[RFC] [patch 1/2] add non_init_kernel_text_address

[Srinivasa Ds <srinivasa@in.ibm.com>]

Changing regular_kernel_text_address() to persistent_kernel_text_address().

Since __init functions are discarded and its memory freed once
initialization completes, It would be better if we enable kprobes
to refuse probing __init functions. The attached patchset will do
that.

This patch creates persistent_kernel_text_address() to identify
"non_init" text area.


Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>



---
 include/linux/kernel.h |    2 ++
 kernel/extable.c       |   16 +++++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

Index: linux-2.6.24-rc5-mm1/include/linux/kernel.h
===================================================================
--- linux-2.6.24-rc5-mm1.orig/include/linux/kernel.h
+++ linux-2.6.24-rc5-mm1/include/linux/kernel.h
@@ -169,6 +169,8 @@ extern unsigned long long memparse(char 
 extern int core_kernel_text(unsigned long addr);
 extern int __kernel_text_address(unsigned long addr);
 extern int kernel_text_address(unsigned long addr);
+extern int persistent_kernel_text_address(unsigned long addr);
+extern int persistent_core_kernel_text(unsigned long addr);
 struct pid;
 extern struct pid *session_of_pgrp(struct pid *pgrp);
 
Index: linux-2.6.24-rc5-mm1/kernel/extable.c
===================================================================
--- linux-2.6.24-rc5-mm1.orig/kernel/extable.c
+++ linux-2.6.24-rc5-mm1/kernel/extable.c
@@ -40,11 +40,18 @@ const struct exception_table_entry *sear
 	return e;
 }
 
-int core_kernel_text(unsigned long addr)
+int persistent_core_kernel_text(unsigned long addr)
 {
 	if (addr >= (unsigned long)_stext &&
 	    addr <= (unsigned long)_etext)
 		return 1;
+	return 0;
+}
+
+int core_kernel_text(unsigned long addr)
+{
+	if (persistent_core_kernel_text(addr))
+		return 1;
 
 	if (addr >= (unsigned long)_sinittext &&
 	    addr <= (unsigned long)_einittext)
@@ -65,3 +72,10 @@ int kernel_text_address(unsigned long ad
 		return 1;
 	return module_text_address(addr) != NULL;
 }
+
+int persistent_kernel_text_address(unsigned long addr)
+{
+	if (persistent_core_kernel_text(addr))
+		return 1;
+	return module_text_address(addr) != NULL;
+}