[PATCH] arm: ftrace: work with CONFIG_DEBUG_SET_MODULE_RONX

From: Rabin Vincent
Date: Wed Apr 02 2014 - 18:10:57 EST


Make ftrace work with CONFIG_DEBUG_SET_MODULE_RONX by making module text
writable around the place where ftrace does its work, like it is done on
x86 in the patch which introduced CONFIG_DEBUG_SET_MODULE_RONX,
84e1c6bb38eb ("x86: Add RO/NX protection for loadable kernel modules").

Signed-off-by: Rabin Vincent <rabin@xxxxxx>
---
arch/arm/kernel/ftrace.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 34e5664..70ce654 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -14,6 +14,7 @@

#include <linux/ftrace.h>
#include <linux/uaccess.h>
+#include <linux/module.h>

#include <asm/cacheflush.h>
#include <asm/opcodes.h>
@@ -63,6 +64,18 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
}
#endif

+int ftrace_arch_code_modify_prepare(void)
+{
+ set_all_modules_text_rw();
+ return 0;
+}
+
+int ftrace_arch_code_modify_post_process(void)
+{
+ set_all_modules_text_ro();
+ return 0;
+}
+
static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
{
return arm_gen_branch_link(pc, addr);
--
1.9.1

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