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-rw-r--r--kernel/arch/tile/mm/init.c983
1 files changed, 983 insertions, 0 deletions
diff --git a/kernel/arch/tile/mm/init.c b/kernel/arch/tile/mm/init.c
new file mode 100644
index 000000000..5bd252e3f
--- /dev/null
+++ b/kernel/arch/tile/mm/init.c
@@ -0,0 +1,983 @@
+/*
+ * Copyright (C) 1995 Linus Torvalds
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/poison.h>
+#include <linux/bootmem.h>
+#include <linux/slab.h>
+#include <linux/proc_fs.h>
+#include <linux/efi.h>
+#include <linux/memory_hotplug.h>
+#include <linux/uaccess.h>
+#include <asm/mmu_context.h>
+#include <asm/processor.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/dma.h>
+#include <asm/fixmap.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/homecache.h>
+#include <hv/hypervisor.h>
+#include <arch/chip.h>
+
+#include "migrate.h"
+
+#define clear_pgd(pmdptr) (*(pmdptr) = hv_pte(0))
+
+#ifndef __tilegx__
+unsigned long VMALLOC_RESERVE = CONFIG_VMALLOC_RESERVE;
+EXPORT_SYMBOL(VMALLOC_RESERVE);
+#endif
+
+/* Create an L2 page table */
+static pte_t * __init alloc_pte(void)
+{
+ return __alloc_bootmem(L2_KERNEL_PGTABLE_SIZE, HV_PAGE_TABLE_ALIGN, 0);
+}
+
+/*
+ * L2 page tables per controller. We allocate these all at once from
+ * the bootmem allocator and store them here. This saves on kernel L2
+ * page table memory, compared to allocating a full 64K page per L2
+ * page table, and also means that in cases where we use huge pages,
+ * we are guaranteed to later be able to shatter those huge pages and
+ * switch to using these page tables instead, without requiring
+ * further allocation. Each l2_ptes[] entry points to the first page
+ * table for the first hugepage-size piece of memory on the
+ * controller; other page tables are just indexed directly, i.e. the
+ * L2 page tables are contiguous in memory for each controller.
+ */
+static pte_t *l2_ptes[MAX_NUMNODES];
+static int num_l2_ptes[MAX_NUMNODES];
+
+static void init_prealloc_ptes(int node, int pages)
+{
+ BUG_ON(pages & (PTRS_PER_PTE - 1));
+ if (pages) {
+ num_l2_ptes[node] = pages;
+ l2_ptes[node] = __alloc_bootmem(pages * sizeof(pte_t),
+ HV_PAGE_TABLE_ALIGN, 0);
+ }
+}
+
+pte_t *get_prealloc_pte(unsigned long pfn)
+{
+ int node = pfn_to_nid(pfn);
+ pfn &= ~(-1UL << (NR_PA_HIGHBIT_SHIFT - PAGE_SHIFT));
+ BUG_ON(node >= MAX_NUMNODES);
+ BUG_ON(pfn >= num_l2_ptes[node]);
+ return &l2_ptes[node][pfn];
+}
+
+/*
+ * What caching do we expect pages from the heap to have when
+ * they are allocated during bootup? (Once we've installed the
+ * "real" swapper_pg_dir.)
+ */
+static int initial_heap_home(void)
+{
+ if (hash_default)
+ return PAGE_HOME_HASH;
+ return smp_processor_id();
+}
+
+/*
+ * Place a pointer to an L2 page table in a middle page
+ * directory entry.
+ */
+static void __init assign_pte(pmd_t *pmd, pte_t *page_table)
+{
+ phys_addr_t pa = __pa(page_table);
+ unsigned long l2_ptfn = pa >> HV_LOG2_PAGE_TABLE_ALIGN;
+ pte_t pteval = hv_pte_set_ptfn(__pgprot(_PAGE_TABLE), l2_ptfn);
+ BUG_ON((pa & (HV_PAGE_TABLE_ALIGN-1)) != 0);
+ pteval = pte_set_home(pteval, initial_heap_home());
+ *(pte_t *)pmd = pteval;
+ if (page_table != (pte_t *)pmd_page_vaddr(*pmd))
+ BUG();
+}
+
+#ifdef __tilegx__
+
+static inline pmd_t *alloc_pmd(void)
+{
+ return __alloc_bootmem(L1_KERNEL_PGTABLE_SIZE, HV_PAGE_TABLE_ALIGN, 0);
+}
+
+static inline void assign_pmd(pud_t *pud, pmd_t *pmd)
+{
+ assign_pte((pmd_t *)pud, (pte_t *)pmd);
+}
+
+#endif /* __tilegx__ */
+
+/* Replace the given pmd with a full PTE table. */
+void __init shatter_pmd(pmd_t *pmd)
+{
+ pte_t *pte = get_prealloc_pte(pte_pfn(*(pte_t *)pmd));
+ assign_pte(pmd, pte);
+}
+
+#ifdef __tilegx__
+static pmd_t *__init get_pmd(pgd_t pgtables[], unsigned long va)
+{
+ pud_t *pud = pud_offset(&pgtables[pgd_index(va)], va);
+ if (pud_none(*pud))
+ assign_pmd(pud, alloc_pmd());
+ return pmd_offset(pud, va);
+}
+#else
+static pmd_t *__init get_pmd(pgd_t pgtables[], unsigned long va)
+{
+ return pmd_offset(pud_offset(&pgtables[pgd_index(va)], va), va);
+}
+#endif
+
+/*
+ * This function initializes a certain range of kernel virtual memory
+ * with new bootmem page tables, everywhere page tables are missing in
+ * the given range.
+ */
+
+/*
+ * NOTE: The pagetables are allocated contiguous on the physical space
+ * so we can cache the place of the first one and move around without
+ * checking the pgd every time.
+ */
+static void __init page_table_range_init(unsigned long start,
+ unsigned long end, pgd_t *pgd)
+{
+ unsigned long vaddr;
+ start = round_down(start, PMD_SIZE);
+ end = round_up(end, PMD_SIZE);
+ for (vaddr = start; vaddr < end; vaddr += PMD_SIZE) {
+ pmd_t *pmd = get_pmd(pgd, vaddr);
+ if (pmd_none(*pmd))
+ assign_pte(pmd, alloc_pte());
+ }
+}
+
+
+static int __initdata ktext_hash = 1; /* .text pages */
+static int __initdata kdata_hash = 1; /* .data and .bss pages */
+int __write_once hash_default = 1; /* kernel allocator pages */
+EXPORT_SYMBOL(hash_default);
+int __write_once kstack_hash = 1; /* if no homecaching, use h4h */
+
+/*
+ * CPUs to use to for striping the pages of kernel data. If hash-for-home
+ * is available, this is only relevant if kcache_hash sets up the
+ * .data and .bss to be page-homed, and we don't want the default mode
+ * of using the full set of kernel cpus for the striping.
+ */
+static __initdata struct cpumask kdata_mask;
+static __initdata int kdata_arg_seen;
+
+int __write_once kdata_huge; /* if no homecaching, small pages */
+
+
+/* Combine a generic pgprot_t with cache home to get a cache-aware pgprot. */
+static pgprot_t __init construct_pgprot(pgprot_t prot, int home)
+{
+ prot = pte_set_home(prot, home);
+ if (home == PAGE_HOME_IMMUTABLE) {
+ if (ktext_hash)
+ prot = hv_pte_set_mode(prot, HV_PTE_MODE_CACHE_HASH_L3);
+ else
+ prot = hv_pte_set_mode(prot, HV_PTE_MODE_CACHE_NO_L3);
+ }
+ return prot;
+}
+
+/*
+ * For a given kernel data VA, how should it be cached?
+ * We return the complete pgprot_t with caching bits set.
+ */
+static pgprot_t __init init_pgprot(ulong address)
+{
+ int cpu;
+ unsigned long page;
+ enum { CODE_DELTA = MEM_SV_START - PAGE_OFFSET };
+
+ /* For kdata=huge, everything is just hash-for-home. */
+ if (kdata_huge)
+ return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
+
+ /*
+ * We map the aliased pages of permanent text so we can
+ * update them if necessary, for ftrace, etc.
+ */
+ if (address < (ulong) _sinittext - CODE_DELTA)
+ return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
+
+ /* We map read-only data non-coherent for performance. */
+ if ((address >= (ulong) __start_rodata &&
+ address < (ulong) __end_rodata) ||
+ address == (ulong) empty_zero_page) {
+ return construct_pgprot(PAGE_KERNEL_RO, PAGE_HOME_IMMUTABLE);
+ }
+
+#ifndef __tilegx__
+ /* Force the atomic_locks[] array page to be hash-for-home. */
+ if (address == (ulong) atomic_locks)
+ return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
+#endif
+
+ /*
+ * Everything else that isn't data or bss is heap, so mark it
+ * with the initial heap home (hash-for-home, or this cpu). This
+ * includes any addresses after the loaded image and any address before
+ * __init_end, since we already captured the case of text before
+ * _sinittext, and __pa(einittext) is approximately __pa(__init_begin).
+ *
+ * All the LOWMEM pages that we mark this way will get their
+ * struct page homecache properly marked later, in set_page_homes().
+ * The HIGHMEM pages we leave with a default zero for their
+ * homes, but with a zero free_time we don't have to actually
+ * do a flush action the first time we use them, either.
+ */
+ if (address >= (ulong) _end || address < (ulong) __init_end)
+ return construct_pgprot(PAGE_KERNEL, initial_heap_home());
+
+ /* Use hash-for-home if requested for data/bss. */
+ if (kdata_hash)
+ return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
+
+ /*
+ * Otherwise we just hand out consecutive cpus. To avoid
+ * requiring this function to hold state, we just walk forward from
+ * __end_rodata by PAGE_SIZE, skipping the readonly and init data, to
+ * reach the requested address, while walking cpu home around
+ * kdata_mask. This is typically no more than a dozen or so iterations.
+ */
+ page = (((ulong)__end_rodata) + PAGE_SIZE - 1) & PAGE_MASK;
+ BUG_ON(address < page || address >= (ulong)_end);
+ cpu = cpumask_first(&kdata_mask);
+ for (; page < address; page += PAGE_SIZE) {
+ if (page >= (ulong)&init_thread_union &&
+ page < (ulong)&init_thread_union + THREAD_SIZE)
+ continue;
+ if (page == (ulong)empty_zero_page)
+ continue;
+#ifndef __tilegx__
+ if (page == (ulong)atomic_locks)
+ continue;
+#endif
+ cpu = cpumask_next(cpu, &kdata_mask);
+ if (cpu == NR_CPUS)
+ cpu = cpumask_first(&kdata_mask);
+ }
+ return construct_pgprot(PAGE_KERNEL, cpu);
+}
+
+/*
+ * This function sets up how we cache the kernel text. If we have
+ * hash-for-home support, normally that is used instead (see the
+ * kcache_hash boot flag for more information). But if we end up
+ * using a page-based caching technique, this option sets up the
+ * details of that. In addition, the "ktext=nocache" option may
+ * always be used to disable local caching of text pages, if desired.
+ */
+
+static int __initdata ktext_arg_seen;
+static int __initdata ktext_small;
+static int __initdata ktext_local;
+static int __initdata ktext_all;
+static int __initdata ktext_nondataplane;
+static int __initdata ktext_nocache;
+static struct cpumask __initdata ktext_mask;
+
+static int __init setup_ktext(char *str)
+{
+ if (str == NULL)
+ return -EINVAL;
+
+ /* If you have a leading "nocache", turn off ktext caching */
+ if (strncmp(str, "nocache", 7) == 0) {
+ ktext_nocache = 1;
+ pr_info("ktext: disabling local caching of kernel text\n");
+ str += 7;
+ if (*str == ',')
+ ++str;
+ if (*str == '\0')
+ return 0;
+ }
+
+ ktext_arg_seen = 1;
+
+ /* Default setting: use a huge page */
+ if (strcmp(str, "huge") == 0)
+ pr_info("ktext: using one huge locally cached page\n");
+
+ /* Pay TLB cost but get no cache benefit: cache small pages locally */
+ else if (strcmp(str, "local") == 0) {
+ ktext_small = 1;
+ ktext_local = 1;
+ pr_info("ktext: using small pages with local caching\n");
+ }
+
+ /* Neighborhood cache ktext pages on all cpus. */
+ else if (strcmp(str, "all") == 0) {
+ ktext_small = 1;
+ ktext_all = 1;
+ pr_info("ktext: using maximal caching neighborhood\n");
+ }
+
+
+ /* Neighborhood ktext pages on specified mask */
+ else if (cpulist_parse(str, &ktext_mask) == 0) {
+ if (cpumask_weight(&ktext_mask) > 1) {
+ ktext_small = 1;
+ pr_info("ktext: using caching neighborhood %*pbl with small pages\n",
+ cpumask_pr_args(&ktext_mask));
+ } else {
+ pr_info("ktext: caching on cpu %*pbl with one huge page\n",
+ cpumask_pr_args(&ktext_mask));
+ }
+ }
+
+ else if (*str)
+ return -EINVAL;
+
+ return 0;
+}
+
+early_param("ktext", setup_ktext);
+
+
+static inline pgprot_t ktext_set_nocache(pgprot_t prot)
+{
+ if (!ktext_nocache)
+ prot = hv_pte_set_nc(prot);
+ else
+ prot = hv_pte_set_no_alloc_l2(prot);
+ return prot;
+}
+
+/* Temporary page table we use for staging. */
+static pgd_t pgtables[PTRS_PER_PGD]
+ __attribute__((aligned(HV_PAGE_TABLE_ALIGN)));
+
+/*
+ * This maps the physical memory to kernel virtual address space, a total
+ * of max_low_pfn pages, by creating page tables starting from address
+ * PAGE_OFFSET.
+ *
+ * This routine transitions us from using a set of compiled-in large
+ * pages to using some more precise caching, including removing access
+ * to code pages mapped at PAGE_OFFSET (executed only at MEM_SV_START)
+ * marking read-only data as locally cacheable, striping the remaining
+ * .data and .bss across all the available tiles, and removing access
+ * to pages above the top of RAM (thus ensuring a page fault from a bad
+ * virtual address rather than a hypervisor shoot down for accessing
+ * memory outside the assigned limits).
+ */
+static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
+{
+ unsigned long long irqmask;
+ unsigned long address, pfn;
+ pmd_t *pmd;
+ pte_t *pte;
+ int pte_ofs;
+ const struct cpumask *my_cpu_mask = cpumask_of(smp_processor_id());
+ struct cpumask kstripe_mask;
+ int rc, i;
+
+ if (ktext_arg_seen && ktext_hash) {
+ pr_warn("warning: \"ktext\" boot argument ignored if \"kcache_hash\" sets up text hash-for-home\n");
+ ktext_small = 0;
+ }
+
+ if (kdata_arg_seen && kdata_hash) {
+ pr_warn("warning: \"kdata\" boot argument ignored if \"kcache_hash\" sets up data hash-for-home\n");
+ }
+
+ if (kdata_huge && !hash_default) {
+ pr_warn("warning: disabling \"kdata=huge\"; requires kcache_hash=all or =allbutstack\n");
+ kdata_huge = 0;
+ }
+
+ /*
+ * Set up a mask for cpus to use for kernel striping.
+ * This is normally all cpus, but minus dataplane cpus if any.
+ * If the dataplane covers the whole chip, we stripe over
+ * the whole chip too.
+ */
+ cpumask_copy(&kstripe_mask, cpu_possible_mask);
+ if (!kdata_arg_seen)
+ kdata_mask = kstripe_mask;
+
+ /* Allocate and fill in L2 page tables */
+ for (i = 0; i < MAX_NUMNODES; ++i) {
+#ifdef CONFIG_HIGHMEM
+ unsigned long end_pfn = node_lowmem_end_pfn[i];
+#else
+ unsigned long end_pfn = node_end_pfn[i];
+#endif
+ unsigned long end_huge_pfn = 0;
+
+ /* Pre-shatter the last huge page to allow per-cpu pages. */
+ if (kdata_huge)
+ end_huge_pfn = end_pfn - (HPAGE_SIZE >> PAGE_SHIFT);
+
+ pfn = node_start_pfn[i];
+
+ /* Allocate enough memory to hold L2 page tables for node. */
+ init_prealloc_ptes(i, end_pfn - pfn);
+
+ address = (unsigned long) pfn_to_kaddr(pfn);
+ while (pfn < end_pfn) {
+ BUG_ON(address & (HPAGE_SIZE-1));
+ pmd = get_pmd(pgtables, address);
+ pte = get_prealloc_pte(pfn);
+ if (pfn < end_huge_pfn) {
+ pgprot_t prot = init_pgprot(address);
+ *(pte_t *)pmd = pte_mkhuge(pfn_pte(pfn, prot));
+ for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE;
+ pfn++, pte_ofs++, address += PAGE_SIZE)
+ pte[pte_ofs] = pfn_pte(pfn, prot);
+ } else {
+ if (kdata_huge)
+ printk(KERN_DEBUG "pre-shattered huge page at %#lx\n",
+ address);
+ for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE;
+ pfn++, pte_ofs++, address += PAGE_SIZE) {
+ pgprot_t prot = init_pgprot(address);
+ pte[pte_ofs] = pfn_pte(pfn, prot);
+ }
+ assign_pte(pmd, pte);
+ }
+ }
+ }
+
+ /*
+ * Set or check ktext_map now that we have cpu_possible_mask
+ * and kstripe_mask to work with.
+ */
+ if (ktext_all)
+ cpumask_copy(&ktext_mask, cpu_possible_mask);
+ else if (ktext_nondataplane)
+ ktext_mask = kstripe_mask;
+ else if (!cpumask_empty(&ktext_mask)) {
+ /* Sanity-check any mask that was requested */
+ struct cpumask bad;
+ cpumask_andnot(&bad, &ktext_mask, cpu_possible_mask);
+ cpumask_and(&ktext_mask, &ktext_mask, cpu_possible_mask);
+ if (!cpumask_empty(&bad))
+ pr_info("ktext: not using unavailable cpus %*pbl\n",
+ cpumask_pr_args(&bad));
+ if (cpumask_empty(&ktext_mask)) {
+ pr_warn("ktext: no valid cpus; caching on %d\n",
+ smp_processor_id());
+ cpumask_copy(&ktext_mask,
+ cpumask_of(smp_processor_id()));
+ }
+ }
+
+ address = MEM_SV_START;
+ pmd = get_pmd(pgtables, address);
+ pfn = 0; /* code starts at PA 0 */
+ if (ktext_small) {
+ /* Allocate an L2 PTE for the kernel text */
+ int cpu = 0;
+ pgprot_t prot = construct_pgprot(PAGE_KERNEL_EXEC,
+ PAGE_HOME_IMMUTABLE);
+
+ if (ktext_local) {
+ if (ktext_nocache)
+ prot = hv_pte_set_mode(prot,
+ HV_PTE_MODE_UNCACHED);
+ else
+ prot = hv_pte_set_mode(prot,
+ HV_PTE_MODE_CACHE_NO_L3);
+ } else {
+ prot = hv_pte_set_mode(prot,
+ HV_PTE_MODE_CACHE_TILE_L3);
+ cpu = cpumask_first(&ktext_mask);
+
+ prot = ktext_set_nocache(prot);
+ }
+
+ BUG_ON(address != (unsigned long)_text);
+ pte = NULL;
+ for (; address < (unsigned long)_einittext;
+ pfn++, address += PAGE_SIZE) {
+ pte_ofs = pte_index(address);
+ if (pte_ofs == 0) {
+ if (pte)
+ assign_pte(pmd++, pte);
+ pte = alloc_pte();
+ }
+ if (!ktext_local) {
+ prot = set_remote_cache_cpu(prot, cpu);
+ cpu = cpumask_next(cpu, &ktext_mask);
+ if (cpu == NR_CPUS)
+ cpu = cpumask_first(&ktext_mask);
+ }
+ pte[pte_ofs] = pfn_pte(pfn, prot);
+ }
+ if (pte)
+ assign_pte(pmd, pte);
+ } else {
+ pte_t pteval = pfn_pte(0, PAGE_KERNEL_EXEC);
+ pteval = pte_mkhuge(pteval);
+ if (ktext_hash) {
+ pteval = hv_pte_set_mode(pteval,
+ HV_PTE_MODE_CACHE_HASH_L3);
+ pteval = ktext_set_nocache(pteval);
+ } else
+ if (cpumask_weight(&ktext_mask) == 1) {
+ pteval = set_remote_cache_cpu(pteval,
+ cpumask_first(&ktext_mask));
+ pteval = hv_pte_set_mode(pteval,
+ HV_PTE_MODE_CACHE_TILE_L3);
+ pteval = ktext_set_nocache(pteval);
+ } else if (ktext_nocache)
+ pteval = hv_pte_set_mode(pteval,
+ HV_PTE_MODE_UNCACHED);
+ else
+ pteval = hv_pte_set_mode(pteval,
+ HV_PTE_MODE_CACHE_NO_L3);
+ for (; address < (unsigned long)_einittext;
+ pfn += PFN_DOWN(HPAGE_SIZE), address += HPAGE_SIZE)
+ *(pte_t *)(pmd++) = pfn_pte(pfn, pteval);
+ }
+
+ /* Set swapper_pgprot here so it is flushed to memory right away. */
+ swapper_pgprot = init_pgprot((unsigned long)swapper_pg_dir);
+
+ /*
+ * Since we may be changing the caching of the stack and page
+ * table itself, we invoke an assembly helper to do the
+ * following steps:
+ *
+ * - flush the cache so we start with an empty slate
+ * - install pgtables[] as the real page table
+ * - flush the TLB so the new page table takes effect
+ */
+ irqmask = interrupt_mask_save_mask();
+ interrupt_mask_set_mask(-1ULL);
+ rc = flush_and_install_context(__pa(pgtables),
+ init_pgprot((unsigned long)pgtables),
+ __this_cpu_read(current_asid),
+ cpumask_bits(my_cpu_mask));
+ interrupt_mask_restore_mask(irqmask);
+ BUG_ON(rc != 0);
+
+ /* Copy the page table back to the normal swapper_pg_dir. */
+ memcpy(pgd_base, pgtables, sizeof(pgtables));
+ __install_page_table(pgd_base, __this_cpu_read(current_asid),
+ swapper_pgprot);
+
+ /*
+ * We just read swapper_pgprot and thus brought it into the cache,
+ * with its new home & caching mode. When we start the other CPUs,
+ * they're going to reference swapper_pgprot via their initial fake
+ * VA-is-PA mappings, which cache everything locally. At that
+ * time, if it's in our cache with a conflicting home, the
+ * simulator's coherence checker will complain. So, flush it out
+ * of our cache; we're not going to ever use it again anyway.
+ */
+ __insn_finv(&swapper_pgprot);
+}
+
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ * On Tile, the only valid things for which we can just hand out unchecked
+ * PTEs are the kernel code and data. Anything else might change its
+ * homing with time, and we wouldn't know to adjust the /dev/mem PTEs.
+ * Note that init_thread_union is released to heap soon after boot,
+ * so we include it in the init data.
+ *
+ * For TILE-Gx, we might want to consider allowing access to PA
+ * regions corresponding to PCI space, etc.
+ */
+int devmem_is_allowed(unsigned long pagenr)
+{
+ return pagenr < kaddr_to_pfn(_end) &&
+ !(pagenr >= kaddr_to_pfn(&init_thread_union) ||
+ pagenr < kaddr_to_pfn(__init_end)) &&
+ !(pagenr >= kaddr_to_pfn(_sinittext) ||
+ pagenr <= kaddr_to_pfn(_einittext-1));
+}
+
+#ifdef CONFIG_HIGHMEM
+static void __init permanent_kmaps_init(pgd_t *pgd_base)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long vaddr;
+
+ vaddr = PKMAP_BASE;
+ page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
+
+ pgd = swapper_pg_dir + pgd_index(vaddr);
+ pud = pud_offset(pgd, vaddr);
+ pmd = pmd_offset(pud, vaddr);
+ pte = pte_offset_kernel(pmd, vaddr);
+ pkmap_page_table = pte;
+}
+#endif /* CONFIG_HIGHMEM */
+
+
+#ifndef CONFIG_64BIT
+static void __init init_free_pfn_range(unsigned long start, unsigned long end)
+{
+ unsigned long pfn;
+ struct page *page = pfn_to_page(start);
+
+ for (pfn = start; pfn < end; ) {
+ /* Optimize by freeing pages in large batches */
+ int order = __ffs(pfn);
+ int count, i;
+ struct page *p;
+
+ if (order >= MAX_ORDER)
+ order = MAX_ORDER-1;
+ count = 1 << order;
+ while (pfn + count > end) {
+ count >>= 1;
+ --order;
+ }
+ for (p = page, i = 0; i < count; ++i, ++p) {
+ __ClearPageReserved(p);
+ /*
+ * Hacky direct set to avoid unnecessary
+ * lock take/release for EVERY page here.
+ */
+ p->_count.counter = 0;
+ p->_mapcount.counter = -1;
+ }
+ init_page_count(page);
+ __free_pages(page, order);
+ adjust_managed_page_count(page, count);
+
+ page += count;
+ pfn += count;
+ }
+}
+
+static void __init set_non_bootmem_pages_init(void)
+{
+ struct zone *z;
+ for_each_zone(z) {
+ unsigned long start, end;
+ int nid = z->zone_pgdat->node_id;
+#ifdef CONFIG_HIGHMEM
+ int idx = zone_idx(z);
+#endif
+
+ start = z->zone_start_pfn;
+ end = start + z->spanned_pages;
+ start = max(start, node_free_pfn[nid]);
+ start = max(start, max_low_pfn);
+
+#ifdef CONFIG_HIGHMEM
+ if (idx == ZONE_HIGHMEM)
+ totalhigh_pages += z->spanned_pages;
+#endif
+ if (kdata_huge) {
+ unsigned long percpu_pfn = node_percpu_pfn[nid];
+ if (start < percpu_pfn && end > percpu_pfn)
+ end = percpu_pfn;
+ }
+#ifdef CONFIG_PCI
+ if (start <= pci_reserve_start_pfn &&
+ end > pci_reserve_start_pfn) {
+ if (end > pci_reserve_end_pfn)
+ init_free_pfn_range(pci_reserve_end_pfn, end);
+ end = pci_reserve_start_pfn;
+ }
+#endif
+ init_free_pfn_range(start, end);
+ }
+}
+#endif
+
+/*
+ * paging_init() sets up the page tables - note that all of lowmem is
+ * already mapped by head.S.
+ */
+void __init paging_init(void)
+{
+#ifdef __tilegx__
+ pud_t *pud;
+#endif
+ pgd_t *pgd_base = swapper_pg_dir;
+
+ kernel_physical_mapping_init(pgd_base);
+
+ /* Fixed mappings, only the page table structure has to be created. */
+ page_table_range_init(fix_to_virt(__end_of_fixed_addresses - 1),
+ FIXADDR_TOP, pgd_base);
+
+#ifdef CONFIG_HIGHMEM
+ permanent_kmaps_init(pgd_base);
+#endif
+
+#ifdef __tilegx__
+ /*
+ * Since GX allocates just one pmd_t array worth of vmalloc space,
+ * we go ahead and allocate it statically here, then share it
+ * globally. As a result we don't have to worry about any task
+ * changing init_mm once we get up and running, and there's no
+ * need for e.g. vmalloc_sync_all().
+ */
+ BUILD_BUG_ON(pgd_index(VMALLOC_START) != pgd_index(VMALLOC_END - 1));
+ pud = pud_offset(pgd_base + pgd_index(VMALLOC_START), VMALLOC_START);
+ assign_pmd(pud, alloc_pmd());
+#endif
+}
+
+
+/*
+ * Walk the kernel page tables and derive the page_home() from
+ * the PTEs, so that set_pte() can properly validate the caching
+ * of all PTEs it sees.
+ */
+void __init set_page_homes(void)
+{
+}
+
+static void __init set_max_mapnr_init(void)
+{
+#ifdef CONFIG_FLATMEM
+ max_mapnr = max_low_pfn;
+#endif
+}
+
+void __init mem_init(void)
+{
+ int i;
+#ifndef __tilegx__
+ void *last;
+#endif
+
+#ifdef CONFIG_FLATMEM
+ BUG_ON(!mem_map);
+#endif
+
+#ifdef CONFIG_HIGHMEM
+ /* check that fixmap and pkmap do not overlap */
+ if (PKMAP_ADDR(LAST_PKMAP-1) >= FIXADDR_START) {
+ pr_err("fixmap and kmap areas overlap - this will crash\n");
+ pr_err("pkstart: %lxh pkend: %lxh fixstart %lxh\n",
+ PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP-1), FIXADDR_START);
+ BUG();
+ }
+#endif
+
+ set_max_mapnr_init();
+
+ /* this will put all bootmem onto the freelists */
+ free_all_bootmem();
+
+#ifndef CONFIG_64BIT
+ /* count all remaining LOWMEM and give all HIGHMEM to page allocator */
+ set_non_bootmem_pages_init();
+#endif
+
+ mem_init_print_info(NULL);
+
+ /*
+ * In debug mode, dump some interesting memory mappings.
+ */
+#ifdef CONFIG_HIGHMEM
+ printk(KERN_DEBUG " KMAP %#lx - %#lx\n",
+ FIXADDR_START, FIXADDR_TOP + PAGE_SIZE - 1);
+ printk(KERN_DEBUG " PKMAP %#lx - %#lx\n",
+ PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP) - 1);
+#endif
+ printk(KERN_DEBUG " VMALLOC %#lx - %#lx\n",
+ _VMALLOC_START, _VMALLOC_END - 1);
+#ifdef __tilegx__
+ for (i = MAX_NUMNODES-1; i >= 0; --i) {
+ struct pglist_data *node = &node_data[i];
+ if (node->node_present_pages) {
+ unsigned long start = (unsigned long)
+ pfn_to_kaddr(node->node_start_pfn);
+ unsigned long end = start +
+ (node->node_present_pages << PAGE_SHIFT);
+ printk(KERN_DEBUG " MEM%d %#lx - %#lx\n",
+ i, start, end - 1);
+ }
+ }
+#else
+ last = high_memory;
+ for (i = MAX_NUMNODES-1; i >= 0; --i) {
+ if ((unsigned long)vbase_map[i] != -1UL) {
+ printk(KERN_DEBUG " LOWMEM%d %#lx - %#lx\n",
+ i, (unsigned long) (vbase_map[i]),
+ (unsigned long) (last-1));
+ last = vbase_map[i];
+ }
+ }
+#endif
+
+#ifndef __tilegx__
+ /*
+ * Convert from using one lock for all atomic operations to
+ * one per cpu.
+ */
+ __init_atomic_per_cpu();
+#endif
+}
+
+/*
+ * this is for the non-NUMA, single node SMP system case.
+ * Specifically, in the case of x86, we will always add
+ * memory to the highmem for now.
+ */
+#ifndef CONFIG_NEED_MULTIPLE_NODES
+int arch_add_memory(u64 start, u64 size)
+{
+ struct pglist_data *pgdata = &contig_page_data;
+ struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+
+ return __add_pages(zone, start_pfn, nr_pages);
+}
+
+int remove_memory(u64 start, u64 size)
+{
+ return -EINVAL;
+}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+ /* TODO */
+ return -EBUSY;
+}
+#endif
+#endif
+
+struct kmem_cache *pgd_cache;
+
+void __init pgtable_cache_init(void)
+{
+ pgd_cache = kmem_cache_create("pgd", SIZEOF_PGD, SIZEOF_PGD, 0, NULL);
+ if (!pgd_cache)
+ panic("pgtable_cache_init(): Cannot create pgd cache");
+}
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+static long __write_once initfree;
+#else
+static long __write_once initfree = 1;
+#endif
+
+/* Select whether to free (1) or mark unusable (0) the __init pages. */
+static int __init set_initfree(char *str)
+{
+ long val;
+ if (kstrtol(str, 0, &val) == 0) {
+ initfree = val;
+ pr_info("initfree: %s free init pages\n",
+ initfree ? "will" : "won't");
+ }
+ return 1;
+}
+__setup("initfree=", set_initfree);
+
+static void free_init_pages(char *what, unsigned long begin, unsigned long end)
+{
+ unsigned long addr = (unsigned long) begin;
+
+ if (kdata_huge && !initfree) {
+ pr_warn("Warning: ignoring initfree=0: incompatible with kdata=huge\n");
+ initfree = 1;
+ }
+ end = (end + PAGE_SIZE - 1) & PAGE_MASK;
+ local_flush_tlb_pages(NULL, begin, PAGE_SIZE, end - begin);
+ for (addr = begin; addr < end; addr += PAGE_SIZE) {
+ /*
+ * Note we just reset the home here directly in the
+ * page table. We know this is safe because our caller
+ * just flushed the caches on all the other cpus,
+ * and they won't be touching any of these pages.
+ */
+ int pfn = kaddr_to_pfn((void *)addr);
+ struct page *page = pfn_to_page(pfn);
+ pte_t *ptep = virt_to_kpte(addr);
+ if (!initfree) {
+ /*
+ * If debugging page accesses then do not free
+ * this memory but mark them not present - any
+ * buggy init-section access will create a
+ * kernel page fault:
+ */
+ pte_clear(&init_mm, addr, ptep);
+ continue;
+ }
+ if (pte_huge(*ptep))
+ BUG_ON(!kdata_huge);
+ else
+ set_pte_at(&init_mm, addr, ptep,
+ pfn_pte(pfn, PAGE_KERNEL));
+ memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
+ free_reserved_page(page);
+ }
+ pr_info("Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
+}
+
+void free_initmem(void)
+{
+ const unsigned long text_delta = MEM_SV_START - PAGE_OFFSET;
+
+ /*
+ * Evict the cache on all cores to avoid incoherence.
+ * We are guaranteed that no one will touch the init pages any more.
+ */
+ homecache_evict(&cpu_cacheable_map);
+
+ /* Free the data pages that we won't use again after init. */
+ free_init_pages("unused kernel data",
+ (unsigned long)__init_begin,
+ (unsigned long)__init_end);
+
+ /*
+ * Free the pages mapped from 0xc0000000 that correspond to code
+ * pages from MEM_SV_START that we won't use again after init.
+ */
+ free_init_pages("unused kernel text",
+ (unsigned long)_sinittext - text_delta,
+ (unsigned long)_einittext - text_delta);
+ /* Do a global TLB flush so everyone sees the changes. */
+ flush_tlb_all();
+}