11 Sep
2020
11 Sep
'20
9:44 a.m.
On Fri, Sep 04, 2020 at 04:31:43PM -0400, Gabriel Krisman Bertazi wrote:
+struct syscall_user_dispatch {
- char __user *selector;
- unsigned long dispatcher_start;
- unsigned long dispatcher_end;
+};
+int do_syscall_user_dispatch(struct pt_regs *regs) +{
- struct syscall_user_dispatch *sd = ¤t->syscall_dispatch;
- unsigned long ip = instruction_pointer(regs);
- char state;
- if (likely(ip >= sd->dispatcher_start && ip <= sd->dispatcher_end))
return 0;
If you use {offset,size}, instead of {start,end}, you can write the above like:
if (ip - sd->dispatcher_offset < sd->dispatcher_size) return 0;
which is just a single branch.