1 files changed, 291 insertions, 0 deletions
diff --git a/arch/sh/kernel/io_trapped.c b/arch/sh/kernel/io_trapped.c
new file mode 100644
index 000000000..e803b14ef
--- /dev/null
+++ b/arch/sh/kernel/io_trapped.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Trapped io support
+ *
+ * Copyright (C) 2008 Magnus Damm
+ *
+ * Intercept io operations by trapping.
+ */
+#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 <linux/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_warn("unable to install trapped io filter\n");
+	return -1;
+}
+
+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;
+}
+
+static struct trapped_io *lookup_tiop(unsigned long address)
+{
+	pgd_t *pgd_k;
+	p4d_t *p4d_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;
+
+	p4d_k = p4d_offset(pgd_k, address);
+	if (!p4d_present(*p4d_k))
+		return NULL;
+
+	pud_k = pud_offset(p4d_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)
+{
+	insn_size_t instruction;
+	int tmp;
+
+	if (trapped_io_disable)
+		return 0;
+	if (!lookup_tiop(address))
+		return 0;
+
+	WARN_ON(user_mode(regs));
+
+	if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc),
+				     sizeof(instruction))) {
+		return 0;
+	}
+
+	tmp = handle_unaligned_access(instruction, regs,
+				      &trapped_io_access, 1, address);
+	return tmp == 0;
+}