ARM: Add arm_memblock_steal() to allocate memory away from the kernel

Several platforms are now using the memblock_alloc+memblock_free+
memblock_remove trick to obtain memory which won't be mapped in the
kernel's page tables.  Most platforms do this (correctly) in the
->reserve callback.  However, OMAP has started to call these functions
outside of this callback, and this is extremely unsafe - memory will
not be unmapped, and could well be given out after memblock is no
longer responsible for its management.

So, provide arm_memblock_steal() to perform this function, and ensure
that it panic()s if it is used inappropriately.  Convert everyone
over, including OMAP.

As a result, OMAP with OMAP4_ERRATA_I688 enabled will panic on boot
with this change.  Mark this option as BROKEN and make it depend on
BROKEN.  OMAP needs to be fixed, or 137d105d50 (ARM: OMAP4: Fix
errata i688 with MPU interconnect barriers.) reverted until such
time it can be fixed correctly.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 6 insertions, 9 deletions

diff --git a/arch/arm/mach-imx/mach-mx31_3ds.c b/arch/arm/mach-imx/mach-mx31_3ds.c
index 89c33258639f..4d1aab154400 100644
--- a/arch/arm/mach-imx/mach-mx31_3ds.c
+++ b/arch/arm/mach-imx/mach-mx31_3ds.c
@@ -36,6 +36,7 @@
 #include <asm/mach/time.h>
 #include <asm/memory.h>
 #include <asm/mach/map.h>
+#include <asm/memblock.h>
 #include <mach/common.h>
 #include <mach/iomux-mx3.h>
 #include <mach/3ds_debugboard.h>
@@ -754,10 +755,8 @@ static struct sys_timer mx31_3ds_timer = {
 static void __init mx31_3ds_reserve(void)
 {
 	/* reserve MX31_3DS_CAMERA_BUF_SIZE bytes for mx3-camera */
-	mx3_camera_base = memblock_alloc(MX31_3DS_CAMERA_BUF_SIZE,
+	mx3_camera_base = arm_memblock_steal(MX31_3DS_CAMERA_BUF_SIZE,
 					 MX31_3DS_CAMERA_BUF_SIZE);
-	memblock_free(mx3_camera_base, MX31_3DS_CAMERA_BUF_SIZE);
-	memblock_remove(mx3_camera_base, MX31_3DS_CAMERA_BUF_SIZE);
 }
 
 MACHINE_START(MX31_3DS, "Freescale MX31PDK (3DS)")
diff --git a/arch/arm/mach-imx/mach-mx31moboard.c b/arch/arm/mach-imx/mach-mx31moboard.c
index b95981dacb2b..f225262b5c38 100644
--- a/arch/arm/mach-imx/mach-mx31moboard.c
+++ b/arch/arm/mach-imx/mach-mx31moboard.c
@@ -41,6 +41,7 @@
 #include <asm/mach/arch.h>
 #include <asm/mach/time.h>
 #include <asm/mach/map.h>
+#include <asm/memblock.h>
 #include <mach/board-mx31moboard.h>
 #include <mach/common.h>
 #include <mach/hardware.h>
@@ -584,10 +585,8 @@ struct sys_timer mx31moboard_timer = {
 static void __init mx31moboard_reserve(void)
 {
 	/* reserve 4 MiB for mx3-camera */
-	mx3_camera_base = memblock_alloc(MX3_CAMERA_BUF_SIZE,
+	mx3_camera_base = arm_memblock_steal(MX3_CAMERA_BUF_SIZE,
 			MX3_CAMERA_BUF_SIZE);
-	memblock_free(mx3_camera_base, MX3_CAMERA_BUF_SIZE);
-	memblock_remove(mx3_camera_base, MX3_CAMERA_BUF_SIZE);
 }
 
 MACHINE_START(MX31MOBOARD, "EPFL Mobots mx31moboard")
diff --git a/arch/arm/mach-imx/mach-pcm037.c b/arch/arm/mach-imx/mach-pcm037.c
index d7e151669ed3..e48854b9d990 100644
--- a/arch/arm/mach-imx/mach-pcm037.c
+++ b/arch/arm/mach-imx/mach-pcm037.c
@@ -39,6 +39,7 @@
 #include <asm/mach/arch.h>
 #include <asm/mach/time.h>
 #include <asm/mach/map.h>
+#include <asm/memblock.h>
 #include <mach/common.h>
 #include <mach/hardware.h>
 #include <mach/iomux-mx3.h>
@@ -680,10 +681,8 @@ struct sys_timer pcm037_timer = {
 static void __init pcm037_reserve(void)
 {
 	/* reserve 4 MiB for mx3-camera */
-	mx3_camera_base = memblock_alloc(MX3_CAMERA_BUF_SIZE,
+	mx3_camera_base = arm_memblock_steal(MX3_CAMERA_BUF_SIZE,
 			MX3_CAMERA_BUF_SIZE);
-	memblock_free(mx3_camera_base, MX3_CAMERA_BUF_SIZE);
-	memblock_remove(mx3_camera_base, MX3_CAMERA_BUF_SIZE);
 }
 
 MACHINE_START(PCM037, "Phytec Phycore pcm037")