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Commit 53b87cf0 authored by Matt Fleming's avatar Matt Fleming
Browse files

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: default avatarJan Beulich <jbeulich@suse.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent e913ca7d

arch/x86/mm/init_64.c

+8 −1
Original line number Diff line number Diff line
@@ -108,13 +108,13 @@ void sync_global_pgds(unsigned long start, unsigned long end) 
	for (address = start; address <= end; address += PGDIR_SIZE) {

		const pgd_t *pgd_ref = pgd_offset_k(address);

		struct page *page;

		pgd_t *pgd;



		if (pgd_none(*pgd_ref))

			continue;



		spin_lock(&pgd_lock);

		list_for_each_entry(page, &pgd_list, lru) {

			pgd_t *pgd;

			spinlock_t *pgt_lock;



			pgd = (pgd_t *)page_address(page) + pgd_index(address);
@@ -130,6 +130,13 @@ void sync_global_pgds(unsigned long start, unsigned long end) 


			spin_unlock(pgt_lock);

		}



		pgd = __va(real_mode_header->trampoline_pgd);

		pgd += pgd_index(address);



		if (pgd_none(*pgd))

			set_pgd(pgd, *pgd_ref);



		spin_unlock(&pgd_lock);

	}

}

arch/x86/mm/ioremap.c

+105 −0
Original line number Diff line number Diff line
@@ -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.

arch/x86/realmode/init.c

+15 −2
Original line number Diff line number Diff line
@@ -78,8 +78,21 @@ void __init setup_real_mode(void) 
	*trampoline_cr4_features = read_cr4();



	trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);

	trampoline_pgd[0] = __pa(level3_ident_pgt) + _KERNPG_TABLE;

	trampoline_pgd[511] = __pa(level3_kernel_pgt) + _KERNPG_TABLE;



	/*

	 * Create an identity mapping for all of physical memory.

	 */

	for (i = 0; i <= pgd_index(max_pfn << PAGE_SHIFT); i++) {

		int index = pgd_index(PAGE_OFFSET) + i;



		trampoline_pgd[i] = (u64)pgd_val(swapper_pg_dir[index]);

	}



	/*

	 * Copy the upper-half of the kernel pages tables.

	 */

	for (i = pgd_index(PAGE_OFFSET); i < PTRS_PER_PGD; i++)

		trampoline_pgd[i] = (u64)pgd_val(swapper_pg_dir[i]);

#endif

}