@@ -8,7 +8,6 @@ generic-y += emergency-restart.h
generic-y += exec.h
generic-y += extable.h
generic-y += ftrace.h
-generic-y += futex.h
generic-y += hw_irq.h
generic-y += irq_regs.h
generic-y += irq_work.h
new file mode 100644
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_UM_FUTEX_H
+#define _ASM_UM_FUTEX_H
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/errno.h>
+
+
+int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr);
+int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+ u32 oldval, u32 newval);
+
+#endif
@@ -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);