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1bc54c0311
This is some preliminary work to improve TLB management on SW loaded TLB powerpc platforms. This introduce support for non-atomic PTE operations in pgtable-ppc32.h and removes write back to the PTE from the TLB miss handlers. In addition, the DSI interrupt code no longer tries to fixup write permission, this is left to generic code, and _PAGE_HWWRITE is gone. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
103 lines
2.9 KiB
C
103 lines
2.9 KiB
C
/*
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* Modifications by Matt Porter (mporter@mvista.com) to support
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* PPC44x Book E processors.
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*
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* This file contains the routines for initializing the MMU
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* on the 4xx series of chips.
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* -- paulus
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*
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* Derived from arch/ppc/mm/init.c:
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/init.h>
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#include <asm/mmu.h>
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#include <asm/system.h>
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#include <asm/page.h>
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#include <asm/cacheflush.h>
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#include "mmu_decl.h"
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/* Used by the 44x TLB replacement exception handler.
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* Just needed it declared someplace.
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*/
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unsigned int tlb_44x_index; /* = 0 */
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unsigned int tlb_44x_hwater = PPC44x_TLB_SIZE - 1 - PPC44x_EARLY_TLBS;
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int icache_44x_need_flush;
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static void __init ppc44x_update_tlb_hwater(void)
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{
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extern unsigned int tlb_44x_patch_hwater_D[];
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extern unsigned int tlb_44x_patch_hwater_I[];
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/* The TLB miss handlers hard codes the watermark in a cmpli
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* instruction to improve performances rather than loading it
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* from the global variable. Thus, we patch the instructions
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* in the 2 TLB miss handlers when updating the value
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*/
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tlb_44x_patch_hwater_D[0] = (tlb_44x_patch_hwater_D[0] & 0xffff0000) |
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tlb_44x_hwater;
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flush_icache_range((unsigned long)&tlb_44x_patch_hwater_D[0],
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(unsigned long)&tlb_44x_patch_hwater_D[1]);
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tlb_44x_patch_hwater_I[0] = (tlb_44x_patch_hwater_I[0] & 0xffff0000) |
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tlb_44x_hwater;
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flush_icache_range((unsigned long)&tlb_44x_patch_hwater_I[0],
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(unsigned long)&tlb_44x_patch_hwater_I[1]);
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}
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/*
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* "Pins" a 256MB TLB entry in AS0 for kernel lowmem
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*/
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static void __init ppc44x_pin_tlb(unsigned int virt, unsigned int phys)
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{
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unsigned int entry = tlb_44x_hwater--;
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ppc44x_update_tlb_hwater();
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__asm__ __volatile__(
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"tlbwe %2,%3,%4\n"
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"tlbwe %1,%3,%5\n"
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"tlbwe %0,%3,%6\n"
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:
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: "r" (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G),
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"r" (phys),
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"r" (virt | PPC44x_TLB_VALID | PPC44x_TLB_256M),
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"r" (entry),
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"i" (PPC44x_TLB_PAGEID),
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"i" (PPC44x_TLB_XLAT),
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"i" (PPC44x_TLB_ATTRIB));
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}
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void __init MMU_init_hw(void)
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{
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ppc44x_update_tlb_hwater();
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flush_instruction_cache();
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}
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unsigned long __init mmu_mapin_ram(void)
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{
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unsigned long addr;
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/* Pin in enough TLBs to cover any lowmem not covered by the
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* initial 256M mapping established in head_44x.S */
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for (addr = PPC_PIN_SIZE; addr < lowmem_end_addr;
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addr += PPC_PIN_SIZE)
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ppc44x_pin_tlb(addr + PAGE_OFFSET, addr);
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return total_lowmem;
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}
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