linux/arch/ppc64/mm/hash_native.c

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/*
* native hashtable management.
*
* SMP scalability work:
* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
*
* 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/spinlock.h>
#include <linux/bitops.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <asm/abs_addr.h>
#include <asm/machdep.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include <asm/cputable.h>
#define HPTE_LOCK_BIT 3
static DEFINE_SPINLOCK(native_tlbie_lock);
static inline void native_lock_hpte(hpte_t *hptep)
{
unsigned long *word = &hptep->v;
while (1) {
if (!test_and_set_bit(HPTE_LOCK_BIT, word))
break;
while(test_bit(HPTE_LOCK_BIT, word))
cpu_relax();
}
}
static inline void native_unlock_hpte(hpte_t *hptep)
{
unsigned long *word = &hptep->v;
asm volatile("lwsync":::"memory");
clear_bit(HPTE_LOCK_BIT, word);
}
long native_hpte_insert(unsigned long hpte_group, unsigned long va,
unsigned long prpn, unsigned long vflags,
unsigned long rflags)
{
hpte_t *hptep = htab_address + hpte_group;
unsigned long hpte_v, hpte_r;
int i;
for (i = 0; i < HPTES_PER_GROUP; i++) {
if (! (hptep->v & HPTE_V_VALID)) {
/* retry with lock held */
native_lock_hpte(hptep);
if (! (hptep->v & HPTE_V_VALID))
break;
native_unlock_hpte(hptep);
}
hptep++;
}
if (i == HPTES_PER_GROUP)
return -1;
hpte_v = (va >> 23) << HPTE_V_AVPN_SHIFT | vflags | HPTE_V_VALID;
if (vflags & HPTE_V_LARGE)
va &= ~(1UL << HPTE_V_AVPN_SHIFT);
hpte_r = (prpn << HPTE_R_RPN_SHIFT) | rflags;
hptep->r = hpte_r;
/* Guarantee the second dword is visible before the valid bit */
__asm__ __volatile__ ("eieio" : : : "memory");
/*
* Now set the first dword including the valid bit
* NOTE: this also unlocks the hpte
*/
hptep->v = hpte_v;
__asm__ __volatile__ ("ptesync" : : : "memory");
return i | (!!(vflags & HPTE_V_SECONDARY) << 3);
}
static long native_hpte_remove(unsigned long hpte_group)
{
hpte_t *hptep;
int i;
int slot_offset;
unsigned long hpte_v;
/* pick a random entry to start at */
slot_offset = mftb() & 0x7;
for (i = 0; i < HPTES_PER_GROUP; i++) {
hptep = htab_address + hpte_group + slot_offset;
hpte_v = hptep->v;
if ((hpte_v & HPTE_V_VALID) && !(hpte_v & HPTE_V_BOLTED)) {
/* retry with lock held */
native_lock_hpte(hptep);
hpte_v = hptep->v;
if ((hpte_v & HPTE_V_VALID)
&& !(hpte_v & HPTE_V_BOLTED))
break;
native_unlock_hpte(hptep);
}
slot_offset++;
slot_offset &= 0x7;
}
if (i == HPTES_PER_GROUP)
return -1;
/* Invalidate the hpte. NOTE: this also unlocks it */
hptep->v = 0;
return i;
}
static inline void set_pp_bit(unsigned long pp, hpte_t *addr)
{
unsigned long old;
unsigned long *p = &addr->r;
__asm__ __volatile__(
"1: ldarx %0,0,%3\n\
rldimi %0,%2,0,61\n\
stdcx. %0,0,%3\n\
bne 1b"
: "=&r" (old), "=m" (*p)
: "r" (pp), "r" (p), "m" (*p)
: "cc");
}
/*
* Only works on small pages. Yes its ugly to have to check each slot in
* the group but we only use this during bootup.
*/
static long native_hpte_find(unsigned long vpn)
{
hpte_t *hptep;
unsigned long hash;
unsigned long i, j;
long slot;
unsigned long hpte_v;
hash = hpt_hash(vpn, 0);
for (j = 0; j < 2; j++) {
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
for (i = 0; i < HPTES_PER_GROUP; i++) {
hptep = htab_address + slot;
hpte_v = hptep->v;
if ((HPTE_V_AVPN_VAL(hpte_v) == (vpn >> 11))
&& (hpte_v & HPTE_V_VALID)
&& ( !!(hpte_v & HPTE_V_SECONDARY) == j)) {
/* HPTE matches */
if (j)
slot = -slot;
return slot;
}
++slot;
}
hash = ~hash;
}
return -1;
}
static long native_hpte_updatepp(unsigned long slot, unsigned long newpp,
unsigned long va, int large, int local)
{
hpte_t *hptep = htab_address + slot;
unsigned long hpte_v;
unsigned long avpn = va >> 23;
int ret = 0;
if (large)
avpn &= ~1;
native_lock_hpte(hptep);
hpte_v = hptep->v;
/* Even if we miss, we need to invalidate the TLB */
if ((HPTE_V_AVPN_VAL(hpte_v) != avpn)
|| !(hpte_v & HPTE_V_VALID)) {
native_unlock_hpte(hptep);
ret = -1;
} else {
set_pp_bit(newpp, hptep);
native_unlock_hpte(hptep);
}
/* Ensure it is out of the tlb too */
if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
tlbiel(va);
} else {
int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
if (lock_tlbie)
spin_lock(&native_tlbie_lock);
tlbie(va, large);
if (lock_tlbie)
spin_unlock(&native_tlbie_lock);
}
return ret;
}
/*
* Update the page protection bits. Intended to be used to create
* guard pages for kernel data structures on pages which are bolted
* in the HPT. Assumes pages being operated on will not be stolen.
* Does not work on large pages.
*
* No need to lock here because we should be the only user.
*/
static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea)
{
unsigned long vsid, va, vpn, flags = 0;
long slot;
hpte_t *hptep;
int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
vsid = get_kernel_vsid(ea);
va = (vsid << 28) | (ea & 0x0fffffff);
vpn = va >> PAGE_SHIFT;
slot = native_hpte_find(vpn);
if (slot == -1)
panic("could not find page to bolt\n");
hptep = htab_address + slot;
set_pp_bit(newpp, hptep);
/* Ensure it is out of the tlb too */
if (lock_tlbie)
spin_lock_irqsave(&native_tlbie_lock, flags);
tlbie(va, 0);
if (lock_tlbie)
spin_unlock_irqrestore(&native_tlbie_lock, flags);
}
static void native_hpte_invalidate(unsigned long slot, unsigned long va,
int large, int local)
{
hpte_t *hptep = htab_address + slot;
unsigned long hpte_v;
unsigned long avpn = va >> 23;
unsigned long flags;
int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
if (large)
avpn &= ~1;
local_irq_save(flags);
native_lock_hpte(hptep);
hpte_v = hptep->v;
/* Even if we miss, we need to invalidate the TLB */
if ((HPTE_V_AVPN_VAL(hpte_v) != avpn)
|| !(hpte_v & HPTE_V_VALID)) {
native_unlock_hpte(hptep);
} else {
/* Invalidate the hpte. NOTE: this also unlocks it */
hptep->v = 0;
}
/* Invalidate the tlb */
if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
tlbiel(va);
} else {
if (lock_tlbie)
spin_lock(&native_tlbie_lock);
tlbie(va, large);
if (lock_tlbie)
spin_unlock(&native_tlbie_lock);
}
local_irq_restore(flags);
}
/*
* clear all mappings on kexec. All cpus are in real mode (or they will
* be when they isi), and we are the only one left. We rely on our kernel
* mapping being 0xC0's and the hardware ignoring those two real bits.
*
* TODO: add batching support when enabled. remember, no dynamic memory here,
* athough there is the control page available...
*/
static void native_hpte_clear(void)
{
unsigned long slot, slots, flags;
hpte_t *hptep = htab_address;
unsigned long hpte_v;
unsigned long pteg_count;
pteg_count = htab_hash_mask + 1;
local_irq_save(flags);
/* we take the tlbie lock and hold it. Some hardware will
* deadlock if we try to tlbie from two processors at once.
*/
spin_lock(&native_tlbie_lock);
slots = pteg_count * HPTES_PER_GROUP;
for (slot = 0; slot < slots; slot++, hptep++) {
/*
* we could lock the pte here, but we are the only cpu
* running, right? and for crash dump, we probably
* don't want to wait for a maybe bad cpu.
*/
hpte_v = hptep->v;
if (hpte_v & HPTE_V_VALID) {
hptep->v = 0;
tlbie(slot2va(hpte_v, slot), hpte_v & HPTE_V_LARGE);
}
}
spin_unlock(&native_tlbie_lock);
local_irq_restore(flags);
}
static void native_flush_hash_range(unsigned long context,
unsigned long number, int local)
{
unsigned long vsid, vpn, va, hash, secondary, slot, flags, avpn;
int i, j;
hpte_t *hptep;
unsigned long hpte_v;
struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
/* XXX fix for large ptes */
unsigned long large = 0;
local_irq_save(flags);
j = 0;
for (i = 0; i < number; i++) {
if (batch->addr[i] < KERNELBASE)
vsid = get_vsid(context, batch->addr[i]);
else
vsid = get_kernel_vsid(batch->addr[i]);
va = (vsid << 28) | (batch->addr[i] & 0x0fffffff);
batch->vaddr[j] = va;
if (large)
vpn = va >> HPAGE_SHIFT;
else
vpn = va >> PAGE_SHIFT;
hash = hpt_hash(vpn, large);
secondary = (pte_val(batch->pte[i]) & _PAGE_SECONDARY) >> 15;
if (secondary)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += (pte_val(batch->pte[i]) & _PAGE_GROUP_IX) >> 12;
hptep = htab_address + slot;
avpn = va >> 23;
if (large)
avpn &= ~0x1UL;
native_lock_hpte(hptep);
hpte_v = hptep->v;
/* Even if we miss, we need to invalidate the TLB */
if ((HPTE_V_AVPN_VAL(hpte_v) != avpn)
|| !(hpte_v & HPTE_V_VALID)) {
native_unlock_hpte(hptep);
} else {
/* Invalidate the hpte. NOTE: this also unlocks it */
hptep->v = 0;
}
j++;
}
if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
asm volatile("ptesync":::"memory");
for (i = 0; i < j; i++)
__tlbiel(batch->vaddr[i]);
asm volatile("ptesync":::"memory");
} else {
int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
if (lock_tlbie)
spin_lock(&native_tlbie_lock);
asm volatile("ptesync":::"memory");
for (i = 0; i < j; i++)
__tlbie(batch->vaddr[i], 0);
asm volatile("eieio; tlbsync; ptesync":::"memory");
if (lock_tlbie)
spin_unlock(&native_tlbie_lock);
}
local_irq_restore(flags);
}
#ifdef CONFIG_PPC_PSERIES
/* Disable TLB batching on nighthawk */
static inline int tlb_batching_enabled(void)
{
struct device_node *root = of_find_node_by_path("/");
int enabled = 1;
if (root) {
const char *model = get_property(root, "model", NULL);
if (model && !strcmp(model, "IBM,9076-N81"))
enabled = 0;
of_node_put(root);
}
return enabled;
}
#else
static inline int tlb_batching_enabled(void)
{
return 1;
}
#endif
void hpte_init_native(void)
{
ppc_md.hpte_invalidate = native_hpte_invalidate;
ppc_md.hpte_updatepp = native_hpte_updatepp;
ppc_md.hpte_updateboltedpp = native_hpte_updateboltedpp;
ppc_md.hpte_insert = native_hpte_insert;
ppc_md.hpte_remove = native_hpte_remove;
ppc_md.hpte_clear_all = native_hpte_clear;
if (tlb_batching_enabled())
ppc_md.flush_hash_range = native_flush_hash_range;
htab_finish_init();
}