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linux-zen-desktop/arch/powerpc/mm/book3s64/hash_utils.c

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2023-08-30 17:31:07 +02:00
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PowerPC64 port by Mike Corrigan and Dave Engebretsen
* {mikejc|engebret}@us.ibm.com
*
* Copyright (c) 2000 Mike Corrigan <mikejc@us.ibm.com>
*
* SMP scalability work:
* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
*
* Module name: htab.c
*
* Description:
* PowerPC Hashed Page Table functions
*/
#undef DEBUG
#undef DEBUG_LOW
#define pr_fmt(fmt) "hash-mmu: " fmt
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/sched/mm.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/sysctl.h>
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/cache.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/memblock.h>
#include <linux/context_tracking.h>
#include <linux/libfdt.h>
#include <linux/pkeys.h>
#include <linux/hugetlb.h>
#include <linux/cpu.h>
#include <linux/pgtable.h>
#include <linux/debugfs.h>
#include <linux/random.h>
#include <linux/elf-randomize.h>
#include <linux/of_fdt.h>
#include <asm/interrupt.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/page.h>
#include <asm/types.h>
#include <linux/uaccess.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/eeh.h>
#include <asm/tlb.h>
#include <asm/cacheflush.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/copro.h>
#include <asm/udbg.h>
#include <asm/code-patching.h>
#include <asm/fadump.h>
#include <asm/firmware.h>
#include <asm/tm.h>
#include <asm/trace.h>
#include <asm/ps3.h>
#include <asm/pte-walk.h>
#include <asm/asm-prototypes.h>
#include <asm/ultravisor.h>
#include <mm/mmu_decl.h>
#include "internal.h"
#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
#ifdef DEBUG_LOW
#define DBG_LOW(fmt...) udbg_printf(fmt)
#else
#define DBG_LOW(fmt...)
#endif
#define KB (1024)
#define MB (1024*KB)
#define GB (1024L*MB)
/*
* Note: pte --> Linux PTE
* HPTE --> PowerPC Hashed Page Table Entry
*
* Execution context:
* htab_initialize is called with the MMU off (of course), but
* the kernel has been copied down to zero so it can directly
* reference global data. At this point it is very difficult
* to print debug info.
*
*/
static unsigned long _SDR1;
u8 hpte_page_sizes[1 << LP_BITS];
EXPORT_SYMBOL_GPL(hpte_page_sizes);
struct hash_pte *htab_address;
unsigned long htab_size_bytes;
unsigned long htab_hash_mask;
EXPORT_SYMBOL_GPL(htab_hash_mask);
int mmu_linear_psize = MMU_PAGE_4K;
EXPORT_SYMBOL_GPL(mmu_linear_psize);
int mmu_virtual_psize = MMU_PAGE_4K;
int mmu_vmalloc_psize = MMU_PAGE_4K;
EXPORT_SYMBOL_GPL(mmu_vmalloc_psize);
int mmu_io_psize = MMU_PAGE_4K;
int mmu_kernel_ssize = MMU_SEGSIZE_256M;
EXPORT_SYMBOL_GPL(mmu_kernel_ssize);
int mmu_highuser_ssize = MMU_SEGSIZE_256M;
u16 mmu_slb_size = 64;
EXPORT_SYMBOL_GPL(mmu_slb_size);
#ifdef CONFIG_PPC_64K_PAGES
int mmu_ci_restrictions;
#endif
static u8 *linear_map_hash_slots;
static unsigned long linear_map_hash_count;
struct mmu_hash_ops mmu_hash_ops;
EXPORT_SYMBOL(mmu_hash_ops);
/*
* These are definitions of page sizes arrays to be used when none
* is provided by the firmware.
*/
/*
* Fallback (4k pages only)
*/
static struct mmu_psize_def mmu_psize_defaults[] = {
[MMU_PAGE_4K] = {
.shift = 12,
.sllp = 0,
.penc = {[MMU_PAGE_4K] = 0, [1 ... MMU_PAGE_COUNT - 1] = -1},
.avpnm = 0,
.tlbiel = 0,
},
};
/*
* POWER4, GPUL, POWER5
*
* Support for 16Mb large pages
*/
static struct mmu_psize_def mmu_psize_defaults_gp[] = {
[MMU_PAGE_4K] = {
.shift = 12,
.sllp = 0,
.penc = {[MMU_PAGE_4K] = 0, [1 ... MMU_PAGE_COUNT - 1] = -1},
.avpnm = 0,
.tlbiel = 1,
},
[MMU_PAGE_16M] = {
.shift = 24,
.sllp = SLB_VSID_L,
.penc = {[0 ... MMU_PAGE_16M - 1] = -1, [MMU_PAGE_16M] = 0,
[MMU_PAGE_16M + 1 ... MMU_PAGE_COUNT - 1] = -1 },
.avpnm = 0x1UL,
.tlbiel = 0,
},
};
static inline void tlbiel_hash_set_isa206(unsigned int set, unsigned int is)
{
unsigned long rb;
rb = (set << PPC_BITLSHIFT(51)) | (is << PPC_BITLSHIFT(53));
asm volatile("tlbiel %0" : : "r" (rb));
}
/*
* tlbiel instruction for hash, set invalidation
* i.e., r=1 and is=01 or is=10 or is=11
*/
static __always_inline void tlbiel_hash_set_isa300(unsigned int set, unsigned int is,
unsigned int pid,
unsigned int ric, unsigned int prs)
{
unsigned long rb;
unsigned long rs;
unsigned int r = 0; /* hash format */
rb = (set << PPC_BITLSHIFT(51)) | (is << PPC_BITLSHIFT(53));
rs = ((unsigned long)pid << PPC_BITLSHIFT(31));
asm volatile(PPC_TLBIEL(%0, %1, %2, %3, %4)
: : "r"(rb), "r"(rs), "i"(ric), "i"(prs), "i"(r)
: "memory");
}
static void tlbiel_all_isa206(unsigned int num_sets, unsigned int is)
{
unsigned int set;
asm volatile("ptesync": : :"memory");
for (set = 0; set < num_sets; set++)
tlbiel_hash_set_isa206(set, is);
ppc_after_tlbiel_barrier();
}
static void tlbiel_all_isa300(unsigned int num_sets, unsigned int is)
{
unsigned int set;
asm volatile("ptesync": : :"memory");
/*
* Flush the partition table cache if this is HV mode.
*/
if (early_cpu_has_feature(CPU_FTR_HVMODE))
tlbiel_hash_set_isa300(0, is, 0, 2, 0);
/*
* Now invalidate the process table cache. UPRT=0 HPT modes (what
* current hardware implements) do not use the process table, but
* add the flushes anyway.
*
* From ISA v3.0B p. 1078:
* The following forms are invalid.
* * PRS=1, R=0, and RIC!=2 (The only process-scoped
* HPT caching is of the Process Table.)
*/
tlbiel_hash_set_isa300(0, is, 0, 2, 1);
/*
* Then flush the sets of the TLB proper. Hash mode uses
* partition scoped TLB translations, which may be flushed
* in !HV mode.
*/
for (set = 0; set < num_sets; set++)
tlbiel_hash_set_isa300(set, is, 0, 0, 0);
ppc_after_tlbiel_barrier();
asm volatile(PPC_ISA_3_0_INVALIDATE_ERAT "; isync" : : :"memory");
}
void hash__tlbiel_all(unsigned int action)
{
unsigned int is;
switch (action) {
case TLB_INVAL_SCOPE_GLOBAL:
is = 3;
break;
case TLB_INVAL_SCOPE_LPID:
is = 2;
break;
default:
BUG();
}
if (early_cpu_has_feature(CPU_FTR_ARCH_300))
tlbiel_all_isa300(POWER9_TLB_SETS_HASH, is);
else if (early_cpu_has_feature(CPU_FTR_ARCH_207S))
tlbiel_all_isa206(POWER8_TLB_SETS, is);
else if (early_cpu_has_feature(CPU_FTR_ARCH_206))
tlbiel_all_isa206(POWER7_TLB_SETS, is);
else
WARN(1, "%s called on pre-POWER7 CPU\n", __func__);
}
/*
* 'R' and 'C' update notes:
* - Under pHyp or KVM, the updatepp path will not set C, thus it *will*
* create writeable HPTEs without C set, because the hcall H_PROTECT
* that we use in that case will not update C
* - The above is however not a problem, because we also don't do that
* fancy "no flush" variant of eviction and we use H_REMOVE which will
* do the right thing and thus we don't have the race I described earlier
*
* - Under bare metal, we do have the race, so we need R and C set
* - We make sure R is always set and never lost
* - C is _PAGE_DIRTY, and *should* always be set for a writeable mapping
*/
unsigned long htab_convert_pte_flags(unsigned long pteflags, unsigned long flags)
{
unsigned long rflags = 0;
/* _PAGE_EXEC -> NOEXEC */
if ((pteflags & _PAGE_EXEC) == 0)
rflags |= HPTE_R_N;
/*
* PPP bits:
* Linux uses slb key 0 for kernel and 1 for user.
* kernel RW areas are mapped with PPP=0b000
* User area is mapped with PPP=0b010 for read/write
* or PPP=0b011 for read-only (including writeable but clean pages).
*/
if (pteflags & _PAGE_PRIVILEGED) {
/*
* Kernel read only mapped with ppp bits 0b110
*/
if (!(pteflags & _PAGE_WRITE)) {
if (mmu_has_feature(MMU_FTR_KERNEL_RO))
rflags |= (HPTE_R_PP0 | 0x2);
else
rflags |= 0x3;
}
} else {
if (pteflags & _PAGE_RWX)
rflags |= 0x2;
if (!((pteflags & _PAGE_WRITE) && (pteflags & _PAGE_DIRTY)))
rflags |= 0x1;
}
/*
* We can't allow hardware to update hpte bits. Hence always
* set 'R' bit and set 'C' if it is a write fault
*/
rflags |= HPTE_R_R;
if (pteflags & _PAGE_DIRTY)
rflags |= HPTE_R_C;
/*
* Add in WIG bits
*/
if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_TOLERANT)
rflags |= HPTE_R_I;
else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_NON_IDEMPOTENT)
rflags |= (HPTE_R_I | HPTE_R_G);
else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_SAO)
rflags |= (HPTE_R_W | HPTE_R_I | HPTE_R_M);
else
/*
* Add memory coherence if cache inhibited is not set
*/
rflags |= HPTE_R_M;
rflags |= pte_to_hpte_pkey_bits(pteflags, flags);
return rflags;
}
int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
unsigned long pstart, unsigned long prot,
int psize, int ssize)
{
unsigned long vaddr, paddr;
unsigned int step, shift;
int ret = 0;
shift = mmu_psize_defs[psize].shift;
step = 1 << shift;
prot = htab_convert_pte_flags(prot, HPTE_USE_KERNEL_KEY);
DBG("htab_bolt_mapping(%lx..%lx -> %lx (%lx,%d,%d)\n",
vstart, vend, pstart, prot, psize, ssize);
/* Carefully map only the possible range */
vaddr = ALIGN(vstart, step);
paddr = ALIGN(pstart, step);
vend = ALIGN_DOWN(vend, step);
for (; vaddr < vend; vaddr += step, paddr += step) {
unsigned long hash, hpteg;
unsigned long vsid = get_kernel_vsid(vaddr, ssize);
unsigned long vpn = hpt_vpn(vaddr, vsid, ssize);
unsigned long tprot = prot;
bool secondary_hash = false;
/*
* If we hit a bad address return error.
*/
if (!vsid)
return -1;
/* Make kernel text executable */
if (overlaps_kernel_text(vaddr, vaddr + step))
tprot &= ~HPTE_R_N;
/*
* If relocatable, check if it overlaps interrupt vectors that
* are copied down to real 0. For relocatable kernel
* (e.g. kdump case) we copy interrupt vectors down to real
* address 0. Mark that region as executable. This is
* because on p8 system with relocation on exception feature
* enabled, exceptions are raised with MMU (IR=DR=1) ON. Hence
* in order to execute the interrupt handlers in virtual
* mode the vector region need to be marked as executable.
*/
if ((PHYSICAL_START > MEMORY_START) &&
overlaps_interrupt_vector_text(vaddr, vaddr + step))
tprot &= ~HPTE_R_N;
hash = hpt_hash(vpn, shift, ssize);
hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
BUG_ON(!mmu_hash_ops.hpte_insert);
repeat:
ret = mmu_hash_ops.hpte_insert(hpteg, vpn, paddr, tprot,
HPTE_V_BOLTED, psize, psize,
ssize);
if (ret == -1) {
/*
* Try to keep bolted entries in primary.
* Remove non bolted entries and try insert again
*/
ret = mmu_hash_ops.hpte_remove(hpteg);
if (ret != -1)
ret = mmu_hash_ops.hpte_insert(hpteg, vpn, paddr, tprot,
HPTE_V_BOLTED, psize, psize,
ssize);
if (ret == -1 && !secondary_hash) {
secondary_hash = true;
hpteg = ((~hash & htab_hash_mask) * HPTES_PER_GROUP);
goto repeat;
}
}
if (ret < 0)
break;
cond_resched();
if (debug_pagealloc_enabled_or_kfence() &&
(paddr >> PAGE_SHIFT) < linear_map_hash_count)
linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
}
return ret < 0 ? ret : 0;
}
int htab_remove_mapping(unsigned long vstart, unsigned long vend,
int psize, int ssize)
{
unsigned long vaddr, time_limit;
unsigned int step, shift;
int rc;
int ret = 0;
shift = mmu_psize_defs[psize].shift;
step = 1 << shift;
if (!mmu_hash_ops.hpte_removebolted)
return -ENODEV;
/* Unmap the full range specificied */
vaddr = ALIGN_DOWN(vstart, step);
time_limit = jiffies + HZ;
for (;vaddr < vend; vaddr += step) {
rc = mmu_hash_ops.hpte_removebolted(vaddr, psize, ssize);
/*
* For large number of mappings introduce a cond_resched()
* to prevent softlockup warnings.
*/
if (time_after(jiffies, time_limit)) {
cond_resched();
time_limit = jiffies + HZ;
}
if (rc == -ENOENT) {
ret = -ENOENT;
continue;
}
if (rc < 0)
return rc;
}
return ret;
}
static bool disable_1tb_segments __ro_after_init;
static int __init parse_disable_1tb_segments(char *p)
{
disable_1tb_segments = true;
return 0;
}
early_param("disable_1tb_segments", parse_disable_1tb_segments);
bool stress_hpt_enabled __initdata;
static int __init parse_stress_hpt(char *p)
{
stress_hpt_enabled = true;
return 0;
}
early_param("stress_hpt", parse_stress_hpt);
__ro_after_init DEFINE_STATIC_KEY_FALSE(stress_hpt_key);
/*
* per-CPU array allocated if we enable stress_hpt.
*/
#define STRESS_MAX_GROUPS 16
struct stress_hpt_struct {
unsigned long last_group[STRESS_MAX_GROUPS];
};
static inline int stress_nr_groups(void)
{
/*
* LPAR H_REMOVE flushes TLB, so need some number > 1 of entries
* to allow practical forward progress. Bare metal returns 1, which
* seems to help uncover more bugs.
*/
if (firmware_has_feature(FW_FEATURE_LPAR))
return STRESS_MAX_GROUPS;
else
return 1;
}
static struct stress_hpt_struct *stress_hpt_struct;
static int __init htab_dt_scan_seg_sizes(unsigned long node,
const char *uname, int depth,
void *data)
{
const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
const __be32 *prop;
int size = 0;
/* We are scanning "cpu" nodes only */
if (type == NULL || strcmp(type, "cpu") != 0)
return 0;
prop = of_get_flat_dt_prop(node, "ibm,processor-segment-sizes", &size);
if (prop == NULL)
return 0;
for (; size >= 4; size -= 4, ++prop) {
if (be32_to_cpu(prop[0]) == 40) {
DBG("1T segment support detected\n");
if (disable_1tb_segments) {
DBG("1T segments disabled by command line\n");
break;
}
cur_cpu_spec->mmu_features |= MMU_FTR_1T_SEGMENT;
return 1;
}
}
cur_cpu_spec->mmu_features &= ~MMU_FTR_NO_SLBIE_B;
return 0;
}
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 0x14:
idx = MMU_PAGE_1M;
break;
case 0x18:
idx = MMU_PAGE_16M;
break;
case 0x22:
idx = MMU_PAGE_16G;
break;
}
return idx;
}
static int __init htab_dt_scan_page_sizes(unsigned long node,
const char *uname, int depth,
void *data)
{
const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
const __be32 *prop;
int size = 0;
/* We are scanning "cpu" nodes only */
if (type == NULL || strcmp(type, "cpu") != 0)
return 0;
prop = of_get_flat_dt_prop(node, "ibm,segment-page-sizes", &size);
if (!prop)
return 0;
pr_info("Page sizes from device-tree:\n");
size /= 4;
cur_cpu_spec->mmu_features &= ~(MMU_FTR_16M_PAGE);
while(size > 0) {
unsigned int base_shift = be32_to_cpu(prop[0]);
unsigned int slbenc = be32_to_cpu(prop[1]);
unsigned int lpnum = be32_to_cpu(prop[2]);
struct mmu_psize_def *def;
int idx, base_idx;
size -= 3; prop += 3;
base_idx = get_idx_from_shift(base_shift);
if (base_idx < 0) {
/* skip the pte encoding also */
prop += lpnum * 2; size -= lpnum * 2;
continue;
}
def = &mmu_psize_defs[base_idx];
if (base_idx == MMU_PAGE_16M)
cur_cpu_spec->mmu_features |= MMU_FTR_16M_PAGE;
def->shift = base_shift;
if (base_shift <= 23)
def->avpnm = 0;
else
def->avpnm = (1 << (base_shift - 23)) - 1;
def->sllp = slbenc;
/*
* We don't know for sure what's up with tlbiel, so
* for now we only set it for 4K and 64K pages
*/
if (base_idx == MMU_PAGE_4K || base_idx == MMU_PAGE_64K)
def->tlbiel = 1;
else
def->tlbiel = 0;
while (size > 0 && lpnum) {
unsigned int shift = be32_to_cpu(prop[0]);
int penc = be32_to_cpu(prop[1]);
prop += 2; size -= 2;
lpnum--;
idx = get_idx_from_shift(shift);
if (idx < 0)
continue;
if (penc == -1)
pr_err("Invalid penc for base_shift=%d "
"shift=%d\n", base_shift, shift);
def->penc[idx] = penc;
pr_info("base_shift=%d: shift=%d, sllp=0x%04lx,"
" avpnm=0x%08lx, tlbiel=%d, penc=%d\n",
base_shift, shift, def->sllp,
def->avpnm, def->tlbiel, def->penc[idx]);
}
}
return 1;
}
#ifdef CONFIG_HUGETLB_PAGE
/*
* Scan for 16G memory blocks that have been set aside for huge pages
* and reserve those blocks for 16G huge pages.
*/
static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
const char *uname, int depth,
void *data) {
const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
const __be64 *addr_prop;
const __be32 *page_count_prop;
unsigned int expected_pages;
long unsigned int phys_addr;
long unsigned int block_size;
/* We are scanning "memory" nodes only */
if (type == NULL || strcmp(type, "memory") != 0)
return 0;
/*
* This property is the log base 2 of the number of virtual pages that
* will represent this memory block.
*/
page_count_prop = of_get_flat_dt_prop(node, "ibm,expected#pages", NULL);
if (page_count_prop == NULL)
return 0;
expected_pages = (1 << be32_to_cpu(page_count_prop[0]));
addr_prop = of_get_flat_dt_prop(node, "reg", NULL);
if (addr_prop == NULL)
return 0;
phys_addr = be64_to_cpu(addr_prop[0]);
block_size = be64_to_cpu(addr_prop[1]);
if (block_size != (16 * GB))
return 0;
printk(KERN_INFO "Huge page(16GB) memory: "
"addr = 0x%lX size = 0x%lX pages = %d\n",
phys_addr, block_size, expected_pages);
if (phys_addr + block_size * expected_pages <= memblock_end_of_DRAM()) {
memblock_reserve(phys_addr, block_size * expected_pages);
pseries_add_gpage(phys_addr, block_size, expected_pages);
}
return 0;
}
#endif /* CONFIG_HUGETLB_PAGE */
static void __init mmu_psize_set_default_penc(void)
{
int bpsize, apsize;
for (bpsize = 0; bpsize < MMU_PAGE_COUNT; bpsize++)
for (apsize = 0; apsize < MMU_PAGE_COUNT; apsize++)
mmu_psize_defs[bpsize].penc[apsize] = -1;
}
#ifdef CONFIG_PPC_64K_PAGES
static bool __init might_have_hea(void)
{
/*
* The HEA ethernet adapter requires awareness of the
* GX bus. Without that awareness we can easily assume
* we will never see an HEA ethernet device.
*/
#ifdef CONFIG_IBMEBUS
return !cpu_has_feature(CPU_FTR_ARCH_207S) &&
firmware_has_feature(FW_FEATURE_SPLPAR);
#else
return false;
#endif
}
#endif /* #ifdef CONFIG_PPC_64K_PAGES */
static void __init htab_scan_page_sizes(void)
{
int rc;
/* se the invalid penc to -1 */
mmu_psize_set_default_penc();
/* Default to 4K pages only */
memcpy(mmu_psize_defs, mmu_psize_defaults,
sizeof(mmu_psize_defaults));
/*
* Try to find the available page sizes in the device-tree
*/
rc = of_scan_flat_dt(htab_dt_scan_page_sizes, NULL);
if (rc == 0 && early_mmu_has_feature(MMU_FTR_16M_PAGE)) {
/*
* Nothing in the device-tree, but the CPU supports 16M pages,
* so let's fallback on a known size list for 16M capable CPUs.
*/
memcpy(mmu_psize_defs, mmu_psize_defaults_gp,
sizeof(mmu_psize_defaults_gp));
}
#ifdef CONFIG_HUGETLB_PAGE
if (!hugetlb_disabled && !early_radix_enabled() ) {
/* Reserve 16G huge page memory sections for huge pages */
of_scan_flat_dt(htab_dt_scan_hugepage_blocks, NULL);
}
#endif /* CONFIG_HUGETLB_PAGE */
}
/*
* Fill in the hpte_page_sizes[] array.
* We go through the mmu_psize_defs[] array looking for all the
* supported base/actual page size combinations. Each combination
* has a unique pagesize encoding (penc) value in the low bits of
* the LP field of the HPTE. For actual page sizes less than 1MB,
* some of the upper LP bits are used for RPN bits, meaning that
* we need to fill in several entries in hpte_page_sizes[].
*
* In diagrammatic form, with r = RPN bits and z = page size bits:
* PTE LP actual page size
* rrrr rrrz >=8KB
* rrrr rrzz >=16KB
* rrrr rzzz >=32KB
* rrrr zzzz >=64KB
* ...
*
* The zzzz bits are implementation-specific but are chosen so that
* no encoding for a larger page size uses the same value in its
* low-order N bits as the encoding for the 2^(12+N) byte page size
* (if it exists).
*/
static void __init init_hpte_page_sizes(void)
{
long int ap, bp;
long int shift, penc;
for (bp = 0; bp < MMU_PAGE_COUNT; ++bp) {
if (!mmu_psize_defs[bp].shift)
continue; /* not a supported page size */
for (ap = bp; ap < MMU_PAGE_COUNT; ++ap) {
penc = mmu_psize_defs[bp].penc[ap];
if (penc == -1 || !mmu_psize_defs[ap].shift)
continue;
shift = mmu_psize_defs[ap].shift - LP_SHIFT;
if (shift <= 0)
continue; /* should never happen */
/*
* For page sizes less than 1MB, this loop
* replicates the entry for all possible values
* of the rrrr bits.
*/
while (penc < (1 << LP_BITS)) {
hpte_page_sizes[penc] = (ap << 4) | bp;
penc += 1 << shift;
}
}
}
}
static void __init htab_init_page_sizes(void)
{
bool aligned = true;
init_hpte_page_sizes();
if (!debug_pagealloc_enabled_or_kfence()) {
/*
* Pick a size for the linear mapping. Currently, we only
* support 16M, 1M and 4K which is the default
*/
if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) &&
(unsigned long)_stext % 0x1000000) {
if (mmu_psize_defs[MMU_PAGE_16M].shift)
pr_warn("Kernel not 16M aligned, disabling 16M linear map alignment\n");
aligned = false;
}
if (mmu_psize_defs[MMU_PAGE_16M].shift && aligned)
mmu_linear_psize = MMU_PAGE_16M;
else if (mmu_psize_defs[MMU_PAGE_1M].shift)
mmu_linear_psize = MMU_PAGE_1M;
}
#ifdef CONFIG_PPC_64K_PAGES
/*
* Pick a size for the ordinary pages. Default is 4K, we support
* 64K for user mappings and vmalloc if supported by the processor.
* We only use 64k for ioremap if the processor
* (and firmware) support cache-inhibited large pages.
* If not, we use 4k and set mmu_ci_restrictions so that
* hash_page knows to switch processes that use cache-inhibited
* mappings to 4k pages.
*/
if (mmu_psize_defs[MMU_PAGE_64K].shift) {
mmu_virtual_psize = MMU_PAGE_64K;
mmu_vmalloc_psize = MMU_PAGE_64K;
if (mmu_linear_psize == MMU_PAGE_4K)
mmu_linear_psize = MMU_PAGE_64K;
if (mmu_has_feature(MMU_FTR_CI_LARGE_PAGE)) {
/*
* When running on pSeries using 64k pages for ioremap
* would stop us accessing the HEA ethernet. So if we
* have the chance of ever seeing one, stay at 4k.
*/
if (!might_have_hea())
mmu_io_psize = MMU_PAGE_64K;
} else
mmu_ci_restrictions = 1;
}
#endif /* CONFIG_PPC_64K_PAGES */
#ifdef CONFIG_SPARSEMEM_VMEMMAP
/*
* We try to use 16M pages for vmemmap if that is supported
* and we have at least 1G of RAM at boot
*/
if (mmu_psize_defs[MMU_PAGE_16M].shift &&
memblock_phys_mem_size() >= 0x40000000)
mmu_vmemmap_psize = MMU_PAGE_16M;
else
mmu_vmemmap_psize = mmu_virtual_psize;
#endif /* CONFIG_SPARSEMEM_VMEMMAP */
printk(KERN_DEBUG "Page orders: linear mapping = %d, "
"virtual = %d, io = %d"
#ifdef CONFIG_SPARSEMEM_VMEMMAP
", vmemmap = %d"
#endif
"\n",
mmu_psize_defs[mmu_linear_psize].shift,
mmu_psize_defs[mmu_virtual_psize].shift,
mmu_psize_defs[mmu_io_psize].shift
#ifdef CONFIG_SPARSEMEM_VMEMMAP
,mmu_psize_defs[mmu_vmemmap_psize].shift
#endif
);
}
static int __init htab_dt_scan_pftsize(unsigned long node,
const char *uname, int depth,
void *data)
{
const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
const __be32 *prop;
/* We are scanning "cpu" nodes only */
if (type == NULL || strcmp(type, "cpu") != 0)
return 0;
prop = of_get_flat_dt_prop(node, "ibm,pft-size", NULL);
if (prop != NULL) {
/* pft_size[0] is the NUMA CEC cookie */
ppc64_pft_size = be32_to_cpu(prop[1]);
return 1;
}
return 0;
}
unsigned htab_shift_for_mem_size(unsigned long mem_size)
{
unsigned memshift = __ilog2(mem_size);
unsigned pshift = mmu_psize_defs[mmu_virtual_psize].shift;
unsigned pteg_shift;
/* round mem_size up to next power of 2 */
if ((1UL << memshift) < mem_size)
memshift += 1;
/* aim for 2 pages / pteg */
pteg_shift = memshift - (pshift + 1);
/*
* 2^11 PTEGS of 128 bytes each, ie. 2^18 bytes is the minimum htab
* size permitted by the architecture.
*/
return max(pteg_shift + 7, 18U);
}
static unsigned long __init htab_get_table_size(void)
{
/*
* If hash size isn't already provided by the platform, we try to
* retrieve it from the device-tree. If it's not there neither, we
* calculate it now based on the total RAM size
*/
if (ppc64_pft_size == 0)
of_scan_flat_dt(htab_dt_scan_pftsize, NULL);
if (ppc64_pft_size)
return 1UL << ppc64_pft_size;
return 1UL << htab_shift_for_mem_size(memblock_phys_mem_size());
}
#ifdef CONFIG_MEMORY_HOTPLUG
static int resize_hpt_for_hotplug(unsigned long new_mem_size)
{
unsigned target_hpt_shift;
if (!mmu_hash_ops.resize_hpt)
return 0;
target_hpt_shift = htab_shift_for_mem_size(new_mem_size);
/*
* To avoid lots of HPT resizes if memory size is fluctuating
* across a boundary, we deliberately have some hysterisis
* here: we immediately increase the HPT size if the target
* shift exceeds the current shift, but we won't attempt to
* reduce unless the target shift is at least 2 below the
* current shift
*/
if (target_hpt_shift > ppc64_pft_size ||
target_hpt_shift < ppc64_pft_size - 1)
return mmu_hash_ops.resize_hpt(target_hpt_shift);
return 0;
}
int hash__create_section_mapping(unsigned long start, unsigned long end,
int nid, pgprot_t prot)
{
int rc;
if (end >= H_VMALLOC_START) {
pr_warn("Outside the supported range\n");
return -1;
}
resize_hpt_for_hotplug(memblock_phys_mem_size());
rc = htab_bolt_mapping(start, end, __pa(start),
pgprot_val(prot), mmu_linear_psize,
mmu_kernel_ssize);
if (rc < 0) {
int rc2 = htab_remove_mapping(start, end, mmu_linear_psize,
mmu_kernel_ssize);
BUG_ON(rc2 && (rc2 != -ENOENT));
}
return rc;
}
int hash__remove_section_mapping(unsigned long start, unsigned long end)
{
int rc = htab_remove_mapping(start, end, mmu_linear_psize,
mmu_kernel_ssize);
if (resize_hpt_for_hotplug(memblock_phys_mem_size()) == -ENOSPC)
pr_warn("Hash collision while resizing HPT\n");
return rc;
}
#endif /* CONFIG_MEMORY_HOTPLUG */
static void __init hash_init_partition_table(phys_addr_t hash_table,
unsigned long htab_size)
{
mmu_partition_table_init();
/*
* PS field (VRMA page size) is not used for LPID 0, hence set to 0.
* For now, UPRT is 0 and we have no segment table.
*/
htab_size = __ilog2(htab_size) - 18;
mmu_partition_table_set_entry(0, hash_table | htab_size, 0, false);
pr_info("Partition table %p\n", partition_tb);
}
void hpt_clear_stress(void);
static struct timer_list stress_hpt_timer;
static void stress_hpt_timer_fn(struct timer_list *timer)
{
int next_cpu;
hpt_clear_stress();
if (!firmware_has_feature(FW_FEATURE_LPAR))
tlbiel_all();
next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask);
if (next_cpu >= nr_cpu_ids)
next_cpu = cpumask_first(cpu_online_mask);
stress_hpt_timer.expires = jiffies + msecs_to_jiffies(10);
add_timer_on(&stress_hpt_timer, next_cpu);
}
static void __init htab_initialize(void)
{
unsigned long table;
unsigned long pteg_count;
unsigned long prot;
phys_addr_t base = 0, size = 0, end;
u64 i;
DBG(" -> htab_initialize()\n");
if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) {
mmu_kernel_ssize = MMU_SEGSIZE_1T;
mmu_highuser_ssize = MMU_SEGSIZE_1T;
printk(KERN_INFO "Using 1TB segments\n");
}
if (stress_slb_enabled)
static_branch_enable(&stress_slb_key);
if (stress_hpt_enabled) {
unsigned long tmp;
static_branch_enable(&stress_hpt_key);
// Too early to use nr_cpu_ids, so use NR_CPUS
tmp = memblock_phys_alloc_range(sizeof(struct stress_hpt_struct) * NR_CPUS,
__alignof__(struct stress_hpt_struct),
0, MEMBLOCK_ALLOC_ANYWHERE);
memset((void *)tmp, 0xff, sizeof(struct stress_hpt_struct) * NR_CPUS);
stress_hpt_struct = __va(tmp);
timer_setup(&stress_hpt_timer, stress_hpt_timer_fn, 0);
stress_hpt_timer.expires = jiffies + msecs_to_jiffies(10);
add_timer(&stress_hpt_timer);
}
/*
* Calculate the required size of the htab. We want the number of
* PTEGs to equal one half the number of real pages.
*/
htab_size_bytes = htab_get_table_size();
pteg_count = htab_size_bytes >> 7;
htab_hash_mask = pteg_count - 1;
if (firmware_has_feature(FW_FEATURE_LPAR) ||
firmware_has_feature(FW_FEATURE_PS3_LV1)) {
/* Using a hypervisor which owns the htab */
htab_address = NULL;
_SDR1 = 0;
#ifdef CONFIG_FA_DUMP
/*
* If firmware assisted dump is active firmware preserves
* the contents of htab along with entire partition memory.
* Clear the htab if firmware assisted dump is active so
* that we dont end up using old mappings.
*/
if (is_fadump_active() && mmu_hash_ops.hpte_clear_all)
mmu_hash_ops.hpte_clear_all();
#endif
} else {
unsigned long limit = MEMBLOCK_ALLOC_ANYWHERE;
#ifdef CONFIG_PPC_CELL
/*
* Cell may require the hash table down low when using the
* Axon IOMMU in order to fit the dynamic region over it, see
* comments in cell/iommu.c
*/
if (fdt_subnode_offset(initial_boot_params, 0, "axon") > 0) {
limit = 0x80000000;
pr_info("Hash table forced below 2G for Axon IOMMU\n");
}
#endif /* CONFIG_PPC_CELL */
table = memblock_phys_alloc_range(htab_size_bytes,
htab_size_bytes,
0, limit);
if (!table)
panic("ERROR: Failed to allocate %pa bytes below %pa\n",
&htab_size_bytes, &limit);
DBG("Hash table allocated at %lx, size: %lx\n", table,
htab_size_bytes);
htab_address = __va(table);
/* htab absolute addr + encoded htabsize */
_SDR1 = table + __ilog2(htab_size_bytes) - 18;
/* Initialize the HPT with no entries */
memset((void *)table, 0, htab_size_bytes);
if (!cpu_has_feature(CPU_FTR_ARCH_300))
/* Set SDR1 */
mtspr(SPRN_SDR1, _SDR1);
else
hash_init_partition_table(table, htab_size_bytes);
}
prot = pgprot_val(PAGE_KERNEL);
if (debug_pagealloc_enabled_or_kfence()) {
linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
linear_map_hash_slots = memblock_alloc_try_nid(
linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT,
ppc64_rma_size, NUMA_NO_NODE);
if (!linear_map_hash_slots)
panic("%s: Failed to allocate %lu bytes max_addr=%pa\n",
__func__, linear_map_hash_count, &ppc64_rma_size);
}
/* create bolted the linear mapping in the hash table */
for_each_mem_range(i, &base, &end) {
size = end - base;
base = (unsigned long)__va(base);
DBG("creating mapping for region: %lx..%lx (prot: %lx)\n",
base, size, prot);
if ((base + size) >= H_VMALLOC_START) {
pr_warn("Outside the supported range\n");
continue;
}
BUG_ON(htab_bolt_mapping(base, base + size, __pa(base),
prot, mmu_linear_psize, mmu_kernel_ssize));
}
memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
/*
* If we have a memory_limit and we've allocated TCEs then we need to
* explicitly map the TCE area at the top of RAM. We also cope with the
* case that the TCEs start below memory_limit.
* tce_alloc_start/end are 16MB aligned so the mapping should work
* for either 4K or 16MB pages.
*/
if (tce_alloc_start) {
tce_alloc_start = (unsigned long)__va(tce_alloc_start);
tce_alloc_end = (unsigned long)__va(tce_alloc_end);
if (base + size >= tce_alloc_start)
tce_alloc_start = base + size + 1;
BUG_ON(htab_bolt_mapping(tce_alloc_start, tce_alloc_end,
__pa(tce_alloc_start), prot,
mmu_linear_psize, mmu_kernel_ssize));
}
DBG(" <- htab_initialize()\n");
}
#undef KB
#undef MB
void __init hash__early_init_devtree(void)
{
/* Initialize segment sizes */
of_scan_flat_dt(htab_dt_scan_seg_sizes, NULL);
/* Initialize page sizes */
htab_scan_page_sizes();
}
static struct hash_mm_context init_hash_mm_context;
void __init hash__early_init_mmu(void)
{
#ifndef CONFIG_PPC_64K_PAGES
/*
* We have code in __hash_page_4K() and elsewhere, which assumes it can
* do the following:
* new_pte |= (slot << H_PAGE_F_GIX_SHIFT) & (H_PAGE_F_SECOND | H_PAGE_F_GIX);
*
* Where the slot number is between 0-15, and values of 8-15 indicate
* the secondary bucket. For that code to work H_PAGE_F_SECOND and
* H_PAGE_F_GIX must occupy four contiguous bits in the PTE, and
* H_PAGE_F_SECOND must be placed above H_PAGE_F_GIX. Assert that here
* with a BUILD_BUG_ON().
*/
BUILD_BUG_ON(H_PAGE_F_SECOND != (1ul << (H_PAGE_F_GIX_SHIFT + 3)));
#endif /* CONFIG_PPC_64K_PAGES */
htab_init_page_sizes();
/*
* initialize page table size
*/
__pte_frag_nr = H_PTE_FRAG_NR;
__pte_frag_size_shift = H_PTE_FRAG_SIZE_SHIFT;
__pmd_frag_nr = H_PMD_FRAG_NR;
__pmd_frag_size_shift = H_PMD_FRAG_SIZE_SHIFT;
__pte_index_size = H_PTE_INDEX_SIZE;
__pmd_index_size = H_PMD_INDEX_SIZE;
__pud_index_size = H_PUD_INDEX_SIZE;
__pgd_index_size = H_PGD_INDEX_SIZE;
__pud_cache_index = H_PUD_CACHE_INDEX;
__pte_table_size = H_PTE_TABLE_SIZE;
__pmd_table_size = H_PMD_TABLE_SIZE;
__pud_table_size = H_PUD_TABLE_SIZE;
__pgd_table_size = H_PGD_TABLE_SIZE;
/*
* 4k use hugepd format, so for hash set then to
* zero
*/
__pmd_val_bits = HASH_PMD_VAL_BITS;
__pud_val_bits = HASH_PUD_VAL_BITS;
__pgd_val_bits = HASH_PGD_VAL_BITS;
__kernel_virt_start = H_KERN_VIRT_START;
__vmalloc_start = H_VMALLOC_START;
__vmalloc_end = H_VMALLOC_END;
__kernel_io_start = H_KERN_IO_START;
__kernel_io_end = H_KERN_IO_END;
vmemmap = (struct page *)H_VMEMMAP_START;
ioremap_bot = IOREMAP_BASE;
#ifdef CONFIG_PCI
pci_io_base = ISA_IO_BASE;
#endif
/* Select appropriate backend */
if (firmware_has_feature(FW_FEATURE_PS3_LV1))
ps3_early_mm_init();
else if (firmware_has_feature(FW_FEATURE_LPAR))
hpte_init_pseries();
else if (IS_ENABLED(CONFIG_PPC_HASH_MMU_NATIVE))
hpte_init_native();
if (!mmu_hash_ops.hpte_insert)
panic("hash__early_init_mmu: No MMU hash ops defined!\n");
/*
* Initialize the MMU Hash table and create the linear mapping
* of memory. Has to be done before SLB initialization as this is
* currently where the page size encoding is obtained.
*/
htab_initialize();
init_mm.context.hash_context = &init_hash_mm_context;
mm_ctx_set_slb_addr_limit(&init_mm.context, SLB_ADDR_LIMIT_DEFAULT);
pr_info("Initializing hash mmu with SLB\n");
/* Initialize SLB management */
slb_initialize();
if (cpu_has_feature(CPU_FTR_ARCH_206)
&& cpu_has_feature(CPU_FTR_HVMODE))
tlbiel_all();
}
#ifdef CONFIG_SMP
void hash__early_init_mmu_secondary(void)
{
/* Initialize hash table for that CPU */
if (!firmware_has_feature(FW_FEATURE_LPAR)) {
if (!cpu_has_feature(CPU_FTR_ARCH_300))
mtspr(SPRN_SDR1, _SDR1);
else
set_ptcr_when_no_uv(__pa(partition_tb) |
(PATB_SIZE_SHIFT - 12));
}
/* Initialize SLB */
slb_initialize();
if (cpu_has_feature(CPU_FTR_ARCH_206)
&& cpu_has_feature(CPU_FTR_HVMODE))
tlbiel_all();
#ifdef CONFIG_PPC_MEM_KEYS
if (mmu_has_feature(MMU_FTR_PKEY))
mtspr(SPRN_UAMOR, default_uamor);
#endif
}
#endif /* CONFIG_SMP */
/*
* Called by asm hashtable.S for doing lazy icache flush
*/
unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
{
struct page *page;
if (!pfn_valid(pte_pfn(pte)))
return pp;
page = pte_page(pte);
/* page is dirty */
if (!test_bit(PG_dcache_clean, &page->flags) && !PageReserved(page)) {
if (trap == INTERRUPT_INST_STORAGE) {
flush_dcache_icache_page(page);
set_bit(PG_dcache_clean, &page->flags);
} else
pp |= HPTE_R_N;
}
return pp;
}
static unsigned int get_paca_psize(unsigned long addr)
{
unsigned char *psizes;
unsigned long index, mask_index;
if (addr < SLICE_LOW_TOP) {
psizes = get_paca()->mm_ctx_low_slices_psize;
index = GET_LOW_SLICE_INDEX(addr);
} else {
psizes = get_paca()->mm_ctx_high_slices_psize;
index = GET_HIGH_SLICE_INDEX(addr);
}
mask_index = index & 0x1;
return (psizes[index >> 1] >> (mask_index * 4)) & 0xF;
}
/*
* Demote a segment to using 4k pages.
* For now this makes the whole process use 4k pages.
*/
#ifdef CONFIG_PPC_64K_PAGES
void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
{
if (get_slice_psize(mm, addr) == MMU_PAGE_4K)
return;
slice_set_range_psize(mm, addr, 1, MMU_PAGE_4K);
copro_flush_all_slbs(mm);
if ((get_paca_psize(addr) != MMU_PAGE_4K) && (current->mm == mm)) {
copy_mm_to_paca(mm);
slb_flush_and_restore_bolted();
}
}
#endif /* CONFIG_PPC_64K_PAGES */
#ifdef CONFIG_PPC_SUBPAGE_PROT
/*
* This looks up a 2-bit protection code for a 4k subpage of a 64k page.
* Userspace sets the subpage permissions using the subpage_prot system call.
*
* Result is 0: full permissions, _PAGE_RW: read-only,
* _PAGE_RWX: no access.
*/
static int subpage_protection(struct mm_struct *mm, unsigned long ea)
{
struct subpage_prot_table *spt = mm_ctx_subpage_prot(&mm->context);
u32 spp = 0;
u32 **sbpm, *sbpp;
if (!spt)
return 0;
if (ea >= spt->maxaddr)
return 0;
if (ea < 0x100000000UL) {
/* addresses below 4GB use spt->low_prot */
sbpm = spt->low_prot;
} else {
sbpm = spt->protptrs[ea >> SBP_L3_SHIFT];
if (!sbpm)
return 0;
}
sbpp = sbpm[(ea >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)];
if (!sbpp)
return 0;
spp = sbpp[(ea >> PAGE_SHIFT) & (SBP_L1_COUNT - 1)];
/* extract 2-bit bitfield for this 4k subpage */
spp >>= 30 - 2 * ((ea >> 12) & 0xf);
/*
* 0 -> full permission
* 1 -> Read only
* 2 -> no access.
* We return the flag that need to be cleared.
*/
spp = ((spp & 2) ? _PAGE_RWX : 0) | ((spp & 1) ? _PAGE_WRITE : 0);
return spp;
}
#else /* CONFIG_PPC_SUBPAGE_PROT */
static inline int subpage_protection(struct mm_struct *mm, unsigned long ea)
{
return 0;
}
#endif
void hash_failure_debug(unsigned long ea, unsigned long access,
unsigned long vsid, unsigned long trap,
int ssize, int psize, int lpsize, unsigned long pte)
{
if (!printk_ratelimit())
return;
pr_info("mm: Hashing failure ! EA=0x%lx access=0x%lx current=%s\n",
ea, access, current->comm);
pr_info(" trap=0x%lx vsid=0x%lx ssize=%d base psize=%d psize %d pte=0x%lx\n",
trap, vsid, ssize, psize, lpsize, pte);
}
static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
int psize, bool user_region)
{
if (user_region) {
if (psize != get_paca_psize(ea)) {
copy_mm_to_paca(mm);
slb_flush_and_restore_bolted();
}
} else if (get_paca()->vmalloc_sllp !=
mmu_psize_defs[mmu_vmalloc_psize].sllp) {
get_paca()->vmalloc_sllp =
mmu_psize_defs[mmu_vmalloc_psize].sllp;
slb_vmalloc_update();
}
}
/*
* Result code is:
* 0 - handled
* 1 - normal page fault
* -1 - critical hash insertion error
* -2 - access not permitted by subpage protection mechanism
*/
int hash_page_mm(struct mm_struct *mm, unsigned long ea,
unsigned long access, unsigned long trap,
unsigned long flags)
{
bool is_thp;
pgd_t *pgdir;
unsigned long vsid;
pte_t *ptep;
unsigned hugeshift;
int rc, user_region = 0;
int psize, ssize;
DBG_LOW("hash_page(ea=%016lx, access=%lx, trap=%lx\n",
ea, access, trap);
trace_hash_fault(ea, access, trap);
/* Get region & vsid */
switch (get_region_id(ea)) {
case USER_REGION_ID:
user_region = 1;
if (! mm) {
DBG_LOW(" user region with no mm !\n");
rc = 1;
goto bail;
}
psize = get_slice_psize(mm, ea);
ssize = user_segment_size(ea);
vsid = get_user_vsid(&mm->context, ea, ssize);
break;
case VMALLOC_REGION_ID:
vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
psize = mmu_vmalloc_psize;
ssize = mmu_kernel_ssize;
flags |= HPTE_USE_KERNEL_KEY;
break;
case IO_REGION_ID:
vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
psize = mmu_io_psize;
ssize = mmu_kernel_ssize;
flags |= HPTE_USE_KERNEL_KEY;
break;
default:
/*
* Not a valid range
* Send the problem up to do_page_fault()
*/
rc = 1;
goto bail;
}
DBG_LOW(" mm=%p, mm->pgdir=%p, vsid=%016lx\n", mm, mm->pgd, vsid);
/* Bad address. */
if (!vsid) {
DBG_LOW("Bad address!\n");
rc = 1;
goto bail;
}
/* Get pgdir */
pgdir = mm->pgd;
if (pgdir == NULL) {
rc = 1;
goto bail;
}
/* Check CPU locality */
if (user_region && mm_is_thread_local(mm))
flags |= HPTE_LOCAL_UPDATE;
#ifndef CONFIG_PPC_64K_PAGES
/*
* If we use 4K pages and our psize is not 4K, then we might
* be hitting a special driver mapping, and need to align the
* address before we fetch the PTE.
*
* It could also be a hugepage mapping, in which case this is
* not necessary, but it's not harmful, either.
*/
if (psize != MMU_PAGE_4K)
ea &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
#endif /* CONFIG_PPC_64K_PAGES */
/* Get PTE and page size from page tables */
ptep = find_linux_pte(pgdir, ea, &is_thp, &hugeshift);
if (ptep == NULL || !pte_present(*ptep)) {
DBG_LOW(" no PTE !\n");
rc = 1;
goto bail;
}
/*
* Add _PAGE_PRESENT to the required access perm. If there are parallel
* updates to the pte that can possibly clear _PAGE_PTE, catch that too.
*
* We can safely use the return pte address in rest of the function
* because we do set H_PAGE_BUSY which prevents further updates to pte
* from generic code.
*/
access |= _PAGE_PRESENT | _PAGE_PTE;
/*
* Pre-check access permissions (will be re-checked atomically
* in __hash_page_XX but this pre-check is a fast path
*/
if (!check_pte_access(access, pte_val(*ptep))) {
DBG_LOW(" no access !\n");
rc = 1;
goto bail;
}
if (hugeshift) {
if (is_thp)
rc = __hash_page_thp(ea, access, vsid, (pmd_t *)ptep,
trap, flags, ssize, psize);
#ifdef CONFIG_HUGETLB_PAGE
else
rc = __hash_page_huge(ea, access, vsid, ptep, trap,
flags, ssize, hugeshift, psize);
#else
else {
/*
* if we have hugeshift, and is not transhuge with
* hugetlb disabled, something is really wrong.
*/
rc = 1;
WARN_ON(1);
}
#endif
if (current->mm == mm)
check_paca_psize(ea, mm, psize, user_region);
goto bail;
}
#ifndef CONFIG_PPC_64K_PAGES
DBG_LOW(" i-pte: %016lx\n", pte_val(*ptep));
#else
DBG_LOW(" i-pte: %016lx %016lx\n", pte_val(*ptep),
pte_val(*(ptep + PTRS_PER_PTE)));
#endif
/* Do actual hashing */
#ifdef CONFIG_PPC_64K_PAGES
/* If H_PAGE_4K_PFN is set, make sure this is a 4k segment */
if ((pte_val(*ptep) & H_PAGE_4K_PFN) && psize == MMU_PAGE_64K) {
demote_segment_4k(mm, ea);
psize = MMU_PAGE_4K;
}
/*
* If this PTE is non-cacheable and we have restrictions on
* using non cacheable large pages, then we switch to 4k
*/
if (mmu_ci_restrictions && psize == MMU_PAGE_64K && pte_ci(*ptep)) {
if (user_region) {
demote_segment_4k(mm, ea);
psize = MMU_PAGE_4K;
} else if (ea < VMALLOC_END) {
/*
* some driver did a non-cacheable mapping
* in vmalloc space, so switch vmalloc
* to 4k pages
*/
printk(KERN_ALERT "Reducing vmalloc segment "
"to 4kB pages because of "
"non-cacheable mapping\n");
psize = mmu_vmalloc_psize = MMU_PAGE_4K;
copro_flush_all_slbs(mm);
}
}
#endif /* CONFIG_PPC_64K_PAGES */
if (current->mm == mm)
check_paca_psize(ea, mm, psize, user_region);
#ifdef CONFIG_PPC_64K_PAGES
if (psize == MMU_PAGE_64K)
rc = __hash_page_64K(ea, access, vsid, ptep, trap,
flags, ssize);
else
#endif /* CONFIG_PPC_64K_PAGES */
{
int spp = subpage_protection(mm, ea);
if (access & spp)
rc = -2;
else
rc = __hash_page_4K(ea, access, vsid, ptep, trap,
flags, ssize, spp);
}
/*
* Dump some info in case of hash insertion failure, they should
* never happen so it is really useful to know if/when they do
*/
if (rc == -1)
hash_failure_debug(ea, access, vsid, trap, ssize, psize,
psize, pte_val(*ptep));
#ifndef CONFIG_PPC_64K_PAGES
DBG_LOW(" o-pte: %016lx\n", pte_val(*ptep));
#else
DBG_LOW(" o-pte: %016lx %016lx\n", pte_val(*ptep),
pte_val(*(ptep + PTRS_PER_PTE)));
#endif
DBG_LOW(" -> rc=%d\n", rc);
bail:
return rc;
}
EXPORT_SYMBOL_GPL(hash_page_mm);
int hash_page(unsigned long ea, unsigned long access, unsigned long trap,
unsigned long dsisr)
{
unsigned long flags = 0;
struct mm_struct *mm = current->mm;
if ((get_region_id(ea) == VMALLOC_REGION_ID) ||
(get_region_id(ea) == IO_REGION_ID))
mm = &init_mm;
if (dsisr & DSISR_NOHPTE)
flags |= HPTE_NOHPTE_UPDATE;
return hash_page_mm(mm, ea, access, trap, flags);
}
EXPORT_SYMBOL_GPL(hash_page);
DEFINE_INTERRUPT_HANDLER(do_hash_fault)
{
unsigned long ea = regs->dar;
unsigned long dsisr = regs->dsisr;
unsigned long access = _PAGE_PRESENT | _PAGE_READ;
unsigned long flags = 0;
struct mm_struct *mm;
unsigned int region_id;
long err;
if (unlikely(dsisr & (DSISR_BAD_FAULT_64S | DSISR_KEYFAULT))) {
hash__do_page_fault(regs);
return;
}
region_id = get_region_id(ea);
if ((region_id == VMALLOC_REGION_ID) || (region_id == IO_REGION_ID))
mm = &init_mm;
else
mm = current->mm;
if (dsisr & DSISR_NOHPTE)
flags |= HPTE_NOHPTE_UPDATE;
if (dsisr & DSISR_ISSTORE)
access |= _PAGE_WRITE;
/*
* We set _PAGE_PRIVILEGED only when
* kernel mode access kernel space.
*
* _PAGE_PRIVILEGED is NOT set
* 1) when kernel mode access user space
* 2) user space access kernel space.
*/
access |= _PAGE_PRIVILEGED;
if (user_mode(regs) || (region_id == USER_REGION_ID))
access &= ~_PAGE_PRIVILEGED;
if (TRAP(regs) == INTERRUPT_INST_STORAGE)
access |= _PAGE_EXEC;
err = hash_page_mm(mm, ea, access, TRAP(regs), flags);
if (unlikely(err < 0)) {
// failed to insert a hash PTE due to an hypervisor error
if (user_mode(regs)) {
if (IS_ENABLED(CONFIG_PPC_SUBPAGE_PROT) && err == -2)
_exception(SIGSEGV, regs, SEGV_ACCERR, ea);
else
_exception(SIGBUS, regs, BUS_ADRERR, ea);
} else {
bad_page_fault(regs, SIGBUS);
}
err = 0;
} else if (err) {
hash__do_page_fault(regs);
}
}
static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
{
int psize = get_slice_psize(mm, ea);
/* We only prefault standard pages for now */
if (unlikely(psize != mm_ctx_user_psize(&mm->context)))
return false;
/*
* Don't prefault if subpage protection is enabled for the EA.
*/
if (unlikely((psize == MMU_PAGE_4K) && subpage_protection(mm, ea)))
return false;
return true;
}
static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea,
bool is_exec, unsigned long trap)
{
unsigned long vsid;
pgd_t *pgdir;
int rc, ssize, update_flags = 0;
unsigned long access = _PAGE_PRESENT | _PAGE_READ | (is_exec ? _PAGE_EXEC : 0);
unsigned long flags;
BUG_ON(get_region_id(ea) != USER_REGION_ID);
if (!should_hash_preload(mm, ea))
return;
DBG_LOW("hash_preload(mm=%p, mm->pgdir=%p, ea=%016lx, access=%lx,"
" trap=%lx\n", mm, mm->pgd, ea, access, trap);
/* Get Linux PTE if available */
pgdir = mm->pgd;
if (pgdir == NULL)
return;
/* Get VSID */
ssize = user_segment_size(ea);
vsid = get_user_vsid(&mm->context, ea, ssize);
if (!vsid)
return;
#ifdef CONFIG_PPC_64K_PAGES
/* If either H_PAGE_4K_PFN or cache inhibited is set (and we are on
* a 64K kernel), then we don't preload, hash_page() will take
* care of it once we actually try to access the page.
* That way we don't have to duplicate all of the logic for segment
* page size demotion here
* Called with PTL held, hence can be sure the value won't change in
* between.
*/
if ((pte_val(*ptep) & H_PAGE_4K_PFN) || pte_ci(*ptep))
return;
#endif /* CONFIG_PPC_64K_PAGES */
/*
* __hash_page_* must run with interrupts off, including PMI interrupts
* off, as it sets the H_PAGE_BUSY bit.
*
* It's otherwise possible for perf interrupts to hit at any time and
* may take a hash fault reading the user stack, which could take a
* hash miss and deadlock on the same H_PAGE_BUSY bit.
*
* Interrupts must also be off for the duration of the
* mm_is_thread_local test and update, to prevent preempt running the
* mm on another CPU (XXX: this may be racy vs kthread_use_mm).
*/
powerpc_local_irq_pmu_save(flags);
/* Is that local to this CPU ? */
if (mm_is_thread_local(mm))
update_flags |= HPTE_LOCAL_UPDATE;
/* Hash it in */
#ifdef CONFIG_PPC_64K_PAGES
if (mm_ctx_user_psize(&mm->context) == MMU_PAGE_64K)
rc = __hash_page_64K(ea, access, vsid, ptep, trap,
update_flags, ssize);
else
#endif /* CONFIG_PPC_64K_PAGES */
rc = __hash_page_4K(ea, access, vsid, ptep, trap, update_flags,
ssize, subpage_protection(mm, ea));
/* Dump some info in case of hash insertion failure, they should
* never happen so it is really useful to know if/when they do
*/
if (rc == -1)
hash_failure_debug(ea, access, vsid, trap, ssize,
mm_ctx_user_psize(&mm->context),
mm_ctx_user_psize(&mm->context),
pte_val(*ptep));
powerpc_local_irq_pmu_restore(flags);
}
/*
* This is called at the end of handling a user page fault, when the
* fault has been handled by updating a PTE in the linux page tables.
* We use it to preload an HPTE into the hash table corresponding to
* the updated linux PTE.
*
* This must always be called with the pte lock held.
*/
void __update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
pte_t *ptep)
{
/*
* We don't need to worry about _PAGE_PRESENT here because we are
* called with either mm->page_table_lock held or ptl lock held
*/
unsigned long trap;
bool is_exec;
/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
if (!pte_young(*ptep) || address >= TASK_SIZE)
return;
/*
* We try to figure out if we are coming from an instruction
* access fault and pass that down to __hash_page so we avoid
* double-faulting on execution of fresh text. We have to test
* for regs NULL since init will get here first thing at boot.
*
* We also avoid filling the hash if not coming from a fault.
*/
trap = current->thread.regs ? TRAP(current->thread.regs) : 0UL;
switch (trap) {
case 0x300:
is_exec = false;
break;
case 0x400:
is_exec = true;
break;
default:
return;
}
hash_preload(vma->vm_mm, ptep, address, is_exec, trap);
}
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
static inline void tm_flush_hash_page(int local)
{
/*
* Transactions are not aborted by tlbiel, only tlbie. Without, syncing a
* page back to a block device w/PIO could pick up transactional data
* (bad!) so we force an abort here. Before the sync the page will be
* made read-only, which will flush_hash_page. BIG ISSUE here: if the
* kernel uses a page from userspace without unmapping it first, it may
* see the speculated version.
*/
if (local && cpu_has_feature(CPU_FTR_TM) && current->thread.regs &&
MSR_TM_ACTIVE(current->thread.regs->msr)) {
tm_enable();
tm_abort(TM_CAUSE_TLBI);
}
}
#else
static inline void tm_flush_hash_page(int local)
{
}
#endif
/*
* Return the global hash slot, corresponding to the given PTE, which contains
* the HPTE.
*/
unsigned long pte_get_hash_gslot(unsigned long vpn, unsigned long shift,
int ssize, real_pte_t rpte, unsigned int subpg_index)
{
unsigned long hash, gslot, hidx;
hash = hpt_hash(vpn, shift, ssize);
hidx = __rpte_to_hidx(rpte, subpg_index);
if (hidx & _PTEIDX_SECONDARY)
hash = ~hash;
gslot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
gslot += hidx & _PTEIDX_GROUP_IX;
return gslot;
}
void flush_hash_page(unsigned long vpn, real_pte_t pte, int psize, int ssize,
unsigned long flags)
{
unsigned long index, shift, gslot;
int local = flags & HPTE_LOCAL_UPDATE;
DBG_LOW("flush_hash_page(vpn=%016lx)\n", vpn);
pte_iterate_hashed_subpages(pte, psize, vpn, index, shift) {
gslot = pte_get_hash_gslot(vpn, shift, ssize, pte, index);
DBG_LOW(" sub %ld: gslot=%lx\n", index, gslot);
/*
* We use same base page size and actual psize, because we don't
* use these functions for hugepage
*/
mmu_hash_ops.hpte_invalidate(gslot, vpn, psize, psize,
ssize, local);
} pte_iterate_hashed_end();
tm_flush_hash_page(local);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void flush_hash_hugepage(unsigned long vsid, unsigned long addr,
pmd_t *pmdp, unsigned int psize, int ssize,
unsigned long flags)
{
int i, max_hpte_count, valid;
unsigned long s_addr;
unsigned char *hpte_slot_array;
unsigned long hidx, shift, vpn, hash, slot;
int local = flags & HPTE_LOCAL_UPDATE;
s_addr = addr & HPAGE_PMD_MASK;
hpte_slot_array = get_hpte_slot_array(pmdp);
/*
* IF we try to do a HUGE PTE update after a withdraw is done.
* we will find the below NULL. This happens when we do
* split_huge_pmd
*/
if (!hpte_slot_array)
return;
if (mmu_hash_ops.hugepage_invalidate) {
mmu_hash_ops.hugepage_invalidate(vsid, s_addr, hpte_slot_array,
psize, ssize, local);
goto tm_abort;
}
/*
* No bluk hpte removal support, invalidate each entry
*/
shift = mmu_psize_defs[psize].shift;
max_hpte_count = HPAGE_PMD_SIZE >> shift;
for (i = 0; i < max_hpte_count; i++) {
/*
* 8 bits per each hpte entries
* 000| [ secondary group (one bit) | hidx (3 bits) | valid bit]
*/
valid = hpte_valid(hpte_slot_array, i);
if (!valid)
continue;
hidx = hpte_hash_index(hpte_slot_array, i);
/* get the vpn */
addr = s_addr + (i * (1ul << shift));
vpn = hpt_vpn(addr, vsid, ssize);
hash = hpt_hash(vpn, shift, ssize);
if (hidx & _PTEIDX_SECONDARY)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += hidx & _PTEIDX_GROUP_IX;
mmu_hash_ops.hpte_invalidate(slot, vpn, psize,
MMU_PAGE_16M, ssize, local);
}
tm_abort:
tm_flush_hash_page(local);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
void flush_hash_range(unsigned long number, int local)
{
if (mmu_hash_ops.flush_hash_range)
mmu_hash_ops.flush_hash_range(number, local);
else {
int i;
struct ppc64_tlb_batch *batch =
this_cpu_ptr(&ppc64_tlb_batch);
for (i = 0; i < number; i++)
flush_hash_page(batch->vpn[i], batch->pte[i],
batch->psize, batch->ssize, local);
}
}
long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
unsigned long pa, unsigned long rflags,
unsigned long vflags, int psize, int ssize)
{
unsigned long hpte_group;
long slot;
repeat:
hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
/* Insert into the hash table, primary slot */
slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, vflags,
psize, psize, ssize);
/* Primary is full, try the secondary */
if (unlikely(slot == -1)) {
hpte_group = (~hash & htab_hash_mask) * HPTES_PER_GROUP;
slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags,
vflags | HPTE_V_SECONDARY,
psize, psize, ssize);
if (slot == -1) {
if (mftb() & 0x1)
hpte_group = (hash & htab_hash_mask) *
HPTES_PER_GROUP;
mmu_hash_ops.hpte_remove(hpte_group);
goto repeat;
}
}
return slot;
}
void hpt_clear_stress(void)
{
int cpu = raw_smp_processor_id();
int g;
for (g = 0; g < stress_nr_groups(); g++) {
unsigned long last_group;
last_group = stress_hpt_struct[cpu].last_group[g];
if (last_group != -1UL) {
int i;
for (i = 0; i < HPTES_PER_GROUP; i++) {
if (mmu_hash_ops.hpte_remove(last_group) == -1)
break;
}
stress_hpt_struct[cpu].last_group[g] = -1;
}
}
}
void hpt_do_stress(unsigned long ea, unsigned long hpte_group)
{
unsigned long last_group;
int cpu = raw_smp_processor_id();
last_group = stress_hpt_struct[cpu].last_group[stress_nr_groups() - 1];
if (hpte_group == last_group)
return;
if (last_group != -1UL) {
int i;
/*
* Concurrent CPUs might be inserting into this group, so
* give up after a number of iterations, to prevent a live
* lock.
*/
for (i = 0; i < HPTES_PER_GROUP; i++) {
if (mmu_hash_ops.hpte_remove(last_group) == -1)
break;
}
stress_hpt_struct[cpu].last_group[stress_nr_groups() - 1] = -1;
}
if (ea >= PAGE_OFFSET) {
/*
* We would really like to prefetch to get the TLB loaded, then
* remove the PTE before returning from fault interrupt, to
* increase the hash fault rate.
*
* Unfortunately QEMU TCG does not model the TLB in a way that
* makes this possible, and systemsim (mambo) emulator does not
* bring in TLBs with prefetches (although loads/stores do
* work for non-CI PTEs).
*
* So remember this PTE and clear it on the next hash fault.
*/
memmove(&stress_hpt_struct[cpu].last_group[1],
&stress_hpt_struct[cpu].last_group[0],
(stress_nr_groups() - 1) * sizeof(unsigned long));
stress_hpt_struct[cpu].last_group[0] = hpte_group;
}
}
#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
static DEFINE_RAW_SPINLOCK(linear_map_hash_lock);
static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
{
unsigned long hash;
unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
unsigned long vpn = hpt_vpn(vaddr, vsid, mmu_kernel_ssize);
unsigned long mode = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL), HPTE_USE_KERNEL_KEY);
long ret;
hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize);
/* Don't create HPTE entries for bad address */
if (!vsid)
return;
if (linear_map_hash_slots[lmi] & 0x80)
return;
ret = hpte_insert_repeating(hash, vpn, __pa(vaddr), mode,
HPTE_V_BOLTED,
mmu_linear_psize, mmu_kernel_ssize);
BUG_ON (ret < 0);
raw_spin_lock(&linear_map_hash_lock);
BUG_ON(linear_map_hash_slots[lmi] & 0x80);
linear_map_hash_slots[lmi] = ret | 0x80;
raw_spin_unlock(&linear_map_hash_lock);
}
static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
{
unsigned long hash, hidx, slot;
unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
unsigned long vpn = hpt_vpn(vaddr, vsid, mmu_kernel_ssize);
hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize);
raw_spin_lock(&linear_map_hash_lock);
if (!(linear_map_hash_slots[lmi] & 0x80)) {
raw_spin_unlock(&linear_map_hash_lock);
return;
}
hidx = linear_map_hash_slots[lmi] & 0x7f;
linear_map_hash_slots[lmi] = 0;
raw_spin_unlock(&linear_map_hash_lock);
if (hidx & _PTEIDX_SECONDARY)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += hidx & _PTEIDX_GROUP_IX;
mmu_hash_ops.hpte_invalidate(slot, vpn, mmu_linear_psize,
mmu_linear_psize,
mmu_kernel_ssize, 0);
}
void hash__kernel_map_pages(struct page *page, int numpages, int enable)
{
unsigned long flags, vaddr, lmi;
int i;
local_irq_save(flags);
for (i = 0; i < numpages; i++, page++) {
vaddr = (unsigned long)page_address(page);
lmi = __pa(vaddr) >> PAGE_SHIFT;
if (lmi >= linear_map_hash_count)
continue;
if (enable)
kernel_map_linear_page(vaddr, lmi);
else
kernel_unmap_linear_page(vaddr, lmi);
}
local_irq_restore(flags);
}
#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_KFENCE */
void hash__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);
/*
* On virtualized systems the first entry is our RMA region aka VRMA,
* non-virtualized 64-bit hash MMU systems don't have a limitation
* on real mode access.
*
* For guests on platforms before POWER9, we clamp the it limit to 1G
* to avoid some funky things such as RTAS bugs etc...
*
* On POWER9 we limit to 1TB in case the host erroneously told us that
* the RMA was >1TB. Effective address bits 0:23 are treated as zero
* (meaning the access is aliased to zero i.e. addr = addr % 1TB)
* for virtual real mode addressing and so it doesn't make sense to
* have an area larger than 1TB as it can't be addressed.
*/
if (!early_cpu_has_feature(CPU_FTR_HVMODE)) {
ppc64_rma_size = first_memblock_size;
if (!early_cpu_has_feature(CPU_FTR_ARCH_300))
ppc64_rma_size = min_t(u64, ppc64_rma_size, 0x40000000);
else
ppc64_rma_size = min_t(u64, ppc64_rma_size,
1UL << SID_SHIFT_1T);
/* Finally limit subsequent allocations */
memblock_set_current_limit(ppc64_rma_size);
} else {
ppc64_rma_size = ULONG_MAX;
}
}
#ifdef CONFIG_DEBUG_FS
static int hpt_order_get(void *data, u64 *val)
{
*val = ppc64_pft_size;
return 0;
}
static int hpt_order_set(void *data, u64 val)
{
int ret;
if (!mmu_hash_ops.resize_hpt)
return -ENODEV;
cpus_read_lock();
ret = mmu_hash_ops.resize_hpt(val);
cpus_read_unlock();
return ret;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_hpt_order, hpt_order_get, hpt_order_set, "%llu\n");
static int __init hash64_debugfs(void)
{
debugfs_create_file("hpt_order", 0600, arch_debugfs_dir, NULL,
&fops_hpt_order);
return 0;
}
machine_device_initcall(pseries, hash64_debugfs);
#endif /* CONFIG_DEBUG_FS */
void __init print_system_hash_info(void)
{
pr_info("ppc64_pft_size = 0x%llx\n", ppc64_pft_size);
if (htab_hash_mask)
pr_info("htab_hash_mask = 0x%lx\n", htab_hash_mask);
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
/*
* If we are using 1TB segments and we are allowed to randomise
* the heap, we can put it above 1TB so it is backed by a 1TB
* segment. Otherwise the heap will be in the bottom 1TB
* which always uses 256MB segments and this may result in a
* performance penalty.
*/
if (is_32bit_task())
return randomize_page(mm->brk, SZ_32M);
else if (!radix_enabled() && mmu_highuser_ssize == MMU_SEGSIZE_1T)
return randomize_page(max_t(unsigned long, mm->brk, SZ_1T), SZ_1G);
else
return randomize_page(mm->brk, SZ_1G);
}