mptcp/openmptcprouter
1
0
Fork 0
mirror of https://github.com/Ysurac/openmptcprouter.git synced 2025-03-09 15:40:20 +00:00
Code Issues Releases Wiki Activity

Fix RPI kernel compile

Browse source
This commit is contained in:
Ycarus 2018-08-29 09:57:51 +02:00
parent e8f9b01b2d
commit e4f3240c3f
1 changed files with 0 additions and 84 deletions
Download patch file Download diff file Expand all files Collapse all files

84
root/target/linux/brcm2708/patches-4.14/0374-Arm-mm-ftrace-Only-set-text-back-to-ro-after-kernel-.patch
View file

@ -1,84 +0,0 @@
From 786b6ff17f8612ba9af84ac379d4b494f39f55c5 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <rostedt@goodmis.org>
Date: Wed, 23 Aug 2017 13:58:36 -0400
Subject: [PATCH 374/374] Arm: mm: ftrace: Only set text back to ro after
kernel has been marked ro
ftrace needs to modify the kernel text in order to enable function tracing.
For security reasons, the kernel text is marked to read-only (ro) at the end
of system bootup. When enabling function tracing after that, ftrace calls
arch specific code that needs to enable the modification of kernel text
while ftrace does the update, and reset it back again when finished.
The issue arises when function tracing is enabled during system bootup. The
text hasn't been marked as read-only yet, but the same code to modify the
kernel is executed, and when it is finished, it will cause the kernel to
become read-only. This causes issues for other init code that requires
modification of kernel text during system bootup. This appears to cause
issue with Raspberry Pi 2.
By implementing the feature that is used in x86 to deal with this issue, it
fixes the problem. The solution is simple. Have a variable
(kernel_set_to_readonly) get set when the system finished boot and marks the
kernel to readonly. If that variable is not set, both
kernel_set_to_readonly() and kernel_set_to_rw() return without doing any
modifications. Those functions are used by ftrace to change the permissions
of the kernel text. By not doing anything, ftrace will not mess with the
permissions when it is enabled at system bootup.
Link: http://lkml.kernel.org/r/20170821153402.7so2u364htvt6tnf@camel2.lan
Link: https://github.com/raspberrypi/linux/issues/2166#issuecomment-323355145
Reported-by: Matthias Reichl <hias@horus.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Phil Elwell <phil@raspberrypi.org>
Cc: linux-rpi-kernel@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@vger.kernel.org
Fixes: 80d6b0c2ee ("ARM: mm: allow text and rodata sections to be read-only")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Matthias Reichl <hias@horus.com>
Acked-by: Kees Cook <keescook@chromium.org>
---
arch/arm/mm/init.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 0f6d1537f330..82175c047222 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -745,19 +745,29 @@ static int __mark_rodata_ro(void *unused)
return 0;
}
+static int kernel_set_to_readonly;
+
void mark_rodata_ro(void)
{
+ kernel_set_to_readonly = 1;
+
stop_machine(__mark_rodata_ro, NULL, NULL);
}
void set_kernel_text_rw(void)
{
+ if (!kernel_set_to_readonly)
+ return;
+
set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
current->active_mm);
}
void set_kernel_text_ro(void)
{
+ if (!kernel_set_to_readonly)
+ return;
+
set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
current->active_mm);
}
--
2.16.1