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authorMatt Fleming <matt.fleming@intel.com>2012-09-07 18:23:51 +0100
committerMatt Fleming <matt.fleming@intel.com>2012-10-30 10:39:19 +0000
commit53b87cf088e2ea68d7c59619d0214cc15bb76133 (patch)
treeafa920fe2dc6e11dc023147fc6bffafcf19a2508 /arch/x86/mm/ioremap.c
parente913ca7d16d70b75367ff56a3b201980501d542c (diff)
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 <jbeulich@suse.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Diffstat (limited to 'arch/x86/mm/ioremap.c')
-rw-r--r--arch/x86/mm/ioremap.c105
1 files changed, 105 insertions, 0 deletions
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 78fe3f1ac49f..e190f7b56653 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.