mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 23:46:42 +07:00
e0a04cffa4
My mincore also forgot about crossing vmas. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
230 lines
5.7 KiB
C
230 lines
5.7 KiB
C
/*
|
|
* linux/mm/mincore.c
|
|
*
|
|
* Copyright (C) 1994-2006 Linus Torvalds
|
|
*/
|
|
|
|
/*
|
|
* The mincore() system call.
|
|
*/
|
|
#include <linux/slab.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/swapops.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
#include <asm/pgtable.h>
|
|
|
|
/*
|
|
* Later we can get more picky about what "in core" means precisely.
|
|
* For now, simply check to see if the page is in the page cache,
|
|
* and is up to date; i.e. that no page-in operation would be required
|
|
* at this time if an application were to map and access this page.
|
|
*/
|
|
static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
|
|
{
|
|
unsigned char present = 0;
|
|
struct page *page;
|
|
|
|
/*
|
|
* When tmpfs swaps out a page from a file, any process mapping that
|
|
* file will not get a swp_entry_t in its pte, but rather it is like
|
|
* any other file mapping (ie. marked !present and faulted in with
|
|
* tmpfs's .nopage). So swapped out tmpfs mappings are tested here.
|
|
*
|
|
* However when tmpfs moves the page from pagecache and into swapcache,
|
|
* it is still in core, but the find_get_page below won't find it.
|
|
* No big deal, but make a note of it.
|
|
*/
|
|
page = find_get_page(mapping, pgoff);
|
|
if (page) {
|
|
present = PageUptodate(page);
|
|
page_cache_release(page);
|
|
}
|
|
|
|
return present;
|
|
}
|
|
|
|
/*
|
|
* Do a chunk of "sys_mincore()". We've already checked
|
|
* all the arguments, we hold the mmap semaphore: we should
|
|
* just return the amount of info we're asked for.
|
|
*/
|
|
static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages)
|
|
{
|
|
pgd_t *pgd;
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *ptep;
|
|
spinlock_t *ptl;
|
|
unsigned long nr;
|
|
int i;
|
|
pgoff_t pgoff;
|
|
struct vm_area_struct *vma = find_vma(current->mm, addr);
|
|
|
|
/*
|
|
* find_vma() didn't find anything above us, or we're
|
|
* in an unmapped hole in the address space: ENOMEM.
|
|
*/
|
|
if (!vma || addr < vma->vm_start)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* Calculate how many pages there are left in the last level of the
|
|
* PTE array for our address.
|
|
*/
|
|
nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1));
|
|
|
|
/*
|
|
* Don't overrun this vma
|
|
*/
|
|
nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT);
|
|
|
|
/*
|
|
* Don't return more than the caller asked for
|
|
*/
|
|
nr = min(nr, pages);
|
|
|
|
pgd = pgd_offset(vma->vm_mm, addr);
|
|
if (pgd_none_or_clear_bad(pgd))
|
|
goto none_mapped;
|
|
pud = pud_offset(pgd, addr);
|
|
if (pud_none_or_clear_bad(pud))
|
|
goto none_mapped;
|
|
pmd = pmd_offset(pud, addr);
|
|
if (pmd_none_or_clear_bad(pmd))
|
|
goto none_mapped;
|
|
|
|
ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
|
|
for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) {
|
|
unsigned char present;
|
|
pte_t pte = *ptep;
|
|
|
|
if (pte_present(pte)) {
|
|
present = 1;
|
|
|
|
} else if (pte_none(pte)) {
|
|
if (vma->vm_file) {
|
|
pgoff = linear_page_index(vma, addr);
|
|
present = mincore_page(vma->vm_file->f_mapping,
|
|
pgoff);
|
|
} else
|
|
present = 0;
|
|
|
|
} else if (pte_file(pte)) {
|
|
pgoff = pte_to_pgoff(pte);
|
|
present = mincore_page(vma->vm_file->f_mapping, pgoff);
|
|
|
|
} else { /* pte is a swap entry */
|
|
swp_entry_t entry = pte_to_swp_entry(pte);
|
|
if (is_migration_entry(entry)) {
|
|
/* migration entries are always uptodate */
|
|
present = 1;
|
|
} else {
|
|
#ifdef CONFIG_SWAP
|
|
pgoff = entry.val;
|
|
present = mincore_page(&swapper_space, pgoff);
|
|
#else
|
|
WARN_ON(1);
|
|
present = 1;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
vec[i] = present;
|
|
}
|
|
pte_unmap_unlock(ptep-1, ptl);
|
|
|
|
return nr;
|
|
|
|
none_mapped:
|
|
if (vma->vm_file) {
|
|
pgoff = linear_page_index(vma, addr);
|
|
for (i = 0; i < nr; i++, pgoff++)
|
|
vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
|
|
} else {
|
|
for (i = 0; i < nr; i++)
|
|
vec[i] = 0;
|
|
}
|
|
|
|
return nr;
|
|
}
|
|
|
|
/*
|
|
* The mincore(2) system call.
|
|
*
|
|
* mincore() returns the memory residency status of the pages in the
|
|
* current process's address space specified by [addr, addr + len).
|
|
* The status is returned in a vector of bytes. The least significant
|
|
* bit of each byte is 1 if the referenced page is in memory, otherwise
|
|
* it is zero.
|
|
*
|
|
* Because the status of a page can change after mincore() checks it
|
|
* but before it returns to the application, the returned vector may
|
|
* contain stale information. Only locked pages are guaranteed to
|
|
* remain in memory.
|
|
*
|
|
* return values:
|
|
* zero - success
|
|
* -EFAULT - vec points to an illegal address
|
|
* -EINVAL - addr is not a multiple of PAGE_CACHE_SIZE
|
|
* -ENOMEM - Addresses in the range [addr, addr + len] are
|
|
* invalid for the address space of this process, or
|
|
* specify one or more pages which are not currently
|
|
* mapped
|
|
* -EAGAIN - A kernel resource was temporarily unavailable.
|
|
*/
|
|
asmlinkage long sys_mincore(unsigned long start, size_t len,
|
|
unsigned char __user * vec)
|
|
{
|
|
long retval;
|
|
unsigned long pages;
|
|
unsigned char *tmp;
|
|
|
|
/* Check the start address: needs to be page-aligned.. */
|
|
if (start & ~PAGE_CACHE_MASK)
|
|
return -EINVAL;
|
|
|
|
/* ..and we need to be passed a valid user-space range */
|
|
if (!access_ok(VERIFY_READ, (void __user *) start, len))
|
|
return -ENOMEM;
|
|
|
|
/* This also avoids any overflows on PAGE_CACHE_ALIGN */
|
|
pages = len >> PAGE_SHIFT;
|
|
pages += (len & ~PAGE_MASK) != 0;
|
|
|
|
if (!access_ok(VERIFY_WRITE, vec, pages))
|
|
return -EFAULT;
|
|
|
|
tmp = (void *) __get_free_page(GFP_USER);
|
|
if (!tmp)
|
|
return -EAGAIN;
|
|
|
|
retval = 0;
|
|
while (pages) {
|
|
/*
|
|
* Do at most PAGE_SIZE entries per iteration, due to
|
|
* the temporary buffer size.
|
|
*/
|
|
down_read(¤t->mm->mmap_sem);
|
|
retval = do_mincore(start, tmp, min(pages, PAGE_SIZE));
|
|
up_read(¤t->mm->mmap_sem);
|
|
|
|
if (retval <= 0)
|
|
break;
|
|
if (copy_to_user(vec, tmp, retval)) {
|
|
retval = -EFAULT;
|
|
break;
|
|
}
|
|
pages -= retval;
|
|
vec += retval;
|
|
start += retval << PAGE_SHIFT;
|
|
retval = 0;
|
|
}
|
|
free_page((unsigned long) tmp);
|
|
return retval;
|
|
}
|