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 (3145B)

      1/*
      2 * This file is subject to the terms and conditions of the GNU General Public
      3 * License.  See the file "COPYING" in the main directory of this archive
      4 * for more details.
      5 *
      6 * (C) Copyright 1995 1996 Linus Torvalds
      7 * (C) Copyright 2001, 2002 Ralf Baechle
      8 */
      9#include <linux/export.h>
     10#include <asm/addrspace.h>
     11#include <asm/byteorder.h>
     12#include <linux/ioport.h>
     13#include <linux/sched.h>
     14#include <linux/slab.h>
     15#include <linux/vmalloc.h>
     16#include <linux/mm_types.h>
     17#include <linux/io.h>
     18#include <asm/cacheflush.h>
     19#include <asm/tlbflush.h>
     20#include <ioremap.h>
     21
     22#define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
     23#define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
     24
     25static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
     26			       void *arg)
     27{
     28	unsigned long i;
     29
     30	for (i = 0; i < nr_pages; i++) {
     31		if (pfn_valid(start_pfn + i) &&
     32		    !PageReserved(pfn_to_page(start_pfn + i)))
     33			return 1;
     34	}
     35
     36	return 0;
     37}
     38
     39/*
     40 * ioremap_prot     -   map bus memory into CPU space
     41 * @phys_addr:    bus address of the memory
     42 * @size:      size of the resource to map
     43 *
     44 * ioremap_prot gives the caller control over cache coherency attributes (CCA)
     45 */
     46void __iomem *ioremap_prot(phys_addr_t phys_addr, unsigned long size,
     47		unsigned long prot_val)
     48{
     49	unsigned long flags = prot_val & _CACHE_MASK;
     50	unsigned long offset, pfn, last_pfn;
     51	struct vm_struct *area;
     52	phys_addr_t last_addr;
     53	unsigned long vaddr;
     54	void __iomem *cpu_addr;
     55
     56	cpu_addr = plat_ioremap(phys_addr, size, flags);
     57	if (cpu_addr)
     58		return cpu_addr;
     59
     60	phys_addr = fixup_bigphys_addr(phys_addr, size);
     61
     62	/* Don't allow wraparound or zero size */
     63	last_addr = phys_addr + size - 1;
     64	if (!size || last_addr < phys_addr)
     65		return NULL;
     66
     67	/*
     68	 * Map uncached objects in the low 512mb of address space using KSEG1,
     69	 * otherwise map using page tables.
     70	 */
     71	if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
     72	    flags == _CACHE_UNCACHED)
     73		return (void __iomem *) CKSEG1ADDR(phys_addr);
     74
     75	/*
     76	 * Don't allow anybody to remap RAM that may be allocated by the page
     77	 * allocator, since that could lead to races & data clobbering.
     78	 */
     79	pfn = PFN_DOWN(phys_addr);
     80	last_pfn = PFN_DOWN(last_addr);
     81	if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
     82				  __ioremap_check_ram) == 1) {
     83		WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
     84			  &phys_addr, &last_addr);
     85		return NULL;
     86	}
     87
     88	/*
     89	 * Mappings have to be page-aligned
     90	 */
     91	offset = phys_addr & ~PAGE_MASK;
     92	phys_addr &= PAGE_MASK;
     93	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
     94
     95	/*
     96	 * Ok, go for it..
     97	 */
     98	area = get_vm_area(size, VM_IOREMAP);
     99	if (!area)
    100		return NULL;
    101	vaddr = (unsigned long)area->addr;
    102
    103	flags |= _PAGE_GLOBAL | _PAGE_PRESENT | __READABLE | __WRITEABLE;
    104	if (ioremap_page_range(vaddr, vaddr + size, phys_addr,
    105			__pgprot(flags))) {
    106		free_vm_area(area);
    107		return NULL;
    108	}
    109
    110	return (void __iomem *)(vaddr + offset);
    111}
    112EXPORT_SYMBOL(ioremap_prot);
    113
    114void iounmap(const volatile void __iomem *addr)
    115{
    116	if (!plat_iounmap(addr) && !IS_KSEG1(addr))
    117		vunmap((void *)((unsigned long)addr & PAGE_MASK));
    118}
    119EXPORT_SYMBOL(iounmap);