forked from Minki/linux
b13d618b44
This and the following patches aim to optimize the code dealing with
page tables and TLB operations. Each patch reduces the time it takes
to gzip a 16 MB file slightly, but I expect things like fork() and
mmap() will improve somewhat more.
This patch deals with the low-level TLB operations:
* Remove unused _TLBEHI_I define
* Use gcc builtins instead of inline assembly
* Remove a few unnecessary pipeline flushes and nops
* Introduce NR_TLB_ENTRIES define and use it instead of hardcoding it
to 32 a few places throughout the code.
* Use sysreg bitops instead of hardcoded shifts and masks
* Make a few needlessly global functions static
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
376 lines
8.3 KiB
C
376 lines
8.3 KiB
C
/*
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* AVR32 TLB operations
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*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/mm.h>
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#include <asm/mmu_context.h>
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/* TODO: Get the correct number from the CONFIG1 system register */
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#define NR_TLB_ENTRIES 32
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static void show_dtlb_entry(unsigned int index)
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{
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u32 tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
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unsigned long flags;
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local_irq_save(flags);
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mmucr_save = sysreg_read(MMUCR);
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tlbehi_save = sysreg_read(TLBEHI);
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mmucr = SYSREG_BFINS(DRP, index, mmucr_save);
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sysreg_write(MMUCR, mmucr);
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__builtin_tlbr();
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cpu_sync_pipeline();
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tlbehi = sysreg_read(TLBEHI);
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tlbelo = sysreg_read(TLBELO);
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printk("%2u: %c %c %02x %05x %05x %o %o %c %c %c %c\n",
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index,
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SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
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SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
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SYSREG_BFEXT(ASID, tlbehi),
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SYSREG_BFEXT(VPN, tlbehi) >> 2,
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SYSREG_BFEXT(PFN, tlbelo) >> 2,
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SYSREG_BFEXT(AP, tlbelo),
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SYSREG_BFEXT(SZ, tlbelo),
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SYSREG_BFEXT(TLBELO_C, tlbelo) ? 'C' : ' ',
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SYSREG_BFEXT(B, tlbelo) ? 'B' : ' ',
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SYSREG_BFEXT(W, tlbelo) ? 'W' : ' ',
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SYSREG_BFEXT(TLBELO_D, tlbelo) ? 'D' : ' ');
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sysreg_write(MMUCR, mmucr_save);
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sysreg_write(TLBEHI, tlbehi_save);
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cpu_sync_pipeline();
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local_irq_restore(flags);
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}
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void dump_dtlb(void)
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{
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unsigned int i;
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printk("ID V G ASID VPN PFN AP SZ C B W D\n");
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for (i = 0; i < NR_TLB_ENTRIES; i++)
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show_dtlb_entry(i);
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}
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static void update_dtlb(unsigned long address, pte_t pte)
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{
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u32 tlbehi;
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u32 mmucr;
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/*
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* We're not changing the ASID here, so no need to flush the
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* pipeline.
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*/
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tlbehi = sysreg_read(TLBEHI);
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tlbehi = SYSREG_BF(ASID, SYSREG_BFEXT(ASID, tlbehi));
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tlbehi |= address & MMU_VPN_MASK;
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tlbehi |= SYSREG_BIT(TLBEHI_V);
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sysreg_write(TLBEHI, tlbehi);
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/* Does this mapping already exist? */
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__builtin_tlbs();
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mmucr = sysreg_read(MMUCR);
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if (mmucr & SYSREG_BIT(MMUCR_N)) {
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/* Not found -- pick a not-recently-accessed entry */
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unsigned int rp;
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u32 tlbar = sysreg_read(TLBARLO);
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rp = 32 - fls(tlbar);
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if (rp == 32) {
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rp = 0;
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sysreg_write(TLBARLO, -1L);
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}
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mmucr = SYSREG_BFINS(DRP, rp, mmucr);
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sysreg_write(MMUCR, mmucr);
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}
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sysreg_write(TLBELO, pte_val(pte) & _PAGE_FLAGS_HARDWARE_MASK);
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/* Let's go */
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__builtin_tlbw();
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}
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void update_mmu_cache(struct vm_area_struct *vma,
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unsigned long address, pte_t pte)
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{
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unsigned long flags;
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/* ptrace may call this routine */
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if (vma && current->active_mm != vma->vm_mm)
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return;
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local_irq_save(flags);
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update_dtlb(address, pte);
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local_irq_restore(flags);
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}
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static void __flush_tlb_page(unsigned long asid, unsigned long page)
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{
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u32 mmucr, tlbehi;
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/*
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* Caller is responsible for masking out non-PFN bits in page
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* and changing the current ASID if necessary. This means that
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* we don't need to flush the pipeline after writing TLBEHI.
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*/
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tlbehi = page | asid;
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sysreg_write(TLBEHI, tlbehi);
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__builtin_tlbs();
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mmucr = sysreg_read(MMUCR);
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if (!(mmucr & SYSREG_BIT(MMUCR_N))) {
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unsigned int entry;
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u32 tlbarlo;
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/* Clear the "valid" bit */
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sysreg_write(TLBEHI, tlbehi);
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/* mark the entry as "not accessed" */
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entry = SYSREG_BFEXT(DRP, mmucr);
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tlbarlo = sysreg_read(TLBARLO);
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tlbarlo |= (0x80000000UL >> entry);
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sysreg_write(TLBARLO, tlbarlo);
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/* update the entry with valid bit clear */
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__builtin_tlbw();
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}
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}
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void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
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{
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if (vma->vm_mm && vma->vm_mm->context != NO_CONTEXT) {
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unsigned long flags, asid;
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unsigned long saved_asid = MMU_NO_ASID;
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asid = vma->vm_mm->context & MMU_CONTEXT_ASID_MASK;
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page &= PAGE_MASK;
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local_irq_save(flags);
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if (vma->vm_mm != current->mm) {
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saved_asid = get_asid();
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set_asid(asid);
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}
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__flush_tlb_page(asid, page);
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if (saved_asid != MMU_NO_ASID)
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set_asid(saved_asid);
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local_irq_restore(flags);
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}
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}
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void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
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unsigned long end)
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{
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struct mm_struct *mm = vma->vm_mm;
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if (mm->context != NO_CONTEXT) {
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unsigned long flags;
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int size;
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local_irq_save(flags);
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size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
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if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
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mm->context = NO_CONTEXT;
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if (mm == current->mm)
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activate_context(mm);
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} else {
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unsigned long asid;
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unsigned long saved_asid;
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asid = mm->context & MMU_CONTEXT_ASID_MASK;
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saved_asid = MMU_NO_ASID;
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start &= PAGE_MASK;
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end += (PAGE_SIZE - 1);
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end &= PAGE_MASK;
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if (mm != current->mm) {
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saved_asid = get_asid();
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set_asid(asid);
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}
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while (start < end) {
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__flush_tlb_page(asid, start);
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start += PAGE_SIZE;
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}
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if (saved_asid != MMU_NO_ASID)
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set_asid(saved_asid);
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}
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local_irq_restore(flags);
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}
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}
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/*
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* This function depends on the pages to be flushed having the G
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* (global) bit set in their pte. This is true for all
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* PAGE_KERNEL(_RO) pages.
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*/
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void flush_tlb_kernel_range(unsigned long start, unsigned long end)
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{
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unsigned long flags;
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int size;
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size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
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if (size > (MMU_DTLB_ENTRIES / 4)) { /* Too many entries to flush */
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flush_tlb_all();
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} else {
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unsigned long asid;
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local_irq_save(flags);
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asid = get_asid();
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start &= PAGE_MASK;
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end += (PAGE_SIZE - 1);
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end &= PAGE_MASK;
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while (start < end) {
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__flush_tlb_page(asid, start);
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start += PAGE_SIZE;
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}
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local_irq_restore(flags);
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}
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}
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void flush_tlb_mm(struct mm_struct *mm)
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{
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/* Invalidate all TLB entries of this process by getting a new ASID */
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if (mm->context != NO_CONTEXT) {
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unsigned long flags;
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local_irq_save(flags);
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mm->context = NO_CONTEXT;
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if (mm == current->mm)
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activate_context(mm);
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local_irq_restore(flags);
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}
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}
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void flush_tlb_all(void)
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{
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unsigned long flags;
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local_irq_save(flags);
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sysreg_write(MMUCR, sysreg_read(MMUCR) | SYSREG_BIT(MMUCR_I));
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local_irq_restore(flags);
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}
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#ifdef CONFIG_PROC_FS
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <linux/init.h>
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static void *tlb_start(struct seq_file *tlb, loff_t *pos)
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{
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static unsigned long tlb_index;
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if (*pos >= NR_TLB_ENTRIES)
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return NULL;
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tlb_index = 0;
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return &tlb_index;
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}
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static void *tlb_next(struct seq_file *tlb, void *v, loff_t *pos)
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{
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unsigned long *index = v;
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if (*index >= NR_TLB_ENTRIES - 1)
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return NULL;
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++*pos;
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++*index;
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return index;
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}
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static void tlb_stop(struct seq_file *tlb, void *v)
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{
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}
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static int tlb_show(struct seq_file *tlb, void *v)
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{
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unsigned int tlbehi, tlbehi_save, tlbelo, mmucr, mmucr_save;
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unsigned long flags;
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unsigned long *index = v;
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if (*index == 0)
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seq_puts(tlb, "ID V G ASID VPN PFN AP SZ C B W D\n");
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BUG_ON(*index >= NR_TLB_ENTRIES);
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local_irq_save(flags);
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mmucr_save = sysreg_read(MMUCR);
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tlbehi_save = sysreg_read(TLBEHI);
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mmucr = SYSREG_BFINS(DRP, *index, mmucr_save);
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sysreg_write(MMUCR, mmucr);
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/* TLBR might change the ASID */
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__builtin_tlbr();
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cpu_sync_pipeline();
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tlbehi = sysreg_read(TLBEHI);
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tlbelo = sysreg_read(TLBELO);
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sysreg_write(MMUCR, mmucr_save);
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sysreg_write(TLBEHI, tlbehi_save);
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cpu_sync_pipeline();
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local_irq_restore(flags);
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seq_printf(tlb, "%2lu: %c %c %02x %05x %05x %o %o %c %c %c %c\n",
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*index,
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SYSREG_BFEXT(TLBEHI_V, tlbehi) ? '1' : '0',
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SYSREG_BFEXT(G, tlbelo) ? '1' : '0',
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SYSREG_BFEXT(ASID, tlbehi),
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SYSREG_BFEXT(VPN, tlbehi) >> 2,
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SYSREG_BFEXT(PFN, tlbelo) >> 2,
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SYSREG_BFEXT(AP, tlbelo),
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SYSREG_BFEXT(SZ, tlbelo),
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SYSREG_BFEXT(TLBELO_C, tlbelo) ? '1' : '0',
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SYSREG_BFEXT(B, tlbelo) ? '1' : '0',
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SYSREG_BFEXT(W, tlbelo) ? '1' : '0',
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SYSREG_BFEXT(TLBELO_D, tlbelo) ? '1' : '0');
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return 0;
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}
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static const struct seq_operations tlb_ops = {
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.start = tlb_start,
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.next = tlb_next,
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.stop = tlb_stop,
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.show = tlb_show,
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};
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static int tlb_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &tlb_ops);
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}
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static const struct file_operations proc_tlb_operations = {
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.open = tlb_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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static int __init proctlb_init(void)
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{
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proc_create("tlb", 0, NULL, &proc_tlb_operations);
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return 0;
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}
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late_initcall(proctlb_init);
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#endif /* CONFIG_PROC_FS */
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