int __m4u_get_user_pages(int eModuleID, struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int nr_pages, unsigned int gup_flags,
struct page **pages, struct vm_area_struct **vmas)
{
int i;
unsigned long vm_flags;
int trycnt;
if (nr_pages <= 0)
return 0;
//VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
if(!!pages != !!(gup_flags & FOLL_GET)) {
M4UMSG(" error: __m4u_get_user_pages !!pages != !!(gup_flags & FOLL_GET), pages=0x%x, gup_flags & FOLL_GET=0x%x \n",
(unsigned int)pages, gup_flags & FOLL_GET);
}
/*
* Require read or write permissions.
* If FOLL_FORCE is set, we only require the "MAY" flags.
*/
vm_flags = (gup_flags & FOLL_WRITE) ?
(VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
vm_flags &= (gup_flags & FOLL_FORCE) ?
(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
i = 0;
M4UDBG("Trying to get_user_pages from start vaddr 0x%08x with %d pages\n", start, nr_pages);
do {
struct vm_area_struct *vma;
M4UDBG("For a new vma area from 0x%08x\n", start);
vma = find_extend_vma(mm, start);
if (!vma)
{
M4UMSG("error: the vma is not found, start=0x%x, module=%d \n",
(unsigned int)start, eModuleID);
return i ? i : -EFAULT;
}
if( ((~vma->vm_flags) & (VM_IO|VM_PFNMAP|VM_SHARED|VM_WRITE)) == 0 )
{
M4UMSG("error: m4u_get_pages(): bypass pmem garbage pages! vma->vm_flags=0x%x, start=0x%x, module=%d \n",
(unsigned int)(vma->vm_flags), (unsigned int)start, eModuleID);
return i ? i : -EFAULT;;
}
if(vma->vm_flags & VM_IO)
{
M4UDBG("warning: vma is marked as VM_IO \n");
}
if(vma->vm_flags & VM_PFNMAP)
{
M4UMSG("error: vma permission is not correct, vma->vm_flags=0x%x, start=0x%x, module=%d \n",
(unsigned int)(vma->vm_flags), (unsigned int)start, eModuleID);
M4UMSG("hint: maybe the memory is remapped with un-permitted vma->vm_flags! \n");
//m4u_dump_maps(start);
return i ? i : -EFAULT;;
}
if(!(vm_flags & vma->vm_flags))
{
M4UMSG("error: vm_flags invalid, vm_flags=0x%x, vma->vm_flags=0x%x, start=0x%x, module=%d \n",
(unsigned int)vm_flags,
(unsigned int)(vma->vm_flags),
(unsigned int)start,
eModuleID);
//m4u_dump_maps(start);
return i ? : -EFAULT;
}
do {
struct page *page;
unsigned int foll_flags = gup_flags;
/*
* If we have a pending SIGKILL, don't keep faulting
* pages and potentially allocating memory.
*/
if (unlikely(fatal_signal_pending(current)))
return i ? i : -ERESTARTSYS;
MMProfileLogEx(M4U_MMP_Events[PROFILE_FOLLOW_PAGE], MMProfileFlagStart, eModuleID, start&(~0xFFF));
page = follow_page(vma, start, foll_flags);
MMProfileLogEx(M4U_MMP_Events[PROFILE_FOLLOW_PAGE], MMProfileFlagEnd, eModuleID, 0x1000);
while (!page) {
int ret;
M4UDBG("Trying to allocate for %dth page(vaddr: 0x%08x)\n", i, start);
MMProfileLogEx(M4U_MMP_Events[PROFILE_FORCE_PAGING], MMProfileFlagStart, eModuleID, start&(~0xFFF));
ret = handle_mm_fault(mm, vma, start,
(foll_flags & FOLL_WRITE) ?
FAULT_FLAG_WRITE : 0);
MMProfileLogEx(M4U_MMP_Events[PROFILE_FORCE_PAGING], MMProfileFlagEnd, eModuleID, 0x1000);
if (ret & VM_FAULT_ERROR) {
if (ret & VM_FAULT_OOM) {
M4UMSG("handle_mm_fault() error: no memory, aaddr:0x%08lx (%d pages are allocated), module=%d\n",
start, i, eModuleID);
//m4u_dump_maps(start);
return i ? i : -ENOMEM;
}
if (ret &
(VM_FAULT_HWPOISON|VM_FAULT_SIGBUS)) {
M4UMSG("handle_mm_fault() error: invalide memory address, vaddr:0x%lx (%d pages are allocated), module=%d\n",
start, i, eModuleID);
//m4u_dump_maps(start);
return i ? i : -EFAULT;
}
BUG();
}
if (ret & VM_FAULT_MAJOR)
tsk->maj_flt++;
else
tsk->min_flt++;
/*
* The VM_FAULT_WRITE bit tells us that
* do_wp_page has broken COW when necessary,
* even if maybe_mkwrite decided not to set
* pte_write. We can thus safely do subsequent
* page lookups as if they were reads. But only
* do so when looping for pte_write is futile:
* in some cases userspace may also be wanting
* to write to the gotten user page, which a
* read fault here might prevent (a readonly
* page might get reCOWed by userspace write).
*/
if ((ret & VM_FAULT_WRITE) &&
!(vma->vm_flags & VM_WRITE))
foll_flags &= ~FOLL_WRITE;
MMProfileLogEx(M4U_MMP_Events[PROFILE_FOLLOW_PAGE], MMProfileFlagStart, eModuleID, start&(~0xFFF));
page = follow_page(vma, start, foll_flags);
MMProfileLogEx(M4U_MMP_Events[PROFILE_FOLLOW_PAGE], MMProfileFlagEnd, eModuleID, 0x1000);
}
if (IS_ERR(page)) {
M4UMSG("handle_mm_fault() error: faulty page is returned, vaddr:0x%lx (%d pages are allocated), module=%d \n",
start, i, eModuleID);
//m4u_dump_maps(start);
return i ? i : PTR_ERR(page);
}
if (pages) {
pages[i] = page;
MMProfileLogEx(M4U_MMP_Events[PROFILE_MLOCK], MMProfileFlagStart, eModuleID, start&(~0xFFF));
/* Use retry version to guarantee it will succeed in getting the lock */
trycnt = 3000;
do {
if (trylock_page(page)) {
mlock_vma_page(page);
unlock_page(page);
//make sure hw pte is not 0
{
int i;
for(i=0; i<3000; i++)
{
if(!m4u_user_v2p(start))
{
handle_mm_fault(mm, vma, start, (foll_flags & FOLL_WRITE)? FAULT_FLAG_WRITE : 0);
cond_resched();
}
else
break;
}
if(i==3000)
M4UMSG("error: cannot handle_mm_fault to get hw pte: va=0x%x\n", start);
}
break;
}
} while (trycnt-- > 0);
if(PageMlocked(page)==0)
{
M4UMSG("Can't mlock page\n");
dump_page(page);
}
else
{
unsigned int pfn = page_to_pfn(page);
if(pfn < mlock_cnt_size)
{
pMlock_cnt[page_to_pfn(page)]++;
}
else
{
M4UERR("mlock_cnt_size is too small: pfn=%d, size=%d\n", pfn, mlock_cnt_size);
}
//M4UMSG("lock page:\n");
//dump_page(page);
}
MMProfileLogEx(M4U_MMP_Events[PROFILE_MLOCK], MMProfileFlagEnd, eModuleID, 0x1000);
}
if (vmas)
vmas[i] = vma;
i++;
start += PAGE_SIZE;
nr_pages--;
} while (nr_pages && start < vma->vm_end);
} while (nr_pages);
static struct page *follow_page_pte(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd, unsigned int flags)
{
struct mm_struct *mm = vma->vm_mm;
struct dev_pagemap *pgmap = NULL;
struct page *page;
spinlock_t *ptl;
pte_t *ptep, pte;
retry:
if (unlikely(pmd_bad(*pmd)))
return no_page_table(vma, flags);
ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
pte = *ptep;
if (!pte_present(pte)) {
swp_entry_t entry;
/*
* KSM's break_ksm() relies upon recognizing a ksm page
* even while it is being migrated, so for that case we
* need migration_entry_wait().
*/
if (likely(!(flags & FOLL_MIGRATION)))
goto no_page;
if (pte_none(pte))
goto no_page;
entry = pte_to_swp_entry(pte);
if (!is_migration_entry(entry))
goto no_page;
pte_unmap_unlock(ptep, ptl);
migration_entry_wait(mm, pmd, address);
goto retry;
}
if ((flags & FOLL_NUMA) && pte_protnone(pte))
goto no_page;
if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) {
pte_unmap_unlock(ptep, ptl);
return NULL;
}
page = vm_normal_page(vma, address, pte);
if (!page && pte_devmap(pte) && (flags & FOLL_GET)) {
/*
* Only return device mapping pages in the FOLL_GET case since
* they are only valid while holding the pgmap reference.
*/
pgmap = get_dev_pagemap(pte_pfn(pte), NULL);
if (pgmap)
page = pte_page(pte);
else
goto no_page;
} else if (unlikely(!page)) {
if (flags & FOLL_DUMP) {
/* Avoid special (like zero) pages in core dumps */
page = ERR_PTR(-EFAULT);
goto out;
}
if (is_zero_pfn(pte_pfn(pte))) {
page = pte_page(pte);
} else {
int ret;
ret = follow_pfn_pte(vma, address, ptep, flags);
page = ERR_PTR(ret);
goto out;
}
}
if (flags & FOLL_SPLIT && PageTransCompound(page)) {
int ret;
get_page(page);
pte_unmap_unlock(ptep, ptl);
lock_page(page);
ret = split_huge_page(page);
unlock_page(page);
put_page(page);
if (ret)
return ERR_PTR(ret);
goto retry;
}
if (flags & FOLL_GET) {
get_page(page);
/* drop the pgmap reference now that we hold the page */
if (pgmap) {
put_dev_pagemap(pgmap);
pgmap = NULL;
}
}
if (flags & FOLL_TOUCH) {
if ((flags & FOLL_WRITE) &&
!pte_dirty(pte) && !PageDirty(page))
set_page_dirty(page);
/*
* pte_mkyoung() would be more correct here, but atomic care
* is needed to avoid losing the dirty bit: it is easier to use
* mark_page_accessed().
*/
mark_page_accessed(page);
}
if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
/* Do not mlock pte-mapped THP */
if (PageTransCompound(page))
goto out;
/*
* The preliminary mapping check is mainly to avoid the
* pointless overhead of lock_page on the ZERO_PAGE
* which might bounce very badly if there is contention.
*
* If the page is already locked, we don't need to
* handle it now - vmscan will handle it later if and
* when it attempts to reclaim the page.
*/
if (page->mapping && trylock_page(page)) {
lru_add_drain(); /* push cached pages to LRU */
/*
* Because we lock page here, and migration is
* blocked by the pte's page reference, and we
* know the page is still mapped, we don't even
* need to check for file-cache page truncation.
*/
mlock_vma_page(page);
unlock_page(page);
}
}
out:
pte_unmap_unlock(ptep, ptl);
return page;
no_page:
pte_unmap_unlock(ptep, ptl);
if (!pte_none(pte))
return NULL;
return no_page_table(vma, flags);
}
static struct page *follow_page_pte(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd, unsigned int flags)
{
struct mm_struct *mm = vma->vm_mm;
struct page *page;
spinlock_t *ptl;
pte_t *ptep, pte;
retry:
if (unlikely(pmd_bad(*pmd)))
return no_page_table(vma, flags);
ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
pte = *ptep;
if (!pte_present(pte)) {
swp_entry_t entry;
/*
* KSM's break_ksm() relies upon recognizing a ksm page
* even while it is being migrated, so for that case we
* need migration_entry_wait().
*/
if (likely(!(flags & FOLL_MIGRATION)))
goto no_page;
if (pte_none(pte) || pte_file(pte))
goto no_page;
entry = pte_to_swp_entry(pte);
if (!is_migration_entry(entry))
goto no_page;
pte_unmap_unlock(ptep, ptl);
migration_entry_wait(mm, pmd, address);
goto retry;
}
if ((flags & FOLL_NUMA) && pte_numa(pte))
goto no_page;
if ((flags & FOLL_WRITE) && !pte_write(pte)) {
pte_unmap_unlock(ptep, ptl);
return NULL;
}
page = vm_normal_page(vma, address, pte);
if (unlikely(!page)) {
if ((flags & FOLL_DUMP) ||
!is_zero_pfn(pte_pfn(pte)))
goto bad_page;
page = pte_page(pte);
}
if (flags & FOLL_GET)
get_page_foll(page);
if (flags & FOLL_TOUCH) {
if ((flags & FOLL_WRITE) &&
!pte_dirty(pte) && !PageDirty(page))
set_page_dirty(page);
/*
* pte_mkyoung() would be more correct here, but atomic care
* is needed to avoid losing the dirty bit: it is easier to use
* mark_page_accessed().
*/
mark_page_accessed(page);
}
if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
/*
* The preliminary mapping check is mainly to avoid the
* pointless overhead of lock_page on the ZERO_PAGE
* which might bounce very badly if there is contention.
*
* If the page is already locked, we don't need to
* handle it now - vmscan will handle it later if and
* when it attempts to reclaim the page.
*/
if (page->mapping && trylock_page(page)) {
lru_add_drain(); /* push cached pages to LRU */
/*
* Because we lock page here, and migration is
* blocked by the pte's page reference, and we
* know the page is still mapped, we don't even
* need to check for file-cache page truncation.
*/
mlock_vma_page(page);
unlock_page(page);
}
}
pte_unmap_unlock(ptep, ptl);
return page;
bad_page:
pte_unmap_unlock(ptep, ptl);
return ERR_PTR(-EFAULT);
no_page:
pte_unmap_unlock(ptep, ptl);
if (!pte_none(pte))
return NULL;
return no_page_table(vma, flags);
}
