1 files changed, 116 insertions, 0 deletions
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
new file mode 100644
index 000000000..f60398aeb
--- /dev/null
+++ b/arch/x86/mm/iomap_32.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright © 2008 Ingo Molnar
+ */
+
+#include <asm/iomap.h>
+#include <asm/memtype.h>
+#include <linux/export.h>
+#include <linux/highmem.h>
+
+static int is_io_mapping_possible(resource_size_t base, unsigned long size)
+{
+#if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT)
+	/* There is no way to map greater than 1 << 32 address without PAE */
+	if (base + size > 0x100000000ULL)
+		return 0;
+#endif
+	return 1;
+}
+
+int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot)
+{
+	enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC;
+	int ret;
+
+	if (!is_io_mapping_possible(base, size))
+		return -EINVAL;
+
+	ret = memtype_reserve_io(base, base + size, &pcm);
+	if (ret)
+		return ret;
+
+	*prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm));
+	/* Filter out unsupported __PAGE_KERNEL* bits: */
+	pgprot_val(*prot) &= __default_kernel_pte_mask;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_create_wc);
+
+void iomap_free(resource_size_t base, unsigned long size)
+{
+	memtype_free_io(base, base + size);
+}
+EXPORT_SYMBOL_GPL(iomap_free);
+
+void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
+{
+	unsigned long vaddr;
+	int idx, type;
+
+	preempt_disable();
+	pagefault_disable();
+
+	type = kmap_atomic_idx_push();
+	idx = type + KM_TYPE_NR * smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
+	arch_flush_lazy_mmu_mode();
+
+	return (void *)vaddr;
+}
+
+/*
+ * Map 'pfn' using protections 'prot'
+ */
+void __iomem *
+iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
+{
+	/*
+	 * For non-PAT systems, translate non-WB request to UC- just in
+	 * case the caller set the PWT bit to prot directly without using
+	 * pgprot_writecombine(). UC- translates to uncached if the MTRR
+	 * is UC or WC. UC- gets the real intention, of the user, which is
+	 * "WC if the MTRR is WC, UC if you can't do that."
+	 */
+	if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB)
+		prot = __pgprot(__PAGE_KERNEL |
+				cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS));
+
+	/* Filter out unsupported __PAGE_KERNEL* bits: */
+	pgprot_val(prot) &= __default_kernel_pte_mask;
+
+	return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot);
+}
+EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
+
+void
+iounmap_atomic(void __iomem *kvaddr)
+{
+	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+
+	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
+		int idx, type;
+
+		type = kmap_atomic_idx();
+		idx = type + KM_TYPE_NR * smp_processor_id();
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+#endif
+		/*
+		 * Force other mappings to Oops if they'll try to access this
+		 * pte without first remap it.  Keeping stale mappings around
+		 * is a bad idea also, in case the page changes cacheability
+		 * attributes or becomes a protected page in a hypervisor.
+		 */
+		kpte_clear_flush(kmap_pte-idx, vaddr);
+		kmap_atomic_idx_pop();
+	}
+
+	pagefault_enable();
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(iounmap_atomic);