diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/include/asm/mmu_context.h | 260 | ||||
| -rw-r--r-- | arch/powerpc/kernel/asm-offsets.c | 1 | ||||
| -rw-r--r-- | arch/powerpc/kernel/head_32.S | 12 | ||||
| -rw-r--r-- | arch/powerpc/kernel/ppc_ksyms.c | 3 | ||||
| -rw-r--r-- | arch/powerpc/kernel/swsusp.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/mm/Makefile | 7 | ||||
| -rw-r--r-- | arch/powerpc/mm/mmu_context_32.c | 84 | ||||
| -rw-r--r-- | arch/powerpc/mm/mmu_context_hash32.c | 103 | ||||
| -rw-r--r-- | arch/powerpc/mm/mmu_context_hash64.c (renamed from arch/powerpc/mm/mmu_context_64.c) | 8 | ||||
| -rw-r--r-- | arch/powerpc/mm/mmu_context_nohash.c | 162 | ||||
| -rw-r--r-- | arch/powerpc/platforms/Kconfig.cputype | 10 | ||||
| -rw-r--r-- | arch/powerpc/platforms/powermac/cpufreq_32.c | 2 |
12 files changed, 335 insertions, 319 deletions
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index b570209..ab4f192 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -2,240 +2,26 @@ #define __ASM_POWERPC_MMU_CONTEXT_H #ifdef __KERNEL__ +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/spinlock.h> #include <asm/mmu.h> #include <asm/cputable.h> #include <asm-generic/mm_hooks.h> - -#ifndef CONFIG_PPC64 -#include <asm/atomic.h> -#include <linux/bitops.h> - -/* - * On 32-bit PowerPC 6xx/7xx/7xxx CPUs, we use a set of 16 VSIDs - * (virtual segment identifiers) for each context. Although the - * hardware supports 24-bit VSIDs, and thus >1 million contexts, - * we only use 32,768 of them. That is ample, since there can be - * at most around 30,000 tasks in the system anyway, and it means - * that we can use a bitmap to indicate which contexts are in use. - * Using a bitmap means that we entirely avoid all of the problems - * that we used to have when the context number overflowed, - * particularly on SMP systems. - * -- paulus. - */ - -/* - * 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. Note, if this - * function is changed then arch/ppc/mm/hashtable.S will have to be - * changed to correspond. - */ -#define CTX_TO_VSID(ctx, va) (((ctx) * (897 * 16) + ((va) >> 28) * 0x111) \ - & 0xffffff) - -/* - The MPC8xx has only 16 contexts. We rotate through them on each - task switch. A better way would be to keep track of tasks that - own contexts, and implement an LRU usage. That way very active - tasks don't always have to pay the TLB reload overhead. The - kernel pages are mapped shared, so the kernel can run on behalf - of any task that makes a kernel entry. Shared does not mean they - are not protected, just that the ASID comparison is not performed. - -- Dan - - The IBM4xx 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. - -- Dan - */ - -static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) -{ -} - -#ifdef CONFIG_8xx -#define NO_CONTEXT 16 -#define LAST_CONTEXT 15 -#define FIRST_CONTEXT 0 - -#elif defined(CONFIG_4xx) -#define NO_CONTEXT 256 -#define LAST_CONTEXT 255 -#define FIRST_CONTEXT 1 - -#elif defined(CONFIG_E200) || defined(CONFIG_E500) -#define NO_CONTEXT 256 -#define LAST_CONTEXT 255 -#define FIRST_CONTEXT 1 - -#else - -/* PPC 6xx, 7xx CPUs */ -#define NO_CONTEXT ((unsigned long) -1) -#define LAST_CONTEXT 32767 -#define FIRST_CONTEXT 1 -#endif - -/* - * Set the current MMU context. - * On 32-bit PowerPCs (other than the 8xx embedded chips), this is done by - * loading 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(unsigned long contextid, 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 unsigned long next_mmu_context; - -/* - * If 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. - */ -#if LAST_CONTEXT < 30000 -#define FEW_CONTEXTS 1 -extern atomic_t nr_free_contexts; -extern struct mm_struct *context_mm[LAST_CONTEXT+1]; -extern void steal_context(void); -#endif - -/* - * Get a new mmu context for the address space described by `mm'. - */ -static inline void get_mmu_context(struct mm_struct *mm) -{ - unsigned long ctx; - - if (mm->context.id != NO_CONTEXT) - return; -#ifdef FEW_CONTEXTS - while (atomic_dec_if_positive(&nr_free_contexts) < 0) - steal_context(); -#endif - 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.id = ctx; -#ifdef FEW_CONTEXTS - context_mm[ctx] = mm; -#endif -} +#include <asm/cputhreads.h> /* - * Set up the context for a new address space. + * Most if the context management is out of line */ -static inline int init_new_context(struct task_struct *t, struct mm_struct *mm) -{ - mm->context.id = NO_CONTEXT; - return 0; -} - -/* - * We're finished using the context for an address space. - */ -static inline void destroy_context(struct mm_struct *mm) -{ - preempt_disable(); - if (mm->context.id != NO_CONTEXT) { - clear_bit(mm->context.id, context_map); - mm->context.id = NO_CONTEXT; -#ifdef FEW_CONTEXTS - atomic_inc(&nr_free_contexts); -#endif - } - preempt_enable(); -} - -static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, - struct task_struct *tsk) -{ -#ifdef CONFIG_ALTIVEC - if (cpu_has_feature(CPU_FTR_ALTIVEC)) - asm volatile ("dssall;\n" -#ifndef CONFIG_POWER4 - "sync;\n" /* G4 needs a sync here, G5 apparently not */ -#endif - : : ); -#endif /* CONFIG_ALTIVEC */ - - tsk->thread.pgdir = next->pgd; - - if (!cpu_isset(smp_processor_id(), next->cpu_vm_mask)) - cpu_set(smp_processor_id(), next->cpu_vm_mask); - - /* No need to flush userspace segments if the mm doesnt change */ - if (prev == next) - return; - - /* Setup new userspace context */ - get_mmu_context(next); - set_context(next->context.id, next->pgd); -} - -#define deactivate_mm(tsk,mm) do { } while (0) - -/* - * After we have set current->mm to a new value, this activates - * the context for the new mm so we see the new mappings. - */ -#define activate_mm(active_mm, mm) switch_mm(active_mm, mm, current) - extern void mmu_context_init(void); - - -#else - -#include <linux/kernel.h> -#include <linux/mm.h> -#include <linux/sched.h> - -/* - * Copyright (C) 2001 PPC 64 Team, IBM Corp - * - * 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. - */ - -static inline void enter_lazy_tlb(struct mm_struct *mm, - struct task_struct *tsk) -{ -} - -/* - * The proto-VSID space has 2^35 - 1 segments available for user mappings. - * Each segment contains 2^28 bytes. Each context maps 2^44 bytes, - * so we can support 2^19-1 contexts (19 == 35 + 28 - 44). - */ -#define NO_CONTEXT 0 -#define MAX_CONTEXT ((1UL << 19) - 1) - extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm); extern void destroy_context(struct mm_struct *mm); +extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next); extern void switch_stab(struct task_struct *tsk, struct mm_struct *mm); extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm); +extern void set_context(unsigned long id, pgd_t *pgd); /* * switch_mm is the entry point called from the architecture independent @@ -244,22 +30,39 @@ extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm); static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) { - if (!cpu_isset(smp_processor_id(), next->cpu_vm_mask)) - cpu_set(smp_processor_id(), next->cpu_vm_mask); + /* Mark this context has been used on the new CPU */ + cpu_set(smp_processor_id(), next->cpu_vm_mask); + + /* 32-bit keeps track of the current PGDIR in the thread struct */ +#ifdef CONFIG_PPC32 + tsk->thread.pgdir = next->pgd; +#endif /* CONFIG_PPC32 */ - /* No need to flush userspace segments if the mm doesnt change */ + /* Nothing else to do if we aren't actually switching */ if (prev == next) return; + /* We must stop all altivec streams before changing the HW + * context + */ #ifdef CONFIG_ALTIVEC if (cpu_has_feature(CPU_FTR_ALTIVEC)) asm volatile ("dssall"); #endif /* CONFIG_ALTIVEC */ + /* The actual HW switching method differs between the various + * sub architectures. + */ +#ifdef CONFIG_PPC_STD_MMU_64 if (cpu_has_feature(CPU_FTR_SLB)) switch_slb(tsk, next); else switch_stab(tsk, next); +#else + /* Out of line for now */ + switch_mmu_context(prev, next); +#endif + } #define deactivate_mm(tsk,mm) do { } while (0) @@ -277,6 +80,11 @@ static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next) local_irq_restore(flags); } -#endif /* CONFIG_PPC64 */ +/* We don't currently use enter_lazy_tlb() for anything */ +static inline void enter_lazy_tlb(struct mm_struct *mm, + struct task_struct *tsk) +{ +} + #endif /* __KERNEL__ */ #endif /* __ASM_POWERPC_MMU_CONTEXT_H */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 050abfd..c05ab1d 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -60,6 +60,7 @@ int main(void) { DEFINE(THREAD, offsetof(struct task_struct, thread)); DEFINE(MM, offsetof(struct task_struct, mm)); + DEFINE(MMCONTEXTID, offsetof(struct mm_struct, context.id)); #ifdef CONFIG_PPC64 DEFINE(AUDITCONTEXT, offsetof(struct task_struct, audit_context)); #else diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index 0c32682..be9f9e5 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -31,6 +31,7 @@ #include <asm/ppc_asm.h> #include <asm/asm-offsets.h> #include <asm/ptrace.h> +#include <asm/bug.h> /* 601 only have IBAT; cr0.eq is set on 601 when using this macro */ #define LOAD_BAT(n, reg, RA, RB) \ @@ -1070,9 +1071,14 @@ start_here: RFI /* + * void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next); + * * Set up the segment registers for a new context. */ -_ENTRY(set_context) +_ENTRY(switch_mmu_context) + lwz r3,MMCONTEXTID(r4) + cmpwi cr0,r3,0 + blt- 4f mulli r3,r3,897 /* multiply context by skew factor */ rlwinm r3,r3,4,8,27 /* VSID = (context & 0xfffff) << 4 */ addis r3,r3,0x6000 /* Set Ks, Ku bits */ @@ -1083,6 +1089,7 @@ _ENTRY(set_context) /* Context switch the PTE pointer for the Abatron BDI2000. * The PGDIR is passed as second argument. */ + lwz r4,MM_PGD(r4) lis r5, KERNELBASE@h lwz r5, 0xf0(r5) stw r4, 0x4(r5) @@ -1098,6 +1105,9 @@ _ENTRY(set_context) sync isync blr +4: trap + EMIT_BUG_ENTRY 4b,__FILE__,__LINE__,0 + blr /* * An undocumented "feature" of 604e requires that the v bit diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c index 260089d..341b3d3 100644 --- a/arch/powerpc/kernel/ppc_ksyms.c +++ b/arch/powerpc/kernel/ppc_ksyms.c @@ -174,8 +174,7 @@ EXPORT_SYMBOL(cacheable_memcpy); #endif #ifdef CONFIG_PPC32 -EXPORT_SYMBOL(next_mmu_context); -EXPORT_SYMBOL(set_context); +EXPORT_SYMBOL(switch_mmu_context); #endif #ifdef CONFIG_PPC_STD_MMU_32 diff --git a/arch/powerpc/kernel/swsusp.c b/arch/powerpc/kernel/swsusp.c index 77b7b34..560c961 100644 --- a/arch/powerpc/kernel/swsusp.c +++ b/arch/powerpc/kernel/swsusp.c @@ -34,6 +34,6 @@ void save_processor_state(void) void restore_processor_state(void) { #ifdef CONFIG_PPC32 - set_context(current->active_mm->context.id, current->active_mm->pgd); + switch_mmu_context(NULL, current->active_mm); #endif } diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile index 148de35..923bd3f 100644 --- a/arch/powerpc/mm/Makefile +++ b/arch/powerpc/mm/Makefile @@ -8,15 +8,16 @@ endif obj-y := fault.o mem.o pgtable.o \ init_$(CONFIG_WORD_SIZE).o \ - pgtable_$(CONFIG_WORD_SIZE).o \ - mmu_context_$(CONFIG_WORD_SIZE).o + pgtable_$(CONFIG_WORD_SIZE).o +obj-$(CONFIG_PPC_MMU_NOHASH) += mmu_context_nohash.o hash-$(CONFIG_PPC_NATIVE) := hash_native_64.o obj-$(CONFIG_PPC64) += hash_utils_64.o \ slb_low.o slb.o stab.o \ gup.o mmap.o $(hash-y) obj-$(CONFIG_PPC_STD_MMU_32) += ppc_mmu_32.o obj-$(CONFIG_PPC_STD_MMU) += hash_low_$(CONFIG_WORD_SIZE).o \ - tlb_hash$(CONFIG_WORD_SIZE).o + tlb_hash$(CONFIG_WORD_SIZE).o \ + mmu_context_hash$(CONFIG_WORD_SIZE).o obj-$(CONFIG_40x) += 40x_mmu.o obj-$(CONFIG_44x) += 44x_mmu.o obj-$(CONFIG_FSL_BOOKE) += fsl_booke_mmu.o diff --git a/arch/powerpc/mm/mmu_context_32.c b/arch/powerpc/mm/mmu_context_32.c deleted file mode 100644 index cc32ba4..0000000 --- a/arch/powerpc/mm/mmu_context_32.c +++ /dev/null @@ -1,84 +0,0 @@ -/* - * This file contains the routines for handling the MMU on those - * PowerPC implementations where the MMU substantially follows the - * architecture specification. This includes the 6xx, 7xx, 7xxx, - * 8260, and POWER3 implementations but excludes the 8xx and 4xx. - * -- 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 - * - * 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/mmu_context.h> -#include <asm/tlbflush.h> - -unsigned long next_mmu_context; -unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; -#ifdef FEW_CONTEXTS -atomic_t nr_free_contexts; -struct mm_struct *context_mm[LAST_CONTEXT+1]; -void steal_context(void); -#endif /* FEW_CONTEXTS */ - -/* - * Initialize the context management stuff. - */ -void __init -mmu_context_init(void) -{ - /* - * Some processors have too few contexts to reserve one for - * init_mm, and require using context 0 for a normal task. - * Other processors reserve the use of context zero for the kernel. - * This code assumes FIRST_CONTEXT < 32. - */ - context_map[0] = (1 << FIRST_CONTEXT) - 1; - next_mmu_context = FIRST_CONTEXT; -#ifdef FEW_CONTEXTS - atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1); -#endif /* FEW_CONTEXTS */ -} - -#ifdef FEW_CONTEXTS -/* - * Steal a context from a task that has one at the moment. - * This is only used on 8xx and 4xx and we presently assume that - * they don't do SMP. If they do then this will have to check - * whether the MM we steal is in use. - * We also assume that this is only used on systems that don't - * use an MMU hash table - this is true for 8xx and 4xx. - * 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 was motivated to do it. - * -- paulus - */ -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); -} -#endif /* FEW_CONTEXTS */ diff --git a/arch/powerpc/mm/mmu_context_hash32.c b/arch/powerpc/mm/mmu_context_hash32.c new file mode 100644 index 0000000..0dfba2b --- /dev/null +++ b/arch/powerpc/mm/mmu_context_hash32.c @@ -0,0 +1,103 @@ +/* + * This file contains the routines for handling the MMU on those + * PowerPC implementations where the MMU substantially follows the + * architecture specification. This includes the 6xx, 7xx, 7xxx, + * 8260, and POWER3 implementations but excludes the 8xx and 4xx. + * -- 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 + * + * 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/mmu_context.h> +#include <asm/tlbflush.h> + +/* + * On 32-bit PowerPC 6xx/7xx/7xxx CPUs, we use a set of 16 VSIDs + * (virtual segment identifiers) for each context. Although the + * hardware supports 24-bit VSIDs, and thus >1 million contexts, + * we only use 32,768 of them. That is ample, since there can be + * at most around 30,000 tasks in the system anyway, and it means + * that we can use a bitmap to indicate which contexts are in use. + * Using a bitmap means that we entirely avoid all of the problems + * that we used to have when the context number overflowed, + * particularly on SMP systems. + * -- paulus. + */ +#define NO_CONTEXT ((unsigned long) -1) +#define LAST_CONTEXT 32767 +#define FIRST_CONTEXT 1 + +/* + * 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. Note, if this + * function is changed then arch/ppc/mm/hashtable.S will have to be + * changed to correspond. + * + * + * CTX_TO_VSID(ctx, va) (((ctx) * (897 * 16) + ((va) >> 28) * 0x111) \ + * & 0xffffff) + */ + +static unsigned long next_mmu_context; +static unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; + + +/* + * Set up the context for a new address space. + */ +int init_new_context(struct task_struct *t, struct mm_struct *mm) +{ + unsigned long 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.id = ctx; + + return 0; +} + +/* + * We're finished using the context for an address space. + */ +void destroy_context(struct mm_struct *mm) +{ + preempt_disable(); + if (mm->context.id != NO_CONTEXT) { + clear_bit(mm->context.id, context_map); + mm->context.id = NO_CONTEXT; + } + preempt_enable(); +} + +/* + * Initialize the context management stuff. + */ +void __init mmu_context_init(void) +{ + /* Reserve context 0 for kernel use */ + context_map[0] = (1 << FIRST_CONTEXT) - 1; + next_mmu_context = FIRST_CONTEXT; +} diff --git a/arch/powerpc/mm/mmu_context_64.c b/arch/powerpc/mm/mmu_context_hash64.c index 1db38ba..dbeb86a 100644 --- a/arch/powerpc/mm/mmu_context_64.c +++ b/arch/powerpc/mm/mmu_context_hash64.c @@ -24,6 +24,14 @@ static DEFINE_SPINLOCK(mmu_context_lock); static DEFINE_IDR(mmu_context_idr); +/* + * The proto-VSID space has 2^35 - 1 segments available for user mappings. + * Each segment contains 2^28 bytes. Each context maps 2^44 bytes, + * so we can support 2^19-1 contexts (19 == 35 + 28 - 44). + */ +#define NO_CONTEXT 0 +#define MAX_CONTEXT ((1UL << 19) - 1) + int init_new_context(struct task_struct *tsk, struct mm_struct *mm) { int index; diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c new file mode 100644 index 0000000..00e0215 --- /dev/null +++ b/arch/powerpc/mm/mmu_context_nohash.c @@ -0,0 +1,162 @@ +/* + * This file contains the routines for handling the MMU on those + * PowerPC implementations where the MMU is not using the hash + * table, such as 8xx, 4xx, BookE's etc... + * + * Copyright 2008 Ben Herrenschmidt <benh@kernel.crashing.org> + * IBM Corp. + * + * Derived from previous arch/powerpc/mm/mmu_context.c + * and arch/powerpc/include/asm/mmu_context.h + * + * 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/mmu_context.h> +#include <asm/tlbflush.h> + +/* + * The MPC8xx has only 16 contexts. We rotate through them on each + * task switch. A better way would be to keep track of tasks that + * own contexts, and implement an LRU usage. That way very active + * tasks don't always have to pay the TLB reload overhead. The + * kernel pages are mapped shared, so the kernel can run on behalf + * of any task that makes a kernel entry. Shared does not mean they + * are not protected, just that the ASID comparison is not performed. + * -- Dan + * + * The IBM4xx 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. + * -- Dan + */ + +#ifdef CONFIG_8xx +#define NO_CONTEXT 16 +#define LAST_CONTEXT 15 +#define FIRST_CONTEXT 0 + +#elif defined(CONFIG_4xx) +#define NO_CONTEXT 256 +#define LAST_CONTEXT 255 +#define FIRST_CONTEXT 1 + +#elif defined(CONFIG_E200) || defined(CONFIG_E500) +#define NO_CONTEXT 256 +#define LAST_CONTEXT 255 +#define FIRST_CONTEXT 1 + +#else +#error Unsupported processor type +#endif + +static unsigned long next_mmu_context; +static unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; +static atomic_t nr_free_contexts; +static struct mm_struct *context_mm[LAST_CONTEXT+1]; +static void steal_context(void); + +/* Steal a context from a task that has one at the moment. + * This is only used on 8xx and 4xx and we presently assume that + * they don't do SMP. If they do then this will have to check + * whether the MM we steal is in use. + * We also assume that this is only used on systems that don't + * use an MMU hash table - this is true for 8xx and 4xx. + * 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 was motivated to do it. + * -- paulus + */ +static 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); +} + + +/* + * Get a new mmu context for the address space described by `mm'. + */ +static inline void get_mmu_context(struct mm_struct *mm) +{ + unsigned long ctx; + + if (mm->context.id != 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.id = ctx; + context_mm[ctx] = mm; +} + +void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next) +{ + get_mmu_context(next); + + set_context(next->context.id, next->pgd); +} + +/* + * Set up the context for a new address space. + */ +int init_new_context(struct task_struct *t, struct mm_struct *mm) +{ + mm->context.id = NO_CONTEXT; + return 0; +} + +/* + * We're finished using the context for an address space. + */ +void destroy_context(struct mm_struct *mm) +{ + preempt_disable(); + if (mm->context.id != NO_CONTEXT) { + clear_bit(mm->context.id, context_map); + mm->context.id = NO_CONTEXT; + atomic_inc(&nr_free_contexts); + } + preempt_enable(); +} + + +/* + * Initialize the context management stuff. + */ +void __init mmu_context_init(void) +{ + /* + * Some processors have too few contexts to reserve one for + * init_mm, and require using context 0 for a normal task. + * Other processors reserve the use of context zero 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); +} + diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 548efa5..db61daf 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -195,13 +195,21 @@ config SPE config PPC_STD_MMU bool - depends on 6xx || POWER3 || POWER4 || PPC64 + depends on 6xx || PPC64 default y config PPC_STD_MMU_32 def_bool y depends on PPC_STD_MMU && PPC32 +config PPC_STD_MMU_64 + def_bool y + depends on PPC_STD_MMU && PPC64 + +config PPC_MMU_NOHASH + def_bool y + depends on !PPC_STD_MMU + config PPC_MM_SLICES bool default y if HUGETLB_PAGE || PPC_64K_PAGES diff --git a/arch/powerpc/platforms/powermac/cpufreq_32.c b/arch/powerpc/platforms/powermac/cpufreq_32.c index 792d3ce..65c585b 100644 --- a/arch/powerpc/platforms/powermac/cpufreq_32.c +++ b/arch/powerpc/platforms/powermac/cpufreq_32.c @@ -310,7 +310,7 @@ static int pmu_set_cpu_speed(int low_speed) _set_L3CR(save_l3cr); /* Restore userland MMU context */ - set_context(current->active_mm->context.id, current->active_mm->pgd); + switch_mmu_context(NULL, current->active_mm); #ifdef DEBUG_FREQ printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1)); |
