memblock: Remove rmo_size, burry it in arch/powerpc where it belongs

The RMA (RMO is a misnomer) is a concept specific to ppc64 (in fact
server ppc64 though I hijack it on embedded ppc64 for similar purposes)
and represents the area of memory that can be accessed in real mode
(aka with MMU off), or on embedded, from the exception vectors (which
is bolted in the TLB) which pretty much boils down to the same thing.

We take that out of the generic MEMBLOCK data structure and move it into
arch/powerpc where it belongs, renaming it to "RMA" while at it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index 7ba32e762990..a086ed562606 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -446,4 +446,18 @@ void __cpuinit early_init_mmu_secondary(void)
         __early_init_mmu(0);
 }
 
+void setup_initial_memory_limit(phys_addr_t first_memblock_base,
+                                phys_addr_t first_memblock_size)
+{
+        /* On Embedded 64-bit, we adjust the RMA size to match
+         * the bolted TLB entry. We know for now that only 1G
+         * entries are supported though that may eventually
+         * change. We crop it to the size of the first MEMBLOCK to
+         * avoid going over total available memory just in case...
+         */
+        ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
+
+        /* Finally limit subsequent allocations */
+        memblock_set_current_limit(ppc64_memblock_base + ppc64_rma_size);
+}
 #endif /* CONFIG_PPC64 */