cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ioremap.c (4573B)

      1/*
      2 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
      3 * Copyright (C) 2009 Wind River Systems Inc
      4 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
      5 * Copyright (C) 2004 Microtronix Datacom Ltd.
      6 *
      7 * This file is subject to the terms and conditions of the GNU General Public
      8 * License. See the file "COPYING" in the main directory of this archive
      9 * for more details.
     10 */
     11
     12#include <linux/export.h>
     13#include <linux/sched.h>
     14#include <linux/mm.h>
     15#include <linux/slab.h>
     16#include <linux/vmalloc.h>
     17#include <linux/io.h>
     18
     19#include <asm/cacheflush.h>
     20#include <asm/tlbflush.h>
     21
     22static inline void remap_area_pte(pte_t *pte, unsigned long address,
     23				unsigned long size, unsigned long phys_addr,
     24				unsigned long flags)
     25{
     26	unsigned long end;
     27	unsigned long pfn;
     28	pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ
     29				| _PAGE_WRITE | flags);
     30
     31	address &= ~PMD_MASK;
     32	end = address + size;
     33	if (end > PMD_SIZE)
     34		end = PMD_SIZE;
     35	if (address >= end)
     36		BUG();
     37	pfn = PFN_DOWN(phys_addr);
     38	do {
     39		if (!pte_none(*pte)) {
     40			pr_err("remap_area_pte: page already exists\n");
     41			BUG();
     42		}
     43		set_pte(pte, pfn_pte(pfn, pgprot));
     44		address += PAGE_SIZE;
     45		pfn++;
     46		pte++;
     47	} while (address && (address < end));
     48}
     49
     50static inline int remap_area_pmd(pmd_t *pmd, unsigned long address,
     51				unsigned long size, unsigned long phys_addr,
     52				unsigned long flags)
     53{
     54	unsigned long end;
     55
     56	address &= ~PGDIR_MASK;
     57	end = address + size;
     58	if (end > PGDIR_SIZE)
     59		end = PGDIR_SIZE;
     60	phys_addr -= address;
     61	if (address >= end)
     62		BUG();
     63	do {
     64		pte_t *pte = pte_alloc_kernel(pmd, address);
     65
     66		if (!pte)
     67			return -ENOMEM;
     68		remap_area_pte(pte, address, end - address, address + phys_addr,
     69			flags);
     70		address = (address + PMD_SIZE) & PMD_MASK;
     71		pmd++;
     72	} while (address && (address < end));
     73	return 0;
     74}
     75
     76static int remap_area_pages(unsigned long address, unsigned long phys_addr,
     77				unsigned long size, unsigned long flags)
     78{
     79	int error;
     80	pgd_t *dir;
     81	unsigned long end = address + size;
     82
     83	phys_addr -= address;
     84	dir = pgd_offset(&init_mm, address);
     85	flush_cache_all();
     86	if (address >= end)
     87		BUG();
     88	do {
     89		p4d_t *p4d;
     90		pud_t *pud;
     91		pmd_t *pmd;
     92
     93		error = -ENOMEM;
     94		p4d = p4d_alloc(&init_mm, dir, address);
     95		if (!p4d)
     96			break;
     97		pud = pud_alloc(&init_mm, p4d, address);
     98		if (!pud)
     99			break;
    100		pmd = pmd_alloc(&init_mm, pud, address);
    101		if (!pmd)
    102			break;
    103		if (remap_area_pmd(pmd, address, end - address,
    104			phys_addr + address, flags))
    105			break;
    106		error = 0;
    107		address = (address + PGDIR_SIZE) & PGDIR_MASK;
    108		dir++;
    109	} while (address && (address < end));
    110	flush_tlb_all();
    111	return error;
    112}
    113
    114#define IS_MAPPABLE_UNCACHEABLE(addr) (addr < 0x20000000UL)
    115
    116/*
    117 * Map some physical address range into the kernel address space.
    118 */
    119void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
    120{
    121	struct vm_struct *area;
    122	unsigned long offset;
    123	unsigned long last_addr;
    124	void *addr;
    125
    126	/* Don't allow wraparound or zero size */
    127	last_addr = phys_addr + size - 1;
    128
    129	if (!size || last_addr < phys_addr)
    130		return NULL;
    131
    132	/* Don't allow anybody to remap normal RAM that we're using */
    133	if (phys_addr > PHYS_OFFSET && phys_addr < virt_to_phys(high_memory)) {
    134		char *t_addr, *t_end;
    135		struct page *page;
    136
    137		t_addr = __va(phys_addr);
    138		t_end = t_addr + (size - 1);
    139		for (page = virt_to_page(t_addr);
    140			page <= virt_to_page(t_end); page++)
    141			if (!PageReserved(page))
    142				return NULL;
    143	}
    144
    145	/*
    146	 * Map uncached objects in the low part of address space to
    147	 * CONFIG_NIOS2_IO_REGION_BASE
    148	 */
    149	if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&
    150	    IS_MAPPABLE_UNCACHEABLE(last_addr))
    151		return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);
    152
    153	/* Mappings have to be page-aligned */
    154	offset = phys_addr & ~PAGE_MASK;
    155	phys_addr &= PAGE_MASK;
    156	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
    157
    158	/* Ok, go for it */
    159	area = get_vm_area(size, VM_IOREMAP);
    160	if (!area)
    161		return NULL;
    162	addr = area->addr;
    163	if (remap_area_pages((unsigned long) addr, phys_addr, size, 0)) {
    164		vunmap(addr);
    165		return NULL;
    166	}
    167	return (void __iomem *) (offset + (char *)addr);
    168}
    169EXPORT_SYMBOL(ioremap);
    170
    171/*
    172 * iounmap unmaps nearly everything, so be careful
    173 * it doesn't free currently pointer/page tables anymore but it
    174 * wasn't used anyway and might be added later.
    175 */
    176void iounmap(void __iomem *addr)
    177{
    178	struct vm_struct *p;
    179
    180	if ((unsigned long) addr > CONFIG_NIOS2_IO_REGION_BASE)
    181		return;
    182
    183	p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
    184	if (!p)
    185		pr_err("iounmap: bad address %p\n", addr);
    186	kfree(p);
    187}
    188EXPORT_SYMBOL(iounmap);