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linux-7.2.3/arch/x86/mm/pat/Makefile

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-y				:= set_memory.o memtype.o
+
+obj-$(CONFIG_X86_PAT)		+= memtype_interval.o

linux-7.2.3/arch/x86/mm/pat/cpa-test.c

@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * self test for change_page_attr.
+ *
+ * Clears the a test pte bit on random pages in the direct mapping,
+ * then reverts and compares page tables forwards and afterwards.
+ */
+#include <linux/memblock.h>
+#include <linux/kthread.h>
+#include <linux/random.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+
+#include <asm/cacheflush.h>
+#include <asm/kdebug.h>
+
+/*
+ * Only print the results of the first pass:
+ */
+static __read_mostly int print = 1;
+
+enum {
+	NTEST			= 3 * 100,
+	NPAGES			= 100,
+#ifdef CONFIG_X86_64
+	LPS			= (1 << PMD_SHIFT),
+#elif defined(CONFIG_X86_PAE)
+	LPS			= (1 << PMD_SHIFT),
+#else
+	LPS			= (1 << 22),
+#endif
+	GPS			= (1<<30)
+};
+
+#define PAGE_CPA_TEST	__pgprot(_PAGE_CPA_TEST)
+
+static int pte_testbit(pte_t pte)
+{
+	return pte_flags(pte) & _PAGE_SOFTW1;
+}
+
+struct split_state {
+	long lpg, gpg, spg, exec;
+	long min_exec, max_exec;
+};
+
+static int print_split(struct split_state *s)
+{
+	long i, expected, missed = 0;
+	int err = 0;
+
+	s->lpg = s->gpg = s->spg = s->exec = 0;
+	s->min_exec = ~0UL;
+	s->max_exec = 0;
+	for (i = 0; i < max_pfn_mapped; ) {
+		unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
+		unsigned int level;
+		pte_t *pte;
+
+		pte = lookup_address(addr, &level);
+		if (!pte) {
+			missed++;
+			i++;
+			continue;
+		}
+
+		if (level == PG_LEVEL_1G && sizeof(long) == 8) {
+			s->gpg++;
+			i += GPS/PAGE_SIZE;
+		} else if (level == PG_LEVEL_2M) {
+			if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
+				printk(KERN_ERR
+					"%lx level %d but not PSE %Lx\n",
+					addr, level, (u64)pte_val(*pte));
+				err = 1;
+			}
+			s->lpg++;
+			i += LPS/PAGE_SIZE;
+		} else {
+			s->spg++;
+			i++;
+		}
+		if (!(pte_val(*pte) & _PAGE_NX)) {
+			s->exec++;
+			if (addr < s->min_exec)
+				s->min_exec = addr;
+			if (addr > s->max_exec)
+				s->max_exec = addr;
+		}
+	}
+	if (print) {
+		printk(KERN_INFO
+			" 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
+			s->spg, s->lpg, s->gpg, s->exec,
+			s->min_exec != ~0UL ? s->min_exec : 0,
+			s->max_exec, missed);
+	}
+
+	expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
+	if (expected != i) {
+		printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
+			max_pfn_mapped, expected);
+		return 1;
+	}
+	return err;
+}
+
+static unsigned long addr[NTEST];
+static unsigned int len[NTEST];
+
+static struct page *pages[NPAGES];
+static unsigned long addrs[NPAGES];
+
+/* Change the global bit on random pages in the direct mapping */
+static int pageattr_test(void)
+{
+	struct split_state sa, sb, sc;
+	unsigned long *bm;
+	pte_t *pte, pte0;
+	int failed = 0;
+	unsigned int level;
+	int i, k;
+	int err;
+
+	if (print)
+		printk(KERN_INFO "CPA self-test:\n");
+
+	bm = vzalloc((max_pfn_mapped + 7) / 8);
+	if (!bm) {
+		printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
+		return -ENOMEM;
+	}
+
+	failed += print_split(&sa);
+
+	for (i = 0; i < NTEST; i++) {
+		unsigned long pfn = get_random_u32_below(max_pfn_mapped);
+
+		addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
+		len[i] = get_random_u32_below(NPAGES);
+		len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
+
+		if (len[i] == 0)
+			len[i] = 1;
+
+		pte = NULL;
+		pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
+
+		for (k = 0; k < len[i]; k++) {
+			pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
+			if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
+			    !(pte_val(*pte) & _PAGE_PRESENT)) {
+				addr[i] = 0;
+				break;
+			}
+			if (k == 0) {
+				pte0 = *pte;
+			} else {
+				if (pgprot_val(pte_pgprot(*pte)) !=
+					pgprot_val(pte_pgprot(pte0))) {
+					len[i] = k;
+					break;
+				}
+			}
+			if (test_bit(pfn + k, bm)) {
+				len[i] = k;
+				break;
+			}
+			__set_bit(pfn + k, bm);
+			addrs[k] = addr[i] + k*PAGE_SIZE;
+			pages[k] = pfn_to_page(pfn + k);
+		}
+		if (!addr[i] || !pte || !k) {
+			addr[i] = 0;
+			continue;
+		}
+
+		switch (i % 3) {
+		case 0:
+			err = change_page_attr_set(&addr[i], len[i], PAGE_CPA_TEST, 0);
+			break;
+
+		case 1:
+			err = change_page_attr_set(addrs, len[i], PAGE_CPA_TEST, 1);
+			break;
+
+		case 2:
+			err = cpa_set_pages_array(pages, len[i], PAGE_CPA_TEST);
+			break;
+		}
+
+
+		if (err < 0) {
+			printk(KERN_ERR "CPA %d failed %d\n", i, err);
+			failed++;
+		}
+
+		pte = lookup_address(addr[i], &level);
+		if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
+			printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
+				pte ? (u64)pte_val(*pte) : 0ULL);
+			failed++;
+		}
+		if (level != PG_LEVEL_4K) {
+			printk(KERN_ERR "CPA %lx: unexpected level %d\n",
+				addr[i], level);
+			failed++;
+		}
+
+	}
+	vfree(bm);
+
+	failed += print_split(&sb);
+
+	for (i = 0; i < NTEST; i++) {
+		if (!addr[i])
+			continue;
+		pte = lookup_address(addr[i], &level);
+		if (!pte) {
+			printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
+			failed++;
+			continue;
+		}
+		err = change_page_attr_clear(&addr[i], len[i], PAGE_CPA_TEST, 0);
+		if (err < 0) {
+			printk(KERN_ERR "CPA reverting failed: %d\n", err);
+			failed++;
+		}
+		pte = lookup_address(addr[i], &level);
+		if (!pte || pte_testbit(*pte)) {
+			printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
+				addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
+			failed++;
+		}
+
+	}
+
+	failed += print_split(&sc);
+
+	if (failed) {
+		WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
+		return -EINVAL;
+	} else {
+		if (print)
+			printk(KERN_INFO "ok.\n");
+	}
+
+	return 0;
+}
+
+static int do_pageattr_test(void *__unused)
+{
+	while (!kthread_should_stop()) {
+		schedule_timeout_interruptible(HZ*30);
+		if (pageattr_test() < 0)
+			break;
+		if (print)
+			print--;
+	}
+	return 0;
+}
+
+static int start_pageattr_test(void)
+{
+	struct task_struct *p;
+
+	p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
+	if (!IS_ERR(p))
+		wake_up_process(p);
+	else
+		WARN_ON(1);
+
+	return 0;
+}
+device_initcall(start_pageattr_test);

linux-7.2.3/arch/x86/mm/pat/memtype.h

@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __MEMTYPE_H_
+#define __MEMTYPE_H_
+
+extern int pat_debug_enable;
+
+#define dprintk(fmt, arg...) \
+	do { if (pat_debug_enable) pr_info("x86/PAT: " fmt, ##arg); } while (0)
+
+struct memtype {
+	u64			start;
+	u64			end;
+	u64			subtree_max_end;
+	enum page_cache_mode	type;
+	struct rb_node		rb;
+};
+
+static inline char *cattr_name(enum page_cache_mode pcm)
+{
+	switch (pcm) {
+	case _PAGE_CACHE_MODE_UC:		return "uncached";
+	case _PAGE_CACHE_MODE_UC_MINUS:		return "uncached-minus";
+	case _PAGE_CACHE_MODE_WB:		return "write-back";
+	case _PAGE_CACHE_MODE_WC:		return "write-combining";
+	case _PAGE_CACHE_MODE_WT:		return "write-through";
+	case _PAGE_CACHE_MODE_WP:		return "write-protected";
+	default:				return "broken";
+	}
+}
+
+#ifdef CONFIG_X86_PAT
+extern int memtype_check_insert(struct memtype *entry_new,
+				enum page_cache_mode *new_type);
+extern struct memtype *memtype_erase(u64 start, u64 end);
+extern struct memtype *memtype_lookup(u64 addr);
+extern int memtype_copy_nth_element(struct memtype *entry_out, loff_t pos);
+#else
+static inline int memtype_check_insert(struct memtype *entry_new,
+				       enum page_cache_mode *new_type)
+{ return 0; }
+static inline struct memtype *memtype_erase(u64 start, u64 end)
+{ return NULL; }
+static inline struct memtype *memtype_lookup(u64 addr)
+{ return NULL; }
+static inline int memtype_copy_nth_element(struct memtype *out, loff_t pos)
+{ return 0; }
+#endif
+
+#endif /* __MEMTYPE_H_ */

linux-7.2.3/arch/x86/mm/pat/memtype_interval.c

@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Handle caching attributes in page tables (PAT)
+ *
+ * Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ *          Suresh B Siddha <suresh.b.siddha@intel.com>
+ *
+ * Interval tree used to store the PAT memory type reservations.
+ */
+
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/interval_tree_generic.h>
+#include <linux/sched.h>
+#include <linux/gfp.h>
+#include <linux/pgtable.h>
+
+#include <asm/memtype.h>
+
+#include "memtype.h"
+
+/*
+ * The memtype tree keeps track of memory type for specific
+ * physical memory areas. Without proper tracking, conflicting memory
+ * types in different mappings can cause CPU cache corruption.
+ *
+ * The tree is an interval tree (augmented rbtree) which tree is ordered
+ * by the starting address. The tree can contain multiple entries for
+ * different regions which overlap. All the aliases have the same
+ * cache attributes of course, as enforced by the PAT logic.
+ *
+ * memtype_lock protects the rbtree.
+ */
+
+static inline u64 interval_start(struct memtype *entry)
+{
+	return entry->start;
+}
+
+static inline u64 interval_end(struct memtype *entry)
+{
+	return entry->end - 1;
+}
+
+INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
+		     interval_start, interval_end,
+		     static, interval)
+
+static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
+
+static int memtype_check_conflict(u64 start, u64 end,
+				  enum page_cache_mode reqtype,
+				  enum page_cache_mode *newtype)
+{
+	struct memtype *entry_match;
+	enum page_cache_mode found_type = reqtype;
+
+	entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
+	if (entry_match == NULL)
+		goto success;
+
+	if (entry_match->type != found_type && newtype == NULL)
+		goto failure;
+
+	dprintk("Overlap at 0x%Lx-0x%Lx\n", entry_match->start, entry_match->end);
+	found_type = entry_match->type;
+
+	entry_match = interval_iter_next(entry_match, start, end-1);
+	while (entry_match) {
+		if (entry_match->type != found_type)
+			goto failure;
+
+		entry_match = interval_iter_next(entry_match, start, end-1);
+	}
+success:
+	if (newtype)
+		*newtype = found_type;
+
+	return 0;
+
+failure:
+	pr_info("x86/PAT: %s:%d conflicting memory types %Lx-%Lx %s<->%s\n",
+		current->comm, current->pid, start, end,
+		cattr_name(found_type), cattr_name(entry_match->type));
+
+	return -EBUSY;
+}
+
+int memtype_check_insert(struct memtype *entry_new, enum page_cache_mode *ret_type)
+{
+	int err = 0;
+
+	err = memtype_check_conflict(entry_new->start, entry_new->end, entry_new->type, ret_type);
+	if (err)
+		return err;
+
+	if (ret_type)
+		entry_new->type = *ret_type;
+
+	interval_insert(entry_new, &memtype_rbroot);
+	return 0;
+}
+
+struct memtype *memtype_erase(u64 start, u64 end)
+{
+	struct memtype *entry = interval_iter_first(&memtype_rbroot, start, end - 1);
+
+	while (entry && entry->start < end) {
+		if (entry->start == start && entry->end == end) {
+			interval_remove(entry, &memtype_rbroot);
+			return entry;
+		}
+		entry = interval_iter_next(entry, start, end - 1);
+	}
+	return ERR_PTR(-EINVAL);
+}
+
+struct memtype *memtype_lookup(u64 addr)
+{
+	return interval_iter_first(&memtype_rbroot, addr, addr + PAGE_SIZE-1);
+}
+
+/*
+ * Debugging helper, copy the Nth entry of the tree into a
+ * a copy for printout. This allows us to print out the tree
+ * via debugfs, without holding the memtype_lock too long:
+ */
+#ifdef CONFIG_DEBUG_FS
+int memtype_copy_nth_element(struct memtype *entry_out, loff_t pos)
+{
+	struct memtype *entry_match;
+	int i = 1;
+
+	entry_match = interval_iter_first(&memtype_rbroot, 0, ULONG_MAX);
+
+	while (entry_match && pos != i) {
+		entry_match = interval_iter_next(entry_match, 0, ULONG_MAX);
+		i++;
+	}
+
+	if (entry_match) { /* pos == i */
+		*entry_out = *entry_match;
+		return 0;
+	} else {
+		return 1;
+	}
+}
+#endif