linux-kernel - [PATCH 3/7] modules: Always have struct mod_tree

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Date:   Mon, 24 Jan 2022 09:22:22 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Luis Chamberlain <mcgrof@...nel.org>, Jessica Yu <jeyu@...nel.org>
CC:     Christophe Leroy <christophe.leroy@...roup.eu>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "kgdb-bugreport@...ts.sourceforge.net" 
        <kgdb-bugreport@...ts.sourceforge.net>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
Subject: [PATCH 3/7] modules: Always have struct mod_tree_root

In order to separate text and data, we need to setup
two rb trees.

This also means that struct mod_tree_root is required even without
MODULES_TREE_LOOKUP.

Also remove module_addr_min and module_addr_max as there will
be one min and one max for each tree.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 kernel/module.c | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 201d27643c84..346bc2e7a150 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -85,7 +85,7 @@
  * Mutex protects:
  * 1) List of modules (also safely readable with preempt_disable),
  * 2) module_use links,
- * 3) module_addr_min/module_addr_max.
+ * 3) mod_tree.addr_min/mod_tree.addr_max.
  * (delete and add uses RCU list operations).
  */
 static DEFINE_MUTEX(module_mutex);
@@ -96,6 +96,16 @@ static void do_free_init(struct work_struct *w);
 static DECLARE_WORK(init_free_wq, do_free_init);
 static LLIST_HEAD(init_free_list);
 
+static struct mod_tree_root {
+#ifdef CONFIG_MODULES_TREE_LOOKUP
+	struct latch_tree_root root;
+#endif
+	unsigned long addr_min;
+	unsigned long addr_max;
+} mod_tree __cacheline_aligned = {
+	.addr_min = -1UL,
+};
+
 #ifdef CONFIG_MODULES_TREE_LOOKUP
 
 /*
@@ -149,17 +159,6 @@ static const struct latch_tree_ops mod_tree_ops = {
 	.comp = mod_tree_comp,
 };
 
-static struct mod_tree_root {
-	struct latch_tree_root root;
-	unsigned long addr_min;
-	unsigned long addr_max;
-} mod_tree __cacheline_aligned = {
-	.addr_min = -1UL,
-};
-
-#define module_addr_min mod_tree.addr_min
-#define module_addr_max mod_tree.addr_max
-
 static noinline void __mod_tree_insert(struct mod_tree_node *node)
 {
 	latch_tree_insert(&node->node, &mod_tree.root, &mod_tree_ops);
@@ -209,8 +208,6 @@ static struct module *mod_find(unsigned long addr)
 
 #else /* MODULES_TREE_LOOKUP */
 
-static unsigned long module_addr_min = -1UL, module_addr_max = 0;
-
 static void mod_tree_insert(struct module *mod) { }
 static void mod_tree_remove_init(struct module *mod) { }
 static void mod_tree_remove(struct module *mod) { }
@@ -239,10 +236,10 @@ static void __mod_update_bounds(void *base, unsigned int size)
 	unsigned long min = (unsigned long)base;
 	unsigned long max = min + size;
 
-	if (min < module_addr_min)
-		module_addr_min = min;
-	if (max > module_addr_max)
-		module_addr_max = max;
+	if (min < mod_tree.addr_min)
+		mod_tree.addr_min = min;
+	if (max > mod_tree.addr_max)
+		mod_tree.addr_max = max;
 }
 
 static void mod_update_bounds(struct module *mod)
@@ -4526,14 +4523,14 @@ static void cfi_init(struct module *mod)
 		mod->exit = *exit;
 #endif
 
-	cfi_module_add(mod, module_addr_min);
+	cfi_module_add(mod, mod_tree.addr_min);
 #endif
 }
 
 static void cfi_cleanup(struct module *mod)
 {
 #ifdef CONFIG_CFI_CLANG
-	cfi_module_remove(mod, module_addr_min);
+	cfi_module_remove(mod, mod_tree.addr_min);
 #endif
 }
 
@@ -4717,7 +4714,7 @@ struct module *__module_address(unsigned long addr)
 {
 	struct module *mod;
 
-	if (addr < module_addr_min || addr > module_addr_max)
+	if (addr < mod_tree.addr_min || addr > mod_tree.addr_max)
 		return NULL;
 
 	module_assert_mutex_or_preempt();
-- 
2.33.1