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![Christoph Hellwig](/assets/img/avatar_default.png)
A lot of architectures reuse the same simple ioremap implementation, so start lifting the most simple variant to lib/ioremap.c. It provides ioremap_prot and iounmap, plus a default ioremap that uses prot_noncached, although that can be overridden by asm/io.h. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Palmer Dabbelt <palmer@dabbelt.com>
272 lines
6.1 KiB
C
272 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Re-map IO memory to kernel address space so that we can access it.
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* This is needed for high PCI addresses that aren't mapped in the
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* 640k-1MB IO memory area on PC's
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*
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* (C) Copyright 1995 1996 Linus Torvalds
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*/
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/io.h>
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#include <linux/export.h>
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#include <asm/cacheflush.h>
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#include <asm/pgtable.h>
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#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
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static int __read_mostly ioremap_p4d_capable;
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static int __read_mostly ioremap_pud_capable;
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static int __read_mostly ioremap_pmd_capable;
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static int __read_mostly ioremap_huge_disabled;
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static int __init set_nohugeiomap(char *str)
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{
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ioremap_huge_disabled = 1;
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return 0;
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}
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early_param("nohugeiomap", set_nohugeiomap);
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void __init ioremap_huge_init(void)
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{
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if (!ioremap_huge_disabled) {
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if (arch_ioremap_p4d_supported())
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ioremap_p4d_capable = 1;
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if (arch_ioremap_pud_supported())
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ioremap_pud_capable = 1;
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if (arch_ioremap_pmd_supported())
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ioremap_pmd_capable = 1;
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}
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}
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static inline int ioremap_p4d_enabled(void)
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{
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return ioremap_p4d_capable;
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}
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static inline int ioremap_pud_enabled(void)
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{
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return ioremap_pud_capable;
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}
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static inline int ioremap_pmd_enabled(void)
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{
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return ioremap_pmd_capable;
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}
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#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
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static inline int ioremap_p4d_enabled(void) { return 0; }
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static inline int ioremap_pud_enabled(void) { return 0; }
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static inline int ioremap_pmd_enabled(void) { return 0; }
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#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
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static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
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unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
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{
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pte_t *pte;
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u64 pfn;
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pfn = phys_addr >> PAGE_SHIFT;
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pte = pte_alloc_kernel(pmd, addr);
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if (!pte)
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return -ENOMEM;
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do {
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BUG_ON(!pte_none(*pte));
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set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
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pfn++;
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} while (pte++, addr += PAGE_SIZE, addr != end);
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return 0;
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}
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static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
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unsigned long end, phys_addr_t phys_addr,
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pgprot_t prot)
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{
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if (!ioremap_pmd_enabled())
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return 0;
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if ((end - addr) != PMD_SIZE)
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return 0;
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if (!IS_ALIGNED(addr, PMD_SIZE))
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return 0;
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if (!IS_ALIGNED(phys_addr, PMD_SIZE))
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return 0;
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if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
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return 0;
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return pmd_set_huge(pmd, phys_addr, prot);
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}
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static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
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unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
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{
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pmd_t *pmd;
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unsigned long next;
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pmd = pmd_alloc(&init_mm, pud, addr);
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if (!pmd)
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return -ENOMEM;
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do {
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next = pmd_addr_end(addr, end);
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if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot))
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continue;
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if (ioremap_pte_range(pmd, addr, next, phys_addr, prot))
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return -ENOMEM;
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} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
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return 0;
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}
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static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
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unsigned long end, phys_addr_t phys_addr,
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pgprot_t prot)
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{
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if (!ioremap_pud_enabled())
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return 0;
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if ((end - addr) != PUD_SIZE)
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return 0;
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if (!IS_ALIGNED(addr, PUD_SIZE))
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return 0;
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if (!IS_ALIGNED(phys_addr, PUD_SIZE))
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return 0;
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if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
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return 0;
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return pud_set_huge(pud, phys_addr, prot);
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}
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static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
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unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
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{
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pud_t *pud;
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unsigned long next;
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pud = pud_alloc(&init_mm, p4d, addr);
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if (!pud)
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return -ENOMEM;
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do {
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next = pud_addr_end(addr, end);
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if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot))
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continue;
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if (ioremap_pmd_range(pud, addr, next, phys_addr, prot))
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return -ENOMEM;
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} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
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return 0;
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}
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static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
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unsigned long end, phys_addr_t phys_addr,
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pgprot_t prot)
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{
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if (!ioremap_p4d_enabled())
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return 0;
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if ((end - addr) != P4D_SIZE)
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return 0;
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if (!IS_ALIGNED(addr, P4D_SIZE))
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return 0;
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if (!IS_ALIGNED(phys_addr, P4D_SIZE))
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return 0;
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if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
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return 0;
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return p4d_set_huge(p4d, phys_addr, prot);
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}
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static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
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unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
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{
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p4d_t *p4d;
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unsigned long next;
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p4d = p4d_alloc(&init_mm, pgd, addr);
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if (!p4d)
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return -ENOMEM;
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do {
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next = p4d_addr_end(addr, end);
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if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot))
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continue;
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if (ioremap_pud_range(p4d, addr, next, phys_addr, prot))
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return -ENOMEM;
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} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
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return 0;
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}
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int ioremap_page_range(unsigned long addr,
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unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
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{
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pgd_t *pgd;
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unsigned long start;
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unsigned long next;
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int err;
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might_sleep();
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BUG_ON(addr >= end);
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start = addr;
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pgd = pgd_offset_k(addr);
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do {
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next = pgd_addr_end(addr, end);
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err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot);
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if (err)
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break;
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} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
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flush_cache_vmap(start, end);
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return err;
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}
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#ifdef CONFIG_GENERIC_IOREMAP
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void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
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{
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unsigned long offset, vaddr;
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phys_addr_t last_addr;
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struct vm_struct *area;
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/* Disallow wrap-around or zero size */
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last_addr = addr + size - 1;
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if (!size || last_addr < addr)
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return NULL;
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/* Page-align mappings */
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offset = addr & (~PAGE_MASK);
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addr -= offset;
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size = PAGE_ALIGN(size + offset);
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area = get_vm_area_caller(size, VM_IOREMAP,
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__builtin_return_address(0));
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if (!area)
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return NULL;
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vaddr = (unsigned long)area->addr;
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if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
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free_vm_area(area);
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return NULL;
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}
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return (void __iomem *)(vaddr + offset);
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}
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EXPORT_SYMBOL(ioremap_prot);
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void iounmap(volatile void __iomem *addr)
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{
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vunmap((void *)((unsigned long)addr & PAGE_MASK));
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}
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EXPORT_SYMBOL(iounmap);
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#endif /* CONFIG_GENERIC_IOREMAP */
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