/*
* File: include/asm-blackfin/mmu_context.h
* Based on:
* Author:
*
* Created:
* Description:
*
* Modified:
* Copyright 2004-2006 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
*/
#ifndef __BLACKFIN_MMU_CONTEXT_H__
#define __BLACKFIN_MMU_CONTEXT_H__
#include <linux/gfp.h>
#include <linux/sched.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/cplbinit.h>
/* Note: L1 stacks are CPU-private things, so we bluntly disable this
feature in SMP mode, and use the per-CPU scratch SRAM bank only to
store the PDA instead. */
extern void *current_l1_stack_save;
extern int nr_l1stack_tasks;
extern void *l1_stack_base;
extern unsigned long l1_stack_len;
extern int l1sram_free(const void*);
extern void *l1sram_alloc_max(void*);
static inline void free_l1stack(void)
{
nr_l1stack_tasks--;
if (nr_l1stack_tasks == 0)
l1sram_free(l1_stack_base);
}
static inline unsigned long
alloc_l1stack(unsigned long length, unsigned long *stack_base)
{
if (nr_l1stack_tasks == 0) {
l1_stack_base = l1sram_alloc_max(&l1_stack_len);
if (!l1_stack_base)
return 0;
}
if (l1_stack_len < length) {
if (nr_l1stack_tasks == 0)
l1sram_free(l1_stack_base);
return 0;
}
*stack_base = (unsigned long)l1_stack_base;
nr_l1stack_tasks++;
return l1_stack_len;
}
static inline int
activate_l1stack(struct mm_struct *mm, unsigned long sp_base)
{
if (current_l1_stack_save)
memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
mm->context.l1_stack_save = current_l1_stack_save = (void*)sp_base;
memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
return 1;
}
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(prev, next) switch_mm(prev, next, NULL)
static inline void switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
struct task_struct *tsk)
{
#ifdef CONFIG_MPU
unsigned int cpu = smp_processor_id();
#endif
if (prev_mm == next_mm)
return;
#ifdef CONFIG_MPU
if (prev_mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
flush_switched_cplbs(cpu);
set_mask_dcplbs(next_mm->context.page_rwx_mask, cpu);
}
#endif
#ifdef CONFIG_APP_STACK_L1
/* L1 stack switching. */
if (!next_mm->context.l1_stack_save)
return;
if (next_mm->context.l1_stack_save == current_l1_stack_save)
return;
if (current_l1_stack_save) {
memcpy(current_l1_stack_save, l1_stack_base, l1_stack_len);
}
current_l1_stack_save = next_mm->context.l1_stack_save;
memcpy(l1_stack_base, current_l1_stack_save, l1_stack_len);
#endif
}
#ifdef CONFIG_MPU
static inline void protect_page(struct mm_struct *mm, unsigned long addr,
unsigned long flags)
{
unsigned long *mask = mm->context.page_rwx_mask;
unsigned long page = addr >> 12;
unsigned long idx = page >> 5;
unsigned long bit = 1 << (page & 31);
if (flags & VM_MAYREAD)
mask[idx] |= bit;
else
mask[idx] &= ~bit;
mask += page_mask_nelts;
if (flags & VM_MAYWRITE)
mask[idx] |= bit;
else
mask[idx] &= ~bit;
mask += page_mask_nelts;
if (flags & VM_MAYEXEC)
mask[idx] |= bit;
else
mask[idx] &= ~bit;
}
static inline void update_protections(struct mm_struct *mm)
{
unsigned int cpu = smp_processor_id();
if (mm->context.page_rwx_mask == current_rwx_mask[cpu]) {
flush_switched_cplbs(cpu);
set_mask_dcplbs(mm->context.page_rwx_mask, cpu);
}
}
#endif
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
}
/* Called when creating a new context during fork() or execve(). */
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
#ifdef CONFIG_MPU
unsigned long p = __get_free_pages(GFP_KERNEL, page_mask_order);
mm->context.page_rwx_mask = (unsigned long *)p;
memset(mm->context.page_rwx_mask, 0,
page_mask_nelts * 3 * sizeof(long));
#endif
return 0;
}
static inline void destroy_context(struct mm_struct *mm)
{
struct sram_list_struct *tmp;
#ifdef CONFIG_MPU
unsigned int cpu = smp_processor_id();
#endif
#ifdef CONFIG_APP_STACK_L1
if (current_l1_stack_save == mm->context.l1_stack_save)
current_l1_stack_save = 0;
if (mm->context.l1_stack_save)
free_l1stack();
#endif
while ((tmp = mm->context.sram_list)) {
mm->context.sram_list = tmp->next;
sram_free(tmp->addr);
kfree(tmp);
}
#ifdef CONFIG_MPU
if (current_rwx_mask[cpu] == mm->context.page_rwx_mask)
current_rwx_mask[cpu] = NULL;
free_pages((unsigned long)mm->context.page_rwx_mask, page_mask_order);
#endif
}
#endif
