x86-64: Use explicit sizes in sigcontext.h, prepare for x32

Use explicit sizes (__u64) instead of implicit sizes (unsigned long)
in the definition for sigcontext.h; this will allow this structure to
be shared between the x86-64 native ABI and the x32 ABI.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-4pr1xnnksprt7t0h3w5fw4rv@git.kernel.org

arch/x86/include/asm/sigcontext.h

@@ -230,34 +230,37 @@ struct sigcontext {
  * User-space might still rely on the old definition:
  */
 struct sigcontext {
-	unsigned long r8;
-	unsigned long r9;
-	unsigned long r10;
-	unsigned long r11;
-	unsigned long r12;
-	unsigned long r13;
-	unsigned long r14;
-	unsigned long r15;
-	unsigned long rdi;
-	unsigned long rsi;
-	unsigned long rbp;
-	unsigned long rbx;
-	unsigned long rdx;
-	unsigned long rax;
-	unsigned long rcx;
-	unsigned long rsp;
-	unsigned long rip;
-	unsigned long eflags;		/* RFLAGS */
-	unsigned short cs;
-	unsigned short gs;
-	unsigned short fs;
-	unsigned short __pad0;
-	unsigned long err;
-	unsigned long trapno;
-	unsigned long oldmask;
-	unsigned long cr2;
+	__u64 r8;
+	__u64 r9;
+	__u64 r10;
+	__u64 r11;
+	__u64 r12;
+	__u64 r13;
+	__u64 r14;
+	__u64 r15;
+	__u64 rdi;
+	__u64 rsi;
+	__u64 rbp;
+	__u64 rbx;
+	__u64 rdx;
+	__u64 rax;
+	__u64 rcx;
+	__u64 rsp;
+	__u64 rip;
+	__u64 eflags;		/* RFLAGS */
+	__u16 cs;
+	__u16 gs;
+	__u16 fs;
+	__u16 __pad0;
+	__u64 err;
+	__u64 trapno;
+	__u64 oldmask;
+	__u64 cr2;
 	struct _fpstate __user *fpstate;	/* zero when no FPU context */
-	unsigned long reserved1[8];
+#ifndef __LP64__
+	__u32 __fpstate_pad;
+#endif
+	__u64 reserved1[8];
 };
 #endif /* !__KERNEL__ */