summaryrefslogtreecommitdiffstats
path: root/mm/ioremap.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/ioremap.c')
-rw-r--r--mm/ioremap.c289
1 files changed, 289 insertions, 0 deletions
diff --git a/mm/ioremap.c b/mm/ioremap.c
new file mode 100644
index 000000000..5fa1ab41d
--- /dev/null
+++ b/mm/ioremap.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Re-map IO memory to kernel address space so that we can access it.
+ * This is needed for high PCI addresses that aren't mapped in the
+ * 640k-1MB IO memory area on PC's
+ *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ */
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/io.h>
+#include <linux/export.h>
+#include <asm/cacheflush.h>
+
+#include "pgalloc-track.h"
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+static int __read_mostly ioremap_p4d_capable;
+static int __read_mostly ioremap_pud_capable;
+static int __read_mostly ioremap_pmd_capable;
+static int __read_mostly ioremap_huge_disabled;
+
+static int __init set_nohugeiomap(char *str)
+{
+ ioremap_huge_disabled = 1;
+ return 0;
+}
+early_param("nohugeiomap", set_nohugeiomap);
+
+void __init ioremap_huge_init(void)
+{
+ if (!ioremap_huge_disabled) {
+ if (arch_ioremap_p4d_supported())
+ ioremap_p4d_capable = 1;
+ if (arch_ioremap_pud_supported())
+ ioremap_pud_capable = 1;
+ if (arch_ioremap_pmd_supported())
+ ioremap_pmd_capable = 1;
+ }
+}
+
+static inline int ioremap_p4d_enabled(void)
+{
+ return ioremap_p4d_capable;
+}
+
+static inline int ioremap_pud_enabled(void)
+{
+ return ioremap_pud_capable;
+}
+
+static inline int ioremap_pmd_enabled(void)
+{
+ return ioremap_pmd_capable;
+}
+
+#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
+static inline int ioremap_p4d_enabled(void) { return 0; }
+static inline int ioremap_pud_enabled(void) { return 0; }
+static inline int ioremap_pmd_enabled(void) { return 0; }
+#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+
+static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
+ pgtbl_mod_mask *mask)
+{
+ pte_t *pte;
+ u64 pfn;
+
+ pfn = phys_addr >> PAGE_SHIFT;
+ pte = pte_alloc_kernel_track(pmd, addr, mask);
+ if (!pte)
+ return -ENOMEM;
+ do {
+ BUG_ON(!pte_none(*pte));
+ set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
+ pfn++;
+ } while (pte++, addr += PAGE_SIZE, addr != end);
+ *mask |= PGTBL_PTE_MODIFIED;
+ return 0;
+}
+
+static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr,
+ pgprot_t prot)
+{
+ if (!ioremap_pmd_enabled())
+ return 0;
+
+ if ((end - addr) != PMD_SIZE)
+ return 0;
+
+ if (!IS_ALIGNED(addr, PMD_SIZE))
+ return 0;
+
+ if (!IS_ALIGNED(phys_addr, PMD_SIZE))
+ return 0;
+
+ if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
+ return 0;
+
+ return pmd_set_huge(pmd, phys_addr, prot);
+}
+
+static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
+ pgtbl_mod_mask *mask)
+{
+ pmd_t *pmd;
+ unsigned long next;
+
+ pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
+ if (!pmd)
+ return -ENOMEM;
+ do {
+ next = pmd_addr_end(addr, end);
+
+ if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
+ *mask |= PGTBL_PMD_MODIFIED;
+ continue;
+ }
+
+ if (ioremap_pte_range(pmd, addr, next, phys_addr, prot, mask))
+ return -ENOMEM;
+ } while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
+ return 0;
+}
+
+static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr,
+ pgprot_t prot)
+{
+ if (!ioremap_pud_enabled())
+ return 0;
+
+ if ((end - addr) != PUD_SIZE)
+ return 0;
+
+ if (!IS_ALIGNED(addr, PUD_SIZE))
+ return 0;
+
+ if (!IS_ALIGNED(phys_addr, PUD_SIZE))
+ return 0;
+
+ if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
+ return 0;
+
+ return pud_set_huge(pud, phys_addr, prot);
+}
+
+static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
+ pgtbl_mod_mask *mask)
+{
+ pud_t *pud;
+ unsigned long next;
+
+ pud = pud_alloc_track(&init_mm, p4d, addr, mask);
+ if (!pud)
+ return -ENOMEM;
+ do {
+ next = pud_addr_end(addr, end);
+
+ if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
+ *mask |= PGTBL_PUD_MODIFIED;
+ continue;
+ }
+
+ if (ioremap_pmd_range(pud, addr, next, phys_addr, prot, mask))
+ return -ENOMEM;
+ } while (pud++, phys_addr += (next - addr), addr = next, addr != end);
+ return 0;
+}
+
+static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr,
+ pgprot_t prot)
+{
+ if (!ioremap_p4d_enabled())
+ return 0;
+
+ if ((end - addr) != P4D_SIZE)
+ return 0;
+
+ if (!IS_ALIGNED(addr, P4D_SIZE))
+ return 0;
+
+ if (!IS_ALIGNED(phys_addr, P4D_SIZE))
+ return 0;
+
+ if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
+ return 0;
+
+ return p4d_set_huge(p4d, phys_addr, prot);
+}
+
+static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
+ pgtbl_mod_mask *mask)
+{
+ p4d_t *p4d;
+ unsigned long next;
+
+ p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
+ if (!p4d)
+ return -ENOMEM;
+ do {
+ next = p4d_addr_end(addr, end);
+
+ if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
+ *mask |= PGTBL_P4D_MODIFIED;
+ continue;
+ }
+
+ if (ioremap_pud_range(p4d, addr, next, phys_addr, prot, mask))
+ return -ENOMEM;
+ } while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
+ return 0;
+}
+
+int ioremap_page_range(unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
+{
+ pgd_t *pgd;
+ unsigned long start;
+ unsigned long next;
+ int err;
+ pgtbl_mod_mask mask = 0;
+
+ might_sleep();
+ BUG_ON(addr >= end);
+
+ start = addr;
+ pgd = pgd_offset_k(addr);
+ do {
+ next = pgd_addr_end(addr, end);
+ err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot,
+ &mask);
+ if (err)
+ break;
+ } while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
+
+ flush_cache_vmap(start, end);
+
+ if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
+ arch_sync_kernel_mappings(start, end);
+
+ return err;
+}
+
+#ifdef CONFIG_GENERIC_IOREMAP
+void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
+{
+ unsigned long offset, vaddr;
+ phys_addr_t last_addr;
+ struct vm_struct *area;
+
+ /* Disallow wrap-around or zero size */
+ last_addr = addr + size - 1;
+ if (!size || last_addr < addr)
+ return NULL;
+
+ /* Page-align mappings */
+ offset = addr & (~PAGE_MASK);
+ addr -= offset;
+ size = PAGE_ALIGN(size + offset);
+
+ area = get_vm_area_caller(size, VM_IOREMAP,
+ __builtin_return_address(0));
+ if (!area)
+ return NULL;
+ vaddr = (unsigned long)area->addr;
+
+ if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
+ free_vm_area(area);
+ return NULL;
+ }
+
+ return (void __iomem *)(vaddr + offset);
+}
+EXPORT_SYMBOL(ioremap_prot);
+
+void iounmap(volatile void __iomem *addr)
+{
+ vunmap((void *)((unsigned long)addr & PAGE_MASK));
+}
+EXPORT_SYMBOL(iounmap);
+#endif /* CONFIG_GENERIC_IOREMAP */