From 53b87cf088e2ea68d7c59619d0214cc15bb76133 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 7 Sep 2012 18:23:51 +0100 Subject: x86, mm: Include the entire kernel memory map in trampoline_pgd There are various pieces of code in arch/x86 that require a page table with an identity mapping. Make trampoline_pgd a proper kernel page table, it currently only includes the kernel text and module space mapping. One new feature of trampoline_pgd is that it now has mappings for the physical I/O device addresses, which are inserted at ioremap() time. Some broken implementations of EFI firmware require these mappings to always be around. Acked-by: Jan Beulich Signed-off-by: Matt Fleming --- arch/x86/mm/ioremap.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) (limited to 'arch/x86/mm/ioremap.c') diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 78fe3f1..e190f7b 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -50,6 +50,107 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size, return err; } +#ifdef CONFIG_X86_64 +static void ident_pte_range(unsigned long paddr, unsigned long vaddr, + pmd_t *ppmd, pmd_t *vpmd, unsigned long end) +{ + pte_t *ppte = pte_offset_kernel(ppmd, paddr); + pte_t *vpte = pte_offset_kernel(vpmd, vaddr); + + do { + set_pte(ppte, *vpte); + } while (ppte++, vpte++, vaddr += PAGE_SIZE, vaddr != end); +} + +static int ident_pmd_range(unsigned long paddr, unsigned long vaddr, + pud_t *ppud, pud_t *vpud, unsigned long end) +{ + pmd_t *ppmd = pmd_offset(ppud, paddr); + pmd_t *vpmd = pmd_offset(vpud, vaddr); + unsigned long next; + + do { + next = pmd_addr_end(vaddr, end); + + if (!pmd_present(*ppmd)) { + pte_t *ppte = (pte_t *)get_zeroed_page(GFP_KERNEL); + if (!ppte) + return 1; + + set_pmd(ppmd, __pmd(_KERNPG_TABLE | __pa(ppte))); + } + + ident_pte_range(paddr, vaddr, ppmd, vpmd, next); + } while (ppmd++, vpmd++, vaddr = next, vaddr != end); + + return 0; +} + +static int ident_pud_range(unsigned long paddr, unsigned long vaddr, + pgd_t *ppgd, pgd_t *vpgd, unsigned long end) +{ + pud_t *ppud = pud_offset(ppgd, paddr); + pud_t *vpud = pud_offset(vpgd, vaddr); + unsigned long next; + + do { + next = pud_addr_end(vaddr, end); + + if (!pud_present(*ppud)) { + pmd_t *ppmd = (pmd_t *)get_zeroed_page(GFP_KERNEL); + if (!ppmd) + return 1; + + set_pud(ppud, __pud(_KERNPG_TABLE | __pa(ppmd))); + } + + if (ident_pmd_range(paddr, vaddr, ppud, vpud, next)) + return 1; + } while (ppud++, vpud++, vaddr = next, vaddr != end); + + return 0; +} + +static int insert_identity_mapping(resource_size_t paddr, unsigned long vaddr, + unsigned long size) +{ + unsigned long end = vaddr + size; + unsigned long next; + pgd_t *vpgd, *ppgd; + + /* Don't map over the guard hole. */ + if (paddr >= 0x800000000000 || paddr + size > 0x800000000000) + return 1; + + ppgd = __va(real_mode_header->trampoline_pgd) + pgd_index(paddr); + + vpgd = pgd_offset_k(vaddr); + do { + next = pgd_addr_end(vaddr, end); + + if (!pgd_present(*ppgd)) { + pud_t *ppud = (pud_t *)get_zeroed_page(GFP_KERNEL); + if (!ppud) + return 1; + + set_pgd(ppgd, __pgd(_KERNPG_TABLE | __pa(ppud))); + } + + if (ident_pud_range(paddr, vaddr, ppgd, vpgd, next)) + return 1; + } while (ppgd++, vpgd++, vaddr = next, vaddr != end); + + return 0; +} +#else +static inline int insert_identity_mapping(resource_size_t paddr, + unsigned long vaddr, + unsigned long size) +{ + return 0; +} +#endif /* CONFIG_X86_64 */ + /* * Remap an arbitrary physical address space into the kernel virtual * address space. Needed when the kernel wants to access high addresses @@ -163,6 +264,10 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, ret_addr = (void __iomem *) (vaddr + offset); mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr); + if (insert_identity_mapping(phys_addr, vaddr, size)) + printk(KERN_WARNING "ioremap: unable to map 0x%llx in identity pagetable\n", + (unsigned long long)phys_addr); + /* * Check if the request spans more than any BAR in the iomem resource * tree. -- cgit v1.1