linux-kernel - [RFC PATCH v4 21/34] ftrace: sort ftrace entries earlier.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1425306312-3437-22-git-send-email-wangnan0@huawei.com>
Date:	Mon, 2 Mar 2015 22:24:59 +0800
From:	Wang Nan <wangnan0@...wei.com>
To:	<rostedt@...dmis.org>, <masami.hiramatsu.pt@...achi.com>,
	<mingo@...e.hu>, <linux@....linux.org.uk>, <tixy@...aro.org>
CC:	<lizefan@...wei.com>, <linux-kernel@...r.kernel.org>,
	<x86@...nel.org>, <linux-arm-kernel@...ts.infradead.org>
Subject: [RFC PATCH v4 21/34] ftrace: sort ftrace entries earlier.

By extracting mcount sorting code and sort them earliler, futher patches
will be able to determine whether an address is on an ftrace entry or
not using bsearch().

ftrace_sort_mcount_area() will be called before, during and after
ftrace_init (when module insertion). Ensure it sort kernel mcount table
only once.

Signed-off-by: Wang Nan <wangnan0@...wei.com>
---
 include/linux/ftrace.h |  2 ++
 init/main.c            |  1 +
 kernel/trace/ftrace.c  | 38 ++++++++++++++++++++++++++++++++++++--
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 1da6029..8db315a 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -701,8 +701,10 @@ static inline void __ftrace_enabled_restore(int enabled)
 
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 extern void ftrace_init(void);
+extern void ftrace_init_early(void);
 #else
 static inline void ftrace_init(void) { }
+static inline void ftrace_init_early(void) { }
 #endif
 
 /*
diff --git a/init/main.c b/init/main.c
index 679d49e..6d269ac 100644
--- a/init/main.c
+++ b/init/main.c
@@ -518,6 +518,7 @@ asmlinkage __visible void __init start_kernel(void)
 	boot_cpu_init();
 	page_address_init();
 	pr_notice("%s", linux_banner);
+	ftrace_init_early();
 	setup_arch(&command_line);
 	init_kprobes_early();
 	mm_init_cpumask(&init_mm);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6c6cbb1..fa3cdd3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -112,6 +112,7 @@ ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
 static struct ftrace_ops global_ops;
 static struct ftrace_ops control_ops;
+static bool kernel_mcount_sorted = false;
 
 static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
 				   struct ftrace_ops *op, struct pt_regs *regs);
@@ -4743,6 +4744,32 @@ static void ftrace_swap_ips(void *a, void *b, int size)
 	*ipb = t;
 }
 
+static void ftrace_sort_mcount_area(unsigned long *start, unsigned long *end)
+{
+	extern unsigned long __start_mcount_loc[];
+	extern unsigned long __stop_mcount_loc[];
+
+	unsigned long count;
+	bool is_kernel_mcount;
+
+	count = end - start;
+	if (!count)
+		return;
+
+	is_kernel_mcount =
+		(start == __start_mcount_loc) &&
+		(end == __stop_mcount_loc);
+
+	if (is_kernel_mcount && kernel_mcount_sorted)
+		return;
+
+	sort(start, count, sizeof(*start),
+		ftrace_cmp_ips, ftrace_swap_ips);
+
+	if (is_kernel_mcount)
+		kernel_mcount_sorted = true;
+}
+
 static int ftrace_process_locs(struct module *mod,
 			       unsigned long *start,
 			       unsigned long *end)
@@ -4761,8 +4788,7 @@ static int ftrace_process_locs(struct module *mod,
 	if (!count)
 		return 0;
 
-	sort(start, count, sizeof(*start),
-	     ftrace_cmp_ips, ftrace_swap_ips);
+	ftrace_sort_mcount_area(start, end);
 
 	start_pg = ftrace_allocate_pages(count);
 	if (!start_pg)
@@ -4965,6 +4991,14 @@ void __init ftrace_init(void)
 	ftrace_disabled = 1;
 }
 
+void __init ftrace_init_early(void)
+{
+	extern unsigned long __start_mcount_loc[];
+	extern unsigned long __stop_mcount_loc[];
+
+	ftrace_sort_mcount_area(__start_mcount_loc, __stop_mcount_loc);
+}
+
 /* Do nothing if arch does not support this */
 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
 {
-- 
1.8.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/