powerpc/fsl-booke: Fix setup_initial_memory_limit to not blindly map

On FSL Book-E devices we support multiple large TLB sizes and so we can
get into situations in which the initial 1G TLB size is too big and
we're asked for a size that is not mappable by a single entry (like
512M).  The single entry is important because when we bring up secondary
cores they need to ensure any data structure they need to access (eg
PACA or stack) is always mapped.

So we really need to determine what size will actually be mapped by the
first TLB entry to ensure we limit early memory references to that
region.  We refactor the map_mem_in_cams() code to provider a helper
function that we can utilize to determine the size of the first TLB
entry while taking into account size and alignment constraints.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 18 insertions, 3 deletions

diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index afc95c7304ae..6c2eabf707b7 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -642,13 +642,28 @@ void __cpuinit early_init_mmu_secondary(void)
 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
+	/* On non-FSL 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
+	 * change.
+	 *
+	 * on FSL Embedded 64-bit, we adjust the RMA size to match the
+	 * first bolted TLB entry size.  We still limit max to 1G even if
+	 * the TLB could cover more.  This is due to what the early init
+	 * code is setup to do.
+	 *
+	 * 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);
+#ifdef CONFIG_PPC_FSL_BOOK3E
+	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
+		unsigned long linear_sz;
+		linear_sz = calc_cam_sz(first_memblock_size, PAGE_OFFSET,
+					first_memblock_base);
+		ppc64_rma_size = min_t(u64, linear_sz, 0x40000000);
+	} else
+#endif
+		ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
 
 	/* Finally limit subsequent allocations */
 	memblock_set_current_limit(first_memblock_base + ppc64_rma_size);