File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c
new file mode 100644
index 0000000..a1bea91
--- /dev/null
+++ b/arch/alpha/mm/init.c
@@ -0,0 +1,300 @@
+/*
+ * linux/arch/alpha/mm/init.c
+ *
+ * Copyright (C) 1995 Linus Torvalds
+ */
+
+/* 2.3.x zone allocator, 1999 Andrea Arcangeli <andrea@suse.de> */
+
+#include <linux/pagemap.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/swap.h>
+#include <linux/init.h>
+#include <linux/bootmem.h> /* max_low_pfn */
+#include <linux/vmalloc.h>
+#include <linux/gfp.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/hwrpb.h>
+#include <asm/dma.h>
+#include <asm/mmu_context.h>
+#include <asm/console.h>
+#include <asm/tlb.h>
+#include <asm/setup.h>
+#include <asm/sections.h>
+
+extern void die_if_kernel(char *,struct pt_regs *,long);
+
+static struct pcb_struct original_pcb;
+
+pgd_t *
+pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *ret, *init;
+
+ ret = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+ init = pgd_offset(&init_mm, 0UL);
+ if (ret) {
+#ifdef CONFIG_ALPHA_LARGE_VMALLOC
+ memcpy (ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
+ (PTRS_PER_PGD - USER_PTRS_PER_PGD - 1)*sizeof(pgd_t));
+#else
+ pgd_val(ret[PTRS_PER_PGD-2]) = pgd_val(init[PTRS_PER_PGD-2]);
+#endif
+
+ /* The last PGD entry is the VPTB self-map. */
+ pgd_val(ret[PTRS_PER_PGD-1])
+ = pte_val(mk_pte(virt_to_page(ret), PAGE_KERNEL));
+ }
+ return ret;
+}
+
+
+/*
+ * BAD_PAGE is the page that is used for page faults when linux
+ * is out-of-memory. Older versions of linux just did a
+ * do_exit(), but using this instead means there is less risk
+ * for a process dying in kernel mode, possibly leaving an inode
+ * unused etc..
+ *
+ * BAD_PAGETABLE is the accompanying page-table: it is initialized
+ * to point to BAD_PAGE entries.
+ *
+ * ZERO_PAGE is a special page that is used for zero-initialized
+ * data and COW.
+ */
+pmd_t *
+__bad_pagetable(void)
+{
+ memset((void *) EMPTY_PGT, 0, PAGE_SIZE);
+ return (pmd_t *) EMPTY_PGT;
+}
+
+pte_t
+__bad_page(void)
+{
+ memset((void *) EMPTY_PGE, 0, PAGE_SIZE);
+ return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED));
+}
+
+static inline unsigned long
+load_PCB(struct pcb_struct *pcb)
+{
+ register unsigned long sp __asm__("$30");
+ pcb->ksp = sp;
+ return __reload_thread(pcb);
+}
+
+/* Set up initial PCB, VPTB, and other such nicities. */
+
+static inline void
+switch_to_system_map(void)
+{
+ unsigned long newptbr;
+ unsigned long original_pcb_ptr;
+
+ /* Initialize the kernel's page tables. Linux puts the vptb in
+ the last slot of the L1 page table. */
+ memset(swapper_pg_dir, 0, PAGE_SIZE);
+ newptbr = ((unsigned long) swapper_pg_dir - PAGE_OFFSET) >> PAGE_SHIFT;
+ pgd_val(swapper_pg_dir[1023]) =
+ (newptbr << 32) | pgprot_val(PAGE_KERNEL);
+
+ /* Set the vptb. This is often done by the bootloader, but
+ shouldn't be required. */
+ if (hwrpb->vptb != 0xfffffffe00000000UL) {
+ wrvptptr(0xfffffffe00000000UL);
+ hwrpb->vptb = 0xfffffffe00000000UL;
+ hwrpb_update_checksum(hwrpb);
+ }
+
+ /* Also set up the real kernel PCB while we're at it. */
+ init_thread_info.pcb.ptbr = newptbr;
+ init_thread_info.pcb.flags = 1; /* set FEN, clear everything else */
+ original_pcb_ptr = load_PCB(&init_thread_info.pcb);
+ tbia();
+
+ /* Save off the contents of the original PCB so that we can
+ restore the original console's page tables for a clean reboot.
+
+ Note that the PCB is supposed to be a physical address, but
+ since KSEG values also happen to work, folks get confused.
+ Check this here. */
+
+ if (original_pcb_ptr < PAGE_OFFSET) {
+ original_pcb_ptr = (unsigned long)
+ phys_to_virt(original_pcb_ptr);
+ }
+ original_pcb = *(struct pcb_struct *) original_pcb_ptr;
+}
+
+int callback_init_done;
+
+void * __init
+callback_init(void * kernel_end)
+{
+ struct crb_struct * crb;
+ pgd_t *pgd;
+ pmd_t *pmd;
+ void *two_pages;
+
+ /* Starting at the HWRPB, locate the CRB. */
+ crb = (struct crb_struct *)((char *)hwrpb + hwrpb->crb_offset);
+
+ if (alpha_using_srm) {
+ /* Tell the console whither it is to be remapped. */
+ if (srm_fixup(VMALLOC_START, (unsigned long)hwrpb))
+ __halt(); /* "We're boned." --Bender */
+
+ /* Edit the procedure descriptors for DISPATCH and FIXUP. */
+ crb->dispatch_va = (struct procdesc_struct *)
+ (VMALLOC_START + (unsigned long)crb->dispatch_va
+ - crb->map[0].va);
+ crb->fixup_va = (struct procdesc_struct *)
+ (VMALLOC_START + (unsigned long)crb->fixup_va
+ - crb->map[0].va);
+ }
+
+ switch_to_system_map();
+
+ /* Allocate one PGD and one PMD. In the case of SRM, we'll need
+ these to actually remap the console. There is an assumption
+ here that only one of each is needed, and this allows for 8MB.
+ On systems with larger consoles, additional pages will be
+ allocated as needed during the mapping process.
+
+ In the case of not SRM, but not CONFIG_ALPHA_LARGE_VMALLOC,
+ we need to allocate the PGD we use for vmalloc before we start
+ forking other tasks. */
+
+ two_pages = (void *)
+ (((unsigned long)kernel_end + ~PAGE_MASK) & PAGE_MASK);
+ kernel_end = two_pages + 2*PAGE_SIZE;
+ memset(two_pages, 0, 2*PAGE_SIZE);
+
+ pgd = pgd_offset_k(VMALLOC_START);
+ pgd_set(pgd, (pmd_t *)two_pages);
+ pmd = pmd_offset(pgd, VMALLOC_START);
+ pmd_set(pmd, (pte_t *)(two_pages + PAGE_SIZE));
+
+ if (alpha_using_srm) {
+ static struct vm_struct console_remap_vm;
+ unsigned long nr_pages = 0;
+ unsigned long vaddr;
+ unsigned long i, j;
+
+ /* calculate needed size */
+ for (i = 0; i < crb->map_entries; ++i)
+ nr_pages += crb->map[i].count;
+
+ /* register the vm area */
+ console_remap_vm.flags = VM_ALLOC;
+ console_remap_vm.size = nr_pages << PAGE_SHIFT;
+ vm_area_register_early(&console_remap_vm, PAGE_SIZE);
+
+ vaddr = (unsigned long)console_remap_vm.addr;
+
+ /* Set up the third level PTEs and update the virtual
+ addresses of the CRB entries. */
+ for (i = 0; i < crb->map_entries; ++i) {
+ unsigned long pfn = crb->map[i].pa >> PAGE_SHIFT;
+ crb->map[i].va = vaddr;
+ for (j = 0; j < crb->map[i].count; ++j) {
+ /* Newer consoles (especially on larger
+ systems) may require more pages of
+ PTEs. Grab additional pages as needed. */
+ if (pmd != pmd_offset(pgd, vaddr)) {
+ memset(kernel_end, 0, PAGE_SIZE);
+ pmd = pmd_offset(pgd, vaddr);
+ pmd_set(pmd, (pte_t *)kernel_end);
+ kernel_end += PAGE_SIZE;
+ }
+ set_pte(pte_offset_kernel(pmd, vaddr),
+ pfn_pte(pfn, PAGE_KERNEL));
+ pfn++;
+ vaddr += PAGE_SIZE;
+ }
+ }
+ }
+
+ callback_init_done = 1;
+ return kernel_end;
+}
+
+
+#ifndef CONFIG_DISCONTIGMEM
+/*
+ * paging_init() sets up the memory map.
+ */
+void __init paging_init(void)
+{
+ unsigned long zones_size[MAX_NR_ZONES] = {0, };
+ unsigned long dma_pfn, high_pfn;
+
+ dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
+ high_pfn = max_pfn = max_low_pfn;
+
+ if (dma_pfn >= high_pfn)
+ zones_size[ZONE_DMA] = high_pfn;
+ else {
+ zones_size[ZONE_DMA] = dma_pfn;
+ zones_size[ZONE_NORMAL] = high_pfn - dma_pfn;
+ }
+
+ /* Initialize mem_map[]. */
+ free_area_init(zones_size);
+
+ /* Initialize the kernel's ZERO_PGE. */
+ memset((void *)ZERO_PGE, 0, PAGE_SIZE);
+}
+#endif /* CONFIG_DISCONTIGMEM */
+
+#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM)
+void
+srm_paging_stop (void)
+{
+ /* Move the vptb back to where the SRM console expects it. */
+ swapper_pg_dir[1] = swapper_pg_dir[1023];
+ tbia();
+ wrvptptr(0x200000000UL);
+ hwrpb->vptb = 0x200000000UL;
+ hwrpb_update_checksum(hwrpb);
+
+ /* Reload the page tables that the console had in use. */
+ load_PCB(&original_pcb);
+ tbia();
+}
+#endif
+
+void __init
+mem_init(void)
+{
+ set_max_mapnr(max_low_pfn);
+ high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
+ free_all_bootmem();
+ mem_init_print_info(NULL);
+}
+
+void
+free_initmem(void)
+{
+ free_initmem_default(-1);
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void
+free_initrd_mem(unsigned long start, unsigned long end)
+{
+ free_reserved_area((void *)start, (void *)end, -1, "initrd");
+}
+#endif