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>
This commit is contained in:
Matt Fleming 2012-09-07 18:23:51 +01:00
parent e913ca7d16
commit 53b87cf088
3 changed files with 128 additions and 3 deletions

View File

@ -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);
}
}

View File

@ -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.

View File

@ -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
}