add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/fs/proc/page.c
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@@ -1,5 +1,5 @@
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 // SPDX-License-Identifier: GPL-2.0
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-#include <linux/bootmem.h>
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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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@@ -21,6 +21,21 @@
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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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+
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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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@@ -29,6 +44,7 @@
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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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@@ -37,9 +53,11 @@
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 	u64 pcount;
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 	pfn = src / KPMSIZE;
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-	count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
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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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@@ -48,7 +66,7 @@
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 		 */
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 		ppage = pfn_to_online_page(pfn);
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-		if (!ppage || PageSlab(ppage))
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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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@@ -71,9 +89,9 @@
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 	return ret;
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 }
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-static const struct file_operations proc_kpagecount_operations = {
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-	.llseek = mem_lseek,
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-	.read = kpagecount_read,
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+static const struct proc_ops kpagecount_proc_ops = {
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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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@@ -154,8 +172,8 @@
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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 (PageBalloon(page))
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-		u |= 1 << KPF_BALLOON;
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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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@@ -199,6 +217,9 @@
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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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@@ -206,6 +227,7 @@
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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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@@ -213,9 +235,11 @@
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 	ssize_t ret = 0;
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 	pfn = src / KPMSIZE;
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-	count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
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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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@@ -242,15 +266,16 @@
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 	return ret;
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 }
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-static const struct file_operations proc_kpageflags_operations = {
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-	.llseek = mem_lseek,
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-	.read = kpageflags_read,
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+static const struct proc_ops kpageflags_proc_ops = {
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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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@@ -259,9 +284,11 @@
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 	u64 ino;
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 	pfn = src / KPMSIZE;
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-	count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
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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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@@ -293,18 +320,18 @@
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 	return ret;
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 }
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-static const struct file_operations proc_kpagecgroup_operations = {
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-	.llseek = mem_lseek,
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-	.read = kpagecgroup_read,
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+static const struct proc_ops kpagecgroup_proc_ops = {
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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, &proc_kpagecount_operations);
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-	proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
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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, &proc_kpagecgroup_operations);
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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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 }