diff options
Diffstat (limited to 'arch/x86/mm/ioremap.c')
| -rw-r--r-- | arch/x86/mm/ioremap.c | 501 |
1 files changed, 501 insertions, 0 deletions
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c new file mode 100644 index 000000000000..ed795721ca8e --- /dev/null +++ b/arch/x86/mm/ioremap.c @@ -0,0 +1,501 @@ +/* + * 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/bootmem.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> + +#include <asm/cacheflush.h> +#include <asm/e820.h> +#include <asm/fixmap.h> +#include <asm/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/pgalloc.h> + +enum ioremap_mode { + IOR_MODE_UNCACHED, + IOR_MODE_CACHED, +}; + +#ifdef CONFIG_X86_64 + +unsigned long __phys_addr(unsigned long x) +{ + if (x >= __START_KERNEL_map) + return x - __START_KERNEL_map + phys_base; + return x - PAGE_OFFSET; +} +EXPORT_SYMBOL(__phys_addr); + +#endif + +int page_is_ram(unsigned long pagenr) +{ + unsigned long addr, end; + int i; + + for (i = 0; i < e820.nr_map; i++) { + /* + * Not usable memory: + */ + if (e820.map[i].type != E820_RAM) + continue; + addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT; + end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT; + + /* + * Sanity check: Some BIOSen report areas as RAM that + * are not. Notably the 640->1Mb area, which is the + * PCI BIOS area. + */ + if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) && + end < (BIOS_END >> PAGE_SHIFT)) + continue; + + if ((pagenr >= addr) && (pagenr < end)) + return 1; + } + return 0; +} + +/* + * Fix up the linear direct mapping of the kernel to avoid cache attribute + * conflicts. + */ +static int ioremap_change_attr(unsigned long paddr, unsigned long size, + enum ioremap_mode mode) +{ + unsigned long vaddr = (unsigned long)__va(paddr); + unsigned long nrpages = size >> PAGE_SHIFT; + int err, level; + + /* No change for pages after the last mapping */ + if ((paddr + size - 1) >= (max_pfn_mapped << PAGE_SHIFT)) + return 0; + + /* + * If there is no identity map for this address, + * change_page_attr_addr is unnecessary + */ + if (!lookup_address(vaddr, &level)) + return 0; + + switch (mode) { + case IOR_MODE_UNCACHED: + default: + err = set_memory_uc(vaddr, nrpages); + break; + case IOR_MODE_CACHED: + err = set_memory_wb(vaddr, nrpages); + break; + } + + return err; +} + +/* + * Remap an arbitrary physical address space into the kernel virtual + * address space. Needed when the kernel wants to access high addresses + * directly. + * + * NOTE! We need to allow non-page-aligned mappings too: we will obviously + * have to convert them into an offset in a page-aligned mapping, but the + * caller shouldn't need to know that small detail. + */ +static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size, + enum ioremap_mode mode) +{ + void __iomem *addr; + struct vm_struct *area; + unsigned long offset, last_addr; + pgprot_t prot; + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) + return NULL; + + /* + * Don't remap the low PCI/ISA area, it's always mapped.. + */ + if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS) + return (__force void __iomem *)phys_to_virt(phys_addr); + + /* + * Don't allow anybody to remap normal RAM that we're using.. + */ + for (offset = phys_addr >> PAGE_SHIFT; offset < max_pfn_mapped && + (offset << PAGE_SHIFT) < last_addr; offset++) { + if (page_is_ram(offset)) + return NULL; + } + + switch (mode) { + case IOR_MODE_UNCACHED: + default: + prot = PAGE_KERNEL_NOCACHE; + break; + case IOR_MODE_CACHED: + prot = PAGE_KERNEL; + break; + } + + /* + * Mappings have to be page-aligned + */ + offset = phys_addr & ~PAGE_MASK; + phys_addr &= PAGE_MASK; + size = PAGE_ALIGN(last_addr+1) - phys_addr; + + /* + * Ok, go for it.. + */ + area = get_vm_area(size, VM_IOREMAP); + if (!area) + return NULL; + area->phys_addr = phys_addr; + addr = (void __iomem *) area->addr; + if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size, + phys_addr, prot)) { + remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr)); + return NULL; + } + + if (ioremap_change_attr(phys_addr, size, mode) < 0) { + vunmap(addr); + return NULL; + } + + return (void __iomem *) (offset + (char __iomem *)addr); +} + +/** + * ioremap_nocache - map bus memory into CPU space + * @offset: bus address of the memory + * @size: size of the resource to map + * + * ioremap_nocache performs a platform specific sequence of operations to + * make bus memory CPU accessible via the readb/readw/readl/writeb/ + * writew/writel functions and the other mmio helpers. The returned + * address is not guaranteed to be usable directly as a virtual + * address. + * + * This version of ioremap ensures that the memory is marked uncachable + * on the CPU as well as honouring existing caching rules from things like + * the PCI bus. Note that there are other caches and buffers on many + * busses. In particular driver authors should read up on PCI writes + * + * It's useful if some control registers are in such an area and + * write combining or read caching is not desirable: + * + * Must be freed with iounmap. + */ +void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size) +{ + return __ioremap(phys_addr, size, IOR_MODE_UNCACHED); +} +EXPORT_SYMBOL(ioremap_nocache); + +void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size) +{ + return __ioremap(phys_addr, size, IOR_MODE_CACHED); +} +EXPORT_SYMBOL(ioremap_cache); + +/** + * iounmap - Free a IO remapping + * @addr: virtual address from ioremap_* + * + * Caller must ensure there is only one unmapping for the same pointer. + */ +void iounmap(volatile void __iomem *addr) +{ + struct vm_struct *p, *o; + + if ((void __force *)addr <= high_memory) + return; + + /* + * __ioremap special-cases the PCI/ISA range by not instantiating a + * vm_area and by simply returning an address into the kernel mapping + * of ISA space. So handle that here. + */ + if (addr >= phys_to_virt(ISA_START_ADDRESS) && + addr < phys_to_virt(ISA_END_ADDRESS)) + return; + + addr = (volatile void __iomem *) + (PAGE_MASK & (unsigned long __force)addr); + + /* Use the vm area unlocked, assuming the caller + ensures there isn't another iounmap for the same address + in parallel. Reuse of the virtual address is prevented by + leaving it in the global lists until we're done with it. + cpa takes care of the direct mappings. */ + read_lock(&vmlist_lock); + for (p = vmlist; p; p = p->next) { + if (p->addr == addr) + break; + } + read_unlock(&vmlist_lock); + + if (!p) { + printk(KERN_ERR "iounmap: bad address %p\n", addr); + dump_stack(); + return; + } + + /* Reset the direct mapping. Can block */ + ioremap_change_attr(p->phys_addr, p->size, IOR_MODE_CACHED); + + /* Finally remove it */ + o = remove_vm_area((void *)addr); + BUG_ON(p != o || o == NULL); + kfree(p); +} +EXPORT_SYMBOL(iounmap); + +#ifdef CONFIG_X86_32 + +int __initdata early_ioremap_debug; + +static int __init early_ioremap_debug_setup(char *str) +{ + early_ioremap_debug = 1; + + return 0; +} +early_param("early_ioremap_debug", early_ioremap_debug_setup); + +static __initdata int after_paging_init; +static __initdata unsigned long bm_pte[1024] + __attribute__((aligned(PAGE_SIZE))); + +static inline unsigned long * __init early_ioremap_pgd(unsigned long addr) +{ + return (unsigned long *)swapper_pg_dir + ((addr >> 22) & 1023); +} + +static inline unsigned long * __init early_ioremap_pte(unsigned long addr) +{ + return bm_pte + ((addr >> PAGE_SHIFT) & 1023); +} + +void __init early_ioremap_init(void) +{ + unsigned long *pgd; + + if (early_ioremap_debug) + printk(KERN_INFO "early_ioremap_init()\n"); + + pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN)); + *pgd = __pa(bm_pte) | _PAGE_TABLE; + memset(bm_pte, 0, sizeof(bm_pte)); + /* + * The boot-ioremap range spans multiple pgds, for which + * we are not prepared: + */ + if (pgd != early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))) { + WARN_ON(1); + printk(KERN_WARNING "pgd %p != %p\n", + pgd, early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))); + printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", + fix_to_virt(FIX_BTMAP_BEGIN)); + printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n", + fix_to_virt(FIX_BTMAP_END)); + + printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END); + printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n", + FIX_BTMAP_BEGIN); + } +} + +void __init early_ioremap_clear(void) +{ + unsigned long *pgd; + + if (early_ioremap_debug) + printk(KERN_INFO "early_ioremap_clear()\n"); + + pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN)); + *pgd = 0; + paravirt_release_pt(__pa(pgd) >> PAGE_SHIFT); + __flush_tlb_all(); +} + +void __init early_ioremap_reset(void) +{ + enum fixed_addresses idx; + unsigned long *pte, phys, addr; + + after_paging_init = 1; + for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) { + addr = fix_to_virt(idx); + pte = early_ioremap_pte(addr); + if (!*pte & _PAGE_PRESENT) { + phys = *pte & PAGE_MASK; + set_fixmap(idx, phys); + } + } +} + +static void __init __early_set_fixmap(enum fixed_addresses idx, + unsigned long phys, pgprot_t flags) +{ + unsigned long *pte, addr = __fix_to_virt(idx); + + if (idx >= __end_of_fixed_addresses) { + BUG(); + return; + } + pte = early_ioremap_pte(addr); + if (pgprot_val(flags)) + *pte = (phys & PAGE_MASK) | pgprot_val(flags); + else + *pte = 0; + __flush_tlb_one(addr); +} + +static inline void __init early_set_fixmap(enum fixed_addresses idx, + unsigned long phys) +{ + if (after_paging_init) + set_fixmap(idx, phys); + else + __early_set_fixmap(idx, phys, PAGE_KERNEL); +} + +static inline void __init early_clear_fixmap(enum fixed_addresses idx) +{ + if (after_paging_init) + clear_fixmap(idx); + else + __early_set_fixmap(idx, 0, __pgprot(0)); +} + + +int __initdata early_ioremap_nested; + +static int __init check_early_ioremap_leak(void) +{ + if (!early_ioremap_nested) + return 0; + + printk(KERN_WARNING + "Debug warning: early ioremap leak of %d areas detected.\n", + early_ioremap_nested); + printk(KERN_WARNING + "please boot with early_ioremap_debug and report the dmesg.\n"); + WARN_ON(1); + + return 1; +} +late_initcall(check_early_ioremap_leak); + +void __init *early_ioremap(unsigned long phys_addr, unsigned long size) +{ + unsigned long offset, last_addr; + unsigned int nrpages, nesting; + enum fixed_addresses idx0, idx; + + WARN_ON(system_state != SYSTEM_BOOTING); + + nesting = early_ioremap_nested; + if (early_ioremap_debug) { + printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ", + phys_addr, size, nesting); + dump_stack(); + } + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) { + WARN_ON(1); + return NULL; + } + + if (nesting >= FIX_BTMAPS_NESTING) { + WARN_ON(1); + return NULL; + } + early_ioremap_nested++; + /* + * Mappings have to be page-aligned + */ + offset = phys_addr & ~PAGE_MASK; + phys_addr &= PAGE_MASK; + size = PAGE_ALIGN(last_addr) - phys_addr; + + /* + * Mappings have to fit in the FIX_BTMAP area. + */ + nrpages = size >> PAGE_SHIFT; + if (nrpages > NR_FIX_BTMAPS) { + WARN_ON(1); + return NULL; + } + + /* + * Ok, go for it.. + */ + idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting; + idx = idx0; + while (nrpages > 0) { + early_set_fixmap(idx, phys_addr); + phys_addr += PAGE_SIZE; + --idx; + --nrpages; + } + if (early_ioremap_debug) + printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0)); + + return (void *) (offset + fix_to_virt(idx0)); +} + +void __init early_iounmap(void *addr, unsigned long size) +{ + unsigned long virt_addr; + unsigned long offset; + unsigned int nrpages; + enum fixed_addresses idx; + unsigned int nesting; + + nesting = --early_ioremap_nested; + WARN_ON(nesting < 0); + + if (early_ioremap_debug) { + printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr, + size, nesting); + dump_stack(); + } + + virt_addr = (unsigned long)addr; + if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) { + WARN_ON(1); + return; + } + offset = virt_addr & ~PAGE_MASK; + nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT; + + idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting; + while (nrpages > 0) { + early_clear_fixmap(idx); + --idx; + --nrpages; + } +} + +void __this_fixmap_does_not_exist(void) +{ + WARN_ON(1); +} + +#endif /* CONFIG_X86_32 */ |