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