v4.19.13 snapshot.
diff --git a/arch/x86/include/asm/div64.h b/arch/x86/include/asm/div64.h
new file mode 100644
index 0000000..20a4615
--- /dev/null
+++ b/arch/x86/include/asm/div64.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_DIV64_H
+#define _ASM_X86_DIV64_H
+
+#ifdef CONFIG_X86_32
+
+#include <linux/types.h>
+#include <linux/log2.h>
+
+/*
+ * do_div() is NOT a C function. It wants to return
+ * two values (the quotient and the remainder), but
+ * since that doesn't work very well in C, what it
+ * does is:
+ *
+ * - modifies the 64-bit dividend _in_place_
+ * - returns the 32-bit remainder
+ *
+ * This ends up being the most efficient "calling
+ * convention" on x86.
+ */
+#define do_div(n, base) \
+({ \
+ unsigned long __upper, __low, __high, __mod, __base; \
+ __base = (base); \
+ if (__builtin_constant_p(__base) && is_power_of_2(__base)) { \
+ __mod = n & (__base - 1); \
+ n >>= ilog2(__base); \
+ } else { \
+ asm("" : "=a" (__low), "=d" (__high) : "A" (n));\
+ __upper = __high; \
+ if (__high) { \
+ __upper = __high % (__base); \
+ __high = __high / (__base); \
+ } \
+ asm("divl %2" : "=a" (__low), "=d" (__mod) \
+ : "rm" (__base), "0" (__low), "1" (__upper)); \
+ asm("" : "=A" (n) : "a" (__low), "d" (__high)); \
+ } \
+ __mod; \
+})
+
+static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
+{
+ union {
+ u64 v64;
+ u32 v32[2];
+ } d = { dividend };
+ u32 upper;
+
+ upper = d.v32[1];
+ d.v32[1] = 0;
+ if (upper >= divisor) {
+ d.v32[1] = upper / divisor;
+ upper %= divisor;
+ }
+ asm ("divl %2" : "=a" (d.v32[0]), "=d" (*remainder) :
+ "rm" (divisor), "0" (d.v32[0]), "1" (upper));
+ return d.v64;
+}
+#define div_u64_rem div_u64_rem
+
+static inline u64 mul_u32_u32(u32 a, u32 b)
+{
+ u32 high, low;
+
+ asm ("mull %[b]" : "=a" (low), "=d" (high)
+ : [a] "a" (a), [b] "rm" (b) );
+
+ return low | ((u64)high) << 32;
+}
+#define mul_u32_u32 mul_u32_u32
+
+#else
+# include <asm-generic/div64.h>
+#endif /* CONFIG_X86_32 */
+
+#endif /* _ASM_X86_DIV64_H */