[PATCH 3/9] ARM: oabi-compat: add epoll_pwait handler

Arnd Bergmann
2020-10-30T15:49:39Z

From: Arnd Bergmann <arnd@arndb.de>

The epoll_wait() syscall has a special version for OABI compat
mode to convert the arguments to the EABI structure layout
of the kernel. However, the later epoll_pwait() syscall was
added in arch/arm in linux-2.6.32 without this conversion.

Use the same kind of handler for both.

Fixes: 369842658a36 ("ARM: 5677/1: ARM support for TIF_RESTORE_SIGMASK/pselect6/ppoll/epoll_pwait")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/arm/kernel/sys_oabi-compat.c | 37 ++++++++++++++++++++++++++++---
arch/arm/tools/syscall.tbl | 2 +-
2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c
index 0203e545bbc8..a2b1ae01e5bf 100644
--- a/arch/arm/kernel/sys_oabi-compat.c
+++ b/arch/arm/kernel/sys_oabi-compat.c
@@ -264,9 +264,8 @@ asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
return do_epoll_ctl(epfd, op, fd, &kernel, false);
}

-asmlinkage long sys_oabi_epoll_wait(int epfd,
- struct oabi_epoll_event __user *events,
- int maxevents, int timeout)
+static long do_oabi_epoll_wait(int epfd, struct oabi_epoll_event __user *events,
+ int maxevents, int timeout)
{
struct epoll_event *kbuf;
struct oabi_epoll_event e;
@@ -299,6 +298,38 @@ asmlinkage long sys_oabi_epoll_wait(int epfd,
return err ? -EFAULT : ret;
}

+SYSCALL_DEFINE4(oabi_epoll_wait, int, epfd,
+ struct oabi_epoll_event __user *, events,
+ int, maxevents, int, timeout)
+{
+ return do_oabi_epoll_wait(epfd, events, maxevents, timeout);
+}
+
+/*
+ * Implement the event wait interface for the eventpoll file. It is the kernel
+ * part of the user space epoll_pwait(2).
+ */
+SYSCALL_DEFINE6(oabi_epoll_pwait, int, epfd,
+ struct oabi_epoll_event __user *, events, int, maxevents,
+ int, timeout, const sigset_t __user *, sigmask,
+ size_t, sigsetsize)
+{
+ int error;
+
+ /*
+ * If the caller wants a certain signal mask to be set during the wait,
+ * we apply it here.
+ */
+ error = set_user_sigmask(sigmask, sigsetsize);
+ if (error)
+ return error;
+
+ error = do_oabi_epoll_wait(epfd, events, maxevents, timeout);
+ restore_saved_sigmask_unless(error == -EINTR);
+
+ return error;
+}
+
struct oabi_sembuf {
unsigned short sem_num;
short sem_op;
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index d056a548358e..330cf0aa04c4 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -360,7 +360,7 @@
343 common vmsplice sys_vmsplice
344 common move_pages sys_move_pages
345 common getcpu sys_getcpu
-346 common epoll_pwait sys_epoll_pwait
+346 common epoll_pwait sys_epoll_pwait sys_oabi_epoll_pwait
347 common kexec_load sys_kexec_load
348 common utimensat sys_utimensat_time32
349 common signalfd sys_signalfd
--
2.27.0