# \[PATCH\] userfaultfd: register syscall numbers for x86 32bit and x86-64 64bit - Subsystems: ABI/API, THE REST, X86 ARCHITECTURE (32-BIT AND 64-BIT), X86 ENTRY CODE - Maintainers: Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski - Status: REVIEWED ยท 1 review, 0 by maintainers (Pavel Emelyanov) - Reviewed. - 1 review trailer. - List: linux-api - 3 messages, 3 authors - Page: https://ratatoskr.run/linux-api/2015/07/4546830/t ## \[PATCH\] userfaultfd: register syscall numbers for x86 32bit and x86-64 64bit - From: Andrea Arcangeli \ - Date: 2015-07-30 15:34:34 - Message: https://ratatoskr.run/linux-api/2015/07/4546830.md ```text This registers the official numbers of the userfaultfd syscall for x86 32bit and x86-64 64bit. This registration allows to ship kernels in production using these two syscall numbers for userfaultfd. Acked-by: Pavel Emelyanov Signed-off-by: Andrea Arcangeli --- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + include/linux/syscalls.h | 1 + kernel/sys_ni.c | 1 + 4 files changed, 4 insertions(+) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 25e3cf1..178c5c2 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -380,3 +380,4 @@ 371 i386 recvfrom sys_recvfrom compat_sys_recvfrom 372 i386 recvmsg sys_recvmsg compat_sys_recvmsg 373 i386 shutdown sys_shutdown +374 i386 userfaultfd sys_userfaultfd \ No newline at end of file diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 9ef32d5..81c4906 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/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 diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index b45c45b..0800131 100644 --- a/include/linux/syscalls.h +++ b/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 *, diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 7995ef5..8b3e10ea 100644 --- a/kernel/sys_ni.c +++ b/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); ``` ## Re: \[PATCH\] userfaultfd: register syscall numbers for x86 32bit and x86-64 64bit - From: Ingo Molnar \ - Date: 2015-07-31 08:31:39 - Message: https://ratatoskr.run/linux-api/2015/07/4547364.md ```text * Andrea Arcangeli [ref] wrote: > This registers the official numbers of the userfaultfd syscall for x86 > 32bit and x86-64 64bit. This registration allows to ship kernels in > production using these two syscall numbers for userfaultfd. > > Acked-by: Pavel Emelyanov > Signed-off-by: Andrea Arcangeli > --- > arch/x86/entry/syscalls/syscall_32.tbl | 1 + > arch/x86/entry/syscalls/syscall_64.tbl | 1 + > include/linux/syscalls.h | 1 + > kernel/sys_ni.c | 1 + > 4 files changed, 4 insertions(+) Hm, is there consensus on the upstream desirability of this sytem call? Thanks, Ingo ``` ## Re: \[PATCH\] userfaultfd: register syscall numbers for x86 32bit and x86-64 64bit - From: Dr. David Alan Gilbert \ - Date: 2015-07-31 09:14:01 - Message: https://ratatoskr.run/linux-api/2015/07/4547410.md ```text * Ingo Molnar (mingo@kernel.org) wrote: > > * Andrea Arcangeli [ref] wrote: > > > This registers the official numbers of the userfaultfd syscall for x86 > > 32bit and x86-64 64bit. This registration allows to ship kernels in > > production using these two syscall numbers for userfaultfd. > > > > Acked-by: Pavel Emelyanov > > Signed-off-by: Andrea Arcangeli > > --- > > arch/x86/entry/syscalls/syscall_32.tbl | 1 + > > arch/x86/entry/syscalls/syscall_64.tbl | 1 + > > include/linux/syscalls.h | 1 + > > kernel/sys_ni.c | 1 + > > 4 files changed, 4 insertions(+) > > Hm, is there consensus on the upstream desirability of this sytem call? I hope so: a) It's generic enough that there's interest in using it in a range of projects - there's nothing QEMU specific in it. b) It's worked very well on the QEMU code that I wrote that uses it for postcopy, and has been solid doing that for many months now. c) I'm not aware of any suggestions for a different, generic solution to solve the same set of problems. d) It's got a good self test, that's survived heavy testing. e) I think Andrea has addressed all previous comments on it. Dave > > Thanks, > > Ingo -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK ```