343 lines
8.1 KiB
C
343 lines
8.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/memblock.h>
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#include <linux/compiler.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/ksm.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/huge_mm.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/hugetlb.h>
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#include <linux/memremap.h>
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#include <linux/memcontrol.h>
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#include <linux/mmu_notifier.h>
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#include <linux/page_idle.h>
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#include <linux/kernel-page-flags.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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#define KPMSIZE sizeof(u64)
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#define KPMMASK (KPMSIZE - 1)
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#define KPMBITS (KPMSIZE * BITS_PER_BYTE)
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static inline unsigned long get_max_dump_pfn(void)
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{
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#ifdef CONFIG_SPARSEMEM
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/*
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* The memmap of early sections is completely populated and marked
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* online even if max_pfn does not fall on a section boundary -
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* pfn_to_online_page() will succeed on all pages. Allow inspecting
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* these memmaps.
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*/
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return round_up(max_pfn, PAGES_PER_SECTION);
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#else
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return max_pfn;
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#endif
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}
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/* /proc/kpagecount - an array exposing page counts
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*
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* Each entry is a u64 representing the corresponding
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* physical page count.
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*/
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static ssize_t kpagecount_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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const unsigned long max_dump_pfn = get_max_dump_pfn();
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u64 __user *out = (u64 __user *)buf;
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struct page *ppage;
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unsigned long src = *ppos;
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unsigned long pfn;
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ssize_t ret = 0;
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u64 pcount;
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pfn = src / KPMSIZE;
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if (src & KPMMASK || count & KPMMASK)
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return -EINVAL;
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if (src >= max_dump_pfn * KPMSIZE)
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return 0;
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count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
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while (count > 0) {
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/*
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* TODO: ZONE_DEVICE support requires to identify
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* memmaps that were actually initialized.
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*/
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ppage = pfn_to_online_page(pfn);
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if (!ppage || PageSlab(ppage) || page_has_type(ppage))
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pcount = 0;
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else
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pcount = page_mapcount(ppage);
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if (put_user(pcount, out)) {
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ret = -EFAULT;
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break;
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}
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pfn++;
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out++;
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count -= KPMSIZE;
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cond_resched();
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}
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*ppos += (char __user *)out - buf;
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if (!ret)
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ret = (char __user *)out - buf;
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return ret;
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}
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static const struct proc_ops kpagecount_proc_ops = {
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.proc_flags = PROC_ENTRY_PERMANENT,
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.proc_lseek = mem_lseek,
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.proc_read = kpagecount_read,
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};
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/* /proc/kpageflags - an array exposing page flags
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*
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* Each entry is a u64 representing the corresponding
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* physical page flags.
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*/
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static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
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{
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return ((kflags >> kbit) & 1) << ubit;
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}
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u64 stable_page_flags(struct page *page)
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{
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u64 k;
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u64 u;
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/*
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* pseudo flag: KPF_NOPAGE
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* it differentiates a memory hole from a page with no flags
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*/
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if (!page)
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return 1 << KPF_NOPAGE;
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k = page->flags;
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u = 0;
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/*
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* pseudo flags for the well known (anonymous) memory mapped pages
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*
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* Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
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* simple test in page_mapped() is not enough.
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*/
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if (!PageSlab(page) && page_mapped(page))
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u |= 1 << KPF_MMAP;
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if (PageAnon(page))
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u |= 1 << KPF_ANON;
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if (PageKsm(page))
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u |= 1 << KPF_KSM;
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/*
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* compound pages: export both head/tail info
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* they together define a compound page's start/end pos and order
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*/
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if (PageHead(page))
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u |= 1 << KPF_COMPOUND_HEAD;
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if (PageTail(page))
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u |= 1 << KPF_COMPOUND_TAIL;
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if (PageHuge(page))
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u |= 1 << KPF_HUGE;
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/*
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* PageTransCompound can be true for non-huge compound pages (slab
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* pages or pages allocated by drivers with __GFP_COMP) because it
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* just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
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* to make sure a given page is a thp, not a non-huge compound page.
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*/
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else if (PageTransCompound(page)) {
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struct page *head = compound_head(page);
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if (PageLRU(head) || PageAnon(head))
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u |= 1 << KPF_THP;
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else if (is_huge_zero_page(head)) {
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u |= 1 << KPF_ZERO_PAGE;
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u |= 1 << KPF_THP;
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}
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} else if (is_zero_pfn(page_to_pfn(page)))
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u |= 1 << KPF_ZERO_PAGE;
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/*
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* Caveats on high order pages: page->_refcount will only be set
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* -1 on the head page; SLUB/SLQB do the same for PG_slab;
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* SLOB won't set PG_slab at all on compound pages.
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*/
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if (PageBuddy(page))
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u |= 1 << KPF_BUDDY;
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else if (page_count(page) == 0 && is_free_buddy_page(page))
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u |= 1 << KPF_BUDDY;
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if (PageOffline(page))
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u |= 1 << KPF_OFFLINE;
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if (PageTable(page))
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u |= 1 << KPF_PGTABLE;
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if (page_is_idle(page))
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u |= 1 << KPF_IDLE;
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u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
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u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
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if (PageTail(page) && PageSlab(compound_head(page)))
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u |= 1 << KPF_SLAB;
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u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
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u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
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u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
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u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
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u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
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u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
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u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
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u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
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if (PageSwapCache(page))
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u |= 1 << KPF_SWAPCACHE;
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u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
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u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
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u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
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#ifdef CONFIG_MEMORY_FAILURE
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u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
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#endif
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#ifdef CONFIG_ARCH_USES_PG_UNCACHED
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u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
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#endif
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u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
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u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
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u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
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u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
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u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
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u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
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#ifdef CONFIG_64BIT
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u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2);
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#endif
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return u;
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};
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static ssize_t kpageflags_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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const unsigned long max_dump_pfn = get_max_dump_pfn();
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u64 __user *out = (u64 __user *)buf;
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struct page *ppage;
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unsigned long src = *ppos;
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unsigned long pfn;
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ssize_t ret = 0;
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pfn = src / KPMSIZE;
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if (src & KPMMASK || count & KPMMASK)
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return -EINVAL;
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if (src >= max_dump_pfn * KPMSIZE)
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return 0;
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count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
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while (count > 0) {
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/*
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* TODO: ZONE_DEVICE support requires to identify
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* memmaps that were actually initialized.
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*/
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ppage = pfn_to_online_page(pfn);
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if (put_user(stable_page_flags(ppage), out)) {
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ret = -EFAULT;
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break;
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}
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pfn++;
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out++;
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count -= KPMSIZE;
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cond_resched();
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}
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*ppos += (char __user *)out - buf;
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if (!ret)
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ret = (char __user *)out - buf;
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return ret;
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}
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static const struct proc_ops kpageflags_proc_ops = {
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.proc_flags = PROC_ENTRY_PERMANENT,
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.proc_lseek = mem_lseek,
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.proc_read = kpageflags_read,
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};
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#ifdef CONFIG_MEMCG
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static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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const unsigned long max_dump_pfn = get_max_dump_pfn();
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u64 __user *out = (u64 __user *)buf;
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struct page *ppage;
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unsigned long src = *ppos;
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unsigned long pfn;
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ssize_t ret = 0;
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u64 ino;
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pfn = src / KPMSIZE;
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if (src & KPMMASK || count & KPMMASK)
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return -EINVAL;
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if (src >= max_dump_pfn * KPMSIZE)
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return 0;
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count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
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while (count > 0) {
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/*
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* TODO: ZONE_DEVICE support requires to identify
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* memmaps that were actually initialized.
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*/
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ppage = pfn_to_online_page(pfn);
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if (ppage)
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ino = page_cgroup_ino(ppage);
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else
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ino = 0;
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if (put_user(ino, out)) {
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ret = -EFAULT;
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break;
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}
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pfn++;
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out++;
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count -= KPMSIZE;
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cond_resched();
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}
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*ppos += (char __user *)out - buf;
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if (!ret)
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ret = (char __user *)out - buf;
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return ret;
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}
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static const struct proc_ops kpagecgroup_proc_ops = {
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.proc_flags = PROC_ENTRY_PERMANENT,
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.proc_lseek = mem_lseek,
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.proc_read = kpagecgroup_read,
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};
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#endif /* CONFIG_MEMCG */
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static int __init proc_page_init(void)
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{
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proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
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proc_create("kpageflags", S_IRUSR, NULL, &kpageflags_proc_ops);
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#ifdef CONFIG_MEMCG
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proc_create("kpagecgroup", S_IRUSR, NULL, &kpagecgroup_proc_ops);
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#endif
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return 0;
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}
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fs_initcall(proc_page_init);
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