Contributors: 44
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Thomas Gleixner |
891 |
30.43% |
11 |
10.09% |
| Linus Torvalds (pre-git) |
542 |
18.51% |
32 |
29.36% |
| Andrew Morton |
390 |
13.32% |
5 |
4.59% |
| Matthew Wilcox |
186 |
6.35% |
1 |
0.92% |
| Max Filippov |
172 |
5.87% |
2 |
1.83% |
| Nico Pitre |
108 |
3.69% |
1 |
0.92% |
| Ira Weiny |
94 |
3.21% |
6 |
5.50% |
| Mel Gorman |
94 |
3.21% |
2 |
1.83% |
| Ard Biesheuvel |
61 |
2.08% |
1 |
0.92% |
| Linus Torvalds |
60 |
2.05% |
6 |
5.50% |
| Christoph Lameter |
53 |
1.81% |
3 |
2.75% |
| OGAWA Hirofumi |
49 |
1.67% |
1 |
0.92% |
| David Hildenbrand |
33 |
1.13% |
2 |
1.83% |
| JoonSoo Kim |
27 |
0.92% |
4 |
3.67% |
| Ryan Roberts |
26 |
0.89% |
1 |
0.92% |
| Arnaldo Carvalho de Melo |
19 |
0.65% |
1 |
0.92% |
| David S. Miller |
19 |
0.65% |
1 |
0.92% |
| Anton Blanchard |
16 |
0.55% |
1 |
0.92% |
| Nicholas Piggin |
13 |
0.44% |
1 |
0.92% |
| Jeremy Fitzhardinge |
11 |
0.38% |
1 |
0.92% |
| Eric Sesterhenn / Snakebyte |
9 |
0.31% |
1 |
0.92% |
| Peter Zijlstra |
7 |
0.24% |
1 |
0.92% |
| Will Deacon |
5 |
0.17% |
2 |
1.83% |
| Paul Mackerras |
5 |
0.17% |
2 |
1.83% |
| Randy Dunlap |
4 |
0.14% |
1 |
0.92% |
| Andi Kleen |
4 |
0.14% |
1 |
0.92% |
| Pete Zaitcev |
3 |
0.10% |
1 |
0.92% |
| Tom Rini |
3 |
0.10% |
1 |
0.92% |
| Jason Wessel |
3 |
0.10% |
1 |
0.92% |
| Miaohe Lin |
2 |
0.07% |
1 |
0.92% |
| Khalid Aziz |
2 |
0.07% |
1 |
0.92% |
| Atsushi Nemoto |
2 |
0.07% |
1 |
0.92% |
| Christoph Hellwig |
2 |
0.07% |
1 |
0.92% |
| Russell King |
2 |
0.07% |
1 |
0.92% |
| Ian Campbell |
2 |
0.07% |
1 |
0.92% |
| Linus Walleij |
1 |
0.03% |
1 |
0.92% |
| Ingo Molnar |
1 |
0.03% |
1 |
0.92% |
| Fabio M. De Francesco |
1 |
0.03% |
1 |
0.92% |
| Li Haifeng |
1 |
0.03% |
1 |
0.92% |
| David Mosberger-Tang |
1 |
0.03% |
1 |
0.92% |
| Changbin Du |
1 |
0.03% |
1 |
0.92% |
| Greg Kroah-Hartman |
1 |
0.03% |
1 |
0.92% |
| Paul Gortmaker |
1 |
0.03% |
1 |
0.92% |
| Uwe Kleine-König |
1 |
0.03% |
1 |
0.92% |
| Total |
2928 |
|
109 |
|
// SPDX-License-Identifier: GPL-2.0
/*
* High memory handling common code and variables.
*
* (C) 1999 Andrea Arcangeli, SuSE GmbH, andrea@suse.de
* Gerhard Wichert, Siemens AG, Gerhard.Wichert@pdb.siemens.de
*
*
* Redesigned the x86 32-bit VM architecture to deal with
* 64-bit physical space. With current x86 CPUs this
* means up to 64 Gigabytes physical RAM.
*
* Rewrote high memory support to move the page cache into
* high memory. Implemented permanent (schedulable) kmaps
* based on Linus' idea.
*
* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
*/
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/mempool.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
#include <linux/kgdb.h>
#include <asm/tlbflush.h>
#include <linux/vmalloc.h>
#ifdef CONFIG_KMAP_LOCAL
static inline int kmap_local_calc_idx(int idx)
{
return idx + KM_MAX_IDX * smp_processor_id();
}
#ifndef arch_kmap_local_map_idx
#define arch_kmap_local_map_idx(idx, pfn) kmap_local_calc_idx(idx)
#endif
#endif /* CONFIG_KMAP_LOCAL */
/*
* Virtual_count is not a pure "count".
* 0 means that it is not mapped, and has not been mapped
* since a TLB flush - it is usable.
* 1 means that there are no users, but it has been mapped
* since the last TLB flush - so we can't use it.
* n means that there are (n-1) current users of it.
*/
#ifdef CONFIG_HIGHMEM
/*
* Architecture with aliasing data cache may define the following family of
* helper functions in its asm/highmem.h to control cache color of virtual
* addresses where physical memory pages are mapped by kmap.
*/
#ifndef get_pkmap_color
/*
* Determine color of virtual address where the page should be mapped.
*/
static inline unsigned int get_pkmap_color(struct page *page)
{
return 0;
}
#define get_pkmap_color get_pkmap_color
/*
* Get next index for mapping inside PKMAP region for page with given color.
*/
static inline unsigned int get_next_pkmap_nr(unsigned int color)
{
static unsigned int last_pkmap_nr;
last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
return last_pkmap_nr;
}
/*
* Determine if page index inside PKMAP region (pkmap_nr) of given color
* has wrapped around PKMAP region end. When this happens an attempt to
* flush all unused PKMAP slots is made.
*/
static inline int no_more_pkmaps(unsigned int pkmap_nr, unsigned int color)
{
return pkmap_nr == 0;
}
/*
* Get the number of PKMAP entries of the given color. If no free slot is
* found after checking that many entries, kmap will sleep waiting for
* someone to call kunmap and free PKMAP slot.
*/
static inline int get_pkmap_entries_count(unsigned int color)
{
return LAST_PKMAP;
}
/*
* Get head of a wait queue for PKMAP entries of the given color.
* Wait queues for different mapping colors should be independent to avoid
* unnecessary wakeups caused by freeing of slots of other colors.
*/
static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color)
{
static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
return &pkmap_map_wait;
}
#endif
unsigned long __nr_free_highpages(void)
{
unsigned long pages = 0;
struct zone *zone;
for_each_populated_zone(zone) {
if (is_highmem(zone))
pages += zone_page_state(zone, NR_FREE_PAGES);
}
return pages;
}
unsigned long __totalhigh_pages(void)
{
unsigned long pages = 0;
struct zone *zone;
for_each_populated_zone(zone) {
if (is_highmem(zone))
pages += zone_managed_pages(zone);
}
return pages;
}
EXPORT_SYMBOL(__totalhigh_pages);
static int pkmap_count[LAST_PKMAP];
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock);
pte_t *pkmap_page_table;
/*
* Most architectures have no use for kmap_high_get(), so let's abstract
* the disabling of IRQ out of the locking in that case to save on a
* potential useless overhead.
*/
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
#define lock_kmap() spin_lock_irq(&kmap_lock)
#define unlock_kmap() spin_unlock_irq(&kmap_lock)
#define lock_kmap_any(flags) spin_lock_irqsave(&kmap_lock, flags)
#define unlock_kmap_any(flags) spin_unlock_irqrestore(&kmap_lock, flags)
#else
#define lock_kmap() spin_lock(&kmap_lock)
#define unlock_kmap() spin_unlock(&kmap_lock)
#define lock_kmap_any(flags) \
do { spin_lock(&kmap_lock); (void)(flags); } while (0)
#define unlock_kmap_any(flags) \
do { spin_unlock(&kmap_lock); (void)(flags); } while (0)
#endif
struct page *__kmap_to_page(void *vaddr)
{
unsigned long base = (unsigned long) vaddr & PAGE_MASK;
struct kmap_ctrl *kctrl = ¤t->kmap_ctrl;
unsigned long addr = (unsigned long)vaddr;
int i;
/* kmap() mappings */
if (WARN_ON_ONCE(addr >= PKMAP_ADDR(0) &&
addr < PKMAP_ADDR(LAST_PKMAP)))
return pte_page(ptep_get(&pkmap_page_table[PKMAP_NR(addr)]));
/* kmap_local_page() mappings */
if (WARN_ON_ONCE(base >= __fix_to_virt(FIX_KMAP_END) &&
base < __fix_to_virt(FIX_KMAP_BEGIN))) {
for (i = 0; i < kctrl->idx; i++) {
unsigned long base_addr;
int idx;
idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
base_addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
if (base_addr == base)
return pte_page(kctrl->pteval[i]);
}
}
return virt_to_page(vaddr);
}
EXPORT_SYMBOL(__kmap_to_page);
static void flush_all_zero_pkmaps(void)
{
int i;
int need_flush = 0;
flush_cache_kmaps();
for (i = 0; i < LAST_PKMAP; i++) {
struct page *page;
pte_t ptent;
/*
* zero means we don't have anything to do,
* >1 means that it is still in use. Only
* a count of 1 means that it is free but
* needs to be unmapped
*/
if (pkmap_count[i] != 1)
continue;
pkmap_count[i] = 0;
/* sanity check */
ptent = ptep_get(&pkmap_page_table[i]);
BUG_ON(pte_none(ptent));
/*
* Don't need an atomic fetch-and-clear op here;
* no-one has the page mapped, and cannot get at
* its virtual address (and hence PTE) without first
* getting the kmap_lock (which is held here).
* So no dangers, even with speculative execution.
*/
page = pte_page(ptent);
pte_clear(&init_mm, PKMAP_ADDR(i), &pkmap_page_table[i]);
set_page_address(page, NULL);
need_flush = 1;
}
if (need_flush)
flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
}
void __kmap_flush_unused(void)
{
lock_kmap();
flush_all_zero_pkmaps();
unlock_kmap();
}
static inline unsigned long map_new_virtual(struct page *page)
{
unsigned long vaddr;
int count;
unsigned int last_pkmap_nr;
unsigned int color = get_pkmap_color(page);
start:
count = get_pkmap_entries_count(color);
/* Find an empty entry */
for (;;) {
last_pkmap_nr = get_next_pkmap_nr(color);
if (no_more_pkmaps(last_pkmap_nr, color)) {
flush_all_zero_pkmaps();
count = get_pkmap_entries_count(color);
}
if (!pkmap_count[last_pkmap_nr])
break; /* Found a usable entry */
if (--count)
continue;
/*
* Sleep for somebody else to unmap their entries
*/
{
DECLARE_WAITQUEUE(wait, current);
wait_queue_head_t *pkmap_map_wait =
get_pkmap_wait_queue_head(color);
__set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(pkmap_map_wait, &wait);
unlock_kmap();
schedule();
remove_wait_queue(pkmap_map_wait, &wait);
lock_kmap();
/* Somebody else might have mapped it while we slept */
if (page_address(page))
return (unsigned long)page_address(page);
/* Re-start */
goto start;
}
}
vaddr = PKMAP_ADDR(last_pkmap_nr);
set_pte_at(&init_mm, vaddr,
&(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
pkmap_count[last_pkmap_nr] = 1;
set_page_address(page, (void *)vaddr);
return vaddr;
}
/**
* kmap_high - map a highmem page into memory
* @page: &struct page to map
*
* Returns the page's virtual memory address.
*
* We cannot call this from interrupts, as it may block.
*/
void *kmap_high(struct page *page)
{
unsigned long vaddr;
/*
* For highmem pages, we can't trust "virtual" until
* after we have the lock.
*/
lock_kmap();
vaddr = (unsigned long)page_address(page);
if (!vaddr)
vaddr = map_new_virtual(page);
pkmap_count[PKMAP_NR(vaddr)]++;
BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2);
unlock_kmap();
return (void *) vaddr;
}
EXPORT_SYMBOL(kmap_high);
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
/**
* kmap_high_get - pin a highmem page into memory
* @page: &struct page to pin
*
* Returns the page's current virtual memory address, or NULL if no mapping
* exists. If and only if a non null address is returned then a
* matching call to kunmap_high() is necessary.
*
* This can be called from any context.
*/
void *kmap_high_get(struct page *page)
{
unsigned long vaddr, flags;
lock_kmap_any(flags);
vaddr = (unsigned long)page_address(page);
if (vaddr) {
BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 1);
pkmap_count[PKMAP_NR(vaddr)]++;
}
unlock_kmap_any(flags);
return (void *) vaddr;
}
#endif
/**
* kunmap_high - unmap a highmem page into memory
* @page: &struct page to unmap
*
* If ARCH_NEEDS_KMAP_HIGH_GET is not defined then this may be called
* only from user context.
*/
void kunmap_high(struct page *page)
{
unsigned long vaddr;
unsigned long nr;
unsigned long flags;
int need_wakeup;
unsigned int color = get_pkmap_color(page);
wait_queue_head_t *pkmap_map_wait;
lock_kmap_any(flags);
vaddr = (unsigned long)page_address(page);
BUG_ON(!vaddr);
nr = PKMAP_NR(vaddr);
/*
* A count must never go down to zero
* without a TLB flush!
*/
need_wakeup = 0;
switch (--pkmap_count[nr]) {
case 0:
BUG();
case 1:
/*
* Avoid an unnecessary wake_up() function call.
* The common case is pkmap_count[] == 1, but
* no waiters.
* The tasks queued in the wait-queue are guarded
* by both the lock in the wait-queue-head and by
* the kmap_lock. As the kmap_lock is held here,
* no need for the wait-queue-head's lock. Simply
* test if the queue is empty.
*/
pkmap_map_wait = get_pkmap_wait_queue_head(color);
need_wakeup = waitqueue_active(pkmap_map_wait);
}
unlock_kmap_any(flags);
/* do wake-up, if needed, race-free outside of the spin lock */
if (need_wakeup)
wake_up(pkmap_map_wait);
}
EXPORT_SYMBOL(kunmap_high);
void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
unsigned start2, unsigned end2)
{
unsigned int i;
BUG_ON(end1 > page_size(page) || end2 > page_size(page));
if (start1 >= end1)
start1 = end1 = 0;
if (start2 >= end2)
start2 = end2 = 0;
for (i = 0; i < compound_nr(page); i++) {
void *kaddr = NULL;
if (start1 >= PAGE_SIZE) {
start1 -= PAGE_SIZE;
end1 -= PAGE_SIZE;
} else {
unsigned this_end = min_t(unsigned, end1, PAGE_SIZE);
if (end1 > start1) {
kaddr = kmap_local_page(page + i);
memset(kaddr + start1, 0, this_end - start1);
}
end1 -= this_end;
start1 = 0;
}
if (start2 >= PAGE_SIZE) {
start2 -= PAGE_SIZE;
end2 -= PAGE_SIZE;
} else {
unsigned this_end = min_t(unsigned, end2, PAGE_SIZE);
if (end2 > start2) {
if (!kaddr)
kaddr = kmap_local_page(page + i);
memset(kaddr + start2, 0, this_end - start2);
}
end2 -= this_end;
start2 = 0;
}
if (kaddr) {
kunmap_local(kaddr);
flush_dcache_page(page + i);
}
if (!end1 && !end2)
break;
}
BUG_ON((start1 | start2 | end1 | end2) != 0);
}
EXPORT_SYMBOL(zero_user_segments);
#endif /* CONFIG_HIGHMEM */
#ifdef CONFIG_KMAP_LOCAL
#include <asm/kmap_size.h>
/*
* With DEBUG_KMAP_LOCAL the stack depth is doubled and every second
* slot is unused which acts as a guard page
*/
#ifdef CONFIG_DEBUG_KMAP_LOCAL
# define KM_INCR 2
#else
# define KM_INCR 1
#endif
static inline int kmap_local_idx_push(void)
{
WARN_ON_ONCE(in_hardirq() && !irqs_disabled());
current->kmap_ctrl.idx += KM_INCR;
BUG_ON(current->kmap_ctrl.idx >= KM_MAX_IDX);
return current->kmap_ctrl.idx - 1;
}
static inline int kmap_local_idx(void)
{
return current->kmap_ctrl.idx - 1;
}
static inline void kmap_local_idx_pop(void)
{
current->kmap_ctrl.idx -= KM_INCR;
BUG_ON(current->kmap_ctrl.idx < 0);
}
#ifndef arch_kmap_local_post_map
# define arch_kmap_local_post_map(vaddr, pteval) do { } while (0)
#endif
#ifndef arch_kmap_local_pre_unmap
# define arch_kmap_local_pre_unmap(vaddr) do { } while (0)
#endif
#ifndef arch_kmap_local_post_unmap
# define arch_kmap_local_post_unmap(vaddr) do { } while (0)
#endif
#ifndef arch_kmap_local_unmap_idx
#define arch_kmap_local_unmap_idx(idx, vaddr) kmap_local_calc_idx(idx)
#endif
#ifndef arch_kmap_local_high_get
static inline void *arch_kmap_local_high_get(struct page *page)
{
return NULL;
}
#endif
#ifndef arch_kmap_local_set_pte
#define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev) \
set_pte_at(mm, vaddr, ptep, ptev)
#endif
/* Unmap a local mapping which was obtained by kmap_high_get() */
static inline bool kmap_high_unmap_local(unsigned long vaddr)
{
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
kunmap_high(pte_page(ptep_get(&pkmap_page_table[PKMAP_NR(vaddr)])));
return true;
}
#endif
return false;
}
static pte_t *__kmap_pte;
static pte_t *kmap_get_pte(unsigned long vaddr, int idx)
{
if (IS_ENABLED(CONFIG_KMAP_LOCAL_NON_LINEAR_PTE_ARRAY))
/*
* Set by the arch if __kmap_pte[-idx] does not produce
* the correct entry.
*/
return virt_to_kpte(vaddr);
if (!__kmap_pte)
__kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
return &__kmap_pte[-idx];
}
void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
{
pte_t pteval, *kmap_pte;
unsigned long vaddr;
int idx;
/*
* Disable migration so resulting virtual address is stable
* across preemption.
*/
migrate_disable();
preempt_disable();
idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
kmap_pte = kmap_get_pte(vaddr, idx);
BUG_ON(!pte_none(ptep_get(kmap_pte)));
pteval = pfn_pte(pfn, prot);
arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte, pteval);
arch_kmap_local_post_map(vaddr, pteval);
current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
preempt_enable();
return (void *)vaddr;
}
EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot);
void *__kmap_local_page_prot(struct page *page, pgprot_t prot)
{
void *kmap;
/*
* To broaden the usage of the actual kmap_local() machinery always map
* pages when debugging is enabled and the architecture has no problems
* with alias mappings.
*/
if (!IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) && !PageHighMem(page))
return page_address(page);
/* Try kmap_high_get() if architecture has it enabled */
kmap = arch_kmap_local_high_get(page);
if (kmap)
return kmap;
return __kmap_local_pfn_prot(page_to_pfn(page), prot);
}
EXPORT_SYMBOL(__kmap_local_page_prot);
void kunmap_local_indexed(const void *vaddr)
{
unsigned long addr = (unsigned long) vaddr & PAGE_MASK;
pte_t *kmap_pte;
int idx;
if (addr < __fix_to_virt(FIX_KMAP_END) ||
addr > __fix_to_virt(FIX_KMAP_BEGIN)) {
if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP)) {
/* This _should_ never happen! See above. */
WARN_ON_ONCE(1);
return;
}
/*
* Handle mappings which were obtained by kmap_high_get()
* first as the virtual address of such mappings is below
* PAGE_OFFSET. Warn for all other addresses which are in
* the user space part of the virtual address space.
*/
if (!kmap_high_unmap_local(addr))
WARN_ON_ONCE(addr < PAGE_OFFSET);
return;
}
preempt_disable();
idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr);
WARN_ON_ONCE(addr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
kmap_pte = kmap_get_pte(addr, idx);
arch_kmap_local_pre_unmap(addr);
pte_clear(&init_mm, addr, kmap_pte);
arch_kmap_local_post_unmap(addr);
current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0);
kmap_local_idx_pop();
preempt_enable();
migrate_enable();
}
EXPORT_SYMBOL(kunmap_local_indexed);
/*
* Invoked before switch_to(). This is safe even when during or after
* clearing the maps an interrupt which needs a kmap_local happens because
* the task::kmap_ctrl.idx is not modified by the unmapping code so a
* nested kmap_local will use the next unused index and restore the index
* on unmap. The already cleared kmaps of the outgoing task are irrelevant
* because the interrupt context does not know about them. The same applies
* when scheduling back in for an interrupt which happens before the
* restore is complete.
*/
void __kmap_local_sched_out(void)
{
struct task_struct *tsk = current;
pte_t *kmap_pte;
int i;
/* Clear kmaps */
for (i = 0; i < tsk->kmap_ctrl.idx; i++) {
pte_t pteval = tsk->kmap_ctrl.pteval[i];
unsigned long addr;
int idx;
/* With debug all even slots are unmapped and act as guard */
if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) {
WARN_ON_ONCE(pte_val(pteval) != 0);
continue;
}
if (WARN_ON_ONCE(pte_none(pteval)))
continue;
/*
* This is a horrible hack for XTENSA to calculate the
* coloured PTE index. Uses the PFN encoded into the pteval
* and the map index calculation because the actual mapped
* virtual address is not stored in task::kmap_ctrl.
* For any sane architecture this is optimized out.
*/
idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
kmap_pte = kmap_get_pte(addr, idx);
arch_kmap_local_pre_unmap(addr);
pte_clear(&init_mm, addr, kmap_pte);
arch_kmap_local_post_unmap(addr);
}
}
void __kmap_local_sched_in(void)
{
struct task_struct *tsk = current;
pte_t *kmap_pte;
int i;
/* Restore kmaps */
for (i = 0; i < tsk->kmap_ctrl.idx; i++) {
pte_t pteval = tsk->kmap_ctrl.pteval[i];
unsigned long addr;
int idx;
/* With debug all even slots are unmapped and act as guard */
if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) {
WARN_ON_ONCE(pte_val(pteval) != 0);
continue;
}
if (WARN_ON_ONCE(pte_none(pteval)))
continue;
/* See comment in __kmap_local_sched_out() */
idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
kmap_pte = kmap_get_pte(addr, idx);
set_pte_at(&init_mm, addr, kmap_pte, pteval);
arch_kmap_local_post_map(addr, pteval);
}
}
void kmap_local_fork(struct task_struct *tsk)
{
if (WARN_ON_ONCE(tsk->kmap_ctrl.idx))
memset(&tsk->kmap_ctrl, 0, sizeof(tsk->kmap_ctrl));
}
#endif
#if defined(HASHED_PAGE_VIRTUAL)
#define PA_HASH_ORDER 7
/*
* Describes one page->virtual association
*/
struct page_address_map {
struct page *page;
void *virtual;
struct list_head list;
};
static struct page_address_map page_address_maps[LAST_PKMAP];
/*
* Hash table bucket
*/
static struct page_address_slot {
struct list_head lh; /* List of page_address_maps */
spinlock_t lock; /* Protect this bucket's list */
} ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];
static struct page_address_slot *page_slot(const struct page *page)
{
return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
}
/**
* page_address - get the mapped virtual address of a page
* @page: &struct page to get the virtual address of
*
* Returns the page's virtual address.
*/
void *page_address(const struct page *page)
{
unsigned long flags;
void *ret;
struct page_address_slot *pas;
if (!PageHighMem(page))
return lowmem_page_address(page);
pas = page_slot(page);
ret = NULL;
spin_lock_irqsave(&pas->lock, flags);
if (!list_empty(&pas->lh)) {
struct page_address_map *pam;
list_for_each_entry(pam, &pas->lh, list) {
if (pam->page == page) {
ret = pam->virtual;
break;
}
}
}
spin_unlock_irqrestore(&pas->lock, flags);
return ret;
}
EXPORT_SYMBOL(page_address);
/**
* set_page_address - set a page's virtual address
* @page: &struct page to set
* @virtual: virtual address to use
*/
void set_page_address(struct page *page, void *virtual)
{
unsigned long flags;
struct page_address_slot *pas;
struct page_address_map *pam;
BUG_ON(!PageHighMem(page));
pas = page_slot(page);
if (virtual) { /* Add */
pam = &page_address_maps[PKMAP_NR((unsigned long)virtual)];
pam->page = page;
pam->virtual = virtual;
spin_lock_irqsave(&pas->lock, flags);
list_add_tail(&pam->list, &pas->lh);
spin_unlock_irqrestore(&pas->lock, flags);
} else { /* Remove */
spin_lock_irqsave(&pas->lock, flags);
list_for_each_entry(pam, &pas->lh, list) {
if (pam->page == page) {
list_del(&pam->list);
break;
}
}
spin_unlock_irqrestore(&pas->lock, flags);
}
}
void __init page_address_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) {
INIT_LIST_HEAD(&page_address_htable[i].lh);
spin_lock_init(&page_address_htable[i].lock);
}
}
#endif /* defined(HASHED_PAGE_VIRTUAL) */