297 строки
6.3 KiB
C
297 строки
6.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Trapped io support
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*
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* Copyright (C) 2008 Magnus Damm
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*
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* Intercept io operations by trapping.
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/bitops.h>
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#include <linux/vmalloc.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <asm/mmu_context.h>
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#include <linux/uaccess.h>
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#include <asm/io.h>
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#include <asm/io_trapped.h>
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#define TRAPPED_PAGES_MAX 16
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#ifdef CONFIG_HAS_IOPORT_MAP
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LIST_HEAD(trapped_io);
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EXPORT_SYMBOL_GPL(trapped_io);
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#endif
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#ifdef CONFIG_HAS_IOMEM
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LIST_HEAD(trapped_mem);
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EXPORT_SYMBOL_GPL(trapped_mem);
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#endif
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static DEFINE_SPINLOCK(trapped_lock);
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static int trapped_io_disable __read_mostly;
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static int __init trapped_io_setup(char *__unused)
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{
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trapped_io_disable = 1;
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return 1;
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}
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__setup("noiotrap", trapped_io_setup);
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int register_trapped_io(struct trapped_io *tiop)
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{
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struct resource *res;
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unsigned long len = 0, flags = 0;
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struct page *pages[TRAPPED_PAGES_MAX];
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int k, n;
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if (unlikely(trapped_io_disable))
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return 0;
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/* structure must be page aligned */
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if ((unsigned long)tiop & (PAGE_SIZE - 1))
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goto bad;
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for (k = 0; k < tiop->num_resources; k++) {
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res = tiop->resource + k;
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len += roundup(resource_size(res), PAGE_SIZE);
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flags |= res->flags;
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}
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/* support IORESOURCE_IO _or_ MEM, not both */
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if (hweight_long(flags) != 1)
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goto bad;
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n = len >> PAGE_SHIFT;
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if (n >= TRAPPED_PAGES_MAX)
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goto bad;
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for (k = 0; k < n; k++)
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pages[k] = virt_to_page(tiop);
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tiop->virt_base = vmap(pages, n, VM_MAP, PAGE_NONE);
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if (!tiop->virt_base)
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goto bad;
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len = 0;
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for (k = 0; k < tiop->num_resources; k++) {
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res = tiop->resource + k;
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pr_info("trapped io 0x%08lx overrides %s 0x%08lx\n",
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(unsigned long)(tiop->virt_base + len),
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res->flags & IORESOURCE_IO ? "io" : "mmio",
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(unsigned long)res->start);
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len += roundup(resource_size(res), PAGE_SIZE);
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}
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tiop->magic = IO_TRAPPED_MAGIC;
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INIT_LIST_HEAD(&tiop->list);
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spin_lock_irq(&trapped_lock);
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#ifdef CONFIG_HAS_IOPORT_MAP
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if (flags & IORESOURCE_IO)
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list_add(&tiop->list, &trapped_io);
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#endif
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#ifdef CONFIG_HAS_IOMEM
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if (flags & IORESOURCE_MEM)
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list_add(&tiop->list, &trapped_mem);
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#endif
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spin_unlock_irq(&trapped_lock);
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return 0;
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bad:
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pr_warn("unable to install trapped io filter\n");
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return -1;
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}
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void __iomem *match_trapped_io_handler(struct list_head *list,
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unsigned long offset,
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unsigned long size)
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{
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unsigned long voffs;
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struct trapped_io *tiop;
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struct resource *res;
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int k, len;
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unsigned long flags;
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spin_lock_irqsave(&trapped_lock, flags);
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list_for_each_entry(tiop, list, list) {
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voffs = 0;
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for (k = 0; k < tiop->num_resources; k++) {
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res = tiop->resource + k;
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if (res->start == offset) {
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spin_unlock_irqrestore(&trapped_lock, flags);
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return tiop->virt_base + voffs;
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}
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len = resource_size(res);
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voffs += roundup(len, PAGE_SIZE);
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}
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}
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spin_unlock_irqrestore(&trapped_lock, flags);
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return NULL;
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}
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static struct trapped_io *lookup_tiop(unsigned long address)
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{
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pgd_t *pgd_k;
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p4d_t *p4d_k;
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pud_t *pud_k;
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pmd_t *pmd_k;
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pte_t *pte_k;
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pte_t entry;
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pgd_k = swapper_pg_dir + pgd_index(address);
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if (!pgd_present(*pgd_k))
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return NULL;
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p4d_k = p4d_offset(pgd_k, address);
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if (!p4d_present(*p4d_k))
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return NULL;
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pud_k = pud_offset(p4d_k, address);
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if (!pud_present(*pud_k))
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return NULL;
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pmd_k = pmd_offset(pud_k, address);
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if (!pmd_present(*pmd_k))
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return NULL;
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pte_k = pte_offset_kernel(pmd_k, address);
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entry = *pte_k;
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return pfn_to_kaddr(pte_pfn(entry));
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}
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static unsigned long lookup_address(struct trapped_io *tiop,
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unsigned long address)
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{
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struct resource *res;
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unsigned long vaddr = (unsigned long)tiop->virt_base;
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unsigned long len;
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int k;
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for (k = 0; k < tiop->num_resources; k++) {
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res = tiop->resource + k;
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len = roundup(resource_size(res), PAGE_SIZE);
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if (address < (vaddr + len))
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return res->start + (address - vaddr);
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vaddr += len;
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}
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return 0;
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}
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static unsigned long long copy_word(unsigned long src_addr, int src_len,
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unsigned long dst_addr, int dst_len)
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{
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unsigned long long tmp = 0;
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switch (src_len) {
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case 1:
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tmp = __raw_readb(src_addr);
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break;
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case 2:
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tmp = __raw_readw(src_addr);
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break;
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case 4:
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tmp = __raw_readl(src_addr);
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break;
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case 8:
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tmp = __raw_readq(src_addr);
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break;
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}
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switch (dst_len) {
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case 1:
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__raw_writeb(tmp, dst_addr);
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break;
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case 2:
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__raw_writew(tmp, dst_addr);
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break;
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case 4:
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__raw_writel(tmp, dst_addr);
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break;
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case 8:
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__raw_writeq(tmp, dst_addr);
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break;
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}
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return tmp;
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}
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static unsigned long from_device(void *dst, const void *src, unsigned long cnt)
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{
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struct trapped_io *tiop;
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unsigned long src_addr = (unsigned long)src;
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unsigned long long tmp;
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pr_debug("trapped io read 0x%08lx (%ld)\n", src_addr, cnt);
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tiop = lookup_tiop(src_addr);
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WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
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src_addr = lookup_address(tiop, src_addr);
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if (!src_addr)
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return cnt;
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tmp = copy_word(src_addr,
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max_t(unsigned long, cnt,
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(tiop->minimum_bus_width / 8)),
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(unsigned long)dst, cnt);
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pr_debug("trapped io read 0x%08lx -> 0x%08llx\n", src_addr, tmp);
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return 0;
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}
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static unsigned long to_device(void *dst, const void *src, unsigned long cnt)
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{
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struct trapped_io *tiop;
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unsigned long dst_addr = (unsigned long)dst;
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unsigned long long tmp;
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pr_debug("trapped io write 0x%08lx (%ld)\n", dst_addr, cnt);
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tiop = lookup_tiop(dst_addr);
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WARN_ON(!tiop || (tiop->magic != IO_TRAPPED_MAGIC));
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dst_addr = lookup_address(tiop, dst_addr);
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if (!dst_addr)
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return cnt;
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tmp = copy_word((unsigned long)src, cnt,
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dst_addr, max_t(unsigned long, cnt,
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(tiop->minimum_bus_width / 8)));
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pr_debug("trapped io write 0x%08lx -> 0x%08llx\n", dst_addr, tmp);
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return 0;
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}
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static struct mem_access trapped_io_access = {
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from_device,
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to_device,
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};
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int handle_trapped_io(struct pt_regs *regs, unsigned long address)
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{
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mm_segment_t oldfs;
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insn_size_t instruction;
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int tmp;
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if (trapped_io_disable)
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return 0;
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if (!lookup_tiop(address))
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return 0;
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WARN_ON(user_mode(regs));
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oldfs = get_fs();
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set_fs(KERNEL_DS);
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if (copy_from_user(&instruction, (void *)(regs->pc),
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sizeof(instruction))) {
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set_fs(oldfs);
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return 0;
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}
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tmp = handle_unaligned_access(instruction, regs,
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&trapped_io_access, 1, address);
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set_fs(oldfs);
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return tmp == 0;
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}
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