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authorSteven Rostedt <rostedt@goodmis.org>2008-08-14 15:45:09 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-14 10:34:47 +0200
commit90d595fe5ca4b685465c068907e6e554760abea8 (patch)
tree03f98454af8c6756177aa053ae7440373007f67d /kernel/module.c
parent68bf21aa15c85d2e9b623dcda2b1ed8893275fa1 (diff)
downloadlinux-90d595fe5ca4b685465c068907e6e554760abea8.tar.gz
ftrace: enable mcount recording for modules
This patch enables the loading of the __mcount_section of modules and
changing all the callers of mcount into nops.

The modification is done before the init_module function is called, so
again, we do not need to use kstop_machine to make these changes.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 661d73db786e..d753fd9d83ec 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -47,6 +47,7 @@
 #include <linux/license.h>
 #include <asm/sections.h>
 #include <linux/tracepoint.h>
+#include <linux/ftrace.h>
 
 #if 0
 #define DEBUGP printk
@@ -1834,6 +1835,7 @@ static noinline struct module *load_module(void __user *umod,
 	unsigned int markersstringsindex;
 	unsigned int tracepointsindex;
 	unsigned int tracepointsstringsindex;
+	unsigned int mcountindex;
 	struct module *mod;
 	long err = 0;
 	void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
@@ -2124,6 +2126,9 @@ static noinline struct module *load_module(void __user *umod,
 	tracepointsstringsindex = find_sec(hdr, sechdrs, secstrings,
 					"__tracepoints_strings");
 
+	mcountindex = find_sec(hdr, sechdrs, secstrings,
+			       "__mcount_loc");
+
 	/* Now do relocations. */
 	for (i = 1; i < hdr->e_shnum; i++) {
 		const char *strtab = (char *)sechdrs[strindex].sh_addr;
@@ -2184,6 +2189,12 @@ static noinline struct module *load_module(void __user *umod,
 			mod->tracepoints + mod->num_tracepoints);
 #endif
 	}
+
+	if (mcountindex) {
+		void *mseg = (void *)sechdrs[mcountindex].sh_addr;
+		ftrace_init_module(mseg, mseg + sechdrs[mcountindex].sh_size);
+	}
+
 	err = module_finalize(hdr, sechdrs, mod);
 	if (err < 0)
 		goto cleanup;