path: root/arch/ia64/mm/init.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Initialize MMU support.
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *	David Mosberger-Tang <davidm@hpl.hp.com>
 */
#include <linux/kernel.h>
#include <linux/init.h>

#include <linux/dma-map-ops.h>
#include <linux/dmar.h>
#include <linux/efi.h>
#include <linux/elf.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/personality.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>
#include <linux/bitops.h>
#include <linux/kexec.h>
#include <linux/swiotlb.h>

#include <asm/dma.h>
#include <asm/io.h>
#include <asm/numa.h>
#include <asm/patch.h>
#include <asm/pgalloc.h>
#include <asm/sal.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/mca.h>

extern void ia64_tlb_init (void);

unsigned long MAX_DMA_ADDRESS = PAGE_OFFSET + 0x100000000UL;

#ifdef CONFIG_VIRTUAL_MEM_MAP
unsigned long VMALLOC_END = VMALLOC_END_INIT;
EXPORT_SYMBOL(VMALLOC_END);
struct page *vmem_map;
EXPORT_SYMBOL(vmem_map);
#endif

struct page *zero_page_memmap_ptr;	/* map entry for zero page */
EXPORT_SYMBOL(zero_page_memmap_ptr);

void
__ia64_sync_icache_dcache (pte_t pte)
{
	unsigned long addr;
	struct page *page;

	page = pte_page(pte);
	addr = (unsigned long) page_address(page);

	if (test_bit(PG_arch_1, &page->flags))
		return;				/* i-cache is already coherent with d-cache */

	flush_icache_range(addr, addr + page_size(page));
	set_bit(PG_arch_1, &page->flags);	/* mark page as clean */
}

/*
 * Since DMA is i-cache coherent, any (complete) pages that were written via
 * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to
 * flush them when they get mapped into an executable vm-area.
 */
void arch_dma_mark_clean(phys_addr_t paddr, size_t size)
{
	unsigned long pfn = PHYS_PFN(paddr);

	do {
		set_bit(PG_arch_1, &pfn_to_page(pfn)->flags);
	} while (++pfn <= PHYS_PFN(paddr + size - 1));
}

inline void
ia64_set_rbs_bot (void)
{
	unsigned long stack_size = rlimit_max(RLIMIT_STACK) & -16;

	if (stack_size > MAX_USER_STACK_SIZE)
		stack_size = MAX_USER_STACK_SIZE;
	current->thread.rbs_bot = PAGE_ALIGN(current->mm->start_stack - stack_size);
}

/*
 * This performs some platform-dependent address space initialization.
 * On IA-64, we want to setup the VM area for the register backing
 * store (which grows upwards) and install the gateway page which is
 * used for signal trampolines, etc.
 */
void
ia64_init_addr_space (void)
{
	struct vm_area_struct *vma;

	ia64_set_rbs_bot();

	/*
	 * If we're out of memory and kmem_cache_alloc() returns NULL, we simply ignore
	 * the problem.  When the process attempts to write to the register backing store
	 * for the first time, it will get a SEGFAULT in this case.
	 */
	vma = vm_area_alloc(current->mm);
	if (vma) {
		vma_set_anonymous(vma);
		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
		vma->vm_end = vma->vm_start + PAGE_SIZE;
		vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
		mmap_write_lock(current->mm);
		if (insert_vm_struct(current->mm, vma)) {
			mmap_write_unlock(current->mm);
			vm_area_free(vma);
			return;
		}
		mmap_write_unlock(current->mm);
	}

	/* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
	if (!(current->personality & MMAP_PAGE_ZERO)) {
		vma = vm_area_alloc(current->mm);
		if (vma) {
			vma_set_anonymous(vma);
			vma->vm_end = PAGE_SIZE;
			vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
			vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
					VM_DONTEXPAND | VM_DONTDUMP;
			mmap_write_lock(current->mm);
			if (insert_vm_struct(current->mm, vma)) {
				mmap_write_unlock(current->mm);
				vm_area_free(vma);
				return;
			}
			mmap_write_unlock(current->mm);
		}
	}
}

void
free_initmem (void)
{
	free_reserved_area(ia64_imva(__init_begin), ia64_imva(__init_end),
			   -1, "unused kernel");
}

void __init
free_initrd_mem (unsigned long start, unsigned long end)
{
	/*
	 * EFI uses 4KB pages while the kernel can use 4KB or bigger.
	 * Thus EFI and the kernel may have different page sizes. It is
	 * therefore possible to have the initrd share the same page as
	 * the end of the kernel (given current setup).
	 *
	 * To avoid freeing/using the wrong page (kernel sized) we:
	 *	- align up the beginning of initrd
	 *	- align down the end of initrd
	 *
	 *  |             |
	 *  |=============| a000
	 *  |             |
	 *  |             |
	 *  |             | 9000
	 *  |/////////////|
	 *  |/////////////|
	 *  |=============| 8000
	 *  |///INITRD////|
	 *  |/////////////|
	 *  |/////////////| 7000
	 *  |             |
	 *  |KKKKKKKKKKKKK|
	 *  |=============| 6000
	 *  |KKKKKKKKKKKKK|
	 *  |KKKKKKKKKKKKK|
	 *  K=kernel using 8KB pages
	 *
	 * In this example, we must free page 8000 ONLY. So we must align up
	 * initrd_start and keep initrd_end as is.
	 */
	start = PAGE_ALIGN(start);
	end = end & PAGE_MASK;

	if (start < end)
		printk(KERN_INFO "Freeing initrd memory: %ldkB freed\n", (end - start) >> 10);

	for (; start < end; start += PAGE_SIZE) {
		if (!virt_addr_valid(start))
			continue;
		free_reserved_page(virt_to_page(start));
	}
}

/*
 * This installs a clean page in the kernel's page table.
 */
static struct page * __init
put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
{
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

	pgd = pgd_offset_k(address);		/* note: this is NOT pgd_offset()! */

	{
		p4d = p4d_alloc(&init_mm, pgd, address);
		if (!p4d)
			goto out;
		pud = pud_alloc(&init_mm, p4d, address);
		if (!pud)
			goto out;
		pmd = pmd_alloc(&init_mm, pud, address);
		if (!pmd)
			goto out;
		pte = pte_alloc_kernel(pmd, address);
		if (!pte)
			goto out;
		if (!pte_none(*pte))
			goto out;
		set_pte(pte, mk_pte(page, pgprot));
	}
  out:
	/* no need for flush_tlb */
	return page;
}

static void __init
setup_gate (void)
{
	struct page *page;

	/*
	 * Map the gate page twice: once read-only to export the ELF
	 * headers etc. and once execute-only page to enable
	 * privilege-promotion via "epc":
	 */
	page = virt_to_page(ia64_imva(__start_gate_section));
	put_kernel_page(