1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/intrinsics.c b/drivers/firmware/efi/libstub/intrinsics.c
index a04ab39292b6..418cd2e6dccc 100644
--- a/drivers/firmware/efi/libstub/intrinsics.c
+++ b/drivers/firmware/efi/libstub/intrinsics.c
@@ -15,8 +15,31 @@ void *__memmove(void *__dest, const void *__src, size_t count) __alias(memmove);
 void *__memset(void *s, int c, size_t count) __alias(memset);
 #endif
 
+static void *efistub_memmove(u8 *dst, const u8 *src, size_t len)
+{
+	if (src > dst || dst >= (src + len))
+		for (size_t i = 0; i < len; i++)
+			dst[i] = src[i];
+	else
+		for (ssize_t i = len - 1; i >= 0; i--)
+			dst[i] = src[i];
+
+	return dst;
+}
+
+static void *efistub_memset(void *dst, int c, size_t len)
+{
+	for (u8 *d = dst; len--; d++)
+		*d = c;
+
+	return dst;
+}
+
 void *memcpy(void *dst, const void *src, size_t len)
 {
+	if (efi_table_attr(efi_system_table, boottime) == NULL)
+		return efistub_memmove(dst, src, len);
+
 	efi_bs_call(copy_mem, dst, src, len);
 	return dst;
 }
@@ -25,6 +48,27 @@ extern void *memmove(void *dst, const void *src, size_t len) __alias(memcpy);
 
 void *memset(void *dst, int c, size_t len)
 {
+	if (efi_table_attr(efi_system_table, boottime) == NULL)
+		return efistub_memset(dst, c, len);
+
 	efi_bs_call(set_mem, dst, len, c & U8_MAX);
 	return dst;
 }
+
+/**
+ * memcmp - Compare two areas of memory
+ * @cs: One area of memory
+ * @ct: Another area of memory
+ * @count: The size of the area.
+ */
+#undef memcmp
+int memcmp(const void *cs, const void *ct, size_t count)
+{
+	const unsigned char *su1, *su2;
+	int res = 0;
+
+	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
+		if ((res = *su1 - *su2) != 0)
+			break;
+	return res;
+}