1 files changed, 541 insertions, 18 deletions

diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index ad2eb4d34dd..92cb18d52ea 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -7,8 +7,8 @@
  *
  *  -- BenH
  *
- * Copyright 2008 Ben Herrenschmidt <benh@kernel.crashing.org>
- *                IBM Corp.
+ * Copyright 2008,2009 Ben Herrenschmidt <benh@kernel.crashing.org>
+ *                     IBM Corp.
  *
  *  Derived from arch/ppc/mm/init.c:
  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
@@ -28,19 +28,140 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/init.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
 #include <linux/preempt.h>
 #include <linux/spinlock.h>
+#include <linux/memblock.h>
+#include <linux/of_fdt.h>
+#include <linux/hugetlb.h>
 
 #include <asm/tlbflush.h>
 #include <asm/tlb.h>
+#include <asm/code-patching.h>
+#include <asm/hugetlb.h>
+#include <asm/paca.h>
 
 #include "mmu_decl.h"
 
 /*
+ * This struct lists the sw-supported page sizes.  The hardawre MMU may support
+ * other sizes not listed here.   The .ind field is only used on MMUs that have
+ * indirect page table entries.
+ */
+#ifdef CONFIG_PPC_BOOK3E_MMU
+#ifdef CONFIG_PPC_FSL_BOOK3E
+struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {
+	[MMU_PAGE_4K] = {
+		.shift	= 12,
+		.enc	= BOOK3E_PAGESZ_4K,
+	},
+	[MMU_PAGE_2M] = {
+		.shift	= 21,
+		.enc	= BOOK3E_PAGESZ_2M,
+	},
+	[MMU_PAGE_4M] = {
+		.shift	= 22,
+		.enc	= BOOK3E_PAGESZ_4M,
+	},
+	[MMU_PAGE_16M] = {
+		.shift	= 24,
+		.enc	= BOOK3E_PAGESZ_16M,
+	},
+	[MMU_PAGE_64M] = {
+		.shift	= 26,
+		.enc	= BOOK3E_PAGESZ_64M,
+	},
+	[MMU_PAGE_256M] = {
+		.shift	= 28,
+		.enc	= BOOK3E_PAGESZ_256M,
+	},
+	[MMU_PAGE_1G] = {
+		.shift	= 30,
+		.enc	= BOOK3E_PAGESZ_1GB,
+	},
+};
+#else
+struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {
+	[MMU_PAGE_4K] = {
+		.shift	= 12,
+		.ind	= 20,
+		.enc	= BOOK3E_PAGESZ_4K,
+	},
+	[MMU_PAGE_16K] = {
+		.shift	= 14,
+		.enc	= BOOK3E_PAGESZ_16K,
+	},
+	[MMU_PAGE_64K] = {
+		.shift	= 16,
+		.ind	= 28,
+		.enc	= BOOK3E_PAGESZ_64K,
+	},
+	[MMU_PAGE_1M] = {
+		.shift	= 20,
+		.enc	= BOOK3E_PAGESZ_1M,
+	},
+	[MMU_PAGE_16M] = {
+		.shift	= 24,
+		.ind	= 36,
+		.enc	= BOOK3E_PAGESZ_16M,
+	},
+	[MMU_PAGE_256M] = {
+		.shift	= 28,
+		.enc	= BOOK3E_PAGESZ_256M,
+	},
+	[MMU_PAGE_1G] = {
+		.shift	= 30,
+		.enc	= BOOK3E_PAGESZ_1GB,
+	},
+};
+#endif /* CONFIG_FSL_BOOKE */
+
+static inline int mmu_get_tsize(int psize)
+{
+	return mmu_psize_defs[psize].enc;
+}
+#else
+static inline int mmu_get_tsize(int psize)
+{
+	/* This isn't used on !Book3E for now */
+	return 0;
+}
+#endif /* CONFIG_PPC_BOOK3E_MMU */
+
+/* The variables below are currently only used on 64-bit Book3E
+ * though this will probably be made common with other nohash
+ * implementations at some point
+ */
+#ifdef CONFIG_PPC64
+
+int mmu_linear_psize;		/* Page size used for the linear mapping */
+int mmu_pte_psize;		/* Page size used for PTE pages */
+int mmu_vmemmap_psize;		/* Page size used for the virtual mem map */
+int book3e_htw_mode;		/* HW tablewalk?  Value is PPC_HTW_* */
+unsigned long linear_map_top;	/* Top of linear mapping */
+
+
+/*
+ * Number of bytes to add to SPRN_SPRG_TLB_EXFRAME on crit/mcheck/debug
+ * exceptions.  This is used for bolted and e6500 TLB miss handlers which
+ * do not modify this SPRG in the TLB miss code; for other TLB miss handlers,
+ * this is set to zero.
+ */
+int extlb_level_exc;
+
+#endif /* CONFIG_PPC64 */
+
+#ifdef CONFIG_PPC_FSL_BOOK3E
+/* next_tlbcam_idx is used to round-robin tlbcam entry assignment */
+DEFINE_PER_CPU(int, next_tlbcam_idx);
+EXPORT_PER_CPU_SYMBOL(next_tlbcam_idx);
+#endif
+
+/*
  * Base TLB flushing operations:
  *
  *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
@@ -67,29 +188,43 @@ void local_flush_tlb_mm(struct mm_struct *mm)
 }
 EXPORT_SYMBOL(local_flush_tlb_mm);
 
-void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
+void __local_flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr,
+			    int tsize, int ind)
 {
 	unsigned int pid;
 
 	preempt_disable();
-	pid = vma ? vma->vm_mm->context.id : 0;
+	pid = mm ? mm->context.id : 0;
 	if (pid != MMU_NO_CONTEXT)
-		_tlbil_va(vmaddr, pid);
+		_tlbil_va(vmaddr, pid, tsize, ind);
 	preempt_enable();
 }
-EXPORT_SYMBOL(local_flush_tlb_page);
 
+void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
+{
+	__local_flush_tlb_page(vma ? vma->vm_mm : NULL, vmaddr,
+			       mmu_get_tsize(mmu_virtual_psize), 0);
+}
+EXPORT_SYMBOL(local_flush_tlb_page);
 
 /*
  * And here are the SMP non-local implementations
  */
 #ifdef CONFIG_SMP
 
-static DEFINE_SPINLOCK(tlbivax_lock);
+static DEFINE_RAW_SPINLOCK(tlbivax_lock);
+
+static int mm_is_core_local(struct mm_struct *mm)
+{
+	return cpumask_subset(mm_cpumask(mm),
+			      topology_thread_cpumask(smp_processor_id()));
+}
 
 struct tlb_flush_param {
 	unsigned long addr;
 	unsigned int pid;
+	unsigned int tsize;
+	unsigned int ind;
 };
 
 static void do_flush_tlb_mm_ipi(void *param)
@@ -103,7 +238,7 @@ static void do_flush_tlb_page_ipi(void *param)
 {
 	struct tlb_flush_param *p = param;
 
-	_tlbil_va(p->addr, p->pid);
+	_tlbil_va(p->addr, p->pid, p->tsize, p->ind);
 }
 
 
@@ -131,7 +266,7 @@ void flush_tlb_mm(struct mm_struct *mm)
 	pid = mm->context.id;
 	if (unlikely(pid == MMU_NO_CONTEXT))
 		goto no_context;
-	if (!cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id()))) {
+	if (!mm_is_core_local(mm)) {
 		struct tlb_flush_param p = { .pid = pid };
 		/* Ignores smp_processor_id() even if set. */
 		smp_call_function_many(mm_cpumask(mm),
@@ -143,41 +278,69 @@ void flush_tlb_mm(struct mm_struct *mm)
 }
 EXPORT_SYMBOL(flush_tlb_mm);
 
-void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
+void __flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr,
+		      int tsize, int ind)
 {
 	struct cpumask *cpu_mask;
 	unsigned int pid;
 
 	preempt_disable();
-	pid = vma ? vma->vm_mm->context.id : 0;
+	pid = mm ? mm->context.id : 0;
 	if (unlikely(pid == MMU_NO_CONTEXT))
 		goto bail;
-	cpu_mask = mm_cpumask(vma->vm_mm);
-	if (!cpumask_equal(cpu_mask, cpumask_of(smp_processor_id()))) {
+	cpu_mask = mm_cpumask(mm);
+	if (!mm_is_core_local(mm)) {
 		/* If broadcast tlbivax is supported, use it */
 		if (mmu_has_feature(MMU_FTR_USE_TLBIVAX_BCAST)) {
 			int lock = mmu_has_feature(MMU_FTR_LOCK_BCAST_INVAL);
 			if (lock)
-				spin_lock(&tlbivax_lock);
-			_tlbivax_bcast(vmaddr, pid);
+				raw_spin_lock(&tlbivax_lock);
+			_tlbivax_bcast(vmaddr, pid, tsize, ind);
 			if (lock)
-				spin_unlock(&tlbivax_lock);
+				raw_spin_unlock(&tlbivax_lock);
 			goto bail;
 		} else {
-			struct tlb_flush_param p = { .pid = pid, .addr = vmaddr };
+			struct tlb_flush_param p = {
+				.pid = pid,
+				.addr = vmaddr,
+				.tsize = tsize,
+				.ind = ind,
+			};
 			/* Ignores smp_processor_id() even if set in cpu_mask */
 			smp_call_function_many(cpu_mask,
 					       do_flush_tlb_page_ipi, &p, 1);
 		}
 	}
-	_tlbil_va(vmaddr, pid);
+	_tlbil_va(vmaddr, pid, tsize, ind);
  bail:
 	preempt_enable();
 }
+
+void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
+{
+#ifdef CONFIG_HUGETLB_PAGE
+	if (vma && is_vm_hugetlb_page(vma))
+		flush_hugetlb_page(vma, vmaddr);
+#endif
+
+	__flush_tlb_page(vma ? vma->vm_mm : NULL, vmaddr,
+			 mmu_get_tsize(mmu_virtual_psize), 0);
+}
 EXPORT_SYMBOL(flush_tlb_page);
 
 #endif /* CONFIG_SMP */
 
+#ifdef CONFIG_PPC_47x
+void __init early_init_mmu_47x(void)
+{
+#ifdef CONFIG_SMP
+	unsigned long root = of_get_flat_dt_root();
+	if (of_get_flat_dt_prop(root, "cooperative-partition", NULL))
+		mmu_clear_feature(MMU_FTR_USE_TLBIVAX_BCAST);
+#endif /* CONFIG_SMP */
+}
+#endif /* CONFIG_PPC_47x */
+
 /*
  * Flush kernel TLB entries in the given range
  */
@@ -207,3 +370,363 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 	flush_tlb_mm(vma->vm_mm);
 }
 EXPORT_SYMBOL(flush_tlb_range);
+
+void tlb_flush(struct mmu_gather *tlb)
+{
+	flush_tlb_mm(tlb->mm);
+}
+
+/*
+ * Below are functions specific to the 64-bit variant of Book3E though that
+ * may change in the future
+ */
+
+#ifdef CONFIG_PPC64
+
+/*
+ * Handling of virtual linear page tables or indirect TLB entries
+ * flushing when PTE pages are freed
+ */
+void tlb_flush_pgtable(struct mmu_gather *tlb, unsigned long address)
+{
+	int tsize = mmu_psize_defs[mmu_pte_psize].enc;
+
+	if (book3e_htw_mode != PPC_HTW_NONE) {
+		unsigned long start = address & PMD_MASK;
+		unsigned long end = address + PMD_SIZE;
+		unsigned long size = 1UL << mmu_psize_defs[mmu_pte_psize].shift;
+
+		/* This isn't the most optimal, ideally we would factor out the
+		 * while preempt & CPU mask mucking around, or even the IPI but
+		 * it will do for now
+		 */
+		while (start < end) {
+			__flush_tlb_page(tlb->mm, start, tsize, 1);
+			start += size;
+		}
+	} else {
+		unsigned long rmask = 0xf000000000000000ul;
+		unsigned long rid = (address & rmask) | 0x1000000000000000ul;
+		unsigned long vpte = address & ~rmask;
+
+#ifdef CONFIG_PPC_64K_PAGES
+		vpte = (vpte >> (PAGE_SHIFT - 4)) & ~0xfffful;
+#else
+		vpte = (vpte >> (PAGE_SHIFT - 3)) & ~0xffful;
+#endif
+		vpte |= rid;
+		__flush_tlb_page(tlb->mm, vpte, tsize, 0);
+	}
+}
+
+static void setup_page_sizes(void)
+{
+	unsigned int tlb0cfg;
+	unsigned int tlb0ps;
+	unsigned int eptcfg;
+	int i, psize;
+
+#ifdef CONFIG_PPC_FSL_BOOK3E
+	unsigned int mmucfg = mfspr(SPRN_MMUCFG);
+	int fsl_mmu = mmu_has_feature(MMU_FTR_TYPE_FSL_E);
+
+	if (fsl_mmu && (mmucfg & MMUCFG_MAVN) == MMUCFG_MAVN_V1) {
+		unsigned int tlb1cfg = mfspr(SPRN_TLB1CFG);
+		unsigned int min_pg, max_pg;
+
+		min_pg = (tlb1cfg & TLBnCFG_MINSIZE) >> TLBnCFG_MINSIZE_SHIFT;
+		max_pg = (tlb1cfg & TLBnCFG_MAXSIZE) >> TLBnCFG_MAXSIZE_SHIFT;
+
+		for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
+			struct mmu_psize_def *def;
+			unsigned int shift;
+
+			def = &mmu_psize_defs[psize];
+			shift = def->shift;
+
+			if (shift == 0 || shift & 1)
+				continue;
+
+			/* adjust to be in terms of 4^shift Kb */
+			shift = (shift - 10) >> 1;
+
+			if ((shift >= min_pg) && (shift <= max_pg))
+				def->flags |= MMU_PAGE_SIZE_DIRECT;
+		}
+
+		goto out;
+	}
+
+	if (fsl_mmu && (mmucfg & MMUCFG_MAVN) == MMUCFG_MAVN_V2) {
+		u32 tlb1cfg, tlb1ps;
+
+		tlb0cfg = mfspr(SPRN_TLB0CFG);
+		tlb1cfg = mfspr(SPRN_TLB1CFG);
+		tlb1ps = mfspr(SPRN_TLB1PS);
+		eptcfg = mfspr(SPRN_EPTCFG);
+
+		if ((tlb1cfg & TLBnCFG_IND) && (tlb0cfg & TLBnCFG_PT))
+			book3e_htw_mode = PPC_HTW_E6500;
+
+		/*
+		 * We expect 4K subpage size and unrestricted indirect size.
+		 * The lack of a restriction on indirect size is a Freescale
+		 * extension, indicated by PSn = 0 but SPSn != 0.
+		 */
+		if (eptcfg != 2)
+			book3e_htw_mode = PPC_HTW_NONE;
+
+		for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
+			struct mmu_psize_def *def = &mmu_psize_defs[psize];
+
+			if (tlb1ps & (1U << (def->shift - 10))) {
+				def->flags |= MMU_PAGE_SIZE_DIRECT;
+
+				if (book3e_htw_mode && psize == MMU_PAGE_2M)
+					def->flags |= MMU_PAGE_SIZE_INDIRECT;
+			}
+		}
+
+		goto out;
+	}
+#endif
+
+	tlb0cfg = mfspr(SPRN_TLB0CFG);
+	tlb0ps = mfspr(SPRN_TLB0PS);
+	eptcfg = mfspr(SPRN_EPTCFG);
+
+	/* Look for supported direct sizes */
+	for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
+		struct mmu_psize_def *def = &mmu_psize_defs[psize];
+
+		if (tlb0ps & (1U << (def->shift - 10)))
+			def->flags |= MMU_PAGE_SIZE_DIRECT;
+	}
+
+	/* Indirect page sizes supported ? */
+	if ((tlb0cfg & TLBnCFG_IND) == 0 ||
+	    (tlb0cfg & TLBnCFG_PT) == 0)
+		goto out;
+
+	book3e_htw_mode = PPC_HTW_IBM;
+
+	/* Now, we only deal with one IND page size for each
+	 * direct size. Hopefully all implementations today are
+	 * unambiguous, but we might want to be careful in the
+	 * future.
+	 */
+	for (i = 0; i < 3; i++) {
+		unsigned int ps, sps;
+
+		sps = eptcfg & 0x1f;
+		eptcfg >>= 5;
+		ps = eptcfg & 0x1f;
+		eptcfg >>= 5;
+		if (!ps || !sps)
+			continue;
+		for (psize = 0; psize < MMU_PAGE_COUNT; psize++) {
+			struct mmu_psize_def *def = &mmu_psize_defs[psize];
+
+			if (ps == (def->shift - 10))
+				def->flags |= MMU_PAGE_SIZE_INDIRECT;
+			if (sps == (def->shift - 10))
+				def->ind = ps + 10;
+		}
+	}
+
+out:
+	/* Cleanup array and print summary */
+	pr_info("MMU: Supported page sizes\n");
+	for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
+		struct mmu_psize_def *def = &mmu_psize_defs[psize];
+		const char *__page_type_names[] = {
+			"unsupported",
+			"direct",
+			"indirect",
+			"direct & indirect"
+		};
+		if (def->flags == 0) {
+			def->shift = 0;	
+			continue;
+		}
+		pr_info("  %8ld KB as %s\n", 1ul << (def->shift - 10),
+			__page_type_names[def->flags & 0x3]);
+	}
+}
+
+static void setup_mmu_htw(void)
+{
+	/*
+	 * If we want to use HW tablewalk, enable it by patching the TLB miss
+	 * handlers to branch to the one dedicated to it.
+	 */
+
+	switch (book3e_htw_mode) {
+	case PPC_HTW_IBM:
+		patch_exception(0x1c0, exc_data_tlb_miss_htw_book3e);
+		patch_exception(0x1e0, exc_instruction_tlb_miss_htw_book3e);
+		break;
+#ifdef CONFIG_PPC_FSL_BOOK3E
+	case PPC_HTW_E6500:
+		extlb_level_exc = EX_TLB_SIZE;
+		patch_exception(0x1c0, exc_data_tlb_miss_e6500_book3e);
+		patch_exception(0x1e0, exc_instruction_tlb_miss_e6500_book3e);
+		break;
+#endif
+	}
+	pr_info("MMU: Book3E HW tablewalk %s\n",
+		book3e_htw_mode != PPC_HTW_NONE ? "enabled" : "not supported");
+}
+
+/*
+ * Early initialization of the MMU TLB code
+ */
+static void __early_init_mmu(int boot_cpu)
+{
+	unsigned int mas4;
+
+	/* XXX This will have to be decided at runtime, but right
+	 * now our boot and TLB miss code hard wires it. Ideally
+	 * we should find out a suitable page size and patch the
+	 * TLB miss code (either that or use the PACA to store
+	 * the value we want)
+	 */
+	mmu_linear_psize = MMU_PAGE_1G;
+
+	/* XXX This should be decided at runtime based on supported
+	 * page sizes in the TLB, but for now let's assume 16M is
+	 * always there and a good fit (which it probably is)
+	 *
+	 * Freescale booke only supports 4K pages in TLB0, so use that.
+	 */
+	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E))
+		mmu_vmemmap_psize = MMU_PAGE_4K;
+	else
+		mmu_vmemmap_psize = MMU_PAGE_16M;
+
+	/* XXX This code only checks for TLB 0 capabilities and doesn't
+	 *     check what page size combos are supported by the HW. It
+	 *     also doesn't handle the case where a separate array holds
+	 *     the IND entries from the array loaded by the PT.
+	 */
+	if (boot_cpu) {
+		/* Look for supported page sizes */
+		setup_page_sizes();
+
+		/* Look for HW tablewalk support */
+		setup_mmu_htw();
+	}
+
+	/* Set MAS4 based on page table setting */
+
+	mas4 = 0x4 << MAS4_WIMGED_SHIFT;
+	switch (book3e_htw_mode) {
+	case PPC_HTW_E6500:
+		mas4 |= MAS4_INDD;
+		mas4 |= BOOK3E_PAGESZ_2M << MAS4_TSIZED_SHIFT;
+		mas4 |= MAS4_TLBSELD(1);
+		mmu_pte_psize = MMU_PAGE_2M;
+		break;
+
+	case PPC_HTW_IBM:
+		mas4 |= MAS4_INDD;
+#ifdef CONFIG_PPC_64K_PAGES
+		mas4 |=	BOOK3E_PAGESZ_256M << MAS4_TSIZED_SHIFT;
+		mmu_pte_psize = MMU_PAGE_256M;
+#else
+		mas4 |=	BOOK3E_PAGESZ_1M << MAS4_TSIZED_SHIFT;
+		mmu_pte_psize = MMU_PAGE_1M;
+#endif
+		break;
+
+	case PPC_HTW_NONE:
+#ifdef CONFIG_PPC_64K_PAGES
+		mas4 |=	BOOK3E_PAGESZ_64K << MAS4_TSIZED_SHIFT;
+#else
+		mas4 |=	BOOK3E_PAGESZ_4K << MAS4_TSIZED_SHIFT;
+#endif
+		mmu_pte_psize = mmu_virtual_psize;
+		break;
+	}
+	mtspr(SPRN_MAS4, mas4);
+
+	/* Set the global containing the top of the linear mapping
+	 * for use by the TLB miss code
+	 */
+	linear_map_top = memblock_end_of_DRAM();
+
+#ifdef CONFIG_PPC_FSL_BOOK3E
+	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
+		unsigned int num_cams;
+
+		/* use a quarter of the TLBCAM for bolted linear map */
+		num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;
+		linear_map_top = map_mem_in_cams(linear_map_top, num_cams);
+
+		/* limit memory so we dont have linear faults */
+		memblock_enforce_memory_limit(linear_map_top);
+
+		if (book3e_htw_mode == PPC_HTW_NONE) {
+			extlb_level_exc = EX_TLB_SIZE;
+			patch_exception(0x1c0, exc_data_tlb_miss_bolted_book3e);
+			patch_exception(0x1e0,
+				exc_instruction_tlb_miss_bolted_book3e);
+		}
+	}
+#endif
+
+	/* A sync won't hurt us after mucking around with
+	 * the MMU configuration
+	 */
+	mb();
+
+	memblock_set_current_limit(linear_map_top);
+}
+
+void __init early_init_mmu(void)
+{
+	__early_init_mmu(1);
+}
+
+void 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 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.
+	 *
+	 * 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...
+	 */
+#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);
+}
+#else /* ! CONFIG_PPC64 */
+void __init early_init_mmu(void)
+{
+#ifdef CONFIG_PPC_47x
+	early_init_mmu_47x();
+#endif
+}
+#endif /* CONFIG_PPC64 */