microblaze_mmu_v2: Context handling - mmu_context.c/h
Signed-off-by: Michal Simek <monstr@monstr.eu>
This commit is contained in:
Michal Simek
Родитель
5de9612100
Коммит
fc34d1eb1c
|
|
@ -1,21 +1,5 @@
|
||||||
/*
|
#ifdef CONFIG_MMU
|
||||||
* Copyright (C) 2006 Atmark Techno, Inc.
|
# include "mmu_context_mm.h"
|
||||||
*
|
#else
|
||||||
* This file is subject to the terms and conditions of the GNU General Public
|
# include "mmu_context_no.h"
|
||||||
* License. See the file "COPYING" in the main directory of this archive
|
#endif
|
||||||
* for more details.
|
|
||||||
*/
|
|
||||||
|
|
||||||
#ifndef _ASM_MICROBLAZE_MMU_CONTEXT_H
|
|
||||||
#define _ASM_MICROBLAZE_MMU_CONTEXT_H
|
|
||||||
|
|
||||||
# define init_new_context(tsk, mm) ({ 0; })
|
|
||||||
|
|
||||||
# define enter_lazy_tlb(mm, tsk) do {} while (0)
|
|
||||||
# define change_mm_context(old, ctx, _pml4) do {} while (0)
|
|
||||||
# define destroy_context(mm) do {} while (0)
|
|
||||||
# define deactivate_mm(tsk, mm) do {} while (0)
|
|
||||||
# define switch_mm(prev, next, tsk) do {} while (0)
|
|
||||||
# define activate_mm(prev, next) do {} while (0)
|
|
||||||
|
|
||||||
#endif /* _ASM_MICROBLAZE_MMU_CONTEXT_H */
|
|
||||||
|
|
|
||||||
|
|
@ -0,0 +1,140 @@
|
||||||
|
/*
|
||||||
|
* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
|
||||||
|
* Copyright (C) 2008-2009 PetaLogix
|
||||||
|
* Copyright (C) 2006 Atmark Techno, Inc.
|
||||||
|
*
|
||||||
|
* This file is subject to the terms and conditions of the GNU General Public
|
||||||
|
* License. See the file "COPYING" in the main directory of this archive
|
||||||
|
* for more details.
|
||||||
|
*/
|
||||||
|
|
||||||
|
#ifndef _ASM_MICROBLAZE_MMU_CONTEXT_H
|
||||||
|
#define _ASM_MICROBLAZE_MMU_CONTEXT_H
|
||||||
|
|
||||||
|
#include <asm/atomic.h>
|
||||||
|
#include <asm/bitops.h>
|
||||||
|
#include <asm/mmu.h>
|
||||||
|
#include <asm-generic/mm_hooks.h>
|
||||||
|
|
||||||
|
# ifdef __KERNEL__
|
||||||
|
/*
|
||||||
|
* This function defines the mapping from contexts to VSIDs (virtual
|
||||||
|
* segment IDs). We use a skew on both the context and the high 4 bits
|
||||||
|
* of the 32-bit virtual address (the "effective segment ID") in order
|
||||||
|
* to spread out the entries in the MMU hash table.
|
||||||
|
*/
|
||||||
|
# define CTX_TO_VSID(ctx, va) (((ctx) * (897 * 16) + ((va) >> 28) * 0x111) \
|
||||||
|
& 0xffffff)
|
||||||
|
|
||||||
|
/*
|
||||||
|
MicroBlaze has 256 contexts, so we can just rotate through these
|
||||||
|
as a way of "switching" contexts. If the TID of the TLB is zero,
|
||||||
|
the PID/TID comparison is disabled, so we can use a TID of zero
|
||||||
|
to represent all kernel pages as shared among all contexts.
|
||||||
|
*/
|
||||||
|
|
||||||
|
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
|
||||||
|
{
|
||||||
|
}
|
||||||
|
|
||||||
|
# define NO_CONTEXT 256
|
||||||
|
# define LAST_CONTEXT 255
|
||||||
|
# define FIRST_CONTEXT 1
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Set the current MMU context.
|
||||||
|
* This is done byloading up the segment registers for the user part of the
|
||||||
|
* address space.
|
||||||
|
*
|
||||||
|
* Since the PGD is immediately available, it is much faster to simply
|
||||||
|
* pass this along as a second parameter, which is required for 8xx and
|
||||||
|
* can be used for debugging on all processors (if you happen to have
|
||||||
|
* an Abatron).
|
||||||
|
*/
|
||||||
|
extern void set_context(mm_context_t context, pgd_t *pgd);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Bitmap of contexts in use.
|
||||||
|
* The size of this bitmap is LAST_CONTEXT + 1 bits.
|
||||||
|
*/
|
||||||
|
extern unsigned long context_map[];
|
||||||
|
|
||||||
|
/*
|
||||||
|
* This caches the next context number that we expect to be free.
|
||||||
|
* Its use is an optimization only, we can't rely on this context
|
||||||
|
* number to be free, but it usually will be.
|
||||||
|
*/
|
||||||
|
extern mm_context_t next_mmu_context;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Since we don't have sufficient contexts to give one to every task
|
||||||
|
* that could be in the system, we need to be able to steal contexts.
|
||||||
|
* These variables support that.
|
||||||
|
*/
|
||||||
|
extern atomic_t nr_free_contexts;
|
||||||
|
extern struct mm_struct *context_mm[LAST_CONTEXT+1];
|
||||||
|
extern void steal_context(void);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Get a new mmu context for the address space described by `mm'.
|
||||||
|
*/
|
||||||
|
static inline void get_mmu_context(struct mm_struct *mm)
|
||||||
|
{
|
||||||
|
mm_context_t ctx;
|
||||||
|
|
||||||
|
if (mm->context != NO_CONTEXT)
|
||||||
|
return;
|
||||||
|
while (atomic_dec_if_positive(&nr_free_contexts) < 0)
|
||||||
|
steal_context();
|
||||||
|
ctx = next_mmu_context;
|
||||||
|
while (test_and_set_bit(ctx, context_map)) {
|
||||||
|
ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
|
||||||
|
if (ctx > LAST_CONTEXT)
|
||||||
|
ctx = 0;
|
||||||
|
}
|
||||||
|
next_mmu_context = (ctx + 1) & LAST_CONTEXT;
|
||||||
|
mm->context = ctx;
|
||||||
|
context_mm[ctx] = mm;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Set up the context for a new address space.
|
||||||
|
*/
|
||||||
|
# define init_new_context(tsk, mm) (((mm)->context = NO_CONTEXT), 0)
|
||||||
|
|
||||||
|
/*
|
||||||
|
* We're finished using the context for an address space.
|
||||||
|
*/
|
||||||
|
static inline void destroy_context(struct mm_struct *mm)
|
||||||
|
{
|
||||||
|
if (mm->context != NO_CONTEXT) {
|
||||||
|
clear_bit(mm->context, context_map);
|
||||||
|
mm->context = NO_CONTEXT;
|
||||||
|
atomic_inc(&nr_free_contexts);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
|
||||||
|
struct task_struct *tsk)
|
||||||
|
{
|
||||||
|
tsk->thread.pgdir = next->pgd;
|
||||||
|
get_mmu_context(next);
|
||||||
|
set_context(next->context, next->pgd);
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* After we have set current->mm to a new value, this activates
|
||||||
|
* the context for the new mm so we see the new mappings.
|
||||||
|
*/
|
||||||
|
static inline void activate_mm(struct mm_struct *active_mm,
|
||||||
|
struct mm_struct *mm)
|
||||||
|
{
|
||||||
|
current->thread.pgdir = mm->pgd;
|
||||||
|
get_mmu_context(mm);
|
||||||
|
set_context(mm->context, mm->pgd);
|
||||||
|
}
|
||||||
|
|
||||||
|
extern void mmu_context_init(void);
|
||||||
|
|
||||||
|
# endif /* __KERNEL__ */
|
||||||
|
#endif /* _ASM_MICROBLAZE_MMU_CONTEXT_H */
|
||||||
|
|
@ -0,0 +1,23 @@
|
||||||
|
/*
|
||||||
|
* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
|
||||||
|
* Copyright (C) 2008-2009 PetaLogix
|
||||||
|
* Copyright (C) 2006 Atmark Techno, Inc.
|
||||||
|
*
|
||||||
|
* This file is subject to the terms and conditions of the GNU General Public
|
||||||
|
* License. See the file "COPYING" in the main directory of this archive
|
||||||
|
* for more details.
|
||||||
|
*/
|
||||||
|
|
||||||
|
#ifndef _ASM_MICROBLAZE_MMU_CONTEXT_H
|
||||||
|
#define _ASM_MICROBLAZE_MMU_CONTEXT_H
|
||||||
|
|
||||||
|
# define init_new_context(tsk, mm) ({ 0; })
|
||||||
|
|
||||||
|
# define enter_lazy_tlb(mm, tsk) do {} while (0)
|
||||||
|
# define change_mm_context(old, ctx, _pml4) do {} while (0)
|
||||||
|
# define destroy_context(mm) do {} while (0)
|
||||||
|
# define deactivate_mm(tsk, mm) do {} while (0)
|
||||||
|
# define switch_mm(prev, next, tsk) do {} while (0)
|
||||||
|
# define activate_mm(prev, next) do {} while (0)
|
||||||
|
|
||||||
|
#endif /* _ASM_MICROBLAZE_MMU_CONTEXT_H */
|
||||||
|
|
@ -0,0 +1,70 @@
|
||||||
|
/*
|
||||||
|
* This file contains the routines for handling the MMU.
|
||||||
|
*
|
||||||
|
* Copyright (C) 2007 Xilinx, Inc. All rights reserved.
|
||||||
|
*
|
||||||
|
* Derived from arch/ppc/mm/4xx_mmu.c:
|
||||||
|
* -- 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
|
||||||
|
* Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
|
||||||
|
*
|
||||||
|
* 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/mm.h>
|
||||||
|
#include <linux/init.h>
|
||||||
|
|
||||||
|
#include <asm/tlbflush.h>
|
||||||
|
#include <asm/mmu_context.h>
|
||||||
|
|
||||||
|
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];
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Initialize the context management stuff.
|
||||||
|
*/
|
||||||
|
void __init mmu_context_init(void)
|
||||||
|
{
|
||||||
|
/*
|
||||||
|
* The use of context zero is reserved 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 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 were motivated to do it.
|
||||||
|
*/
|
||||||
|
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);
|
||||||
|
}
|
||||||
Загрузка…
Ссылка в новой задаче