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-rw-r--r--fs/proc/page.c338
1 files changed, 338 insertions, 0 deletions
diff --git a/fs/proc/page.c b/fs/proc/page.c
new file mode 100644
index 000000000..9f1077d94
--- /dev/null
+++ b/fs/proc/page.c
@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/memblock.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/ksm.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/huge_mm.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/hugetlb.h>
+#include <linux/memcontrol.h>
+#include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
+#include <linux/kernel-page-flags.h>
+#include <linux/uaccess.h>
+#include "internal.h"
+
+#define KPMSIZE sizeof(u64)
+#define KPMMASK (KPMSIZE - 1)
+#define KPMBITS (KPMSIZE * BITS_PER_BYTE)
+
+static inline unsigned long get_max_dump_pfn(void)
+{
+#ifdef CONFIG_SPARSEMEM
+ /*
+ * The memmap of early sections is completely populated and marked
+ * online even if max_pfn does not fall on a section boundary -
+ * pfn_to_online_page() will succeed on all pages. Allow inspecting
+ * these memmaps.
+ */
+ return round_up(max_pfn, PAGES_PER_SECTION);
+#else
+ return max_pfn;
+#endif
+}
+
+/* /proc/kpagecount - an array exposing page counts
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page count.
+ */
+static ssize_t kpagecount_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ const unsigned long max_dump_pfn = get_max_dump_pfn();
+ u64 __user *out = (u64 __user *)buf;
+ struct page *ppage;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+ u64 pcount;
+
+ pfn = src / KPMSIZE;
+ if (src & KPMMASK || count & KPMMASK)
+ return -EINVAL;
+ if (src >= max_dump_pfn * KPMSIZE)
+ return 0;
+ count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
+
+ while (count > 0) {
+ /*
+ * TODO: ZONE_DEVICE support requires to identify
+ * memmaps that were actually initialized.
+ */
+ ppage = pfn_to_online_page(pfn);
+
+ if (!ppage || PageSlab(ppage) || page_has_type(ppage))
+ pcount = 0;
+ else
+ pcount = page_mapcount(ppage);
+
+ if (put_user(pcount, out)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ pfn++;
+ out++;
+ count -= KPMSIZE;
+
+ cond_resched();
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static const struct proc_ops kpagecount_proc_ops = {
+ .proc_lseek = mem_lseek,
+ .proc_read = kpagecount_read,
+};
+
+/* /proc/kpageflags - an array exposing page flags
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page flags.
+ */
+
+static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
+{
+ return ((kflags >> kbit) & 1) << ubit;
+}
+
+u64 stable_page_flags(struct page *page)
+{
+ u64 k;
+ u64 u;
+
+ /*
+ * pseudo flag: KPF_NOPAGE
+ * it differentiates a memory hole from a page with no flags
+ */
+ if (!page)
+ return 1 << KPF_NOPAGE;
+
+ k = page->flags;
+ u = 0;
+
+ /*
+ * pseudo flags for the well known (anonymous) memory mapped pages
+ *
+ * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
+ * simple test in page_mapped() is not enough.
+ */
+ if (!PageSlab(page) && page_mapped(page))
+ u |= 1 << KPF_MMAP;
+ if (PageAnon(page))
+ u |= 1 << KPF_ANON;
+ if (PageKsm(page))
+ u |= 1 << KPF_KSM;
+
+ /*
+ * compound pages: export both head/tail info
+ * they together define a compound page's start/end pos and order
+ */
+ if (PageHead(page))
+ u |= 1 << KPF_COMPOUND_HEAD;
+ if (PageTail(page))
+ u |= 1 << KPF_COMPOUND_TAIL;
+ if (PageHuge(page))
+ u |= 1 << KPF_HUGE;
+ /*
+ * PageTransCompound can be true for non-huge compound pages (slab
+ * pages or pages allocated by drivers with __GFP_COMP) because it
+ * just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
+ * to make sure a given page is a thp, not a non-huge compound page.
+ */
+ else if (PageTransCompound(page)) {
+ struct page *head = compound_head(page);
+
+ if (PageLRU(head) || PageAnon(head))
+ u |= 1 << KPF_THP;
+ else if (is_huge_zero_page(head)) {
+ u |= 1 << KPF_ZERO_PAGE;
+ u |= 1 << KPF_THP;
+ }
+ } else if (is_zero_pfn(page_to_pfn(page)))
+ u |= 1 << KPF_ZERO_PAGE;
+
+
+ /*
+ * Caveats on high order pages: page->_refcount will only be set
+ * -1 on the head page; SLUB/SLQB do the same for PG_slab;
+ * SLOB won't set PG_slab at all on compound pages.
+ */
+ if (PageBuddy(page))
+ u |= 1 << KPF_BUDDY;
+ else if (page_count(page) == 0 && is_free_buddy_page(page))
+ u |= 1 << KPF_BUDDY;
+
+ if (PageOffline(page))
+ u |= 1 << KPF_OFFLINE;
+ if (PageTable(page))
+ u |= 1 << KPF_PGTABLE;
+
+ if (page_is_idle(page))
+ u |= 1 << KPF_IDLE;
+
+ u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
+
+ u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
+ if (PageTail(page) && PageSlab(compound_head(page)))
+ u |= 1 << KPF_SLAB;
+
+ u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
+ u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
+ u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
+ u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
+
+ u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
+ u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
+ u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
+ u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
+
+ if (PageSwapCache(page))
+ u |= 1 << KPF_SWAPCACHE;
+ u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
+
+ u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
+ u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
+
+#ifdef CONFIG_MEMORY_FAILURE
+ u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
+#endif
+
+#ifdef CONFIG_ARCH_USES_PG_UNCACHED
+ u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
+#endif
+
+ u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
+ u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
+ u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
+ u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
+ u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
+ u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
+#ifdef CONFIG_64BIT
+ u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2);
+#endif
+
+ return u;
+};
+
+static ssize_t kpageflags_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ const unsigned long max_dump_pfn = get_max_dump_pfn();
+ u64 __user *out = (u64 __user *)buf;
+ struct page *ppage;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+
+ pfn = src / KPMSIZE;
+ if (src & KPMMASK || count & KPMMASK)
+ return -EINVAL;
+ if (src >= max_dump_pfn * KPMSIZE)
+ return 0;
+ count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
+
+ while (count > 0) {
+ /*
+ * TODO: ZONE_DEVICE support requires to identify
+ * memmaps that were actually initialized.
+ */
+ ppage = pfn_to_online_page(pfn);
+
+ if (put_user(stable_page_flags(ppage), out)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ pfn++;
+ out++;
+ count -= KPMSIZE;
+
+ cond_resched();
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static const struct proc_ops kpageflags_proc_ops = {
+ .proc_lseek = mem_lseek,
+ .proc_read = kpageflags_read,
+};
+
+#ifdef CONFIG_MEMCG
+static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ const unsigned long max_dump_pfn = get_max_dump_pfn();
+ u64 __user *out = (u64 __user *)buf;
+ struct page *ppage;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+ u64 ino;
+
+ pfn = src / KPMSIZE;
+ if (src & KPMMASK || count & KPMMASK)
+ return -EINVAL;
+ if (src >= max_dump_pfn * KPMSIZE)
+ return 0;
+ count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
+
+ while (count > 0) {
+ /*
+ * TODO: ZONE_DEVICE support requires to identify
+ * memmaps that were actually initialized.
+ */
+ ppage = pfn_to_online_page(pfn);
+
+ if (ppage)
+ ino = page_cgroup_ino(ppage);
+ else
+ ino = 0;
+
+ if (put_user(ino, out)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ pfn++;
+ out++;
+ count -= KPMSIZE;
+
+ cond_resched();
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static const struct proc_ops kpagecgroup_proc_ops = {
+ .proc_lseek = mem_lseek,
+ .proc_read = kpagecgroup_read,
+};
+#endif /* CONFIG_MEMCG */
+
+static int __init proc_page_init(void)
+{
+ proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
+ proc_create("kpageflags", S_IRUSR, NULL, &kpageflags_proc_ops);
+#ifdef CONFIG_MEMCG
+ proc_create("kpagecgroup", S_IRUSR, NULL, &kpagecgroup_proc_ops);
+#endif
+ return 0;
+}
+fs_initcall(proc_page_init);