linux/arch/powerpc/mm/pgtable_64.c
Paul Mackerras 1189be6508 [POWERPC] Use 1TB segments
This makes the kernel use 1TB segments for all kernel mappings and for
user addresses of 1TB and above, on machines which support them
(currently POWER5+, POWER6 and PA6T).

We detect that the machine supports 1TB segments by looking at the
ibm,processor-segment-sizes property in the device tree.

We don't currently use 1TB segments for user addresses < 1T, since
that would effectively prevent 32-bit processes from using huge pages
unless we also had a way to revert to using 256MB segments.  That
would be possible but would involve extra complications (such as
keeping track of which segment size was used when HPTEs were inserted)
and is not addressed here.

Parts of this patch were originally written by Ben Herrenschmidt.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-12 14:05:17 +10:00

235 lines
5.6 KiB
C

/*
* This file contains ioremap and related functions for 64-bit machines.
*
* Derived from arch/ppc64/mm/init.c
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
* and Cort Dougan (PReP) (cort@cs.nmt.edu)
* Copyright (C) 1996 Paul Mackerras
*
* Derived from "arch/i386/mm/init.c"
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* Dave Engebretsen <engebret@us.ibm.com>
* Rework for PPC64 port.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/tlb.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/system.h>
#include <asm/abs_addr.h>
#include <asm/firmware.h>
#include "mmu_decl.h"
unsigned long ioremap_bot = IOREMAP_BASE;
/*
* map_io_page currently only called by __ioremap
* map_io_page adds an entry to the ioremap page table
* and adds an entry to the HPT, possibly bolting it
*/
static int map_io_page(unsigned long ea, unsigned long pa, int flags)
{
pgd_t *pgdp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
if (mem_init_done) {
pgdp = pgd_offset_k(ea);
pudp = pud_alloc(&init_mm, pgdp, ea);
if (!pudp)
return -ENOMEM;
pmdp = pmd_alloc(&init_mm, pudp, ea);
if (!pmdp)
return -ENOMEM;
ptep = pte_alloc_kernel(pmdp, ea);
if (!ptep)
return -ENOMEM;
set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
__pgprot(flags)));
} else {
/*
* If the mm subsystem is not fully up, we cannot create a
* linux page table entry for this mapping. Simply bolt an
* entry in the hardware page table.
*
*/
if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags,
mmu_io_psize, mmu_kernel_ssize)) {
printk(KERN_ERR "Failed to do bolted mapping IO "
"memory at %016lx !\n", pa);
return -ENOMEM;
}
}
return 0;
}
/**
* __ioremap_at - Low level function to establish the page tables
* for an IO mapping
*/
void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
unsigned long flags)
{
unsigned long i;
if ((flags & _PAGE_PRESENT) == 0)
flags |= pgprot_val(PAGE_KERNEL);
WARN_ON(pa & ~PAGE_MASK);
WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
WARN_ON(size & ~PAGE_MASK);
for (i = 0; i < size; i += PAGE_SIZE)
if (map_io_page((unsigned long)ea+i, pa+i, flags))
return NULL;
return (void __iomem *)ea;
}
/**
* __iounmap_from - Low level function to tear down the page tables
* for an IO mapping. This is used for mappings that
* are manipulated manually, like partial unmapping of
* PCI IOs or ISA space.
*/
void __iounmap_at(void *ea, unsigned long size)
{
WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
WARN_ON(size & ~PAGE_MASK);
unmap_kernel_range((unsigned long)ea, size);
}
void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
unsigned long flags)
{
phys_addr_t paligned;
void __iomem *ret;
/*
* Choose an address to map it to.
* Once the imalloc system is running, we use it.
* Before that, we map using addresses going
* up from ioremap_bot. imalloc will use
* the addresses from ioremap_bot through
* IMALLOC_END
*
*/
paligned = addr & PAGE_MASK;
size = PAGE_ALIGN(addr + size) - paligned;
if ((size == 0) || (paligned == 0))
return NULL;
if (mem_init_done) {
struct vm_struct *area;
area = __get_vm_area(size, VM_IOREMAP,
ioremap_bot, IOREMAP_END);
if (area == NULL)
return NULL;
ret = __ioremap_at(paligned, area->addr, size, flags);
if (!ret)
vunmap(area->addr);
} else {
ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
if (ret)
ioremap_bot += size;
}
if (ret)
ret += addr & ~PAGE_MASK;
return ret;
}
void __iomem * ioremap(phys_addr_t addr, unsigned long size)
{
unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;
if (ppc_md.ioremap)
return ppc_md.ioremap(addr, size, flags);
return __ioremap(addr, size, flags);
}
void __iomem * ioremap_flags(phys_addr_t addr, unsigned long size,
unsigned long flags)
{
if (ppc_md.ioremap)
return ppc_md.ioremap(addr, size, flags);
return __ioremap(addr, size, flags);
}
/*
* Unmap an IO region and remove it from imalloc'd list.
* Access to IO memory should be serialized by driver.
*/
void __iounmap(volatile void __iomem *token)
{
void *addr;
if (!mem_init_done)
return;
addr = (void *) ((unsigned long __force)
PCI_FIX_ADDR(token) & PAGE_MASK);
if ((unsigned long)addr < ioremap_bot) {
printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
" at 0x%p\n", addr);
return;
}
vunmap(addr);
}
void iounmap(volatile void __iomem *token)
{
if (ppc_md.iounmap)
ppc_md.iounmap(token);
else
__iounmap(token);
}
EXPORT_SYMBOL(ioremap);
EXPORT_SYMBOL(ioremap_flags);
EXPORT_SYMBOL(__ioremap);
EXPORT_SYMBOL(__ioremap_at);
EXPORT_SYMBOL(iounmap);
EXPORT_SYMBOL(__iounmap);
EXPORT_SYMBOL(__iounmap_at);