powerpc: make iSeries boot again

On ARCH=ppc64 we were getting htab_hash_mask recalculated
to the correct value for our particular machine by accident.
In the merge tree, that code was commented out, so htab_hash_mask
was being corrupted.

We now set ppc64_pft_size instead which gets htab_has_mask
calculated correctly for us later.  We should put an
ibm,pft-size property in the device tree at some point.

Also set -mno-minimal-toc in some makefiles.
Allow iSeries to configure PROC_DEVICETREE.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

arch/powerpc/Kconfig

@@ -570,7 +570,7 @@ config SCHED_SMT
 
 config PROC_DEVICETREE
 	bool "Support for Open Firmware device tree in /proc"
-	depends on PPC_OF && PROC_FS
+	depends on (PPC_OF || PPC_ISERIES) && PROC_FS
 	help
 	  This option adds a device-tree directory under /proc which contains
 	  an image of the device tree that the kernel copies from Open

arch/powerpc/mm/Makefile

@@ -2,6 +2,10 @@
 # Makefile for the linux ppc-specific parts of the memory manager.
 #
 
+ifeq ($(CONFIG_PPC64),y)
+EXTRA_CFLAGS	+= -mno-minimal-toc
+endif
+
 obj-y				:= fault.o mem.o lmb.o
 obj-$(CONFIG_PPC32)		+= init_32.o pgtable_32.o mmu_context_32.o \
 				   tlb_32.o

arch/powerpc/platforms/iseries/Makefile

+EXTRA_CFLAGS	+= -mno-minimal-toc
+
 obj-y += hvlog.o hvlpconfig.o lpardata.o setup.o mf.o lpevents.o \
 	hvcall.o proc.o htab.o iommu.o misc.o
 obj-$(CONFIG_PCI) += pci.o irq.o vpdinfo.o

arch/powerpc/platforms/iseries/setup.c

@@ -430,7 +430,6 @@ static void __init build_iSeries_Memory_Map(void)
 	u32 loadAreaFirstChunk, loadAreaLastChunk, loadAreaSize;
 	u32 nextPhysChunk;
 	u32 hptFirstChunk, hptLastChunk, hptSizeChunks, hptSizePages;
-	u32 num_ptegs;
 	u32 totalChunks,moreChunks;
 	u32 currChunk, thisChunk, absChunk;
 	u32 currDword;
@@ -493,10 +492,7 @@ static void __init build_iSeries_Memory_Map(void)
 	printk("HPT absolute addr = %016lx, size = %dK\n",
 			chunk_to_addr(hptFirstChunk), hptSizeChunks * 256);
 
-	/* Fill in the hashed page table hash mask */
-	num_ptegs = hptSizePages *
-		(PAGE_SIZE / (sizeof(hpte_t) * HPTES_PER_GROUP));
-	htab_hash_mask = num_ptegs - 1;
+	ppc64_pft_size = __ilog2(hptSizePages * PAGE_SIZE);
 
 	/*
 	 * The actual hashed page table is in the hypervisor,