Were I Will Smith's PR person I would immediately reach out to Chris Rock and first meet him privately and apologize earnestly. Then a few possible suggestions: 1. invite him to do a Red Table talk 2. While he is on tour, do a surprise guest appearance on stage and let him roast you, slap you back or whatever playfully, do some back and forth stuff. 3. Next time Chris is either on late night TV or hosting an award show, visit on there 'unannounced'.
The first thing he should have done the day after is reach out to Chris. First thing.