m68k: Make sys_atomic_cmpxchg_32 work on classic m68k
User space access must always go through uaccess accessors, since on
classic m68k user space and kernel space are completely separate.
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Tested-by: Thorsten Glaser <tg@debian.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
index 8623f8d..9a5932e 100644
--- a/arch/m68k/kernel/sys_m68k.c
+++ b/arch/m68k/kernel/sys_m68k.c
@@ -479,9 +479,13 @@
goto bad_access;
}
- mem_value = *mem;
+ /*
+ * No need to check for EFAULT; we know that the page is
+ * present and writable.
+ */
+ __get_user(mem_value, mem);
if (mem_value == oldval)
- *mem = newval;
+ __put_user(newval, mem);
pte_unmap_unlock(pte, ptl);
up_read(&mm->mmap_sem);
