diff options
| -rw-r--r-- | arch/microblaze/include/asm/mmu_context.h | 26 | ||||
| -rw-r--r-- | arch/microblaze/include/asm/mmu_context_mm.h | 140 | ||||
| -rw-r--r-- | arch/microblaze/include/asm/mmu_context_no.h | 23 | ||||
| -rw-r--r-- | arch/microblaze/mm/mmu_context.c | 70 |
4 files changed, 238 insertions, 21 deletions
diff --git a/arch/microblaze/include/asm/mmu_context.h b/arch/microblaze/include/asm/mmu_context.h index 150ca01b74b..385fed16bbf 100644 --- a/arch/microblaze/include/asm/mmu_context.h +++ b/arch/microblaze/include/asm/mmu_context.h @@ -1,21 +1,5 @@ -/* - * 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 */ +#ifdef CONFIG_MMU +# include "mmu_context_mm.h" +#else +# include "mmu_context_no.h" +#endif diff --git a/arch/microblaze/include/asm/mmu_context_mm.h b/arch/microblaze/include/asm/mmu_context_mm.h new file mode 100644 index 00000000000..3e5c254e8d1 --- /dev/null +++ b/arch/microblaze/include/asm/mmu_context_mm.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 */ diff --git a/arch/microblaze/include/asm/mmu_context_no.h b/arch/microblaze/include/asm/mmu_context_no.h new file mode 100644 index 00000000000..ba556719015 --- /dev/null +++ b/arch/microblaze/include/asm/mmu_context_no.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 */ diff --git a/arch/microblaze/mm/mmu_context.c b/arch/microblaze/mm/mmu_context.c new file mode 100644 index 00000000000..26ff82f4fa8 --- /dev/null +++ b/arch/microblaze/mm/mmu_context.c @@ -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); +} |