// SPDX-License-Identifier: GPL-2.0-or-later /* * OpenRISC tlb.c * * Linux architectural port borrowing liberally from similar works of * others. All original copyrights apply as per the original source * declaration. * * Modifications for the OpenRISC architecture: * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> * Copyright (C) 2010-2011 Julius Baxter <julius.baxter@orsoc.se> * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> */ #include <linux/sched.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/string.h> #include <linux/types.h> #include <linux/ptrace.h> #include <linux/mman.h> #include <linux/mm.h> #include <linux/init.h> #include <asm/tlbflush.h> #include <asm/mmu_context.h> #include <asm/spr_defs.h> #define NO_CONTEXT -1 #define NUM_DTLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \ SPR_DMMUCFGR_NTS_OFF)) #define NUM_ITLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \ SPR_IMMUCFGR_NTS_OFF)) #define DTLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_DTLB_SETS-1)) #define ITLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_ITLB_SETS-1)) /* * Invalidate all TLB entries. * * This comes down to setting the 'valid' bit for all xTLBMR registers to 0. * Easiest way to accomplish this is to just zero out the xTLBMR register * completely. * */ void local_flush_tlb_all(void) { int i; unsigned long num_tlb_sets; /* Determine number of sets for IMMU. */ /* FIXME: Assumption is I & D nsets equal. */ num_tlb_sets = NUM_ITLB_SETS; for (i = 0; i < num_tlb_sets; i++) { mtspr_off(SPR_DTLBMR_BASE(0), i, 0); mtspr_off(SPR_ITLBMR_BASE(0), i, 0); } } #define have_dtlbeir (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_TEIRI) #define have_itlbeir (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_TEIRI) /* * Invalidate a single page. This is what the xTLBEIR register is for. * * There's no point in checking the vma for PAGE_EXEC to determine whether it's * the data or instruction TLB that should be flushed... that would take more * than the few instructions that the following compiles down to! * * The case where we don't have the xTLBEIR register really only works for * MMU's with a single way and is hard-coded that way. */ #define flush_dtlb_page_eir(addr) mtspr(SPR_DTLBEIR, addr) #define flush_dtlb_page_no_eir(addr) \ mtspr_off(SPR_DTLBMR_BASE(0), DTLB_OFFSET(addr), 0); #define flush_itlb_page_eir(addr) mtspr(SPR_ITLBEIR, addr) #define flush_itlb_page_no_eir(addr) \ mtspr_off(SPR_ITLBMR_BASE(0), ITLB_OFFSET(addr), 0); void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long addr) { if (have_dtlbeir) flush_dtlb_page_eir(addr); else flush_dtlb_page_no_eir(addr); if (have_itlbeir) flush_itlb_page_eir(addr); else flush_itlb_page_no_eir(addr); } void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) { int addr; bool dtlbeir; bool itlbeir; dtlbeir = have_dtlbeir; itlbeir = have_itlbeir; for (addr = start; addr < end; addr += PAGE_SIZE) { if (dtlbeir) flush_dtlb_page_eir(addr); else flush_dtlb_page_no_eir(addr); if (itlbeir) flush_itlb_page_eir(addr); else flush_itlb_page_no_eir(addr); } } /* * Invalidate the selected mm context only. * * FIXME: Due to some bug here, we're flushing everything for now. * This should be changed to loop over over mm and call flush_tlb_range. */ void local_flush_tlb_mm(struct mm_struct *mm) { /* Was seeing bugs with the mm struct passed to us. Scrapped most of this function. */ /* Several architectures do this */ local_flush_tlb_all(); } /* called in schedule() just before actually doing the switch_to */ void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *next_tsk) { unsigned int cpu; if (unlikely(prev == next)) return; cpu = smp_processor_id(); cpumask_clear_cpu(cpu, mm_cpumask(prev)); cpumask_set_cpu(cpu, mm_cpumask(next)); /* remember the pgd for the fault handlers * this is similar to the pgd register in some other CPU's. * we need our own copy of it because current and active_mm * might be invalid at points where we still need to derefer * the pgd. */ current_pgd[cpu] = next->pgd; /* We don't have context support implemented, so flush all * entries belonging to previous map */ local_flush_tlb_mm(prev); } /* * Initialize the context related info for a new mm_struct * instance. */ int init_new_context(struct task_struct *tsk, struct mm_struct *mm) { mm->context = NO_CONTEXT; return 0; } /* called by __exit_mm to destroy the used MMU context if any before * destroying the mm itself. this is only called when the last user of the mm * drops it. */ void destroy_context(struct mm_struct *mm) { flush_tlb_mm(mm); } /* called once during VM initialization, from init.c */ void __init tlb_init(void) { /* Do nothing... */ /* invalidate the entire TLB */ /* flush_tlb_all(); */ }