[PATCH] Change 64bit epoll ABI for AMD64

As discussed earlier. The 64bit epoll ABI on AMD64 is changed to
match 32bit. This way we avoid emulation overhead.

To catch old binaries I allocate new syscall slots.

include/asm-x86_64/unistd.h

@@ -486,10 +486,10 @@ __SYSCALL(__NR_get_thread_area, sys_ni_syscall)	/* use arch_prctl */
 __SYSCALL(__NR_lookup_dcookie, sys_lookup_dcookie)
 #define __NR_epoll_create	213
 __SYSCALL(__NR_epoll_create, sys_epoll_create)
-#define __NR_epoll_ctl	214
-__SYSCALL(__NR_epoll_ctl, sys_epoll_ctl)
-#define __NR_epoll_wait	215
-__SYSCALL(__NR_epoll_wait, sys_epoll_wait)
+#define __NR_epoll_ctl_old	214
+__SYSCALL(__NR_epoll_ctl_old, sys_ni_syscall)
+#define __NR_epoll_wait_old	215
+__SYSCALL(__NR_epoll_wait_old, sys_ni_syscall)
 #define __NR_remap_file_pages	216
 __SYSCALL(__NR_remap_file_pages, sys_remap_file_pages)
 #define __NR_getdents64	217
@@ -522,8 +522,12 @@ __SYSCALL(__NR_clock_getres, sys_clock_getres)
 __SYSCALL(__NR_clock_nanosleep, sys_clock_nanosleep)
 #define __NR_exit_group		231
 __SYSCALL(__NR_exit_group, sys_exit_group)
+#define __NR_epoll_wait		232
+__SYSCALL(__NR_epoll_wait, sys_epoll_wait)
+#define __NR_epoll_ctl		233
+__SYSCALL(__NR_epoll_ctl, sys_epoll_ctl)
 
-#define __NR_syscall_max __NR_exit_group
+#define __NR_syscall_max __NR_epoll_ctl
 #ifndef __NO_STUBS
 
 /* user-visible error numbers are in the range -1 - -4095 */

include/linux/eventpoll.h

@@ -23,10 +23,20 @@
 /* Set the Edge Triggered behaviour for the target file descriptor */
 #define EPOLLET (1 << 31)
 
+/* 
+ * On x86-64 make the 64bit structure have the same alignment as the
+ * 32bit structure. This makes 32bit emulation easier.
+ */
+#ifdef __x86_64__
+#define EPOLL_PACKED __attribute__((packed))
+#else
+#define EPOLL_PACKED
+#endif
+
 struct epoll_event {
 	__u32 events;
 	__u64 data;
-};
+} EPOLL_PACKED;
 
 #ifdef __KERNEL__