Globalfoundries is not owned by AMD. The fabs were spun off to be sold to Mubadala when AMD could not afford this operation anymore.
Which triggered a contract renegotiation with Intel. Do you think their lawyers never thought of saying FU to either company and these companies simply doing what they've been doing sans license? Something that's been in play since the early 2000s? You think it never occurred to them they could use a FRAND lawsuit to get their way?
Intel allows three companies to use x86: Intel, AMD and VIA, which now are licensed to deal with TSMC and Globalfoundries. These companies are only allowed to make what AMD order, nothing on their own to sell as a spinoff. The x86 cross licensing agreement is ever evolving. Patents within the license on old instruction sets, specifically how they were implemented and how they work, such as Pentiums are now expired and incredibly useless in this day and age. Intel and AMD used to patent more and more than the other on the basis that one would infringe and it would open a slew of lawsuits. Instead, they ended up doing a cross patenting license. In the event AMD is sold off, the license agreement is dead, however, a new licensing deal is brought up as the new company technically inherited via purchase the assets of AMD. VIA has a license with Intel because they bought out a company that Intel previously had a licensing agreement with. The same one with AMD, however, Intel didn't want to negotiate with them and were successfully sued. So now VIA has a licensing contract similar to AMD's with Intel. If they fall, their successor starts a new contract with Intel. There were companies who countered the issue of licensing by partnering up with IBM who at the time (and still does, I believe) a licensing agreement with Intel to use x86.
TL;DR: If AMD goes belly up, no FRAND lawsuit will apply. However, government inquiries into Intel may start
IF Intel doesn't draw up the same contract with the new AMD owners and would see large anti-competitive fines from governments around the globe. This was never a one way deal. Intel gets to use AMD's x86-64 and AMD gets to use Intel's x86. All other companies that create processors with these sets already have deals in place with both AMD and Intel. They didn't start it on their own.
Any company is free to use x86 and x86-64 architecture if they draft an agreement with both companies or partner up with a fabrication company that has a deal with both companies.
The issue lies in fabrication startup costs if you don't want to partner up with a company that's already fabricating hardware through partnership or licensing deal with Intel and AMD.
