typedef __signed__ long long __s64;
 typedef unsigned long long __u64;
 #endif

+typedef __s64 __compat_aligned_s64;
+typedef __u64 __compat_aligned_u64;
+
 #endif /* __ASSEMBLY__ */

-- 
1.8.1.4

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