Merge tag 'uml-for-linus-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / arch / x86 / um / syscalls_64.c

diff --git a/arch/x86/um/syscalls_64.c b/arch/x86/um/syscalls_64.c
index 27b29ae..6a00a28 100644 (file)
--- a/arch/x86/um/syscalls_64.c
+++ b/arch/x86/um/syscalls_64.c
@@ -16,60 +16,24 @@
 long arch_prctl(struct task_struct *task, int option,
                unsigned long __user *arg2)
 {
-       unsigned long *ptr = arg2, tmp;
-       long ret;
-       int pid = task->mm->context.id.u.pid;
-
-       /*
-        * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
-        * be safe), we need to call arch_prctl on the host because
-        * setting %fs may result in something else happening (like a
-        * GDT or thread.fs being set instead).  So, we let the host
-        * fiddle the registers and thread struct and restore the
-        * registers afterwards.
-        *
-        * So, the saved registers are stored to the process (this
-        * needed because a stub may have been the last thing to run),
-        * arch_prctl is run on the host, then the registers are read
-        * back.
-        */
-       switch (option) {
-       case ARCH_SET_FS:
-       case ARCH_SET_GS:
-               ret = restore_pid_registers(pid, &current->thread.regs.regs);
-               if (ret)
-                       return ret;
-               break;
-       case ARCH_GET_FS:
-       case ARCH_GET_GS:
-               /*
-                * With these two, we read to a local pointer and
-                * put_user it to the userspace pointer that we were
-                * given.  If addr isn't valid (because it hasn't been
-                * faulted in or is just bogus), we want put_user to
-                * fault it in (or return -EFAULT) instead of having
-                * the host return -EFAULT.
-                */
-               ptr = &tmp;
-       }
-
-       ret = os_arch_prctl(pid, option, ptr);
-       if (ret)
-               return ret;
+       long ret = -EINVAL;
 
        switch (option) {
        case ARCH_SET_FS:
-               current->thread.arch.fs = (unsigned long) ptr;
-               ret = save_registers(pid, &current->thread.regs.regs);
+               current->thread.regs.regs.gp[FS_BASE / sizeof(unsigned long)] =
+                       (unsigned long) arg2;
+               ret = 0;
                break;
        case ARCH_SET_GS:
-               ret = save_registers(pid, &current->thread.regs.regs);
+               current->thread.regs.regs.gp[GS_BASE / sizeof(unsigned long)] =
+                       (unsigned long) arg2;
+               ret = 0;
                break;
        case ARCH_GET_FS:
-               ret = put_user(tmp, arg2);
+               ret = put_user(current->thread.regs.regs.gp[FS_BASE / sizeof(unsigned long)], arg2);
                break;
        case ARCH_GET_GS:
-               ret = put_user(tmp, arg2);
+               ret = put_user(current->thread.regs.regs.gp[GS_BASE / sizeof(unsigned long)], arg2);
                break;
        }
 
@@ -83,10 +47,10 @@ SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
 
 void arch_switch_to(struct task_struct *to)
 {
-       if ((to->thread.arch.fs == 0) || (to->mm == NULL))
-               return;
-
-       arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
+       /*
+        * Nothing needs to be done on x86_64.
+        * The FS_BASE/GS_BASE registers are saved in the ptrace register set.
+        */
 }
 
 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,