mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 08:19:28 +00:00
127 lines
2.8 KiB
C
127 lines
2.8 KiB
C
![]() |
/*
|
||
|
* linux/arch/cris/mm/tlb.c
|
||
|
*
|
||
|
* Copyright (C) 2000, 2001 Axis Communications AB
|
||
|
*
|
||
|
* Authors: Bjorn Wesen (bjornw@axis.com)
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
#include <linux/init.h>
|
||
|
#include <asm/tlb.h>
|
||
|
|
||
|
#define D(x)
|
||
|
|
||
|
/* The TLB can host up to 64 different mm contexts at the same time.
|
||
|
* The running context is R_MMU_CONTEXT, and each TLB entry contains a
|
||
|
* page_id that has to match to give a hit. In page_id_map, we keep track
|
||
|
* of which mm's we have assigned which page_id's, so that we know when
|
||
|
* to invalidate TLB entries.
|
||
|
*
|
||
|
* The last page_id is never running - it is used as an invalid page_id
|
||
|
* so we can make TLB entries that will never match.
|
||
|
*
|
||
|
* Notice that we need to make the flushes atomic, otherwise an interrupt
|
||
|
* handler that uses vmalloced memory might cause a TLB load in the middle
|
||
|
* of a flush causing.
|
||
|
*/
|
||
|
|
||
|
struct mm_struct *page_id_map[NUM_PAGEID];
|
||
|
static int map_replace_ptr = 1; /* which page_id_map entry to replace next */
|
||
|
|
||
|
/*
|
||
|
* Initialize the context related info for a new mm_struct
|
||
|
* instance.
|
||
|
*/
|
||
|
|
||
|
int
|
||
|
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
|
||
|
{
|
||
|
mm->context = NO_CONTEXT;
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/* the following functions are similar to those used in the PPC port */
|
||
|
|
||
|
static inline void
|
||
|
alloc_context(struct mm_struct *mm)
|
||
|
{
|
||
|
struct mm_struct *old_mm;
|
||
|
|
||
|
D(printk("tlb: alloc context %d (%p)\n", map_replace_ptr, mm));
|
||
|
|
||
|
/* did we replace an mm ? */
|
||
|
|
||
|
old_mm = page_id_map[map_replace_ptr];
|
||
|
|
||
|
if(old_mm) {
|
||
|
/* throw out any TLB entries belonging to the mm we replace
|
||
|
* in the map
|
||
|
*/
|
||
|
flush_tlb_mm(old_mm);
|
||
|
|
||
|
old_mm->context = NO_CONTEXT;
|
||
|
}
|
||
|
|
||
|
/* insert it into the page_id_map */
|
||
|
|
||
|
mm->context = map_replace_ptr;
|
||
|
page_id_map[map_replace_ptr] = mm;
|
||
|
|
||
|
map_replace_ptr++;
|
||
|
|
||
|
if(map_replace_ptr == INVALID_PAGEID)
|
||
|
map_replace_ptr = 0; /* wrap around */
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* if needed, get a new MMU context for the mm. otherwise nothing is done.
|
||
|
*/
|
||
|
|
||
|
void
|
||
|
get_mmu_context(struct mm_struct *mm)
|
||
|
{
|
||
|
if(mm->context == NO_CONTEXT)
|
||
|
alloc_context(mm);
|
||
|
}
|
||
|
|
||
|
/* called by __exit_mm to destroy the used MMU context if any before
|
||
|
* destroying the mm itself. this is only called when the last user of the mm
|
||
|
* drops it.
|
||
|
*
|
||
|
* the only thing we really need to do here is mark the used PID slot
|
||
|
* as empty.
|
||
|
*/
|
||
|
|
||
|
void
|
||
|
destroy_context(struct mm_struct *mm)
|
||
|
{
|
||
|
if(mm->context != NO_CONTEXT) {
|
||
|
D(printk("destroy_context %d (%p)\n", mm->context, mm));
|
||
|
flush_tlb_mm(mm); /* TODO this might be redundant ? */
|
||
|
page_id_map[mm->context] = NULL;
|
||
|
/* mm->context = NO_CONTEXT; redundant.. mm will be freed */
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* called once during VM initialization, from init.c */
|
||
|
|
||
|
void __init
|
||
|
tlb_init(void)
|
||
|
{
|
||
|
int i;
|
||
|
|
||
|
/* clear the page_id map */
|
||
|
|
||
|
for (i = 1; i < sizeof (page_id_map) / sizeof (page_id_map[0]); i++)
|
||
|
page_id_map[i] = NULL;
|
||
|
|
||
|
/* invalidate the entire TLB */
|
||
|
|
||
|
flush_tlb_all();
|
||
|
|
||
|
/* the init_mm has context 0 from the boot */
|
||
|
|
||
|
page_id_map[0] = &init_mm;
|
||
|
}
|