Description: powerpc/64s: Fix crashes when toggling entry flush barrier
References:
Notes:
 carnil> Introduced in f79643787e0a ("powerpc/64s: flush L1D on kernel entry").
 carnil> Vulnerable versions: 4.4.245 4.9.245 4.14.208 4.19.159 5.4.79 5.9.10 5.10-rc5.
Bugs:
upstream: released (5.13-rc2) [aec86b052df6541cc97c5fca44e5934cbea4963b]
6.7-upstream-stable: N/A "Fixed before branching point"
6.6-upstream-stable: N/A "Fixed before branching point"
6.1-upstream-stable: N/A "Fixed before branching point"
5.10-upstream-stable: released (5.10.38) [d2e3590ca39ccfd8a5a46d8c7f095cb6c7b9ae92]
4.19-upstream-stable: released (4.19.191) [2db22ba4e0e103f00e0512e0ecce36ac78c644f8]
sid: released (5.10.38-1)
6.1-bookworm-security: N/A "Fixed before branching point"
5.10-bullseye-security: N/A "Fixed before branching point"
4.19-buster-security: released (4.19.194-1)