/* * MMU context allocation for 64-bit kernels. * * Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.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. * */ #include <linux/sched.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/string.h> #include <linux/types.h> #include <linux/mm.h> #include <linux/spinlock.h> #include <linux/idr.h> #include <asm/mmu_context.h> static DEFINE_SPINLOCK(mmu_context_lock); static DEFINE_IDR(mmu_context_idr); int init_new_context(struct task_struct *tsk, struct mm_struct *mm) { int index; int err; again: if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL)) return -ENOMEM; spin_lock(&mmu_context_lock); err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index); spin_unlock(&mmu_context_lock); if (err == -EAGAIN) goto again; else if (err) return err; if (index > MAX_CONTEXT) { spin_lock(&mmu_context_lock); idr_remove(&mmu_context_idr, index); spin_unlock(&mmu_context_lock); return -ENOMEM; } /* The old code would re-promote on fork, we don't do that * when using slices as it could cause problem promoting slices * that have been forced down to 4K */ if (slice_mm_new_context(mm)) slice_set_user_psize(mm, mmu_virtual_psize); mm->context.id = index; return 0; } void destroy_context(struct mm_struct *mm) { spin_lock(&mmu_context_lock); idr_remove(&mmu_context_idr, mm->context.id); spin_unlock(&mmu_context_lock); mm->context.id = NO_CONTEXT; }