userfaultfd: activate syscall

This activates the userfaultfd syscall.

arch/powerpc/include/asm/systbl.h

@@ -368,3 +368,4 @@ SYSCALL_SPU(memfd_create)
 SYSCALL_SPU(bpf)
 COMPAT_SYS(execveat)
 PPC64ONLY(switch_endian)
+SYSCALL_SPU(userfaultfd)

arch/powerpc/include/uapi/asm/unistd.h

@@ -386,5 +386,6 @@
 #define __NR_bpf		361
 #define __NR_execveat		362
 #define __NR_switch_endian	363
+#define __NR_userfaultfd	364
 
 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */

arch/x86/syscalls/syscall_32.tbl

@@ -365,3 +365,4 @@
 356	i386	memfd_create		sys_memfd_create
 357	i386	bpf			sys_bpf
 358	i386	execveat		sys_execveat			stub32_execveat
+359	i386	userfaultfd		sys_userfaultfd

arch/x86/syscalls/syscall_64.tbl

@@ -329,6 +329,7 @@
 320	common	kexec_file_load		sys_kexec_file_load
 321	common	bpf			sys_bpf
 322	64	execveat		stub_execveat
+323	common	userfaultfd		sys_userfaultfd
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact

include/linux/syscalls.h

@@ -810,6 +810,7 @@ asmlinkage long sys_timerfd_gettime(int ufd, struct itimerspec __user *otmr);
 asmlinkage long sys_eventfd(unsigned int count);
 asmlinkage long sys_eventfd2(unsigned int count, int flags);
 asmlinkage long sys_memfd_create(const char __user *uname_ptr, unsigned int flags);
+asmlinkage long sys_userfaultfd(int flags);
 asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len);
 asmlinkage long sys_old_readdir(unsigned int, struct old_linux_dirent __user *, unsigned int);
 asmlinkage long sys_pselect6(int, fd_set __user *, fd_set __user *,

kernel/sys_ni.c

@@ -218,6 +218,7 @@ cond_syscall(compat_sys_timerfd_gettime);
 cond_syscall(sys_eventfd);
 cond_syscall(sys_eventfd2);
 cond_syscall(sys_memfd_create);
+cond_syscall(sys_userfaultfd);
 
 /* performance counters: */
 cond_syscall(sys_perf_event_open);