linux/arch/m68k/mm/mcfmmu.c
Greg Ungerer f50bf88df3 m68k: move to a single instance of free_initmem()
Currently each sub-architecture has its own implementation if init_freemem().
There is two different cases that the various implementations deal with.
They either free the init memory, or they don't. We only need a single instance
to cover all cases.

The non-MMU version did some page alignment twidling, but this is not
neccessary. The current linker script enforces page alignment. It also
checked for CONFIG_RAMKERNEL, but this also is not necessary, the linker
script always keeps the init sections in RAM.

The MMU ColdFire version of free_initmem() was empty. There is no reason it
can't carry out the freeing of the init memory. So it is now changed and
tested to do this.

For the other MMU cases the code is the same. For the general Motorola MMU
case we free the init memory. For the SUN3 case we do nothing (though I
think it could safely free the init memory as well).

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2012-11-14 08:50:56 +01:00

195 lines
5 KiB
C

/*
* Based upon linux/arch/m68k/mm/sun3mmu.c
* Based upon linux/arch/ppc/mm/mmu_context.c
*
* Implementations of mm routines specific to the Coldfire MMU.
*
* Copyright (c) 2008 Freescale Semiconductor, Inc.
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/bootmem.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#include <asm/mcf_pgalloc.h>
#include <asm/tlbflush.h>
#define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END))
mm_context_t next_mmu_context;
unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
atomic_t nr_free_contexts;
struct mm_struct *context_mm[LAST_CONTEXT+1];
extern unsigned long num_pages;
/*
* ColdFire paging_init derived from sun3.
*/
void __init paging_init(void)
{
pgd_t *pg_dir;
pte_t *pg_table;
unsigned long address, size;
unsigned long next_pgtable, bootmem_end;
unsigned long zones_size[MAX_NR_ZONES];
enum zone_type zone;
int i;
empty_zero_page = (void *) alloc_bootmem_pages(PAGE_SIZE);
memset((void *) empty_zero_page, 0, PAGE_SIZE);
pg_dir = swapper_pg_dir;
memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));
size = num_pages * sizeof(pte_t);
size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
next_pgtable = (unsigned long) alloc_bootmem_pages(size);
bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
address = PAGE_OFFSET;
while (address < (unsigned long)high_memory) {
pg_table = (pte_t *) next_pgtable;
next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
pgd_val(*pg_dir) = (unsigned long) pg_table;
pg_dir++;
/* now change pg_table to kernel virtual addresses */
for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {
pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
if (address >= (unsigned long) high_memory)
pte_val(pte) = 0;
set_pte(pg_table, pte);
address += PAGE_SIZE;
}
}
current->mm = NULL;
for (zone = 0; zone < MAX_NR_ZONES; zone++)
zones_size[zone] = 0x0;
zones_size[ZONE_DMA] = num_pages;
free_area_init(zones_size);
}
int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
{
unsigned long flags, mmuar, mmutr;
struct mm_struct *mm;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
int asid;
local_irq_save(flags);
mmuar = (dtlb) ? mmu_read(MMUAR) :
regs->pc + (extension_word * sizeof(long));
mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
if (!mm) {
local_irq_restore(flags);
return -1;
}
pgd = pgd_offset(mm, mmuar);
if (pgd_none(*pgd)) {
local_irq_restore(flags);
return -1;
}
pmd = pmd_offset(pgd, mmuar);
if (pmd_none(*pmd)) {
local_irq_restore(flags);
return -1;
}
pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
if (pte_none(*pte) || !pte_present(*pte)) {
local_irq_restore(flags);
return -1;
}
if (write) {
if (!pte_write(*pte)) {
local_irq_restore(flags);
return -1;
}
set_pte(pte, pte_mkdirty(*pte));
}
set_pte(pte, pte_mkyoung(*pte));
asid = mm->context & 0xff;
if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
set_pte(pte, pte_wrprotect(*pte));
mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V;
if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE))
mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT;
mmu_write(MMUTR, mmutr);
mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
if (dtlb)
mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
else
mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);
local_irq_restore(flags);
return 0;
}
/*
* Initialize the context management stuff.
* The following was taken from arch/ppc/mmu_context.c
*/
void __init mmu_context_init(void)
{
/*
* Some processors have too few contexts to reserve one for
* init_mm, and require using context 0 for a normal task.
* Other processors reserve the use of context zero for the kernel.
* This code assumes FIRST_CONTEXT < 32.
*/
context_map[0] = (1 << FIRST_CONTEXT) - 1;
next_mmu_context = FIRST_CONTEXT;
atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
}
/*
* Steal a context from a task that has one at the moment.
* This is only used on 8xx and 4xx and we presently assume that
* they don't do SMP. If they do then thicfpgalloc.hs will have to check
* whether the MM we steal is in use.
* We also assume that this is only used on systems that don't
* use an MMU hash table - this is true for 8xx and 4xx.
* This isn't an LRU system, it just frees up each context in
* turn (sort-of pseudo-random replacement :). This would be the
* place to implement an LRU scheme if anyone was motivated to do it.
* -- paulus
*/
void steal_context(void)
{
struct mm_struct *mm;
/*
* free up context `next_mmu_context'
* if we shouldn't free context 0, don't...
*/
if (next_mmu_context < FIRST_CONTEXT)
next_mmu_context = FIRST_CONTEXT;
mm = context_mm[next_mmu_context];
flush_tlb_mm(mm);
destroy_context(mm);
}