From: Leon Woestenberg <leon@sidebranch.com>
Date: Thu, 22 Dec 2011 19:32:51 +0000 (+0100)
Subject: linux-imx: Workaround kernel oops when devtmpfs is enabled.
X-Git-Tag: 2.1~1954
X-Git-Url: https://code.ossystems.io/gitweb?a=commitdiff_plain;h=eed26a47425f540426013fd3d39c8ad224e7ee93;p=meta-freescale.git

linux-imx: Workaround kernel oops when devtmpfs is enabled.

More details in head of patch.

Signed-off-by: Leon Woestenberg <leon@sidebranch.com>
---

diff --git a/meta-fsl-arm/recipes-kernel/linux/linux-imx/devtmpfs-init-options-alignment.patch b/meta-fsl-arm/recipes-kernel/linux/linux-imx/devtmpfs-init-options-alignment.patch
new file mode 100644
index 00000000..19e5ef2f
--- /dev/null
+++ b/meta-fsl-arm/recipes-kernel/linux/linux-imx/devtmpfs-init-options-alignment.patch
@@ -0,0 +1,38 @@
+Make the devtmpfs options static. This works around an issue that is still
+under investigation.
+
+The toolchain assumes it can generate unaligned accesses for ARMv6+, as these
+cores can handle this, PROVIDED the bit is set in the CP15 control register.
+
+However, Linux sets this bit lazely (upon first trap), which does not work for
+kernel space code.
+
+There was a lengthy thread over this, the agreement was the kernel should not
+have non-aligned structures on stacks anyway.
+
+Forcing this structure to be aligned on the stack did not help, unsure why.
+This requires further investigation.
+
+This fixes a kernel failure if devtmpfs was enabled in the kernel config.
+
+Signed-off-by: Leon Woestenberg <leon@sidebranch.com>
+diff -Nur orig/drivers/base/devtmpfs.c git/drivers/base/devtmpfs.c
+--- orig/drivers/base/devtmpfs.c	2011-12-22 15:11:18.752904263 +0100
++++ git/drivers/base/devtmpfs.c	2011-12-22 18:03:09.060928840 +0100
+@@ -365,6 +365,8 @@
+ 	return err;
+ }
+ 
++static char options[] = "mode=0755";
++
+ /*
+  * Create devtmpfs instance, driver-core devices will add their device
+  * nodes here.
+@@ -373,7 +375,6 @@
+ {
+ 	int err;
+ 	struct vfsmount *mnt;
+-	char options[] = "mode=0755";
+ 
+ 	err = register_filesystem(&dev_fs_type);
+ 	if (err) {
diff --git a/meta-fsl-arm/recipes-kernel/linux/linux-imx_2.6.35.3.bb b/meta-fsl-arm/recipes-kernel/linux/linux-imx_2.6.35.3.bb
index 94bfb6f9..18f6d66c 100644
--- a/meta-fsl-arm/recipes-kernel/linux/linux-imx_2.6.35.3.bb
+++ b/meta-fsl-arm/recipes-kernel/linux/linux-imx_2.6.35.3.bb
@@ -4,7 +4,7 @@
 DESCRIPTION = "Linux kernel for imx platforms"
 LICENSE = "GPLv2"
 LIC_FILES_CHKSUM = "file://COPYING;md5=d7810fab7487fb0aad327b76f1be7cd7"
-PR = "r4"
+PR = "r5"
 
 inherit kernel
 COMPATIBLE_MACHINE = "(imx53qsb|imx53ard)"
@@ -12,6 +12,7 @@ COMPATIBLE_MACHINE = "(imx53qsb|imx53ard)"
 SRC_URI = "git://opensource.freescale.com/pub/scm/imx/linux-2.6-imx.git;tag=rel_imx_2.6.35_11.09.01;protocol=http \
            file://egalax_ts-enable-single-event-support.patch \
            file://plat-mxc-double-dma-zone-max.patch \
+           file://devtmpfs-init-options-alignment.patch \
            file://defconfig \
           "