diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/ppc64/mm/stab.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/ppc64/mm/stab.c')
-rw-r--r-- | arch/ppc64/mm/stab.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/arch/ppc64/mm/stab.c b/arch/ppc64/mm/stab.c new file mode 100644 index 00000000000..31491131d5e --- /dev/null +++ b/arch/ppc64/mm/stab.c @@ -0,0 +1,239 @@ +/* + * PowerPC64 Segment Translation Support. + * + * Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com + * Copyright (c) 2001 Dave Engebretsen + * + * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM + * + * 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/config.h> +#include <asm/pgtable.h> +#include <asm/mmu.h> +#include <asm/mmu_context.h> +#include <asm/paca.h> +#include <asm/cputable.h> + +/* Both the segment table and SLB code uses the following cache */ +#define NR_STAB_CACHE_ENTRIES 8 +DEFINE_PER_CPU(long, stab_cache_ptr); +DEFINE_PER_CPU(long, stab_cache[NR_STAB_CACHE_ENTRIES]); + +/* + * Create a segment table entry for the given esid/vsid pair. + */ +static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid) +{ + unsigned long esid_data, vsid_data; + unsigned long entry, group, old_esid, castout_entry, i; + unsigned int global_entry; + struct stab_entry *ste, *castout_ste; + unsigned long kernel_segment = (esid << SID_SHIFT) >= KERNELBASE; + + vsid_data = vsid << STE_VSID_SHIFT; + esid_data = esid << SID_SHIFT | STE_ESID_KP | STE_ESID_V; + if (! kernel_segment) + esid_data |= STE_ESID_KS; + + /* Search the primary group first. */ + global_entry = (esid & 0x1f) << 3; + ste = (struct stab_entry *)(stab | ((esid & 0x1f) << 7)); + + /* Find an empty entry, if one exists. */ + for (group = 0; group < 2; group++) { + for (entry = 0; entry < 8; entry++, ste++) { + if (!(ste->esid_data & STE_ESID_V)) { + ste->vsid_data = vsid_data; + asm volatile("eieio":::"memory"); + ste->esid_data = esid_data; + return (global_entry | entry); + } + } + /* Now search the secondary group. */ + global_entry = ((~esid) & 0x1f) << 3; + ste = (struct stab_entry *)(stab | (((~esid) & 0x1f) << 7)); + } + + /* + * Could not find empty entry, pick one with a round robin selection. + * Search all entries in the two groups. + */ + castout_entry = get_paca()->stab_rr; + for (i = 0; i < 16; i++) { + if (castout_entry < 8) { + global_entry = (esid & 0x1f) << 3; + ste = (struct stab_entry *)(stab | ((esid & 0x1f) << 7)); + castout_ste = ste + castout_entry; + } else { + global_entry = ((~esid) & 0x1f) << 3; + ste = (struct stab_entry *)(stab | (((~esid) & 0x1f) << 7)); + castout_ste = ste + (castout_entry - 8); + } + + /* Dont cast out the first kernel segment */ + if ((castout_ste->esid_data & ESID_MASK) != KERNELBASE) + break; + + castout_entry = (castout_entry + 1) & 0xf; + } + + get_paca()->stab_rr = (castout_entry + 1) & 0xf; + + /* Modify the old entry to the new value. */ + + /* Force previous translations to complete. DRENG */ + asm volatile("isync" : : : "memory"); + + old_esid = castout_ste->esid_data >> SID_SHIFT; + castout_ste->esid_data = 0; /* Invalidate old entry */ + + asm volatile("sync" : : : "memory"); /* Order update */ + + castout_ste->vsid_data = vsid_data; + asm volatile("eieio" : : : "memory"); /* Order update */ + castout_ste->esid_data = esid_data; + + asm volatile("slbie %0" : : "r" (old_esid << SID_SHIFT)); + /* Ensure completion of slbie */ + asm volatile("sync" : : : "memory"); + + return (global_entry | (castout_entry & 0x7)); +} + +/* + * Allocate a segment table entry for the given ea and mm + */ +static int __ste_allocate(unsigned long ea, struct mm_struct *mm) +{ + unsigned long vsid; + unsigned char stab_entry; + unsigned long offset; + + /* Kernel or user address? */ + if (ea >= KERNELBASE) { + vsid = get_kernel_vsid(ea); + } else { + if ((ea >= TASK_SIZE_USER64) || (! mm)) + return 1; + + vsid = get_vsid(mm->context.id, ea); + } + + stab_entry = make_ste(get_paca()->stab_addr, GET_ESID(ea), vsid); + + if (ea < KERNELBASE) { + offset = __get_cpu_var(stab_cache_ptr); + if (offset < NR_STAB_CACHE_ENTRIES) + __get_cpu_var(stab_cache[offset++]) = stab_entry; + else + offset = NR_STAB_CACHE_ENTRIES+1; + __get_cpu_var(stab_cache_ptr) = offset; + + /* Order update */ + asm volatile("sync":::"memory"); + } + + return 0; +} + +int ste_allocate(unsigned long ea) +{ + return __ste_allocate(ea, current->mm); +} + +/* + * Do the segment table work for a context switch: flush all user + * entries from the table, then preload some probably useful entries + * for the new task + */ +void switch_stab(struct task_struct *tsk, struct mm_struct *mm) +{ + struct stab_entry *stab = (struct stab_entry *) get_paca()->stab_addr; + struct stab_entry *ste; + unsigned long offset = __get_cpu_var(stab_cache_ptr); + unsigned long pc = KSTK_EIP(tsk); + unsigned long stack = KSTK_ESP(tsk); + unsigned long unmapped_base; + + /* Force previous translations to complete. DRENG */ + asm volatile("isync" : : : "memory"); + + if (offset <= NR_STAB_CACHE_ENTRIES) { + int i; + + for (i = 0; i < offset; i++) { + ste = stab + __get_cpu_var(stab_cache[i]); + ste->esid_data = 0; /* invalidate entry */ + } + } else { + unsigned long entry; + + /* Invalidate all entries. */ + ste = stab; + + /* Never flush the first entry. */ + ste += 1; + for (entry = 1; + entry < (PAGE_SIZE / sizeof(struct stab_entry)); + entry++, ste++) { + unsigned long ea; + ea = ste->esid_data & ESID_MASK; + if (ea < KERNELBASE) { + ste->esid_data = 0; + } + } + } + + asm volatile("sync; slbia; sync":::"memory"); + + __get_cpu_var(stab_cache_ptr) = 0; + + /* Now preload some entries for the new task */ + if (test_tsk_thread_flag(tsk, TIF_32BIT)) + unmapped_base = TASK_UNMAPPED_BASE_USER32; + else + unmapped_base = TASK_UNMAPPED_BASE_USER64; + + __ste_allocate(pc, mm); + + if (GET_ESID(pc) == GET_ESID(stack)) + return; + + __ste_allocate(stack, mm); + + if ((GET_ESID(pc) == GET_ESID(unmapped_base)) + || (GET_ESID(stack) == GET_ESID(unmapped_base))) + return; + + __ste_allocate(unmapped_base, mm); + + /* Order update */ + asm volatile("sync" : : : "memory"); +} + +extern void slb_initialize(void); + +/* + * Build an entry for the base kernel segment and put it into + * the segment table or SLB. All other segment table or SLB + * entries are faulted in. + */ +void stab_initialize(unsigned long stab) +{ + unsigned long vsid = get_kernel_vsid(KERNELBASE); + + if (cpu_has_feature(CPU_FTR_SLB)) { + slb_initialize(); + } else { + asm volatile("isync; slbia; isync":::"memory"); + make_ste(stab, GET_ESID(KERNELBASE), vsid); + + /* Order update */ + asm volatile("sync":::"memory"); + } +} |