+++ /dev/null
-/* mmu-context.c: MMU context allocation and management
- *
- * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * 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/sched.h>
-#include <linux/sched/mm.h>
-#include <linux/sched/task.h>
-#include <linux/mm.h>
-#include <asm/tlbflush.h>
-
-#define NR_CXN 4096
-
-static unsigned long cxn_bitmap[NR_CXN / (sizeof(unsigned long) * 8)];
-static LIST_HEAD(cxn_owners_lru);
-static DEFINE_SPINLOCK(cxn_owners_lock);
-
-int __nongpreldata cxn_pinned = -1;
-
-
-/*****************************************************************************/
-/*
- * initialise a new context
- */
-int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
-{
- memset(&mm->context, 0, sizeof(mm->context));
- INIT_LIST_HEAD(&mm->context.id_link);
- mm->context.itlb_cached_pge = 0xffffffffUL;
- mm->context.dtlb_cached_pge = 0xffffffffUL;
-
- return 0;
-} /* end init_new_context() */
-
-/*****************************************************************************/
-/*
- * make sure a kernel MMU context has a CPU context number
- * - call with cxn_owners_lock held
- */
-static unsigned get_cxn(mm_context_t *ctx)
-{
- struct list_head *_p;
- mm_context_t *p;
- unsigned cxn;
-
- if (!list_empty(&ctx->id_link)) {
- list_move_tail(&ctx->id_link, &cxn_owners_lru);
- }
- else {
- /* find the first unallocated context number
- * - 0 is reserved for the kernel
- */
- cxn = find_next_zero_bit(cxn_bitmap, NR_CXN, 1);
- if (cxn < NR_CXN) {
- set_bit(cxn, cxn_bitmap);
- }
- else {
- /* none remaining - need to steal someone else's cxn */
- p = NULL;
- list_for_each(_p, &cxn_owners_lru) {
- p = list_entry(_p, mm_context_t, id_link);
- if (!p->id_busy && p->id != cxn_pinned)
- break;
- }
-
- BUG_ON(_p == &cxn_owners_lru);
-
- cxn = p->id;
- p->id = 0;
- list_del_init(&p->id_link);
- __flush_tlb_mm(cxn);
- }
-
- ctx->id = cxn;
- list_add_tail(&ctx->id_link, &cxn_owners_lru);
- }
-
- return ctx->id;
-} /* end get_cxn() */
-
-/*****************************************************************************/
-/*
- * restore the current TLB miss handler mapped page tables into the MMU context and set up a
- * mapping for the page directory
- */
-void change_mm_context(mm_context_t *old, mm_context_t *ctx, pgd_t *pgd)
-{
- unsigned long _pgd;
-
- _pgd = virt_to_phys(pgd);
-
- /* save the state of the outgoing MMU context */
- old->id_busy = 0;
-
- asm volatile("movsg scr0,%0" : "=r"(old->itlb_cached_pge));
- asm volatile("movsg dampr4,%0" : "=r"(old->itlb_ptd_mapping));
- asm volatile("movsg scr1,%0" : "=r"(old->dtlb_cached_pge));
- asm volatile("movsg dampr5,%0" : "=r"(old->dtlb_ptd_mapping));
-
- /* select an MMU context number */
- spin_lock(&cxn_owners_lock);
- get_cxn(ctx);
- ctx->id_busy = 1;
- spin_unlock(&cxn_owners_lock);
-
- asm volatile("movgs %0,cxnr" : : "r"(ctx->id));
-
- /* restore the state of the incoming MMU context */
- asm volatile("movgs %0,scr0" : : "r"(ctx->itlb_cached_pge));
- asm volatile("movgs %0,dampr4" : : "r"(ctx->itlb_ptd_mapping));
- asm volatile("movgs %0,scr1" : : "r"(ctx->dtlb_cached_pge));
- asm volatile("movgs %0,dampr5" : : "r"(ctx->dtlb_ptd_mapping));
-
- /* map the PGD into uncached virtual memory */
- asm volatile("movgs %0,ttbr" : : "r"(_pgd));
- asm volatile("movgs %0,dampr3"
- :: "r"(_pgd | xAMPRx_L | xAMPRx_M | xAMPRx_SS_16Kb |
- xAMPRx_S | xAMPRx_C | xAMPRx_V));
-
-} /* end change_mm_context() */
-
-/*****************************************************************************/
-/*
- * finished with an MMU context number
- */
-void destroy_context(struct mm_struct *mm)
-{
- mm_context_t *ctx = &mm->context;
-
- spin_lock(&cxn_owners_lock);
-
- if (!list_empty(&ctx->id_link)) {
- if (ctx->id == cxn_pinned)
- cxn_pinned = -1;
-
- list_del_init(&ctx->id_link);
- clear_bit(ctx->id, cxn_bitmap);
- __flush_tlb_mm(ctx->id);
- ctx->id = 0;
- }
-
- spin_unlock(&cxn_owners_lock);
-} /* end destroy_context() */
-
-/*****************************************************************************/
-/*
- * display the MMU context currently a process is currently using
- */
-#ifdef CONFIG_PROC_FS
-char *proc_pid_status_frv_cxnr(struct mm_struct *mm, char *buffer)
-{
- spin_lock(&cxn_owners_lock);
- buffer += sprintf(buffer, "CXNR: %u\n", mm->context.id);
- spin_unlock(&cxn_owners_lock);
-
- return buffer;
-} /* end proc_pid_status_frv_cxnr() */
-#endif
-
-/*****************************************************************************/
-/*
- * (un)pin a process's mm_struct's MMU context ID
- */
-int cxn_pin_by_pid(pid_t pid)
-{
- struct task_struct *tsk;
- struct mm_struct *mm = NULL;
- int ret;
-
- /* unpin if pid is zero */
- if (pid == 0) {
- cxn_pinned = -1;
- return 0;
- }
-
- ret = -ESRCH;
-
- /* get a handle on the mm_struct */
- read_lock(&tasklist_lock);
- tsk = find_task_by_vpid(pid);
- if (tsk) {
- ret = -EINVAL;
-
- task_lock(tsk);
- if (tsk->mm) {
- mm = tsk->mm;
- mmget(mm);
- ret = 0;
- }
- task_unlock(tsk);
- }
- read_unlock(&tasklist_lock);
-
- if (ret < 0)
- return ret;
-
- /* make sure it has a CXN and pin it */
- spin_lock(&cxn_owners_lock);
- cxn_pinned = get_cxn(&mm->context);
- spin_unlock(&cxn_owners_lock);
-
- mmput(mm);
- return 0;
-} /* end cxn_pin_by_pid() */
git.samba.org / sfrench / cifs-2.6.git / blobdiff