linux-kernel - [PATCH 2/7] modules: Add within_module

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Date:   Mon, 24 Jan 2022 09:22:19 +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 2/7] modules: Add within_module_text() macro

Add a macro to check whether an address is within module's text.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 include/linux/module.h | 13 +++++++++++++
 kernel/module.c        | 17 +++++------------
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 33b4db8f5ca5..fc7adb110a81 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -570,6 +570,19 @@ static inline bool within_range(unsigned long addr, void *base, unsigned int siz
 	return addr >= (unsigned long)base && addr < (unsigned long)base + size;
 }
 
+static inline bool within_module_layout_text(unsigned long addr,
+					     const struct module_layout *layout)
+{
+	return within_range(addr, layout->base, layout->text_size);
+}
+
+static inline bool within_module_text(unsigned long addr,
+				      const struct module *mod)
+{
+	return within_module_layout_text(addr, &mod->core_layout) ||
+	       within_module_layout_text(addr, &mod->init_layout);
+}
+
 static inline bool within_module_layout(unsigned long addr,
 					const struct module_layout *layout)
 {
diff --git a/kernel/module.c b/kernel/module.c
index 84a9141a5e15..201d27643c84 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4224,11 +4224,6 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 	return load_module(&info, uargs, flags);
 }
 
-static inline int within(unsigned long addr, void *start, unsigned long size)
-{
-	return ((void *)addr >= start && (void *)addr < start + size);
-}
-
 #ifdef CONFIG_KALLSYMS
 /*
  * This ignores the intensely annoying "mapping symbols" found
@@ -4765,13 +4760,11 @@ bool is_module_text_address(unsigned long addr)
 struct module *__module_text_address(unsigned long addr)
 {
 	struct module *mod = __module_address(addr);
-	if (mod) {
-		/* Make sure it's within the text section. */
-		if (!within(addr, mod->init_layout.base, mod->init_layout.text_size)
-		    && !within(addr, mod->core_layout.base, mod->core_layout.text_size))
-			mod = NULL;
-	}
-	return mod;
+
+	if (mod && within_module_text(addr, mod))
+		return mod;
+
+	return NULL;
 }
 
 /* Don't grab lock, we're oopsing. */
-- 
2.33.1