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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-10-31 16:38:31 +00:00
db71daabad
The existing implementation of ioremap_page_range(), which was taken from i386, does this: flush_cache_all(); /* modify page tables */ flush_tlb_all(); I think this is a bit defensive, so this patch changes the generic implementation to do: /* modify page tables */ flush_cache_vmap(start, end); instead, which is similar to what vmalloc() does. This should still be correct because we never modify existing PTEs. According to James Bottomley: The problem the flush_tlb_all() is trying to solve is to avoid stale tlb entries in the ioremap area. We're just being conservative by flushing on both map and unmap. Technically what vmalloc/vfree does (only flush the tlb on unmap) is just fine because it means that the only tlb entries in the remap area must belong to in-use mappings. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mikael Starvik <starvik@axis.com> Cc: Andi Kleen <ak@suse.de> Cc: <linux-m32r@ml.linux-m32r.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@parisc-linux.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
93 lines
2.1 KiB
C
93 lines
2.1 KiB
C
/*
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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/io.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <asm/cacheflush.h>
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#include <asm/pgtable.h>
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static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
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unsigned long end, unsigned long phys_addr, pgprot_t prot)
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{
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pte_t *pte;
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unsigned long 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 inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
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unsigned long end, unsigned long 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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phys_addr -= addr;
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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_pte_range(pmd, addr, next, phys_addr + addr, prot))
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return -ENOMEM;
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} while (pmd++, addr = next, addr != end);
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return 0;
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}
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static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
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unsigned long end, unsigned long 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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phys_addr -= addr;
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pud = pud_alloc(&init_mm, pgd, 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_pmd_range(pud, addr, next, phys_addr + addr, prot))
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return -ENOMEM;
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} while (pud++, 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, unsigned long 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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BUG_ON(addr >= end);
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start = addr;
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phys_addr -= 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_pud_range(pgd, addr, next, phys_addr+addr, prot);
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if (err)
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break;
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} while (pgd++, 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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