linux/arch/unicore32/mm/ioremap.c
Joonsoo Kim ef93247325 mm, vmalloc: change iterating a vmlist to find_vm_area()
This patchset removes vm_struct list management after initializing
vmalloc.  Adding and removing an entry to vmlist is linear time
complexity, so it is inefficient.  If we maintain this list, overall
time complexity of adding and removing area to vmalloc space is O(N),
although we use rbtree for finding vacant place and it's time complexity
is just O(logN).

And vmlist and vmlist_lock is used many places of outside of vmalloc.c.
It is preferable that we hide this raw data structure and provide
well-defined function for supporting them, because it makes that they
cannot mistake when manipulating theses structure and it makes us easily
maintain vmalloc layer.

For kexec and makedumpfile, I export vmap_area_list, instead of vmlist.
This comes from Atsushi's recommendation.  For more information, please
refer below link.  https://lkml.org/lkml/2012/12/6/184

This patch:

The purpose of iterating a vmlist is finding vm area with specific virtual
address.  find_vm_area() is provided for this purpose and more efficient,
because it uses a rbtree.  So change it.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:33 -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)) {
printk(KERN_WARNING "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");
WARN_ON(1);
}
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);