Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/lib/math/div64.c b/lib/math/div64.c
index 368ca7f..edd1090 100644
--- a/lib/math/div64.c
+++ b/lib/math/div64.c
@@ -190,3 +190,45 @@
return __iter_div_u64_rem(dividend, divisor, remainder);
}
EXPORT_SYMBOL(iter_div_u64_rem);
+
+#ifndef mul_u64_u64_div_u64
+u64 mul_u64_u64_div_u64(u64 a, u64 b, u64 c)
+{
+ u64 res = 0, div, rem;
+ int shift;
+
+ /* can a * b overflow ? */
+ if (ilog2(a) + ilog2(b) > 62) {
+ /*
+ * (b * a) / c is equal to
+ *
+ * (b / c) * a +
+ * (b % c) * a / c
+ *
+ * if nothing overflows. Can the 1st multiplication
+ * overflow? Yes, but we do not care: this can only
+ * happen if the end result can't fit in u64 anyway.
+ *
+ * So the code below does
+ *
+ * res = (b / c) * a;
+ * b = b % c;
+ */
+ div = div64_u64_rem(b, c, &rem);
+ res = div * a;
+ b = rem;
+
+ shift = ilog2(a) + ilog2(b) - 62;
+ if (shift > 0) {
+ /* drop precision */
+ b >>= shift;
+ c >>= shift;
+ if (!c)
+ return res;
+ }
+ }
+
+ return res + div64_u64(a * b, c);
+}
+EXPORT_SYMBOL(mul_u64_u64_div_u64);
+#endif