cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tlb.c (2935B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * This file contains the routines for TLB flushing.
      4 * On machines where the MMU uses a hash table to store virtual to
      5 * physical translations, these routines flush entries from the
      6 * hash table also.
      7 *  -- paulus
      8 *
      9 *  Derived from arch/ppc/mm/init.c:
     10 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
     11 *
     12 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
     13 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
     14 *    Copyright (C) 1996 Paul Mackerras
     15 *
     16 *  Derived from "arch/i386/mm/init.c"
     17 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
     18 */
     19
     20#include <linux/kernel.h>
     21#include <linux/mm.h>
     22#include <linux/init.h>
     23#include <linux/highmem.h>
     24#include <linux/pagemap.h>
     25#include <linux/export.h>
     26
     27#include <asm/tlbflush.h>
     28#include <asm/tlb.h>
     29
     30#include <mm/mmu_decl.h>
     31
     32/*
     33 * TLB flushing:
     34 *
     35 *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
     36 *  - flush_tlb_page(vma, vmaddr) flushes one page
     37 *  - flush_tlb_range(vma, start, end) flushes a range of pages
     38 *  - flush_tlb_kernel_range(start, end) flushes kernel pages
     39 *
     40 * since the hardware hash table functions as an extension of the
     41 * tlb as far as the linux tables are concerned, flush it too.
     42 *    -- Cort
     43 */
     44
     45/*
     46 * For each address in the range, find the pte for the address
     47 * and check _PAGE_HASHPTE bit; if it is set, find and destroy
     48 * the corresponding HPTE.
     49 */
     50void hash__flush_range(struct mm_struct *mm, unsigned long start, unsigned long end)
     51{
     52	pmd_t *pmd;
     53	unsigned long pmd_end;
     54	int count;
     55	unsigned int ctx = mm->context.id;
     56
     57	start &= PAGE_MASK;
     58	if (start >= end)
     59		return;
     60	end = (end - 1) | ~PAGE_MASK;
     61	pmd = pmd_off(mm, start);
     62	for (;;) {
     63		pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
     64		if (pmd_end > end)
     65			pmd_end = end;
     66		if (!pmd_none(*pmd)) {
     67			count = ((pmd_end - start) >> PAGE_SHIFT) + 1;
     68			flush_hash_pages(ctx, start, pmd_val(*pmd), count);
     69		}
     70		if (pmd_end == end)
     71			break;
     72		start = pmd_end + 1;
     73		++pmd;
     74	}
     75}
     76EXPORT_SYMBOL(hash__flush_range);
     77
     78/*
     79 * Flush all the (user) entries for the address space described by mm.
     80 */
     81void hash__flush_tlb_mm(struct mm_struct *mm)
     82{
     83	struct vm_area_struct *mp;
     84
     85	/*
     86	 * It is safe to go down the mm's list of vmas when called
     87	 * from dup_mmap, holding mmap_lock.  It would also be safe from
     88	 * unmap_region or exit_mmap, but not from vmtruncate on SMP -
     89	 * but it seems dup_mmap is the only SMP case which gets here.
     90	 */
     91	for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
     92		hash__flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
     93}
     94EXPORT_SYMBOL(hash__flush_tlb_mm);
     95
     96void hash__flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
     97{
     98	struct mm_struct *mm;
     99	pmd_t *pmd;
    100
    101	mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
    102	pmd = pmd_off(mm, vmaddr);
    103	if (!pmd_none(*pmd))
    104		flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
    105}
    106EXPORT_SYMBOL(hash__flush_tlb_page);