swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 authored by Linus Torvalds on 31 May 2020, 23:49:15 UTC
Linux 5.7
Linux 5.7
Tip revision: 3d77e6a
tlb.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
*/
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sched/signal.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <as-layout.h>
#include <mem_user.h>
#include <os.h>
#include <skas.h>
#include <kern_util.h>
struct host_vm_change {
struct host_vm_op {
enum { NONE, MMAP, MUNMAP, MPROTECT } type;
union {
struct {
unsigned long addr;
unsigned long len;
unsigned int prot;
int fd;
__u64 offset;
} mmap;
struct {
unsigned long addr;
unsigned long len;
} munmap;
struct {
unsigned long addr;
unsigned long len;
unsigned int prot;
} mprotect;
} u;
} ops[1];
int userspace;
int index;
struct mm_struct *mm;
void *data;
int force;
};
#define INIT_HVC(mm, force, userspace) \
((struct host_vm_change) \
{ .ops = { { .type = NONE } }, \
.mm = mm, \
.data = NULL, \
.userspace = userspace, \
.index = 0, \
.force = force })
static void report_enomem(void)
{
printk(KERN_ERR "UML ran out of memory on the host side! "
"This can happen due to a memory limitation or "
"vm.max_map_count has been reached.\n");
}
static int do_ops(struct host_vm_change *hvc, int end,
int finished)
{
struct host_vm_op *op;
int i, ret = 0;
for (i = 0; i < end && !ret; i++) {
op = &hvc->ops[i];
switch (op->type) {
case MMAP:
if (hvc->userspace)
ret = map(&hvc->mm->context.id, op->u.mmap.addr,
op->u.mmap.len, op->u.mmap.prot,
op->u.mmap.fd,
op->u.mmap.offset, finished,
&hvc->data);
else
map_memory(op->u.mmap.addr, op->u.mmap.offset,
op->u.mmap.len, 1, 1, 1);
break;
case MUNMAP:
if (hvc->userspace)
ret = unmap(&hvc->mm->context.id,
op->u.munmap.addr,
op->u.munmap.len, finished,
&hvc->data);
else
ret = os_unmap_memory(
(void *) op->u.munmap.addr,
op->u.munmap.len);
break;
case MPROTECT:
if (hvc->userspace)
ret = protect(&hvc->mm->context.id,
op->u.mprotect.addr,
op->u.mprotect.len,
op->u.mprotect.prot,
finished, &hvc->data);
else
ret = os_protect_memory(
(void *) op->u.mprotect.addr,
op->u.mprotect.len,
1, 1, 1);
break;
default:
printk(KERN_ERR "Unknown op type %d in do_ops\n",
op->type);
BUG();
break;
}
}
if (ret == -ENOMEM)
report_enomem();
return ret;
}
static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
unsigned int prot, struct host_vm_change *hvc)
{
__u64 offset;
struct host_vm_op *last;
int fd = -1, ret = 0;
if (hvc->userspace)
fd = phys_mapping(phys, &offset);
else
offset = phys;
if (hvc->index != 0) {
last = &hvc->ops[hvc->index - 1];
if ((last->type == MMAP) &&
(last->u.mmap.addr + last->u.mmap.len == virt) &&
(last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
(last->u.mmap.offset + last->u.mmap.len == offset)) {
last->u.mmap.len += len;
return 0;
}
}
if (hvc->index == ARRAY_SIZE(hvc->ops)) {
ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
hvc->index = 0;
}
hvc->ops[hvc->index++] = ((struct host_vm_op)
{ .type = MMAP,
.u = { .mmap = { .addr = virt,
.len = len,
.prot = prot,
.fd = fd,
.offset = offset }
} });
return ret;
}
static int add_munmap(unsigned long addr, unsigned long len,
struct host_vm_change *hvc)
{
struct host_vm_op *last;
int ret = 0;
if ((addr >= STUB_START) && (addr < STUB_END))
return -EINVAL;
if (hvc->index != 0) {
last = &hvc->ops[hvc->index - 1];
if ((last->type == MUNMAP) &&
(last->u.munmap.addr + last->u.mmap.len == addr)) {
last->u.munmap.len += len;
return 0;
}
}
if (hvc->index == ARRAY_SIZE(hvc->ops)) {
ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
hvc->index = 0;
}
hvc->ops[hvc->index++] = ((struct host_vm_op)
{ .type = MUNMAP,
.u = { .munmap = { .addr = addr,
.len = len } } });
return ret;
}
static int add_mprotect(unsigned long addr, unsigned long len,
unsigned int prot, struct host_vm_change *hvc)
{
struct host_vm_op *last;
int ret = 0;
if (hvc->index != 0) {
last = &hvc->ops[hvc->index - 1];
if ((last->type == MPROTECT) &&
(last->u.mprotect.addr + last->u.mprotect.len == addr) &&
(last->u.mprotect.prot == prot)) {
last->u.mprotect.len += len;
return 0;
}
}
if (hvc->index == ARRAY_SIZE(hvc->ops)) {
ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
hvc->index = 0;
}
hvc->ops[hvc->index++] = ((struct host_vm_op)
{ .type = MPROTECT,
.u = { .mprotect = { .addr = addr,
.len = len,
.prot = prot } } });
return ret;
}
#define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end,
struct host_vm_change *hvc)
{
pte_t *pte;
int r, w, x, prot, ret = 0;
pte = pte_offset_kernel(pmd, addr);
do {
if ((addr >= STUB_START) && (addr < STUB_END))
continue;
r = pte_read(*pte);
w = pte_write(*pte);
x = pte_exec(*pte);
if (!pte_young(*pte)) {
r = 0;
w = 0;
} else if (!pte_dirty(*pte))
w = 0;
prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
(x ? UM_PROT_EXEC : 0));
if (hvc->force || pte_newpage(*pte)) {
if (pte_present(*pte)) {
if (pte_newpage(*pte))
ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
PAGE_SIZE, prot, hvc);
} else
ret = add_munmap(addr, PAGE_SIZE, hvc);
} else if (pte_newprot(*pte))
ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
*pte = pte_mkuptodate(*pte);
} while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret));
return ret;
}
static inline int update_pmd_range(pud_t *pud, unsigned long addr,
unsigned long end,
struct host_vm_change *hvc)
{
pmd_t *pmd;
unsigned long next;
int ret = 0;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (!pmd_present(*pmd)) {
if (hvc->force || pmd_newpage(*pmd)) {
ret = add_munmap(addr, next - addr, hvc);
pmd_mkuptodate(*pmd);
}
}
else ret = update_pte_range(pmd, addr, next, hvc);
} while (pmd++, addr = next, ((addr < end) && !ret));
return ret;
}
static inline int update_pud_range(p4d_t *p4d, unsigned long addr,
unsigned long end,
struct host_vm_change *hvc)
{
pud_t *pud;
unsigned long next;
int ret = 0;
pud = pud_offset(p4d, addr);
do {
next = pud_addr_end(addr, end);
if (!pud_present(*pud)) {
if (hvc->force || pud_newpage(*pud)) {
ret = add_munmap(addr, next - addr, hvc);
pud_mkuptodate(*pud);
}
}
else ret = update_pmd_range(pud, addr, next, hvc);
} while (pud++, addr = next, ((addr < end) && !ret));
return ret;
}
static inline int update_p4d_range(pgd_t *pgd, unsigned long addr,
unsigned long end,
struct host_vm_change *hvc)
{
p4d_t *p4d;
unsigned long next;
int ret = 0;
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
if (!p4d_present(*p4d)) {
if (hvc->force || p4d_newpage(*p4d)) {
ret = add_munmap(addr, next - addr, hvc);
p4d_mkuptodate(*p4d);
}
} else
ret = update_pud_range(p4d, addr, next, hvc);
} while (p4d++, addr = next, ((addr < end) && !ret));
return ret;
}
void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
unsigned long end_addr, int force)
{
pgd_t *pgd;
struct host_vm_change hvc;
unsigned long addr = start_addr, next;
int ret = 0, userspace = 1;
hvc = INIT_HVC(mm, force, userspace);
pgd = pgd_offset(mm, addr);
do {
next = pgd_addr_end(addr, end_addr);
if (!pgd_present(*pgd)) {
if (force || pgd_newpage(*pgd)) {
ret = add_munmap(addr, next - addr, &hvc);
pgd_mkuptodate(*pgd);
}
} else
ret = update_p4d_range(pgd, addr, next, &hvc);
} while (pgd++, addr = next, ((addr < end_addr) && !ret));
if (!ret)
ret = do_ops(&hvc, hvc.index, 1);
/* This is not an else because ret is modified above */
if (ret) {
printk(KERN_ERR "fix_range_common: failed, killing current "
"process: %d\n", task_tgid_vnr(current));
/* We are under mmap_sem, release it such that current can terminate */
up_write(¤t->mm->mmap_sem);
force_sig(SIGKILL);
do_signal(¤t->thread.regs);
}
}
static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
{
struct mm_struct *mm;
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
unsigned long addr, last;
int updated = 0, err = 0, force = 0, userspace = 0;
struct host_vm_change hvc;
mm = &init_mm;
hvc = INIT_HVC(mm, force, userspace);
for (addr = start; addr < end;) {
pgd = pgd_offset(mm, addr);
if (!pgd_present(*pgd)) {
last = ADD_ROUND(addr, PGDIR_SIZE);
if (last > end)
last = end;
if (pgd_newpage(*pgd)) {
updated = 1;
err = add_munmap(addr, last - addr, &hvc);
if (err < 0)
panic("munmap failed, errno = %d\n",
-err);
}
addr = last;
continue;
}
p4d = p4d_offset(pgd, addr);
if (!p4d_present(*p4d)) {
last = ADD_ROUND(addr, P4D_SIZE);
if (last > end)
last = end;
if (p4d_newpage(*p4d)) {
updated = 1;
err = add_munmap(addr, last - addr, &hvc);
if (err < 0)
panic("munmap failed, errno = %d\n",
-err);
}
addr = last;
continue;
}
pud = pud_offset(p4d, addr);
if (!pud_present(*pud)) {
last = ADD_ROUND(addr, PUD_SIZE);
if (last > end)
last = end;
if (pud_newpage(*pud)) {
updated = 1;
err = add_munmap(addr, last - addr, &hvc);
if (err < 0)
panic("munmap failed, errno = %d\n",
-err);
}
addr = last;
continue;
}
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd)) {
last = ADD_ROUND(addr, PMD_SIZE);
if (last > end)
last = end;
if (pmd_newpage(*pmd)) {
updated = 1;
err = add_munmap(addr, last - addr, &hvc);
if (err < 0)
panic("munmap failed, errno = %d\n",
-err);
}
addr = last;
continue;
}
pte = pte_offset_kernel(pmd, addr);
if (!pte_present(*pte) || pte_newpage(*pte)) {
updated = 1;
err = add_munmap(addr, PAGE_SIZE, &hvc);
if (err < 0)
panic("munmap failed, errno = %d\n",
-err);
if (pte_present(*pte))
err = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
PAGE_SIZE, 0, &hvc);
}
else if (pte_newprot(*pte)) {
updated = 1;
err = add_mprotect(addr, PAGE_SIZE, 0, &hvc);
}
addr += PAGE_SIZE;
}
if (!err)
err = do_ops(&hvc, hvc.index, 1);
if (err < 0)
panic("flush_tlb_kernel failed, errno = %d\n", err);
return updated;
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
{
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
struct mm_struct *mm = vma->vm_mm;
void *flush = NULL;
int r, w, x, prot, err = 0;
struct mm_id *mm_id;
address &= PAGE_MASK;
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
goto kill;
p4d = p4d_offset(pgd, address);
if (!p4d_present(*p4d))
goto kill;
pud = pud_offset(p4d, address);
if (!pud_present(*pud))
goto kill;
pmd = pmd_offset(pud, address);
if (!pmd_present(*pmd))
goto kill;
pte = pte_offset_kernel(pmd, address);
r = pte_read(*pte);
w = pte_write(*pte);
x = pte_exec(*pte);
if (!pte_young(*pte)) {
r = 0;
w = 0;
} else if (!pte_dirty(*pte)) {
w = 0;
}
mm_id = &mm->context.id;
prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
(x ? UM_PROT_EXEC : 0));
if (pte_newpage(*pte)) {
if (pte_present(*pte)) {
unsigned long long offset;
int fd;
fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
err = map(mm_id, address, PAGE_SIZE, prot, fd, offset,
1, &flush);
}
else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
}
else if (pte_newprot(*pte))
err = protect(mm_id, address, PAGE_SIZE, prot, 1, &flush);
if (err) {
if (err == -ENOMEM)
report_enomem();
goto kill;
}
*pte = pte_mkuptodate(*pte);
return;
kill:
printk(KERN_ERR "Failed to flush page for address 0x%lx\n", address);
force_sig(SIGKILL);
}
void flush_tlb_all(void)
{
/*
* Don't bother flushing if this address space is about to be
* destroyed.
*/
if (atomic_read(¤t->mm->mm_users) == 0)
return;
flush_tlb_mm(current->mm);
}
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
flush_tlb_kernel_range_common(start, end);
}
void flush_tlb_kernel_vm(void)
{
flush_tlb_kernel_range_common(start_vm, end_vm);
}
void __flush_tlb_one(unsigned long addr)
{
flush_tlb_kernel_range_common(addr, addr + PAGE_SIZE);
}
static void fix_range(struct mm_struct *mm, unsigned long start_addr,
unsigned long end_addr, int force)
{
/*
* Don't bother flushing if this address space is about to be
* destroyed.
*/
if (atomic_read(&mm->mm_users) == 0)
return;
fix_range_common(mm, start_addr, end_addr, force);
}
void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
if (vma->vm_mm == NULL)
flush_tlb_kernel_range_common(start, end);
else fix_range(vma->vm_mm, start, end, 0);
}
EXPORT_SYMBOL(flush_tlb_range);
void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
unsigned long end)
{
fix_range(mm, start, end, 0);
}
void flush_tlb_mm(struct mm_struct *mm)
{
struct vm_area_struct *vma = mm->mmap;
while (vma != NULL) {
fix_range(mm, vma->vm_start, vma->vm_end, 0);
vma = vma->vm_next;
}
}
void force_flush_all(void)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma = mm->mmap;
while (vma != NULL) {
fix_range(mm, vma->vm_start, vma->vm_end, 1);
vma = vma->vm_next;
}
}