linux/arch/blackfin/mm/init.c
Bernd Schmidt dbdf20db53 Blackfin arch: Faster C implementation of no-MPU CPLB handler
This is a mixture ofcMichael McTernan's patch and the existing cplb-mpu code.

We ditch the old cplb-nompu implementation, which is a good example of
why a good algorithm in a HLL is preferrable to a bad algorithm written in
assembly.  Rather than try to construct a table of all posible CPLBs and
search it, we just create a (smaller) table of memory regions and
their attributes.  Some of the data structures are now unified for both
the mpu and nompu cases.  A lot of needless complexity in cplbinit.c is
removed.

Further optimizations:
  * compile cplbmgr.c with a lot of -ffixed-reg options, and omit saving
    these registers on the stack when entering a CPLB exception.
  * lose cli/nop/nop/sti sequences for some workarounds - these don't
  * make
    sense in an exception context

Additional code unification should be possible after this.

[Mike Frysinger <vapier.adi@gmail.com>:
 - convert CPP if statements to C if statements
 - remove redundant statements
 - use a do...while loop rather than a for loop to get slightly better
   optimization and to avoid gcc "may be used uninitialized" warnings ...
   we know that the [id]cplb_nr_bounds variables will never be 0, so this
   is OK
 - the no-mpu code was the last user of MAX_MEM_SIZE and with that rewritten,
   we can punt it
 - add some BUG_ON() checks to make sure we dont overflow the small
   cplb_bounds array
 - add i/d cplb entries for the bootrom because there is functions/data in
   there we want to access
 - we do not need a NULL trailing entry as any time we access the bounds
   arrays, we use the nr_bounds variable
]

Signed-off-by: Michael McTernan <mmcternan@airvana.com>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
2009-01-07 23:14:38 +08:00

216 lines
6.2 KiB
C

/*
* File: arch/blackfin/mm/init.c
* Based on:
* Author:
*
* Created:
* Description:
*
* Modified:
* Copyright 2004-2007 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/swap.h>
#include <linux/bootmem.h>
#include <linux/uaccess.h>
#include <asm/bfin-global.h>
#include <asm/pda.h>
#include <asm/cplbinit.h>
#include "blackfin_sram.h"
/*
* BAD_PAGE is the page that is used for page faults when linux
* is out-of-memory. Older versions of linux just did a
* do_exit(), but using this instead means there is less risk
* for a process dying in kernel mode, possibly leaving a inode
* unused etc..
*
* BAD_PAGETABLE is the accompanying page-table: it is initialized
* to point to BAD_PAGE entries.
*
* ZERO_PAGE is a special page that is used for zero-initialized
* data and COW.
*/
static unsigned long empty_bad_page_table;
static unsigned long empty_bad_page;
unsigned long empty_zero_page;
extern unsigned long exception_stack[NR_CPUS][1024];
struct blackfin_pda cpu_pda[NR_CPUS];
EXPORT_SYMBOL(cpu_pda);
/*
* paging_init() continues the virtual memory environment setup which
* was begun by the code in arch/head.S.
* The parameters are pointers to where to stick the starting and ending
* addresses of available kernel virtual memory.
*/
void __init paging_init(void)
{
/*
* make sure start_mem is page aligned, otherwise bootmem and
* page_alloc get different views og the world
*/
unsigned long end_mem = memory_end & PAGE_MASK;
pr_debug("start_mem is %#lx virtual_end is %#lx\n", PAGE_ALIGN(memory_start), end_mem);
/*
* initialize the bad page table and bad page to point
* to a couple of allocated pages
*/
empty_bad_page_table = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
empty_bad_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
memset((void *)empty_zero_page, 0, PAGE_SIZE);
/*
* Set up SFC/DFC registers (user data space)
*/
set_fs(KERNEL_DS);
pr_debug("free_area_init -> start_mem is %#lx virtual_end is %#lx\n",
PAGE_ALIGN(memory_start), end_mem);
{
unsigned long zones_size[MAX_NR_ZONES] = { 0, };
zones_size[ZONE_DMA] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
zones_size[ZONE_NORMAL] = 0;
#ifdef CONFIG_HIGHMEM
zones_size[ZONE_HIGHMEM] = 0;
#endif
free_area_init(zones_size);
}
}
asmlinkage void init_pda(void)
{
unsigned int cpu = raw_smp_processor_id();
/* Initialize the PDA fields holding references to other parts
of the memory. The content of such memory is still
undefined at the time of the call, we are only setting up
valid pointers to it. */
memset(&cpu_pda[cpu], 0, sizeof(cpu_pda[cpu]));
cpu_pda[0].next = &cpu_pda[1];
cpu_pda[1].next = &cpu_pda[0];
cpu_pda[cpu].ex_stack = exception_stack[cpu + 1];
#ifdef CONFIG_SMP
cpu_pda[cpu].imask = 0x1f;
#endif
}
void __cpuinit reserve_pda(void)
{
printk(KERN_INFO "PDA for CPU%u reserved at %p\n", smp_processor_id(),
&cpu_pda[smp_processor_id()]);
}
void __init mem_init(void)
{
unsigned int codek = 0, datak = 0, initk = 0;
unsigned int reservedpages = 0, freepages = 0;
unsigned long tmp;
unsigned long start_mem = memory_start;
unsigned long end_mem = memory_end;
end_mem &= PAGE_MASK;
high_memory = (void *)end_mem;
start_mem = PAGE_ALIGN(start_mem);
max_mapnr = num_physpages = MAP_NR(high_memory);
printk(KERN_DEBUG "Kernel managed physical pages: %lu\n", num_physpages);
/* This will put all memory onto the freelists. */
totalram_pages = free_all_bootmem();
reservedpages = 0;
for (tmp = 0; tmp < max_mapnr; tmp++)
if (PageReserved(pfn_to_page(tmp)))
reservedpages++;
freepages = max_mapnr - reservedpages;
/* do not count in kernel image between _rambase and _ramstart */
reservedpages -= (_ramstart - _rambase) >> PAGE_SHIFT;
#if (defined(CONFIG_BFIN_ICACHE) && ANOMALY_05000263)
reservedpages += (_ramend - memory_end - DMA_UNCACHED_REGION) >> PAGE_SHIFT;
#endif
codek = (_etext - _stext) >> 10;
initk = (__init_end - __init_begin) >> 10;
datak = ((_ramstart - _rambase) >> 10) - codek - initk;
printk(KERN_INFO
"Memory available: %luk/%luk RAM, "
"(%uk init code, %uk kernel code, %uk data, %uk dma, %uk reserved)\n",
(unsigned long) freepages << (PAGE_SHIFT-10), _ramend >> 10,
initk, codek, datak, DMA_UNCACHED_REGION >> 10, (reservedpages << (PAGE_SHIFT-10)));
}
static int __init sram_init(void)
{
/* Initialize the blackfin L1 Memory. */
bfin_sram_init();
/* Reserve the PDA space for the boot CPU right after we
* initialized the scratch memory allocator.
*/
reserve_pda();
return 0;
}
pure_initcall(sram_init);
static void __init free_init_pages(const char *what, unsigned long begin, unsigned long end)
{
unsigned long addr;
/* next to check that the page we free is not a partial page */
for (addr = begin; addr + PAGE_SIZE <= end; addr += PAGE_SIZE) {
ClearPageReserved(virt_to_page(addr));
init_page_count(virt_to_page(addr));
free_page(addr);
totalram_pages++;
}
printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
}
#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
#ifndef CONFIG_MPU
free_init_pages("initrd memory", start, end);
#endif
}
#endif
void __init_refok free_initmem(void)
{
#if defined CONFIG_RAMKERNEL && !defined CONFIG_MPU
free_init_pages("unused kernel memory",
(unsigned long)(&__init_begin),
(unsigned long)(&__init_end));
#endif
}