powerpc/fsl-booke-64: Don't limit ppc64_rma_size to one TLB entry

This is required for kdump to work when loaded at at an address that
does not fall within the first TLB entry -- which can easily happen
because while the lower limit is enforced via reserved memory, which
doesn't affect how much is mapped, the upper limit is enforced via a
different mechanism that does.  Thus, more TLB entries are needed than
would normally be used, as the total memory to be mapped might not be a
power of two.

Signed-off-by: Scott Wood <scottwood@freescale.com>

1 files changed, 17 insertions, 7 deletions

diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index a7381fbdd6ab..bb04e4df3100 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -648,7 +648,7 @@ static void early_init_this_mmu(void)
 
 		if (map)
 			linear_map_top = map_mem_in_cams(linear_map_top,
-							 num_cams);
+							 num_cams, false);
 	}
 #endif
 
@@ -746,10 +746,14 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 	 * entries are supported though that may eventually
 	 * 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.
+	 * on FSL Embedded 64-bit, usually all RAM is bolted, but with
+	 * unusual memory sizes it's possible for some RAM to not be mapped
+	 * (such RAM is not used at all by Linux, since we don't support
+	 * highmem on 64-bit).  We limit ppc64_rma_size to what would be
+	 * mappable if this memblock is the only one.  Additional memblocks
+	 * can only increase, not decrease, the amount that ends up getting
+	 * mapped.  We still limit max to 1G even if we'll eventually map
+	 * more.  This is due to what the early init code is set up to do.
 	 *
 	 * We crop it to the size of the first MEMBLOCK to
 	 * avoid going over total available memory just in case...
@@ -757,8 +761,14 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 #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);
+		unsigned int num_cams;
+
+		/* use a quarter of the TLBCAM for bolted linear map */
+		num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;
+
+		linear_sz = map_mem_in_cams(first_memblock_size, num_cams,
+					    true);
+
 		ppc64_rma_size = min_t(u64, linear_sz, 0x40000000);
 	} else
 #endif