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Message-Id: <1487498660-16600-2-git-send-email-hoeun.ryu@gmail.com>
Date: Sun, 19 Feb 2017 19:04:05 +0900
From: Hoeun Ryu <hoeun.ryu@...il.com>
To: kernel-hardening@...ts.openwall.com, linux-kernel@...r.kernel.org
Cc: Hoeun Ryu <hoeun.ryu@...il.com>, Kees Cook <keescook@...omium.org>,
Jessica Yu <jeyu@...hat.com>, Ingo Molnar <mingo@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Emese Revfy <re.emese@...il.com>,
AKASHI Takahiro <takahiro.akashi@...aro.org>,
Fabian Frederick <fabf@...net.be>,
Helge Deller <deller@....de>,
Laura Abbott <labbott@...hat.com>,
Nicholas Piggin <npiggin@...il.com>,
Thomas Gleixner <tglx@...utronix.de>,
Petr Mladek <pmladek@...e.com>, Yang Shi <yang.shi@...aro.org>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Tejun Heo <tj@...nel.org>, Prarit Bhargava <prarit@...hat.com>,
Lokesh Vutla <lokeshvutla@...com>
Subject: [RFC 2/7] init: add set_ro_mostly_after_init_rw/ro function
Add set_ro_mostly_after_init_rw/ro pair to modify memory attributes for
memory marked as `ro_mostly_after_init`.
I am doubtful that this is the right place where these functions reside and
these functions are suitable for all architectures for memory attributes
modification. Please comment.
Signed-off-by: Hoeun Ryu <hoeun.ryu@...il.com>
---
include/linux/init.h | 6 ++++++
init/main.c | 24 ++++++++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/include/linux/init.h b/include/linux/init.h
index 79af096..d68e4f7 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -131,6 +131,12 @@ extern bool rodata_enabled;
#endif
#ifdef CONFIG_STRICT_KERNEL_RWX
void mark_rodata_ro(void);
+
+void set_ro_mostly_after_init_rw(void);
+void set_ro_mostly_after_init_ro(void);
+#else
+static inline void set_ro_mostly_after_init_rw(void) { }
+static inline void set_ro_mostly_after_init_ro(void) { }
#endif
extern void (*late_time_init)(void);
diff --git a/init/main.c b/init/main.c
index 4719abf..a5d4873 100644
--- a/init/main.c
+++ b/init/main.c
@@ -941,6 +941,30 @@ static void mark_readonly(void)
} else
pr_info("Kernel memory protection disabled.\n");
}
+
+void set_ro_mostly_after_init_rw(void)
+{
+ unsigned long start = PFN_ALIGN(__start_data_ro_mostly_after_init);
+ unsigned long end = PFN_ALIGN(&__end_data_ro_mostly_after_init);
+ unsigned long nr_pages = (end - start) >> PAGE_SHIFT;
+
+ if (!rodata_enabled)
+ return;
+
+ set_memory_rw(start, nr_pages);
+}
+
+void set_ro_mostly_after_init_ro(void)
+{
+ unsigned long start = PFN_ALIGN(__start_data_ro_mostly_after_init);
+ unsigned long end = PFN_ALIGN(&__end_data_ro_mostly_after_init);
+ unsigned long nr_pages = (end - start) >> PAGE_SHIFT;
+
+ if (!rodata_enabled)
+ return;
+
+ set_memory_ro(start, nr_pages);
+}
#else
static inline void mark_readonly(void)
{
--
2.7.4
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