microblaze: Highmem support

The first highmem implementation.

Signed-off-by: Michal Simek <monstr@monstr.eu>
This commit is contained in:
Michal Simek 2011-12-15 15:02:37 +01:00
parent baab8a828d
commit 2f2f371f89
6 changed files with 272 additions and 13 deletions

View file

@ -159,20 +159,18 @@ config XILINX_UNCACHED_SHADOW
The feature requires the design to define the RAM memory controller
window to be twice as large as the actual physical memory.
config HIGHMEM_START_BOOL
bool "Set high memory pool address"
depends on ADVANCED_OPTIONS && HIGHMEM
help
This option allows you to set the base address of the kernel virtual
area used to map high memory pages. This can be useful in
optimizing the layout of kernel virtual memory.
Say N here unless you know what you are doing.
config HIGHMEM_START
hex "Virtual start address of high memory pool" if HIGHMEM_START_BOOL
config HIGHMEM
bool "High memory support"
depends on MMU
default "0xfe000000"
help
The address space of Microblaze processors is only 4 Gigabytes large
and it has to accommodate user address space, kernel address
space as well as some memory mapped IO. That means that, if you
have a large amount of physical memory and/or IO, not all of the
memory can be "permanently mapped" by the kernel. The physical
memory that is not permanently mapped is called "high memory".
If unsure, say n.
config LOWMEM_SIZE_BOOL
bool "Set maximum low memory"

View file

@ -21,6 +21,10 @@
#ifndef __ASSEMBLY__
#include <linux/kernel.h>
#include <asm/page.h>
#ifdef CONFIG_HIGHMEM
#include <linux/threads.h>
#include <asm/kmap_types.h>
#endif
#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
@ -44,6 +48,10 @@
*/
enum fixed_addresses {
FIX_HOLE,
#ifdef CONFIG_HIGHMEM
FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * num_possible_cpus()) - 1,
#endif
__end_of_fixed_addresses
};

View file

@ -0,0 +1,96 @@
/*
* highmem.h: virtual kernel memory mappings for high memory
*
* Used in CONFIG_HIGHMEM systems for memory pages which
* are not addressable by direct kernel virtual addresses.
*
* Copyright (C) 1999 Gerhard Wichert, Siemens AG
* Gerhard.Wichert@pdb.siemens.de
*
*
* Redesigned the x86 32-bit VM architecture to deal with
* up to 16 Terabyte physical memory. With current x86 CPUs
* we now support up to 64 Gigabytes physical RAM.
*
* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
*/
#ifndef _ASM_HIGHMEM_H
#define _ASM_HIGHMEM_H
#ifdef __KERNEL__
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#include <asm/fixmap.h>
extern pte_t *kmap_pte;
extern pgprot_t kmap_prot;
extern pte_t *pkmap_page_table;
/*
* Right now we initialize only a single pte table. It can be extended
* easily, subsequent pte tables have to be allocated in one physical
* chunk of RAM.
*/
/*
* We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
* table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
* and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
* in case of 16K/64K/256K page sizes.
*/
#define PKMAP_ORDER PTE_SHIFT
#define LAST_PKMAP (1 << PKMAP_ORDER)
#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
& PMD_MASK)
#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
extern void *kmap_high(struct page *page);
extern void kunmap_high(struct page *page);
extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
extern void __kunmap_atomic(void *kvaddr);
static inline void *kmap(struct page *page)
{
might_sleep();
if (!PageHighMem(page))
return page_address(page);
return kmap_high(page);
}
static inline void kunmap(struct page *page)
{
BUG_ON(in_interrupt());
if (!PageHighMem(page))
return;
kunmap_high(page);
}
static inline void *__kmap_atomic(struct page *page)
{
return kmap_atomic_prot(page, kmap_prot);
}
static inline struct page *kmap_atomic_to_page(void *ptr)
{
unsigned long idx, vaddr = (unsigned long) ptr;
pte_t *pte;
if (vaddr < FIXADDR_START)
return virt_to_page(ptr);
idx = virt_to_fix(vaddr);
pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
return pte_page(*pte);
}
#define flush_cache_kmaps() { flush_icache(); flush_dcache(); }
#endif /* __KERNEL__ */
#endif /* _ASM_HIGHMEM_H */

View file

@ -5,3 +5,4 @@
obj-y := consistent.o init.o
obj-$(CONFIG_MMU) += pgtable.o mmu_context.o fault.o
obj-$(CONFIG_HIGHMEM) += highmem.o

View file

@ -0,0 +1,88 @@
/*
* highmem.c: virtual kernel memory mappings for high memory
*
* PowerPC version, stolen from the i386 version.
*
* Used in CONFIG_HIGHMEM systems for memory pages which
* are not addressable by direct kernel virtual addresses.
*
* Copyright (C) 1999 Gerhard Wichert, Siemens AG
* Gerhard.Wichert@pdb.siemens.de
*
*
* Redesigned the x86 32-bit VM architecture to deal with
* up to 16 Terrabyte physical memory. With current x86 CPUs
* we now support up to 64 Gigabytes physical RAM.
*
* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
*
* Reworked for PowerPC by various contributors. Moved from
* highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
*/
#include <linux/highmem.h>
#include <linux/module.h>
/*
* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
* gives a more generic (and caching) interface. But kmap_atomic can
* be used in IRQ contexts, so in some (very limited) cases we need
* it.
*/
#include <asm/tlbflush.h>
void *kmap_atomic_prot(struct page *page, pgprot_t prot)
{
unsigned long vaddr;
int idx, type;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(*(kmap_pte-idx)));
#endif
set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
local_flush_tlb_page(NULL, vaddr);
return (void *) vaddr;
}
EXPORT_SYMBOL(kmap_atomic_prot);
void __kunmap_atomic(void *kvaddr)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
int type;
if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
pagefault_enable();
return;
}
type = kmap_atomic_idx();
#ifdef CONFIG_DEBUG_HIGHMEM
{
unsigned int idx;
idx = type + KM_TYPE_NR * smp_processor_id();
BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
/*
* force other mappings to Oops if they'll try to access
* this pte without first remap it
*/
pte_clear(&init_mm, vaddr, kmap_pte-idx);
local_flush_tlb_page(NULL, vaddr);
}
#endif
kmap_atomic_idx_pop();
pagefault_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);

View file

@ -49,6 +49,53 @@ unsigned long memory_size;
EXPORT_SYMBOL(memory_size);
unsigned long lowmem_size;
#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
EXPORT_SYMBOL(kmap_pte);
pgprot_t kmap_prot;
EXPORT_SYMBOL(kmap_prot);
static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
vaddr), vaddr);
}
static void __init highmem_init(void)
{
pr_debug("%x\n", (u32)PKMAP_BASE);
map_page(PKMAP_BASE, 0, 0); /* XXX gross */
pkmap_page_table = virt_to_kpte(PKMAP_BASE);
kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
kmap_prot = PAGE_KERNEL;
}
static unsigned long highmem_setup(void)
{
unsigned long pfn;
unsigned long reservedpages = 0;
for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) {
struct page *page = pfn_to_page(pfn);
/* FIXME not sure about */
if (memblock_is_reserved(pfn << PAGE_SHIFT))
continue;
ClearPageReserved(page);
init_page_count(page);
__free_page(page);
totalhigh_pages++;
reservedpages++;
}
totalram_pages += totalhigh_pages;
printk(KERN_INFO "High memory: %luk\n",
totalhigh_pages << (PAGE_SHIFT-10));
return reservedpages;
}
#endif /* CONFIG_HIGHMEM */
/*
* paging_init() sets up the page tables - in fact we've already done this.
*/
@ -66,7 +113,14 @@ static void __init paging_init(void)
/* Clean every zones */
memset(zones_size, 0, sizeof(zones_size));
#ifdef CONFIG_HIGHMEM
highmem_init();
zones_size[ZONE_DMA] = max_low_pfn;
zones_size[ZONE_HIGHMEM] = max_pfn;
#else
zones_size[ZONE_DMA] = max_pfn;
#endif
/* We don't have holes in memory map */
free_area_init_nodes(zones_size);
@ -241,6 +295,10 @@ void __init mem_init(void)
}
}
#ifdef CONFIG_HIGHMEM
reservedpages -= highmem_setup();
#endif
codesize = (unsigned long)&_sdata - (unsigned long)&_stext;
datasize = (unsigned long)&_edata - (unsigned long)&_sdata;
initsize = (unsigned long)&__init_end - (unsigned long)&__init_begin;
@ -259,6 +317,10 @@ void __init mem_init(void)
#ifdef CONFIG_MMU
pr_info("Kernel virtual memory layout:\n");
pr_info(" * 0x%08lx..0x%08lx : fixmap\n", FIXADDR_START, FIXADDR_TOP);
#ifdef CONFIG_HIGHMEM
pr_info(" * 0x%08lx..0x%08lx : highmem PTEs\n",
PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
#endif /* CONFIG_HIGHMEM */
pr_info(" * 0x%08lx..0x%08lx : early ioremap\n",
ioremap_bot, ioremap_base);
pr_info(" * 0x%08lx..0x%08lx : vmalloc & ioremap\n",
@ -346,7 +408,9 @@ asmlinkage void __init mmu_init(void)
if (lowmem_size > CONFIG_LOWMEM_SIZE) {
lowmem_size = CONFIG_LOWMEM_SIZE;
#ifndef CONFIG_HIGHMEM
memory_size = lowmem_size;
#endif
}
mm_cmdline_setup(); /* FIXME parse args from command line - not used */
@ -375,7 +439,11 @@ asmlinkage void __init mmu_init(void)
mapin_ram();
/* Extend vmalloc and ioremap area as big as possible */
#ifdef CONFIG_HIGHMEM
ioremap_base = ioremap_bot = PKMAP_BASE;
#else
ioremap_base = ioremap_bot = FIXADDR_START;
#endif
/* Initialize the context management stuff */
mmu_context_init();