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Diffstat (limited to 'include/asm-ppc/mmu_context.h')
| -rw-r--r-- | include/asm-ppc/mmu_context.h | 198 |
1 files changed, 0 insertions, 198 deletions
diff --git a/include/asm-ppc/mmu_context.h b/include/asm-ppc/mmu_context.h deleted file mode 100644 index 9f097e25b169..000000000000 --- a/include/asm-ppc/mmu_context.h +++ /dev/null @@ -1,198 +0,0 @@ -#ifdef __KERNEL__ -#ifndef __PPC_MMU_CONTEXT_H -#define __PPC_MMU_CONTEXT_H - -#include <linux/bitops.h> - -#include <asm/atomic.h> -#include <asm/mmu.h> -#include <asm/cputable.h> -#include <asm-generic/mm_hooks.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 - -#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 -} - -/* - * Set up the context for a new address space. - */ -static inline int init_new_context(struct task_struct *t, struct mm_struct *mm) -{ - mm->context.id = NO_CONTEXT; - mm->context.vdso_base = 0; - 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; - - /* 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); - -#endif /* __PPC_MMU_CONTEXT_H */ -#endif /* __KERNEL__ */ |