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author | Michael Ellerman <mpe@ellerman.id.au> | 2014-07-10 12:29:19 +1000 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-07-28 14:10:22 +1000 |
commit | 376af5947c0e441ccbf98f0212d4ffbf171528f6 (patch) | |
tree | 8d80f48caea9448257de40a2a9c7279cc80e60b0 /arch/powerpc/mm/stab.c | |
parent | 468a33028edd62549ad3c4dcbc23dd0311c67832 (diff) | |
download | op-kernel-dev-376af5947c0e441ccbf98f0212d4ffbf171528f6.zip op-kernel-dev-376af5947c0e441ccbf98f0212d4ffbf171528f6.tar.gz |
powerpc: Remove STAB code
Old cpus didn't have a Segment Lookaside Buffer (SLB), instead they had
a Segment Table (STAB). Now that we've dropped support for those cpus,
we can remove the STAB support entirely.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/mm/stab.c')
-rw-r--r-- | arch/powerpc/mm/stab.c | 286 |
1 files changed, 0 insertions, 286 deletions
diff --git a/arch/powerpc/mm/stab.c b/arch/powerpc/mm/stab.c deleted file mode 100644 index 3f8efa6..0000000 --- a/arch/powerpc/mm/stab.c +++ /dev/null @@ -1,286 +0,0 @@ -/* - * 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/memblock.h> - -#include <asm/pgtable.h> -#include <asm/mmu.h> -#include <asm/mmu_context.h> -#include <asm/paca.h> -#include <asm/cputable.h> -#include <asm/prom.h> - -struct stab_entry { - unsigned long esid_data; - unsigned long vsid_data; -}; - -#define NR_STAB_CACHE_ENTRIES 8 -static DEFINE_PER_CPU(long, stab_cache_ptr); -static DEFINE_PER_CPU(long [NR_STAB_CACHE_ENTRIES], stab_cache); - -/* - * 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) >= PAGE_OFFSET; - - 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; - eieio(); - 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) != PAGE_OFFSET) - 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; - eieio(); /* 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 (is_kernel_addr(ea)) { - vsid = get_kernel_vsid(ea, MMU_SEGSIZE_256M); - } else { - if ((ea >= TASK_SIZE_USER64) || (! mm)) - return 1; - - vsid = get_vsid(mm->context.id, ea, MMU_SEGSIZE_256M); - } - - stab_entry = make_ste(get_paca()->stab_addr, GET_ESID(ea), vsid); - - if (!is_kernel_addr(ea)) { - 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; - 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"); - - /* - * We need interrupts hard-disabled here, not just soft-disabled, - * so that a PMU interrupt can't occur, which might try to access - * user memory (to get a stack trace) and possible cause an STAB miss - * which would update the stab_cache/stab_cache_ptr per-cpu variables. - */ - hard_irq_disable(); - - offset = __get_cpu_var(stab_cache_ptr); - 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 < (HW_PAGE_SIZE / sizeof(struct stab_entry)); - entry++, ste++) { - unsigned long ea; - ea = ste->esid_data & ESID_MASK; - if (!is_kernel_addr(ea)) { - 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"); -} - -/* - * Allocate segment tables for secondary CPUs. These must all go in - * the first (bolted) segment, so that do_stab_bolted won't get a - * recursive segment miss on the segment table itself. - */ -void __init stabs_alloc(void) -{ - int cpu; - - if (mmu_has_feature(MMU_FTR_SLB)) - return; - - for_each_possible_cpu(cpu) { - unsigned long newstab; - - if (cpu == 0) - continue; /* stab for CPU 0 is statically allocated */ - - newstab = memblock_alloc_base(HW_PAGE_SIZE, HW_PAGE_SIZE, - 1<<SID_SHIFT); - newstab = (unsigned long)__va(newstab); - - memset((void *)newstab, 0, HW_PAGE_SIZE); - - paca[cpu].stab_addr = newstab; - paca[cpu].stab_real = __pa(newstab); - printk(KERN_INFO "Segment table for CPU %d at 0x%llx " - "virtual, 0x%llx absolute\n", - cpu, paca[cpu].stab_addr, paca[cpu].stab_real); - } -} - -/* - * 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(PAGE_OFFSET, MMU_SEGSIZE_256M); - unsigned long stabreal; - - asm volatile("isync; slbia; isync":::"memory"); - make_ste(stab, GET_ESID(PAGE_OFFSET), vsid); - - /* Order update */ - asm volatile("sync":::"memory"); - - /* Set ASR */ - stabreal = get_paca()->stab_real | 0x1ul; - - mtspr(SPRN_ASR, stabreal); -} |