Update EIP-6189: Add transaction validity section

Merged by EIP-Bot.

Author: Pandapip1

EIPS/eip-6189.md

@@ -83,6 +83,18 @@ This opcode remains unchanged; `ADDRESS` points to the address that doesn't have
 
 Transfers to the zero address continue to have the same effect as the `CREATE` opcode, and will cost extra gas as discussed in the [`CREATE` and `CREATE2`](#create-and-create2) section.
 
+### Transaction Validity
+
+The "origin" refers to the account that sent the transaction to be validated.
+
+If the nonce of the origin is `2^64-1`, the origin MUST be updated to the address stored in the `0`th storage slot of the current origin (as if the origin was the address stored in the `0`th storage slot of the current origin). This MUST repeat until a non-alias contract is reached.
+
+If there is more than one alias contract in the chain, the original origin and all subsequent origins (except the last one) MUST have their `0`th storage slot set to the address of the final non-alias contract. Then, the call MUST be forwarded as usual.
+
+An additional `25` gas per account accessed in this manner (including the final one, and including if no aliased accounts were used), in addition to all the regular costs incurred by accessing accounts (see [EIP-2929](./eip-2929.md)) is added to the validation costs. For every account whose `0`th storage slot is updated, it also costs an additional `5000` gas.
+
+Finally, validation proceeds as normal.
+
 ### RPC Endpoint Changes
 
 #### `eth_getStorageAt`