Fix up the "generic" unistd.h ABI to be more useful.

Reserve 16 "architecture-specific" syscall numbers starting at 244.

Allow use of the sys_sync_file_range2() API with the generic unistd.h
by specifying __ARCH_WANT_SYNC_FILE_RANGE2 before including it.

Allow using the generic unistd.h to create the "compat" syscall table
by specifying __SYSCALL_COMPAT before including it.

Use sys_fadvise64_64 for __NR3264_fadvise64 in both 32- and 64-bit mode.

Request the appropriate __ARCH_WANT_COMPAT_SYS_xxx values when
some deprecated syscall modes are selected.

As part of this change to fix up the syscalls, also provide a couple
of missing signal-related syscall prototypes in <linux/syscalls.h>.

Signed-off-by: Chris Metcalf <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>

include/asm-generic/unistd.h

···
 #define __SYSCALL(x, y)
 #endif
 
-#if __BITS_PER_LONG == 32
+#if __BITS_PER_LONG == 32 || defined(__SYSCALL_COMPAT)
 #define __SC_3264(_nr, _32, _64) __SYSCALL(_nr, _32)
 #else
 #define __SC_3264(_nr, _32, _64) __SYSCALL(_nr, _64)
···
 __SYSCALL(__NR_fsync, sys_fsync)
 #define __NR_fdatasync 83
 __SYSCALL(__NR_fdatasync, sys_fdatasync)
+#ifdef __ARCH_WANT_SYNC_FILE_RANGE2
+#define __NR_sync_file_range2 84
+__SYSCALL(__NR_sync_file_range2, sys_sync_file_range2)
+#else
 #define __NR_sync_file_range 84
-__SYSCALL(__NR_sync_file_range, sys_sync_file_range) /* .long sys_sync_file_range2, */
+__SYSCALL(__NR_sync_file_range, sys_sync_file_range)
+#endif
 
 /* fs/timerfd.c */
 #define __NR_timerfd_create 85
···
 __SC_3264(__NR3264_mmap, sys_mmap2, sys_mmap)
 /* mm/fadvise.c */
 #define __NR3264_fadvise64 223
-__SC_3264(__NR3264_fadvise64, sys_fadvise64_64, sys_fadvise64)
+__SYSCALL(__NR3264_fadvise64, sys_fadvise64_64)
 
 /* mm/, CONFIG_MMU only */
 #ifndef __ARCH_NOMMU
···
 #define __NR_recvmmsg 243
 __SYSCALL(__NR_recvmmsg, sys_recvmmsg)
 
+/*
+ * Architectures may provide up to 16 syscalls of their own
+ * starting with this value.
+ */
+#define __NR_arch_specific_syscall 244
+
 #undef __NR_syscalls
-#define __NR_syscalls 244
+#define __NR_syscalls 260
 
 /*
  * All syscalls below here should go away really,
···
 #define __NR_syscalls (__NR_signalfd+1)
 #endif /* __ARCH_WANT_SYSCALL_NO_FLAGS */
 
-#if __BITS_PER_LONG == 32 && defined(__ARCH_WANT_SYSCALL_OFF_T)
+#if (__BITS_PER_LONG == 32 || defined(__SYSCALL_COMPAT)) && \
+     defined(__ARCH_WANT_SYSCALL_OFF_T)
 #define __NR_sendfile 1046
 __SYSCALL(__NR_sendfile, sys_sendfile)
 #define __NR_ftruncate 1047
···
 __SYSCALL(__NR_pause, sys_pause)
 #define __NR_time 1062
 #define __ARCH_WANT_SYS_TIME
+#define __ARCH_WANT_COMPAT_SYS_TIME
 __SYSCALL(__NR_time, sys_time)
 #define __NR_utime 1063
 #define __ARCH_WANT_SYS_UTIME
···
  * Here we map the numbers so that both versions
  * use the same syscall table layout.
  */
-#if __BITS_PER_LONG == 64
+#if __BITS_PER_LONG == 64 && !defined(__SYSCALL_COMPAT)
 #define __NR_fcntl __NR3264_fcntl
 #define __NR_statfs __NR3264_statfs
 #define __NR_fstatfs __NR3264_fstatfs
···
 #endif
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 
 /*
  * "Conditional" syscalls

include/linux/syscalls.h

···
 asmlinkage long sys_delete_module(const char __user *name_user,
 				unsigned int flags);
 
+asmlinkage long sys_rt_sigaction(int sig, const struct sigaction __user *act,
+				 struct sigaction __user *oact,
+				 size_t sigsetsize);
 asmlinkage long sys_rt_sigprocmask(int how, sigset_t __user *set,
 				sigset_t __user *oset, size_t sigsetsize);
 asmlinkage long sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize);
+asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize);
 asmlinkage long sys_rt_sigtimedwait(const sigset_t __user *uthese,
 				siginfo_t __user *uinfo,
 				const struct timespec __user *uts,