6 files changed, 383 insertions, 47 deletions

diff --git a/arch/xtensa/mm/Makefile b/arch/xtensa/mm/Makefile
index f0b646d..f54f78e 100644
--- a/arch/xtensa/mm/Makefile
+++ b/arch/xtensa/mm/Makefile
@@ -4,3 +4,4 @@
 
 obj-y			:= init.o cache.o misc.o
 obj-$(CONFIG_MMU)	+= fault.o mmu.o tlb.o
+obj-$(CONFIG_HIGHMEM)	+= highmem.o
diff --git a/arch/xtensa/mm/cache.c b/arch/xtensa/mm/cache.c
index ba4c47f..63cbb86 100644
--- a/arch/xtensa/mm/cache.c
+++ b/arch/xtensa/mm/cache.c
@@ -59,6 +59,10 @@
  *
  */
 
+#if (DCACHE_WAY_SIZE > PAGE_SIZE) && defined(CONFIG_HIGHMEM)
+#error "HIGHMEM is not supported on cores with aliasing cache."
+#endif
+
 #if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
 
 /*
@@ -179,10 +183,11 @@ update_mmu_cache(struct vm_area_struct * vma, unsigned long addr, pte_t *ptep)
 #else
 	if (!PageReserved(page) && !test_bit(PG_arch_1, &page->flags)
 	    && (vma->vm_flags & VM_EXEC) != 0) {
-	    	unsigned long paddr = (unsigned long) page_address(page);
+		unsigned long paddr = (unsigned long)kmap_atomic(page);
 		__flush_dcache_page(paddr);
 		__invalidate_icache_page(paddr);
 		set_bit(PG_arch_1, &page->flags);
+		kunmap_atomic((void *)paddr);
 	}
 #endif
 }
diff --git a/arch/xtensa/mm/highmem.c b/arch/xtensa/mm/highmem.c
new file mode 100644
index 0000000..17a8c0d
--- /dev/null
+++ b/arch/xtensa/mm/highmem.c
@@ -0,0 +1,72 @@
+/*
+ * High memory support for Xtensa architecture
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file "COPYING" in the main directory of
+ * this archive for more details.
+ *
+ * Copyright (C) 2014 Cadence Design Systems Inc.
+ */
+
+#include <linux/export.h>
+#include <linux/highmem.h>
+#include <asm/tlbflush.h>
+
+static pte_t *kmap_pte;
+
+void *kmap_atomic(struct page *page)
+{
+	enum fixed_addresses idx;
+	unsigned long vaddr;
+	int type;
+
+	pagefault_disable();
+	if (!PageHighMem(page))
+		return page_address(page);
+
+	type = kmap_atomic_idx_push();
+	idx = type + KM_TYPE_NR * smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+	BUG_ON(!pte_none(*(kmap_pte - idx)));
+#endif
+	set_pte(kmap_pte - idx, mk_pte(page, PAGE_KERNEL_EXEC));
+
+	return (void *)vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic);
+
+void __kunmap_atomic(void *kvaddr)
+{
+	int idx, type;
+
+	if (kvaddr >= (void *)FIXADDR_START &&
+	    kvaddr < (void *)FIXADDR_TOP) {
+		type = kmap_atomic_idx();
+		idx = type + KM_TYPE_NR * smp_processor_id();
+
+		/*
+		 * Force other mappings to Oops if they'll try to access this
+		 * pte without first remap it.  Keeping stale mappings around
+		 * is a bad idea also, in case the page changes cacheability
+		 * attributes or becomes a protected page in a hypervisor.
+		 */
+		pte_clear(&init_mm, kvaddr, kmap_pte - idx);
+		local_flush_tlb_kernel_range((unsigned long)kvaddr,
+					     (unsigned long)kvaddr + PAGE_SIZE);
+
+		kmap_atomic_idx_pop();
+	}
+
+	pagefault_enable();
+}
+EXPORT_SYMBOL(__kunmap_atomic);
+
+void __init kmap_init(void)
+{
+	unsigned long kmap_vstart;
+
+	/* cache the first kmap pte */
+	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
+	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
+}
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index aff108d..4224256 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -8,6 +8,7 @@
  * for more details.
  *
  * Copyright (C) 2001 - 2005 Tensilica Inc.
+ * Copyright (C) 2014 Cadence Design Systems Inc.
  *
  * Chris Zankel	<chris@zankel.net>
  * Joe Taylor	<joe@tensilica.com, joetylr@yahoo.com>
@@ -19,6 +20,7 @@
 #include <linux/errno.h>
 #include <linux/bootmem.h>
 #include <linux/gfp.h>
+#include <linux/highmem.h>
 #include <linux/swap.h>
 #include <linux/mman.h>
 #include <linux/nodemask.h>
@@ -27,11 +29,133 @@
 #include <asm/bootparam.h>
 #include <asm/page.h>
 #include <asm/sections.h>
+#include <asm/sysmem.h>
+
+struct sysmem_info sysmem __initdata;
+
+static void __init sysmem_dump(void)
+{
+	unsigned i;
+
+	pr_debug("Sysmem:\n");
+	for (i = 0; i < sysmem.nr_banks; ++i)
+		pr_debug("  0x%08lx - 0x%08lx (%ldK)\n",
+			 sysmem.bank[i].start, sysmem.bank[i].end,
+			 (sysmem.bank[i].end - sysmem.bank[i].start) >> 10);
+}
+
+/*
+ * Find bank with maximal .start such that bank.start <= start
+ */
+static inline struct meminfo * __init find_bank(unsigned long start)
+{
+	unsigned i;
+	struct meminfo *it = NULL;
+
+	for (i = 0; i < sysmem.nr_banks; ++i)
+		if (sysmem.bank[i].start <= start)
+			it = sysmem.bank + i;
+		else
+			break;
+	return it;
+}
+
+/*
+ * Move all memory banks starting at 'from' to a new place at 'to',
+ * adjust nr_banks accordingly.
+ * Both 'from' and 'to' must be inside the sysmem.bank.
+ *
+ * Returns: 0 (success), -ENOMEM (not enough space in the sysmem.bank).
+ */
+static int __init move_banks(struct meminfo *to, struct meminfo *from)
+{
+	unsigned n = sysmem.nr_banks - (from - sysmem.bank);
+
+	if (to > from && to - from + sysmem.nr_banks > SYSMEM_BANKS_MAX)
+		return -ENOMEM;
+	if (to != from)
+		memmove(to, from, n * sizeof(struct meminfo));
+	sysmem.nr_banks += to - from;
+	return 0;
+}
+
+/*
+ * Add new bank to sysmem. Resulting sysmem is the union of bytes of the
+ * original sysmem and the new bank.
+ *
+ * Returns: 0 (success), < 0 (error)
+ */
+int __init add_sysmem_bank(unsigned long start, unsigned long end)
+{
+	unsigned i;
+	struct meminfo *it = NULL;
+	unsigned long sz;
+	unsigned long bank_sz = 0;
+
+	if (start == end ||
+	    (start < end) != (PAGE_ALIGN(start) < (end & PAGE_MASK))) {
+		pr_warn("Ignoring small memory bank 0x%08lx size: %ld bytes\n",
+			start, end - start);
+		return -EINVAL;
+	}
+
+	start = PAGE_ALIGN(start);
+	end &= PAGE_MASK;
+	sz = end - start;
+
+	it = find_bank(start);
+
+	if (it)
+		bank_sz = it->end - it->start;
+
+	if (it && bank_sz >= start - it->start) {
+		if (end - it->start > bank_sz)
+			it->end = end;
+		else
+			return 0;
+	} else {
+		if (!it)
+			it = sysmem.bank;
+		else
+			++it;
+
+		if (it - sysmem.bank < sysmem.nr_banks &&
+		    it->start - start <= sz) {
+			it->start = start;
+			if (it->end - it->start < sz)
+				it->end = end;
+			else
+				return 0;
+		} else {
+			if (move_banks(it + 1, it) < 0) {
+				pr_warn("Ignoring memory bank 0x%08lx size %ld bytes\n",
+					start, end - start);
+				return -EINVAL;
+			}
+			it->start = start;
+			it->end = end;
+			return 0;
+		}
+	}
+	sz = it->end - it->start;
+	for (i = it + 1 - sysmem.bank; i < sysmem.nr_banks; ++i)
+		if (sysmem.bank[i].start - it->start <= sz) {
+			if (sz < sysmem.bank[i].end - it->start)
+				it->end = sysmem.bank[i].end;
+		} else {
+			break;
+		}
+
+	move_banks(it + 1, sysmem.bank + i);
+	return 0;
+}
 
 /*
  * mem_reserve(start, end, must_exist)
  *
  * Reserve some memory from the memory pool.
+ * If must_exist is set and a part of the region being reserved does not exist
+ * memory map is not altered.
  *
  * Parameters:
  *  start	Start of region,
@@ -39,53 +163,69 @@
  *  must_exist	Must exist in memory pool.
  *
  * Returns:
- *  0 (memory area couldn't be mapped)
- * -1 (success)
+ *  0 (success)
+ *  < 0 (error)
  */
 
 int __init mem_reserve(unsigned long start, unsigned long end, int must_exist)
 {
-	int i;
-
-	if (start == end)
-		return 0;
+	struct meminfo *it;
+	struct meminfo *rm = NULL;
+	unsigned long sz;
+	unsigned long bank_sz = 0;
 
 	start = start & PAGE_MASK;
 	end = PAGE_ALIGN(end);
+	sz = end - start;
+	if (!sz)
+		return -EINVAL;
 
-	for (i = 0; i < sysmem.nr_banks; i++)
-		if (start < sysmem.bank[i].end
-		    && end >= sysmem.bank[i].start)
-			break;
+	it = find_bank(start);
+
+	if (it)
+		bank_sz = it->end - it->start;
 
-	if (i == sysmem.nr_banks) {
-		if (must_exist)
-			printk (KERN_WARNING "mem_reserve: [0x%0lx, 0x%0lx) "
-				"not in any region!\n", start, end);
-		return 0;
+	if ((!it || end - it->start > bank_sz) && must_exist) {
+		pr_warn("mem_reserve: [0x%0lx, 0x%0lx) not in any region!\n",
+			start, end);
+		return -EINVAL;
 	}
 
-	if (start > sysmem.bank[i].start) {
-		if (end < sysmem.bank[i].end) {
-			/* split entry */
-			if (sysmem.nr_banks >= SYSMEM_BANKS_MAX)
-				panic("meminfo overflow\n");
-			sysmem.bank[sysmem.nr_banks].start = end;
-			sysmem.bank[sysmem.nr_banks].end = sysmem.bank[i].end;
-			sysmem.nr_banks++;
+	if (it && start - it->start < bank_sz) {
+		if (start == it->start) {
+			if (end - it->start < bank_sz) {
+				it->start = end;
+				return 0;
+			} else {
+				rm = it;
+			}
+		} else {
+			it->end = start;
+			if (end - it->start < bank_sz)
+				return add_sysmem_bank(end,
+						       it->start + bank_sz);
+			++it;
 		}
-		sysmem.bank[i].end = start;
+	}
 
-	} else if (end < sysmem.bank[i].end) {
-		sysmem.bank[i].start = end;
+	if (!it)
+		it = sysmem.bank;
 
-	} else {
-		/* remove entry */
-		sysmem.nr_banks--;
-		sysmem.bank[i].start = sysmem.bank[sysmem.nr_banks].start;
-		sysmem.bank[i].end   = sysmem.bank[sysmem.nr_banks].end;
+	for (; it < sysmem.bank + sysmem.nr_banks; ++it) {
+		if (it->end - start <= sz) {
+			if (!rm)
+				rm = it;
+		} else {
+			if (it->start - start < sz)
+				it->start = end;
+			break;
+		}
 	}
-	return -1;
+
+	if (rm)
+		move_banks(rm, it);
+
+	return 0;
 }
 
 
@@ -99,6 +239,7 @@ void __init bootmem_init(void)
 	unsigned long bootmap_start, bootmap_size;
 	int i;
 
+	sysmem_dump();
 	max_low_pfn = max_pfn = 0;
 	min_low_pfn = ~0;
 
@@ -156,19 +297,13 @@ void __init bootmem_init(void)
 
 void __init zones_init(void)
 {
-	unsigned long zones_size[MAX_NR_ZONES];
-	int i;
-
 	/* All pages are DMA-able, so we put them all in the DMA zone. */
-
-	zones_size[ZONE_DMA] = max_low_pfn - ARCH_PFN_OFFSET;
-	for (i = 1; i < MAX_NR_ZONES; i++)
-		zones_size[i] = 0;
-
+	unsigned long zones_size[MAX_NR_ZONES] = {
+		[ZONE_DMA] = max_low_pfn - ARCH_PFN_OFFSET,
 #ifdef CONFIG_HIGHMEM
-	zones_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
+		[ZONE_HIGHMEM] = max_pfn - max_low_pfn,
 #endif
-
+	};
 	free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL);
 }
 
@@ -178,16 +313,38 @@ void __init zones_init(void)
 
 void __init mem_init(void)
 {
-	max_mapnr = max_low_pfn - ARCH_PFN_OFFSET;
-	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
-
 #ifdef CONFIG_HIGHMEM
-#error HIGHGMEM not implemented in init.c
+	unsigned long tmp;
+
+	reset_all_zones_managed_pages();
+	for (tmp = max_low_pfn; tmp < max_pfn; tmp++)
+		free_highmem_page(pfn_to_page(tmp));
 #endif
 
+	max_mapnr = max_pfn - ARCH_PFN_OFFSET;
+	high_memory = (void *)__va(max_low_pfn << PAGE_SHIFT);
+
 	free_all_bootmem();
 
 	mem_init_print_info(NULL);
+	pr_info("virtual kernel memory layout:\n"
+#ifdef CONFIG_HIGHMEM
+		"    pkmap   : 0x%08lx - 0x%08lx  (%5lu kB)\n"
+		"    fixmap  : 0x%08lx - 0x%08lx  (%5lu kB)\n"
+#endif
+		"    vmalloc : 0x%08x - 0x%08x  (%5u MB)\n"
+		"    lowmem  : 0x%08x - 0x%08lx  (%5lu MB)\n",
+#ifdef CONFIG_HIGHMEM
+		PKMAP_BASE, PKMAP_BASE + LAST_PKMAP * PAGE_SIZE,
+		(LAST_PKMAP*PAGE_SIZE) >> 10,
+		FIXADDR_START, FIXADDR_TOP,
+		(FIXADDR_TOP - FIXADDR_START) >> 10,
+#endif
+		VMALLOC_START, VMALLOC_END,
+		(VMALLOC_END - VMALLOC_START) >> 20,
+		PAGE_OFFSET, PAGE_OFFSET +
+		(max_low_pfn - min_low_pfn) * PAGE_SIZE,
+		((max_low_pfn - min_low_pfn) * PAGE_SIZE) >> 20);
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
@@ -204,3 +361,53 @@ void free_initmem(void)
 {
 	free_initmem_default(-1);
 }
+
+static void __init parse_memmap_one(char *p)
+{
+	char *oldp;
+	unsigned long start_at, mem_size;
+
+	if (!p)
+		return;
+
+	oldp = p;
+	mem_size = memparse(p, &p);
+	if (p == oldp)
+		return;
+
+	switch (*p) {
+	case '@':
+		start_at = memparse(p + 1, &p);
+		add_sysmem_bank(start_at, start_at + mem_size);
+		break;
+
+	case '$':
+		start_at = memparse(p + 1, &p);
+		mem_reserve(start_at, start_at + mem_size, 0);
+		break;
+
+	case 0:
+		mem_reserve(mem_size, 0, 0);
+		break;
+
+	default:
+		pr_warn("Unrecognized memmap syntax: %s\n", p);
+		break;
+	}
+}
+
+static int __init parse_memmap_opt(char *str)
+{
+	while (str) {
+		char *k = strchr(str, ',');
+
+		if (k)
+			*k++ = 0;
+
+		parse_memmap_one(str);
+		str = k;
+	}
+
+	return 0;
+}
+early_param("memmap", parse_memmap_opt);
diff --git a/arch/xtensa/mm/mmu.c b/arch/xtensa/mm/mmu.c
index 861203e..3429b48 100644
--- a/arch/xtensa/mm/mmu.c
+++ b/arch/xtensa/mm/mmu.c
@@ -3,6 +3,7 @@
  *
  * Extracted from init.c
  */
+#include <linux/bootmem.h>
 #include <linux/percpu.h>
 #include <linux/init.h>
 #include <linux/string.h>
@@ -16,9 +17,44 @@
 #include <asm/initialize_mmu.h>
 #include <asm/io.h>
 
+#if defined(CONFIG_HIGHMEM)
+static void * __init init_pmd(unsigned long vaddr)
+{
+	pgd_t *pgd = pgd_offset_k(vaddr);
+	pmd_t *pmd = pmd_offset(pgd, vaddr);
+
+	if (pmd_none(*pmd)) {
+		unsigned i;
+		pte_t *pte = alloc_bootmem_low_pages(PAGE_SIZE);
+
+		for (i = 0; i < 1024; i++)
+			pte_clear(NULL, 0, pte + i);
+
+		set_pmd(pmd, __pmd(((unsigned long)pte) & PAGE_MASK));
+		BUG_ON(pte != pte_offset_kernel(pmd, 0));
+		pr_debug("%s: vaddr: 0x%08lx, pmd: 0x%p, pte: 0x%p\n",
+			 __func__, vaddr, pmd, pte);
+		return pte;
+	} else {
+		return pte_offset_kernel(pmd, 0);
+	}
+}
+
+static void __init fixedrange_init(void)
+{
+	BUILD_BUG_ON(FIXADDR_SIZE > PMD_SIZE);
+	init_pmd(__fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK);
+}
+#endif
+
 void __init paging_init(void)
 {
 	memset(swapper_pg_dir, 0, PAGE_SIZE);
+#ifdef CONFIG_HIGHMEM
+	fixedrange_init();
+	pkmap_page_table = init_pmd(PKMAP_BASE);
+	kmap_init();
+#endif
 }
 
 /*
diff --git a/arch/xtensa/mm/tlb.c b/arch/xtensa/mm/tlb.c
index ade62382..5ece856 100644
--- a/arch/xtensa/mm/tlb.c
+++ b/arch/xtensa/mm/tlb.c
@@ -149,6 +149,21 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 	local_irq_restore(flags);
 }
 
+void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
+{
+	if (end > start && start >= TASK_SIZE && end <= PAGE_OFFSET &&
+	    end - start < _TLB_ENTRIES << PAGE_SHIFT) {
+		start &= PAGE_MASK;
+		while (start < end) {
+			invalidate_itlb_mapping(start);
+			invalidate_dtlb_mapping(start);
+			start += PAGE_SIZE;
+		}
+	} else {
+		local_flush_tlb_all();
+	}
+}
+
 #ifdef CONFIG_DEBUG_TLB_SANITY
 
 static unsigned get_pte_for_vaddr(unsigned vaddr)