powerpc/64: rtas avoid accessing paca in 32-bit mode
Commit
177ba7c647f3 ("powerpc/mm/radix: Limit paca allocation in radix")
limited the paca allocation address to 1G on pSeries because RTAS return
accesses the paca in 32-bit mode:
On return from RTAS we access the paca variables and we have 64 bit
disabled. This requires us to limit paca in 32 bit range.
Fix this by setting ppc64_rma_size to first_memblock_size/1G range.
Avoid this limit by switching to 64-bit mode before accessing any memory.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>