[PATCH v15 1/4] syscall_user_dispatch: helper function to operate on given task

Gregory Price
2023-03-30T21:21:52Z

Preparatory patch ahead of set/get interfaces which will allow a
ptrace to get/set the syscall user dispatch configuration of a task.

This will simplify the set interface and consolidates error paths.

Signed-off-by: Gregory Price <gregory.price@memverge.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/entry/syscall_user_dispatch.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/kernel/entry/syscall_user_dispatch.c b/kernel/entry/syscall_user_dispatch.c
index 0b6379adff6b..22396b234854 100644
--- a/kernel/entry/syscall_user_dispatch.c
+++ b/kernel/entry/syscall_user_dispatch.c
@@ -68,8 +68,9 @@ bool syscall_user_dispatch(struct pt_regs *regs)
return true;
}

-int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
- unsigned long len, char __user *selector)
+static int task_set_syscall_user_dispatch(struct task_struct *task, unsigned long mode,
+ unsigned long offset, unsigned long len,
+ char __user *selector)
{
switch (mode) {
case PR_SYS_DISPATCH_OFF:
@@ -94,15 +95,21 @@ int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
return -EINVAL;
}

- current->syscall_dispatch.selector = selector;
- current->syscall_dispatch.offset = offset;
- current->syscall_dispatch.len = len;
- current->syscall_dispatch.on_dispatch = false;
+ task->syscall_dispatch.selector = selector;
+ task->syscall_dispatch.offset = offset;
+ task->syscall_dispatch.len = len;
+ task->syscall_dispatch.on_dispatch = false;

if (mode == PR_SYS_DISPATCH_ON)
- set_syscall_work(SYSCALL_USER_DISPATCH);
+ set_task_syscall_work(task, SYSCALL_USER_DISPATCH);
else
- clear_syscall_work(SYSCALL_USER_DISPATCH);
+ clear_task_syscall_work(task, SYSCALL_USER_DISPATCH);

return 0;
}
+
+int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
+ unsigned long len, char __user *selector)
+{
+ return task_set_syscall_user_dispatch(current, mode, offset, len, selector);
+}
--
2.39.1