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>

arch/arm/include/asm/memblock.h

@@ -6,4 +6,6 @@ struct machine_desc;
 
 extern void arm_memblock_init(struct meminfo *, struct machine_desc *);
 
+phys_addr_t arm_memblock_steal(phys_addr_t size, phys_addr_t align);
+
 #endif

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)")

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")

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")

arch/arm/mach-omap2/Kconfig

@@ -366,8 +366,8 @@ config OMAP3_SDRC_AC_TIMING
 	  going on could result in system crashes;
 
 config OMAP4_ERRATA_I688
-	bool "OMAP4 errata: Async Bridge Corruption"
-	depends on ARCH_OMAP4
+	bool "OMAP4 errata: Async Bridge Corruption (BROKEN)"
+	depends on ARCH_OMAP4 && BROKEN
 	select ARCH_HAS_BARRIERS
 	help
 	  If a data is stalled inside asynchronous bridge because of back

arch/arm/mach-omap2/omap-secure.c

@@ -16,6 +16,7 @@
 #include <linux/memblock.h>
 
 #include <asm/cacheflush.h>
+#include <asm/memblock.h>
 
 #include <mach/omap-secure.h>
 
@@ -57,20 +58,10 @@ u32 omap_secure_dispatcher(u32 idx, u32 flag, u32 nargs, u32 arg1, u32 arg2,
 /* Allocate the memory to save secure ram */
 int __init omap_secure_ram_reserve_memblock(void)
 {
-	phys_addr_t paddr;
 	u32 size = OMAP_SECURE_RAM_STORAGE;
 
 	size = ALIGN(size, SZ_1M);
-	paddr = memblock_alloc(size, SZ_1M);
-	if (!paddr) {
-		pr_err("%s: failed to reserve %x bytes\n",
-				__func__, size);
-		return -ENOMEM;
-	}
-	memblock_free(paddr, size);
-	memblock_remove(paddr, size);
-
-	omap_secure_memblock_base = paddr;
+	omap_secure_memblock_base = arm_memblock_steal(size, SZ_1M);
 
 	return 0;
 }

arch/arm/mach-omap2/omap4-common.c

@@ -20,6 +20,7 @@
 #include <asm/hardware/gic.h>
 #include <asm/hardware/cache-l2x0.h>
 #include <asm/mach/map.h>
+#include <asm/memblock.h>
 
 #include <plat/irqs.h>
 #include <plat/sram.h>
@@ -61,13 +62,8 @@ static int __init omap_barriers_init(void)
 		return -ENODEV;
 
 	size = ALIGN(PAGE_SIZE, SZ_1M);
-	paddr = memblock_alloc(size, SZ_1M);
-	if (!paddr) {
-		pr_err("%s: failed to reserve 4 Kbytes\n", __func__);
-		return -ENOMEM;
-	}
-	memblock_free(paddr, size);
-	memblock_remove(paddr, size);
+	paddr = arm_memblock_steal(size, SZ_1M);
+
 	dram_io_desc[0].virtual = OMAP4_DRAM_BARRIER_VA;
 	dram_io_desc[0].pfn = __phys_to_pfn(paddr);
 	dram_io_desc[0].length = size;

arch/arm/mm/init.c

@@ -22,6 +22,7 @@
 #include <linux/memblock.h>
 
 #include <asm/mach-types.h>
+#include <asm/memblock.h>
 #include <asm/prom.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
@@ -307,6 +308,21 @@ static void arm_memory_present(void)
 }
 #endif
 
+static bool arm_memblock_steal_permitted = true;
+
+phys_addr_t arm_memblock_steal(phys_addr_t size, phys_addr_t align)
+{
+	phys_addr_t phys;
+
+	BUG_ON(!arm_memblock_steal_permitted);
+
+	phys = memblock_alloc(size, align);
+	memblock_free(phys, size);
+	memblock_remove(phys, size);
+
+	return phys;
+}
+
 void __init arm_memblock_init(struct meminfo *mi, struct machine_desc *mdesc)
 {
 	int i;
@@ -349,6 +365,7 @@ void __init arm_memblock_init(struct meminfo *mi, struct machine_desc *mdesc)
 	if (mdesc->reserve)
 		mdesc->reserve();
 
+	arm_memblock_steal_permitted = false;
 	memblock_allow_resize();
 	memblock_dump_all();
 }

arch/arm/plat-omap/devices.c

@@ -20,6 +20,7 @@
 #include <mach/hardware.h>
 #include <asm/mach-types.h>
 #include <asm/mach/map.h>
+#include <asm/memblock.h>
 
 #include <plat/tc.h>
 #include <plat/board.h>
@@ -164,14 +165,12 @@ void __init omap_dsp_reserve_sdram_memblock(void)
 	if (!size)
 		return;
 
-	paddr = memblock_alloc(size, SZ_1M);
+	paddr = arm_memblock_steal(size, SZ_1M);
 	if (!paddr) {
 		pr_err("%s: failed to reserve %x bytes\n",
 				__func__, size);
 		return;
 	}
-	memblock_free(paddr, size);
-	memblock_remove(paddr, size);
 
 	omap_dsp_phys_mempool_base = paddr;
 }