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linux/arch/powerpc/mm/fsl_booke_mmu.c
Kumar Gala 37dd2badcf [POWERPC] 85xx: Add support for relocatable kernel (and booting at non-zero)
Added support to allow an 85xx kernel to be run from a non-zero physical
address (useful for cooperative asymmetric multiprocessing situations and
kdump).  The support can be configured at compile time by setting
CONFIG_PAGE_OFFSET, CONFIG_KERNEL_START, and CONFIG_PHYSICAL_START as
desired.

Alternatively, the kernel build can set CONFIG_RELOCATABLE.  Setting this
config option causes the kernel to determine at runtime the physical
addresses of CONFIG_PAGE_OFFSET and CONFIG_KERNEL_START.  If
CONFIG_RELOCATABLE is set, then CONFIG_PHYSICAL_START has no meaning.
However, CONFIG_PHYSICAL_START will always be used to set the LOAD program
header physical address field in the resulting ELF image.

Currently we are limited to running at a physical address that is a
multiple of 256M.  This is due to how we map TLBs to cover
lowmem.  This should be fixed to allow 64M or maybe even 16M alignment
in the future.  It is considered an error to try and run a kernel at a
non-aligned physical address.

All the magic for this support is accomplished by proper initialization
of the kernel memory subsystem and use of ARCH_PFN_OFFSET.

The use of ARCH_PFN_OFFSET only affects normal memory and not IO mappings.
ioremap uses map_page and isn't affected by ARCH_PFN_OFFSET.

/dev/mem continues to allow access to any physical address in the system
regardless of how CONFIG_PHYSICAL_START is set.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-24 20:58:01 +10:00

232 lines
5.9 KiB
C

/*
* Modifications by Kumar Gala (galak@kernel.crashing.org) to support
* E500 Book E processors.
*
* Copyright 2004 Freescale Semiconductor, Inc
*
* This file contains the routines for initializing the MMU
* on the 4xx series of chips.
* -- paulus
*
* Derived from arch/ppc/mm/init.c:
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
* 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
*
* 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/ptrace.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 <linux/delay.h>
#include <linux/highmem.h>
#include <asm/pgalloc.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/uaccess.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/setup.h>
#include "mmu_decl.h"
extern void loadcam_entry(unsigned int index);
unsigned int tlbcam_index;
unsigned int num_tlbcam_entries;
static unsigned long __cam0, __cam1, __cam2;
#define NUM_TLBCAMS (16)
struct tlbcam {
u32 MAS0;
u32 MAS1;
u32 MAS2;
u32 MAS3;
u32 MAS7;
} TLBCAM[NUM_TLBCAMS];
struct tlbcamrange {
unsigned long start;
unsigned long limit;
phys_addr_t phys;
} tlbcam_addrs[NUM_TLBCAMS];
extern unsigned int tlbcam_index;
/*
* Return PA for this VA if it is mapped by a CAM, or 0
*/
unsigned long v_mapped_by_tlbcam(unsigned long va)
{
int b;
for (b = 0; b < tlbcam_index; ++b)
if (va >= tlbcam_addrs[b].start && va < tlbcam_addrs[b].limit)
return tlbcam_addrs[b].phys + (va - tlbcam_addrs[b].start);
return 0;
}
/*
* Return VA for a given PA or 0 if not mapped
*/
unsigned long p_mapped_by_tlbcam(unsigned long pa)
{
int b;
for (b = 0; b < tlbcam_index; ++b)
if (pa >= tlbcam_addrs[b].phys
&& pa < (tlbcam_addrs[b].limit-tlbcam_addrs[b].start)
+tlbcam_addrs[b].phys)
return tlbcam_addrs[b].start+(pa-tlbcam_addrs[b].phys);
return 0;
}
/*
* Set up one of the I/D BAT (block address translation) register pairs.
* The parameters are not checked; in particular size must be a power
* of 4 between 4k and 256M.
*/
void settlbcam(int index, unsigned long virt, phys_addr_t phys,
unsigned int size, int flags, unsigned int pid)
{
unsigned int tsize, lz;
asm ("cntlzw %0,%1" : "=r" (lz) : "r" (size));
tsize = (21 - lz) / 2;
#ifdef CONFIG_SMP
if ((flags & _PAGE_NO_CACHE) == 0)
flags |= _PAGE_COHERENT;
#endif
TLBCAM[index].MAS0 = MAS0_TLBSEL(1) | MAS0_ESEL(index) | MAS0_NV(index+1);
TLBCAM[index].MAS1 = MAS1_VALID | MAS1_IPROT | MAS1_TSIZE(tsize) | MAS1_TID(pid);
TLBCAM[index].MAS2 = virt & PAGE_MASK;
TLBCAM[index].MAS2 |= (flags & _PAGE_WRITETHRU) ? MAS2_W : 0;
TLBCAM[index].MAS2 |= (flags & _PAGE_NO_CACHE) ? MAS2_I : 0;
TLBCAM[index].MAS2 |= (flags & _PAGE_COHERENT) ? MAS2_M : 0;
TLBCAM[index].MAS2 |= (flags & _PAGE_GUARDED) ? MAS2_G : 0;
TLBCAM[index].MAS2 |= (flags & _PAGE_ENDIAN) ? MAS2_E : 0;
TLBCAM[index].MAS3 = (phys & PAGE_MASK) | MAS3_SX | MAS3_SR;
TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_SW : 0);
#ifndef CONFIG_KGDB /* want user access for breakpoints */
if (flags & _PAGE_USER) {
TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
}
#else
TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
#endif
tlbcam_addrs[index].start = virt;
tlbcam_addrs[index].limit = virt + size - 1;
tlbcam_addrs[index].phys = phys;
loadcam_entry(index);
}
void invalidate_tlbcam_entry(int index)
{
TLBCAM[index].MAS0 = MAS0_TLBSEL(1) | MAS0_ESEL(index);
TLBCAM[index].MAS1 = ~MAS1_VALID;
loadcam_entry(index);
}
void __init cam_mapin_ram(unsigned long cam0, unsigned long cam1,
unsigned long cam2)
{
settlbcam(0, PAGE_OFFSET, memstart_addr, cam0, _PAGE_KERNEL, 0);
tlbcam_index++;
if (cam1) {
tlbcam_index++;
settlbcam(1, PAGE_OFFSET+cam0, memstart_addr+cam0, cam1, _PAGE_KERNEL, 0);
}
if (cam2) {
tlbcam_index++;
settlbcam(2, PAGE_OFFSET+cam0+cam1, memstart_addr+cam0+cam1, cam2, _PAGE_KERNEL, 0);
}
}
/*
* MMU_init_hw does the chip-specific initialization of the MMU hardware.
*/
void __init MMU_init_hw(void)
{
flush_instruction_cache();
}
unsigned long __init mmu_mapin_ram(void)
{
cam_mapin_ram(__cam0, __cam1, __cam2);
return __cam0 + __cam1 + __cam2;
}
void __init
adjust_total_lowmem(void)
{
phys_addr_t max_lowmem_size = __max_low_memory;
phys_addr_t cam_max_size = 0x10000000;
phys_addr_t ram;
/* adjust CAM size to max_lowmem_size */
if (max_lowmem_size < cam_max_size)
cam_max_size = max_lowmem_size;
/* adjust lowmem size to max_lowmem_size */
ram = min(max_lowmem_size, (phys_addr_t)total_lowmem);
/* Calculate CAM values */
__cam0 = 1UL << 2 * (__ilog2(ram) / 2);
if (__cam0 > cam_max_size)
__cam0 = cam_max_size;
ram -= __cam0;
if (ram) {
__cam1 = 1UL << 2 * (__ilog2(ram) / 2);
if (__cam1 > cam_max_size)
__cam1 = cam_max_size;
ram -= __cam1;
}
if (ram) {
__cam2 = 1UL << 2 * (__ilog2(ram) / 2);
if (__cam2 > cam_max_size)
__cam2 = cam_max_size;
ram -= __cam2;
}
printk(KERN_INFO "Memory CAM mapping: CAM0=%ldMb, CAM1=%ldMb,"
" CAM2=%ldMb residual: %ldMb\n",
__cam0 >> 20, __cam1 >> 20, __cam2 >> 20,
(total_lowmem - __cam0 - __cam1 - __cam2) >> 20);
__max_low_memory = __cam0 + __cam1 + __cam2;
__initial_memory_limit_addr = memstart_addr + __max_low_memory;
}