diff options
Diffstat (limited to 'mm/ioremap.c')
| -rw-r--r-- | mm/ioremap.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/mm/ioremap.c b/mm/ioremap.c new file mode 100644 index 000000000000..5fa1ab41d152 --- /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 */ |