Merge tag 'thermal-v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/therma...

[linux-2.6-microblaze.git] / arch / um / kernel / skas / uaccess.c

diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index 2dec915..6c76df9 100644 (file)
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -11,6 +11,7 @@
 #include <asm/current.h>
 #include <asm/page.h>
 #include <kern_util.h>
+#include <asm/futex.h>
 #include <os.h>
 
 pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
@@ -248,3 +249,138 @@ long __strnlen_user(const void __user *str, long len)
        return 0;
 }
 EXPORT_SYMBOL(__strnlen_user);
+
+/**
+ * arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
+ *                       argument and comparison of the previous
+ *                       futex value with another constant.
+ *
+ * @encoded_op:        encoded operation to execute
+ * @uaddr:     pointer to user space address
+ *
+ * Return:
+ * 0 - On success
+ * -EFAULT - User access resulted in a page fault
+ * -EAGAIN - Atomic operation was unable to complete due to contention
+ * -ENOSYS - Operation not supported
+ */
+
+int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
+{
+       int oldval, ret;
+       struct page *page;
+       unsigned long addr = (unsigned long) uaddr;
+       pte_t *pte;
+
+       ret = -EFAULT;
+       if (!access_ok(uaddr, sizeof(*uaddr)))
+               return -EFAULT;
+       preempt_disable();
+       pte = maybe_map(addr, 1);
+       if (pte == NULL)
+               goto out_inuser;
+
+       page = pte_page(*pte);
+#ifdef CONFIG_64BIT
+       pagefault_disable();
+       addr = (unsigned long) page_address(page) +
+                       (((unsigned long) addr) & ~PAGE_MASK);
+#else
+       addr = (unsigned long) kmap_atomic(page) +
+               ((unsigned long) addr & ~PAGE_MASK);
+#endif
+       uaddr = (u32 *) addr;
+       oldval = *uaddr;
+
+       ret = 0;
+
+       switch (op) {
+       case FUTEX_OP_SET:
+               *uaddr = oparg;
+               break;
+       case FUTEX_OP_ADD:
+               *uaddr += oparg;
+               break;
+       case FUTEX_OP_OR:
+               *uaddr |= oparg;
+               break;
+       case FUTEX_OP_ANDN:
+               *uaddr &= ~oparg;
+               break;
+       case FUTEX_OP_XOR:
+               *uaddr ^= oparg;
+               break;
+       default:
+               ret = -ENOSYS;
+       }
+#ifdef CONFIG_64BIT
+       pagefault_enable();
+#else
+       kunmap_atomic((void *)addr);
+#endif
+
+out_inuser:
+       preempt_enable();
+
+       if (ret == 0)
+               *oval = oldval;
+
+       return ret;
+}
+EXPORT_SYMBOL(arch_futex_atomic_op_inuser);
+
+/**
+ * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
+ *                             uaddr with newval if the current value is
+ *                             oldval.
+ * @uval:      pointer to store content of @uaddr
+ * @uaddr:     pointer to user space address
+ * @oldval:    old value
+ * @newval:    new value to store to @uaddr
+ *
+ * Return:
+ * 0 - On success
+ * -EFAULT - User access resulted in a page fault
+ * -EAGAIN - Atomic operation was unable to complete due to contention
+ * -ENOSYS - Function not implemented (only if !HAVE_FUTEX_CMPXCHG)
+ */
+
+int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+                             u32 oldval, u32 newval)
+{
+       struct page *page;
+       pte_t *pte;
+       int ret = -EFAULT;
+
+       if (!access_ok(uaddr, sizeof(*uaddr)))
+               return -EFAULT;
+
+       preempt_disable();
+       pte = maybe_map((unsigned long) uaddr, 1);
+       if (pte == NULL)
+               goto out_inatomic;
+
+       page = pte_page(*pte);
+#ifdef CONFIG_64BIT
+       pagefault_disable();
+       uaddr = page_address(page) + (((unsigned long) uaddr) & ~PAGE_MASK);
+#else
+       uaddr = kmap_atomic(page) + ((unsigned long) uaddr & ~PAGE_MASK);
+#endif
+
+       *uval = *uaddr;
+
+       ret = cmpxchg(uaddr, oldval, newval);
+
+#ifdef CONFIG_64BIT
+       pagefault_enable();
+#else
+       kunmap_atomic(uaddr);
+#endif
+       ret = 0;
+
+out_inatomic:
+       preempt_enable();
+       return ret;
+}
+EXPORT_SYMBOL(futex_atomic_cmpxchg_inatomic);