linux/arch/powerpc/mm/pgtable-radix.c

804 lines
19 KiB
C

/*
* Page table handling routines for radix page table.
*
* Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/sched/mm.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/machdep.h>
#include <asm/mmu.h>
#include <asm/firmware.h>
#include <asm/powernv.h>
#include <asm/sections.h>
#include <asm/trace.h>
#include <trace/events/thp.h>
static int native_register_process_table(unsigned long base, unsigned long pg_sz,
unsigned long table_size)
{
unsigned long patb1 = base | table_size | PATB_GR;
partition_tb->patb1 = cpu_to_be64(patb1);
return 0;
}
static __ref void *early_alloc_pgtable(unsigned long size)
{
void *pt;
pt = __va(memblock_alloc_base(size, size, MEMBLOCK_ALLOC_ANYWHERE));
memset(pt, 0, size);
return pt;
}
int radix__map_kernel_page(unsigned long ea, unsigned long pa,
pgprot_t flags,
unsigned int map_page_size)
{
pgd_t *pgdp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
/*
* Make sure task size is correct as per the max adddr
*/
BUILD_BUG_ON(TASK_SIZE_USER64 > RADIX_PGTABLE_RANGE);
if (slab_is_available()) {
pgdp = pgd_offset_k(ea);
pudp = pud_alloc(&init_mm, pgdp, ea);
if (!pudp)
return -ENOMEM;
if (map_page_size == PUD_SIZE) {
ptep = (pte_t *)pudp;
goto set_the_pte;
}
pmdp = pmd_alloc(&init_mm, pudp, ea);
if (!pmdp)
return -ENOMEM;
if (map_page_size == PMD_SIZE) {
ptep = pmdp_ptep(pmdp);
goto set_the_pte;
}
ptep = pte_alloc_kernel(pmdp, ea);
if (!ptep)
return -ENOMEM;
} else {
pgdp = pgd_offset_k(ea);
if (pgd_none(*pgdp)) {
pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
BUG_ON(pudp == NULL);
pgd_populate(&init_mm, pgdp, pudp);
}
pudp = pud_offset(pgdp, ea);
if (map_page_size == PUD_SIZE) {
ptep = (pte_t *)pudp;
goto set_the_pte;
}
if (pud_none(*pudp)) {
pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
BUG_ON(pmdp == NULL);
pud_populate(&init_mm, pudp, pmdp);
}
pmdp = pmd_offset(pudp, ea);
if (map_page_size == PMD_SIZE) {
ptep = pmdp_ptep(pmdp);
goto set_the_pte;
}
if (!pmd_present(*pmdp)) {
ptep = early_alloc_pgtable(PAGE_SIZE);
BUG_ON(ptep == NULL);
pmd_populate_kernel(&init_mm, pmdp, ptep);
}
ptep = pte_offset_kernel(pmdp, ea);
}
set_the_pte:
set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, flags));
smp_wmb();
return 0;
}
static inline void __meminit print_mapping(unsigned long start,
unsigned long end,
unsigned long size)
{
if (end <= start)
return;
pr_info("Mapped range 0x%lx - 0x%lx with 0x%lx\n", start, end, size);
}
static int __meminit create_physical_mapping(unsigned long start,
unsigned long end)
{
unsigned long vaddr, addr, mapping_size = 0;
pgprot_t prot;
start = _ALIGN_UP(start, PAGE_SIZE);
for (addr = start; addr < end; addr += mapping_size) {
unsigned long gap, previous_size;
int rc;
gap = end - addr;
previous_size = mapping_size;
if (IS_ALIGNED(addr, PUD_SIZE) && gap >= PUD_SIZE &&
mmu_psize_defs[MMU_PAGE_1G].shift)
mapping_size = PUD_SIZE;
else if (IS_ALIGNED(addr, PMD_SIZE) && gap >= PMD_SIZE &&
mmu_psize_defs[MMU_PAGE_2M].shift)
mapping_size = PMD_SIZE;
else
mapping_size = PAGE_SIZE;
if (mapping_size != previous_size) {
print_mapping(start, addr, previous_size);
start = addr;
}
vaddr = (unsigned long)__va(addr);
if (overlaps_kernel_text(vaddr, vaddr + mapping_size))
prot = PAGE_KERNEL_X;
else
prot = PAGE_KERNEL;
rc = radix__map_kernel_page(vaddr, addr, prot, mapping_size);
if (rc)
return rc;
}
print_mapping(start, addr, mapping_size);
return 0;
}
static void __init radix_init_pgtable(void)
{
unsigned long rts_field;
struct memblock_region *reg;
/* We don't support slb for radix */
mmu_slb_size = 0;
/*
* Create the linear mapping, using standard page size for now
*/
for_each_memblock(memory, reg)
WARN_ON(create_physical_mapping(reg->base,
reg->base + reg->size));
/*
* Allocate Partition table and process table for the
* host.
*/
BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 36), "Process table size too large.");
process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
/*
* Fill in the process table.
*/
rts_field = radix__get_tree_size();
process_tb->prtb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) | RADIX_PGD_INDEX_SIZE);
/*
* Fill in the partition table. We are suppose to use effective address
* of process table here. But our linear mapping also enable us to use
* physical address here.
*/
register_process_table(__pa(process_tb), 0, PRTB_SIZE_SHIFT - 12);
pr_info("Process table %p and radix root for kernel: %p\n", process_tb, init_mm.pgd);
asm volatile("ptesync" : : : "memory");
asm volatile(PPC_TLBIE_5(%0,%1,2,1,1) : :
"r" (TLBIEL_INVAL_SET_LPID), "r" (0));
asm volatile("eieio; tlbsync; ptesync" : : : "memory");
trace_tlbie(0, 0, TLBIEL_INVAL_SET_LPID, 0, 2, 1, 1);
}
static void __init radix_init_partition_table(void)
{
unsigned long rts_field, dw0;
mmu_partition_table_init();
rts_field = radix__get_tree_size();
dw0 = rts_field | __pa(init_mm.pgd) | RADIX_PGD_INDEX_SIZE | PATB_HR;
mmu_partition_table_set_entry(0, dw0, 0);
pr_info("Initializing Radix MMU\n");
pr_info("Partition table %p\n", partition_tb);
}
void __init radix_init_native(void)
{
register_process_table = native_register_process_table;
}
static int __init get_idx_from_shift(unsigned int shift)
{
int idx = -1;
switch (shift) {
case 0xc:
idx = MMU_PAGE_4K;
break;
case 0x10:
idx = MMU_PAGE_64K;
break;
case 0x15:
idx = MMU_PAGE_2M;
break;
case 0x1e:
idx = MMU_PAGE_1G;
break;
}
return idx;
}
static int __init radix_dt_scan_page_sizes(unsigned long node,
const char *uname, int depth,
void *data)
{
int size = 0;
int shift, idx;
unsigned int ap;
const __be32 *prop;
const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
/* We are scanning "cpu" nodes only */
if (type == NULL || strcmp(type, "cpu") != 0)
return 0;
prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
if (!prop)
return 0;
pr_info("Page sizes from device-tree:\n");
for (; size >= 4; size -= 4, ++prop) {
struct mmu_psize_def *def;
/* top 3 bit is AP encoding */
shift = be32_to_cpu(prop[0]) & ~(0xe << 28);
ap = be32_to_cpu(prop[0]) >> 29;
pr_info("Page size shift = %d AP=0x%x\n", shift, ap);
idx = get_idx_from_shift(shift);
if (idx < 0)
continue;
def = &mmu_psize_defs[idx];
def->shift = shift;
def->ap = ap;
}
/* needed ? */
cur_cpu_spec->mmu_features &= ~MMU_FTR_NO_SLBIE_B;
return 1;
}
void __init radix__early_init_devtree(void)
{
int rc;
/*
* Try to find the available page sizes in the device-tree
*/
rc = of_scan_flat_dt(radix_dt_scan_page_sizes, NULL);
if (rc != 0) /* Found */
goto found;
/*
* let's assume we have page 4k and 64k support
*/
mmu_psize_defs[MMU_PAGE_4K].shift = 12;
mmu_psize_defs[MMU_PAGE_4K].ap = 0x0;
mmu_psize_defs[MMU_PAGE_64K].shift = 16;
mmu_psize_defs[MMU_PAGE_64K].ap = 0x5;
found:
#ifdef CONFIG_SPARSEMEM_VMEMMAP
if (mmu_psize_defs[MMU_PAGE_2M].shift) {
/*
* map vmemmap using 2M if available
*/
mmu_vmemmap_psize = MMU_PAGE_2M;
}
#endif /* CONFIG_SPARSEMEM_VMEMMAP */
return;
}
static void update_hid_for_radix(void)
{
unsigned long hid0;
unsigned long rb = 3UL << PPC_BITLSHIFT(53); /* IS = 3 */
asm volatile("ptesync": : :"memory");
/* prs = 0, ric = 2, rs = 0, r = 1 is = 3 */
asm volatile(PPC_TLBIE_5(%0, %4, %3, %2, %1)
: : "r"(rb), "i"(1), "i"(0), "i"(2), "r"(0) : "memory");
/* prs = 1, ric = 2, rs = 0, r = 1 is = 3 */
asm volatile(PPC_TLBIE_5(%0, %4, %3, %2, %1)
: : "r"(rb), "i"(1), "i"(1), "i"(2), "r"(0) : "memory");
asm volatile("eieio; tlbsync; ptesync; isync; slbia": : :"memory");
trace_tlbie(0, 0, rb, 0, 2, 0, 1);
trace_tlbie(0, 0, rb, 0, 2, 1, 1);
/*
* now switch the HID
*/
hid0 = mfspr(SPRN_HID0);
hid0 |= HID0_POWER9_RADIX;
mtspr(SPRN_HID0, hid0);
asm volatile("isync": : :"memory");
/* Wait for it to happen */
while (!(mfspr(SPRN_HID0) & HID0_POWER9_RADIX))
cpu_relax();
}
static void radix_init_amor(void)
{
/*
* In HV mode, we init AMOR (Authority Mask Override Register) so that
* the hypervisor and guest can setup IAMR (Instruction Authority Mask
* Register), enable key 0 and set it to 1.
*
* AMOR = 0b1100 .... 0000 (Mask for key 0 is 11)
*/
mtspr(SPRN_AMOR, (3ul << 62));
}
static void radix_init_iamr(void)
{
unsigned long iamr;
/*
* The IAMR should set to 0 on DD1.
*/
if (cpu_has_feature(CPU_FTR_POWER9_DD1))
iamr = 0;
else
iamr = (1ul << 62);
/*
* Radix always uses key0 of the IAMR to determine if an access is
* allowed. We set bit 0 (IBM bit 1) of key0, to prevent instruction
* fetch.
*/
mtspr(SPRN_IAMR, iamr);
}
void __init radix__early_init_mmu(void)
{
unsigned long lpcr;
#ifdef CONFIG_PPC_64K_PAGES
/* PAGE_SIZE mappings */
mmu_virtual_psize = MMU_PAGE_64K;
#else
mmu_virtual_psize = MMU_PAGE_4K;
#endif
#ifdef CONFIG_SPARSEMEM_VMEMMAP
/* vmemmap mapping */
mmu_vmemmap_psize = mmu_virtual_psize;
#endif
/*
* initialize page table size
*/
__pte_index_size = RADIX_PTE_INDEX_SIZE;
__pmd_index_size = RADIX_PMD_INDEX_SIZE;
__pud_index_size = RADIX_PUD_INDEX_SIZE;
__pgd_index_size = RADIX_PGD_INDEX_SIZE;
__pmd_cache_index = RADIX_PMD_INDEX_SIZE;
__pte_table_size = RADIX_PTE_TABLE_SIZE;
__pmd_table_size = RADIX_PMD_TABLE_SIZE;
__pud_table_size = RADIX_PUD_TABLE_SIZE;
__pgd_table_size = RADIX_PGD_TABLE_SIZE;
__pmd_val_bits = RADIX_PMD_VAL_BITS;
__pud_val_bits = RADIX_PUD_VAL_BITS;
__pgd_val_bits = RADIX_PGD_VAL_BITS;
__kernel_virt_start = RADIX_KERN_VIRT_START;
__kernel_virt_size = RADIX_KERN_VIRT_SIZE;
__vmalloc_start = RADIX_VMALLOC_START;
__vmalloc_end = RADIX_VMALLOC_END;
vmemmap = (struct page *)RADIX_VMEMMAP_BASE;
ioremap_bot = IOREMAP_BASE;
#ifdef CONFIG_PCI
pci_io_base = ISA_IO_BASE;
#endif
/*
* For now radix also use the same frag size
*/
__pte_frag_nr = H_PTE_FRAG_NR;
__pte_frag_size_shift = H_PTE_FRAG_SIZE_SHIFT;
if (!firmware_has_feature(FW_FEATURE_LPAR)) {
radix_init_native();
if (cpu_has_feature(CPU_FTR_POWER9_DD1))
update_hid_for_radix();
lpcr = mfspr(SPRN_LPCR);
mtspr(SPRN_LPCR, lpcr | LPCR_UPRT | LPCR_HR);
radix_init_partition_table();
radix_init_amor();
} else {
radix_init_pseries();
}
memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
radix_init_iamr();
radix_init_pgtable();
}
void radix__early_init_mmu_secondary(void)
{
unsigned long lpcr;
/*
* update partition table control register and UPRT
*/
if (!firmware_has_feature(FW_FEATURE_LPAR)) {
if (cpu_has_feature(CPU_FTR_POWER9_DD1))
update_hid_for_radix();
lpcr = mfspr(SPRN_LPCR);
mtspr(SPRN_LPCR, lpcr | LPCR_UPRT | LPCR_HR);
mtspr(SPRN_PTCR,
__pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
radix_init_amor();
}
radix_init_iamr();
}
void radix__mmu_cleanup_all(void)
{
unsigned long lpcr;
if (!firmware_has_feature(FW_FEATURE_LPAR)) {
lpcr = mfspr(SPRN_LPCR);
mtspr(SPRN_LPCR, lpcr & ~LPCR_UPRT);
mtspr(SPRN_PTCR, 0);
powernv_set_nmmu_ptcr(0);
radix__flush_tlb_all();
}
}
void radix__setup_initial_memory_limit(phys_addr_t first_memblock_base,
phys_addr_t first_memblock_size)
{
/* We don't currently support the first MEMBLOCK not mapping 0
* physical on those processors
*/
BUG_ON(first_memblock_base != 0);
/*
* We limit the allocation that depend on ppc64_rma_size
* to first_memblock_size. We also clamp it to 1GB to
* avoid some funky things such as RTAS bugs.
*
* On radix config we really don't have a limitation
* on real mode access. But keeping it as above works
* well enough.
*/
ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
/*
* Finally limit subsequent allocations. We really don't want
* to limit the memblock allocations to rma_size. FIXME!! should
* we even limit at all ?
*/
memblock_set_current_limit(first_memblock_base + first_memblock_size);
}
#ifdef CONFIG_MEMORY_HOTPLUG
static void free_pte_table(pte_t *pte_start, pmd_t *pmd)
{
pte_t *pte;
int i;
for (i = 0; i < PTRS_PER_PTE; i++) {
pte = pte_start + i;
if (!pte_none(*pte))
return;
}
pte_free_kernel(&init_mm, pte_start);
pmd_clear(pmd);
}
static void free_pmd_table(pmd_t *pmd_start, pud_t *pud)
{
pmd_t *pmd;
int i;
for (i = 0; i < PTRS_PER_PMD; i++) {
pmd = pmd_start + i;
if (!pmd_none(*pmd))
return;
}
pmd_free(&init_mm, pmd_start);
pud_clear(pud);
}
static void remove_pte_table(pte_t *pte_start, unsigned long addr,
unsigned long end)
{
unsigned long next;
pte_t *pte;
pte = pte_start + pte_index(addr);
for (; addr < end; addr = next, pte++) {
next = (addr + PAGE_SIZE) & PAGE_MASK;
if (next > end)
next = end;
if (!pte_present(*pte))
continue;
if (!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(next)) {
/*
* The vmemmap_free() and remove_section_mapping()
* codepaths call us with aligned addresses.
*/
WARN_ONCE(1, "%s: unaligned range\n", __func__);
continue;
}
pte_clear(&init_mm, addr, pte);
}
}
static void remove_pmd_table(pmd_t *pmd_start, unsigned long addr,
unsigned long end)
{
unsigned long next;
pte_t *pte_base;
pmd_t *pmd;
pmd = pmd_start + pmd_index(addr);
for (; addr < end; addr = next, pmd++) {
next = pmd_addr_end(addr, end);
if (!pmd_present(*pmd))
continue;
if (pmd_huge(*pmd)) {
if (!IS_ALIGNED(addr, PMD_SIZE) ||
!IS_ALIGNED(next, PMD_SIZE)) {
WARN_ONCE(1, "%s: unaligned range\n", __func__);
continue;
}
pte_clear(&init_mm, addr, (pte_t *)pmd);
continue;
}
pte_base = (pte_t *)pmd_page_vaddr(*pmd);
remove_pte_table(pte_base, addr, next);
free_pte_table(pte_base, pmd);
}
}
static void remove_pud_table(pud_t *pud_start, unsigned long addr,
unsigned long end)
{
unsigned long next;
pmd_t *pmd_base;
pud_t *pud;
pud = pud_start + pud_index(addr);
for (; addr < end; addr = next, pud++) {
next = pud_addr_end(addr, end);
if (!pud_present(*pud))
continue;
if (pud_huge(*pud)) {
if (!IS_ALIGNED(addr, PUD_SIZE) ||
!IS_ALIGNED(next, PUD_SIZE)) {
WARN_ONCE(1, "%s: unaligned range\n", __func__);
continue;
}
pte_clear(&init_mm, addr, (pte_t *)pud);
continue;
}
pmd_base = (pmd_t *)pud_page_vaddr(*pud);
remove_pmd_table(pmd_base, addr, next);
free_pmd_table(pmd_base, pud);
}
}
static void remove_pagetable(unsigned long start, unsigned long end)
{
unsigned long addr, next;
pud_t *pud_base;
pgd_t *pgd;
spin_lock(&init_mm.page_table_lock);
for (addr = start; addr < end; addr = next) {
next = pgd_addr_end(addr, end);
pgd = pgd_offset_k(addr);
if (!pgd_present(*pgd))
continue;
if (pgd_huge(*pgd)) {
if (!IS_ALIGNED(addr, PGDIR_SIZE) ||
!IS_ALIGNED(next, PGDIR_SIZE)) {
WARN_ONCE(1, "%s: unaligned range\n", __func__);
continue;
}
pte_clear(&init_mm, addr, (pte_t *)pgd);
continue;
}
pud_base = (pud_t *)pgd_page_vaddr(*pgd);
remove_pud_table(pud_base, addr, next);
}
spin_unlock(&init_mm.page_table_lock);
radix__flush_tlb_kernel_range(start, end);
}
int __ref radix__create_section_mapping(unsigned long start, unsigned long end)
{
return create_physical_mapping(start, end);
}
int radix__remove_section_mapping(unsigned long start, unsigned long end)
{
remove_pagetable(start, end);
return 0;
}
#endif /* CONFIG_MEMORY_HOTPLUG */
#ifdef CONFIG_SPARSEMEM_VMEMMAP
int __meminit radix__vmemmap_create_mapping(unsigned long start,
unsigned long page_size,
unsigned long phys)
{
/* Create a PTE encoding */
unsigned long flags = _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_KERNEL_RW;
BUG_ON(radix__map_kernel_page(start, phys, __pgprot(flags), page_size));
return 0;
}
#ifdef CONFIG_MEMORY_HOTPLUG
void radix__vmemmap_remove_mapping(unsigned long start, unsigned long page_size)
{
remove_pagetable(start, start + page_size);
}
#endif
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
unsigned long radix__pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, unsigned long clr,
unsigned long set)
{
unsigned long old;
#ifdef CONFIG_DEBUG_VM
WARN_ON(!radix__pmd_trans_huge(*pmdp));
assert_spin_locked(&mm->page_table_lock);
#endif
old = radix__pte_update(mm, addr, (pte_t *)pmdp, clr, set, 1);
trace_hugepage_update(addr, old, clr, set);
return old;
}
pmd_t radix__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
pmd_t pmd;
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
VM_BUG_ON(radix__pmd_trans_huge(*pmdp));
/*
* khugepaged calls this for normal pmd
*/
pmd = *pmdp;
pmd_clear(pmdp);
/*FIXME!! Verify whether we need this kick below */
kick_all_cpus_sync();
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
return pmd;
}
/*
* For us pgtable_t is pte_t *. Inorder to save the deposisted
* page table, we consider the allocated page table as a list
* head. On withdraw we need to make sure we zero out the used
* list_head memory area.
*/
void radix__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable)
{
struct list_head *lh = (struct list_head *) pgtable;
assert_spin_locked(pmd_lockptr(mm, pmdp));
/* FIFO */
if (!pmd_huge_pte(mm, pmdp))
INIT_LIST_HEAD(lh);
else
list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
pmd_huge_pte(mm, pmdp) = pgtable;
}
pgtable_t radix__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
{
pte_t *ptep;
pgtable_t pgtable;
struct list_head *lh;
assert_spin_locked(pmd_lockptr(mm, pmdp));
/* FIFO */
pgtable = pmd_huge_pte(mm, pmdp);
lh = (struct list_head *) pgtable;
if (list_empty(lh))
pmd_huge_pte(mm, pmdp) = NULL;
else {
pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
list_del(lh);
}
ptep = (pte_t *) pgtable;
*ptep = __pte(0);
ptep++;
*ptep = __pte(0);
return pgtable;
}
pmd_t radix__pmdp_huge_get_and_clear(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old_pmd;
unsigned long old;
old = radix__pmd_hugepage_update(mm, addr, pmdp, ~0UL, 0);
old_pmd = __pmd(old);
/*
* Serialize against find_linux_pte_or_hugepte which does lock-less
* lookup in page tables with local interrupts disabled. For huge pages
* it casts pmd_t to pte_t. Since format of pte_t is different from
* pmd_t we want to prevent transit from pmd pointing to page table
* to pmd pointing to huge page (and back) while interrupts are disabled.
* We clear pmd to possibly replace it with page table pointer in
* different code paths. So make sure we wait for the parallel
* find_linux_pte_or_hugepage to finish.
*/
kick_all_cpus_sync();
return old_pmd;
}
int radix__has_transparent_hugepage(void)
{
/* For radix 2M at PMD level means thp */
if (mmu_psize_defs[MMU_PAGE_2M].shift == PMD_SHIFT)
return 1;
return 0;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */