linux/arch/unicore32/mm/ioremap.c
Andrew Morton 2accff4ef5 arch/unicore32/mm/ioremap.c: return NULL on invalid pfn
__uc32_ioremap_pfn_caller() should return NULL when the pfn is found to be
invalid.

From a recommendation by Guan Xuetao.

Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:53:53 -07:00

255 lines
6.8 KiB
C

/*
* linux/arch/unicore32/mm/ioremap.c
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*
* Re-map IO memory to kernel address space so that we can access it.
*
* This allows a driver to remap an arbitrary region of bus memory into
* virtual space. One should *only* use readl, writel, memcpy_toio and
* so on with such remapped areas.
*
* Because UniCore only has a 32-bit address space we can't address the
* whole of the (physical) PCI space at once. PCI huge-mode addressing
* allows us to circumvent this restriction by splitting PCI space into
* two 2GB chunks and mapping only one at a time into processor memory.
* We use MMU protection domains to trap any attempt to access the bank
* that is not currently mapped. (This isn't fully implemented yet.)
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <asm/cputype.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/sizes.h>
#include <mach/map.h>
#include "mm.h"
/*
* Used by ioremap() and iounmap() code to mark (super)section-mapped
* I/O regions in vm_struct->flags field.
*/
#define VM_UNICORE_SECTION_MAPPING 0x80000000
int ioremap_page(unsigned long virt, unsigned long phys,
const struct mem_type *mtype)
{
return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
__pgprot(mtype->prot_pte));
}
EXPORT_SYMBOL(ioremap_page);
/*
* Section support is unsafe on SMP - If you iounmap and ioremap a region,
* the other CPUs will not see this change until their next context switch.
* Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
* which requires the new ioremap'd region to be referenced, the CPU will
* reference the _old_ region.
*
* Note that get_vm_area_caller() allocates a guard 4K page, so we need to
* mask the size back to 4MB aligned or we will overflow in the loop below.
*/
static void unmap_area_sections(unsigned long virt, unsigned long size)
{
unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1));
pgd_t *pgd;
flush_cache_vunmap(addr, end);
pgd = pgd_offset_k(addr);
do {
pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr);
pmd = *pmdp;
if (!pmd_none(pmd)) {
/*
* Clear the PMD from the page table, and
* increment the kvm sequence so others
* notice this change.
*
* Note: this is still racy on SMP machines.
*/
pmd_clear(pmdp);
/*
* Free the page table, if there was one.
*/
if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
}
addr += PGDIR_SIZE;
pgd++;
} while (addr < end);
flush_tlb_kernel_range(virt, end);
}
static int
remap_area_sections(unsigned long virt, unsigned long pfn,
size_t size, const struct mem_type *type)
{
unsigned long addr = virt, end = virt + size;
pgd_t *pgd;
/*
* Remove and free any PTE-based mapping, and
* sync the current kernel mapping.
*/
unmap_area_sections(virt, size);
pgd = pgd_offset_k(addr);
do {
pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect));
pfn += SZ_4M >> PAGE_SHIFT;
flush_pmd_entry(pmd);
addr += PGDIR_SIZE;
pgd++;
} while (addr < end);
return 0;
}
void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn,
unsigned long offset, size_t size, unsigned int mtype, void *caller)
{
const struct mem_type *type;
int err;
unsigned long addr;
struct vm_struct *area;
/*
* High mappings must be section aligned
*/
if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK))
return NULL;
/*
* Don't allow RAM to be mapped
*/
if (pfn_valid(pfn)) {
WARN(1, "BUG: Your driver calls ioremap() on\n"
"system memory. This leads to architecturally\n"
"unpredictable behaviour, and ioremap() will fail in\n"
"the next kernel release. Please fix your driver.\n");
return NULL;
}
type = get_mem_type(mtype);
if (!type)
return NULL;
/*
* Page align the mapping size, taking account of any offset.
*/
size = PAGE_ALIGN(offset + size);
area = get_vm_area_caller(size, VM_IOREMAP, caller);
if (!area)
return NULL;
addr = (unsigned long)area->addr;
if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
area->flags |= VM_UNICORE_SECTION_MAPPING;
err = remap_area_sections(addr, pfn, size, type);
} else
err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
__pgprot(type->prot_pte));
if (err) {
vunmap((void *)addr);
return NULL;
}
flush_cache_vmap(addr, addr + size);
return (void __iomem *) (offset + addr);
}
void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size,
unsigned int mtype, void *caller)
{
unsigned long last_addr;
unsigned long offset = phys_addr & ~PAGE_MASK;
unsigned long pfn = __phys_to_pfn(phys_addr);
/*
* Don't allow wraparound or zero size
*/
last_addr = phys_addr + size - 1;
if (!size || last_addr < phys_addr)
return NULL;
return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller);
}
/*
* Remap an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access high addresses
* directly.
*
* NOTE! We need to allow non-page-aligned mappings too: we will obviously
* have to convert them into an offset in a page-aligned mapping, but the
* caller shouldn't need to know that small detail.
*/
void __iomem *
__uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
unsigned int mtype)
{
return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype,
__builtin_return_address(0));
}
EXPORT_SYMBOL(__uc32_ioremap_pfn);
void __iomem *
__uc32_ioremap(unsigned long phys_addr, size_t size)
{
return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE,
__builtin_return_address(0));
}
EXPORT_SYMBOL(__uc32_ioremap);
void __iomem *
__uc32_ioremap_cached(unsigned long phys_addr, size_t size)
{
return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE_CACHED,
__builtin_return_address(0));
}
EXPORT_SYMBOL(__uc32_ioremap_cached);
void __uc32_iounmap(volatile void __iomem *io_addr)
{
void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
struct vm_struct *vm;
/*
* If this is a section based mapping we need to handle it
* specially as the VM subsystem does not know how to handle
* such a beast. We need the lock here b/c we need to clear
* all the mappings before the area can be reclaimed
* by someone else.
*/
vm = find_vm_area(addr);
if (vm && (vm->flags & VM_IOREMAP) &&
(vm->flags & VM_UNICORE_SECTION_MAPPING))
unmap_area_sections((unsigned long)vm->addr, vm->size);
vunmap(addr);
}
EXPORT_SYMBOL(__uc32_iounmap);