>>> Matt Fleming <matt@xxxxxxxxxxxxxxxxx> 10/03/12 2:59 PM >>>
>+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;
>+
>+#ifdef CONFIG_X86_32
>+ ppgd = initial_page_table + pgd_index(paddr);
>+
>+ if (paddr >= PAGE_OFFSET || paddr + size > PAGE_OFFSET)
>+ return 1;
>+#else
>+ ppgd = __va(real_mode_header->trampoline_pgd) + pgd_index(paddr);
Missing equivalent code (to the 32-bit one above) here - after all, you're trying
to potentially insert a 52-bit physical address into 48-bit virtual space.
>+#endif
>+
>+ 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;
>+}
>+
>/*
>* Remap an arbitrary physical address space into the kernel virtual
>* address space. Needed when the kernel wants to access high addresses
>@@ -163,6 +258,10 @@ 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);
Isn't that going to trigger quite frequently on 32-bit kernels?
Jan
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