Merge tag 'char-misc-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc updates from Greg KH:
 "Here is the big char/misc driver update for 4.6-rc1.

  The majority of the patches here is hwtracing and some new mic
  drivers, but there's a lot of other driver updates as well.  Full
  details in the shortlog.

  All have been in linux-next for a while with no reported issues"

* tag 'char-misc-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (238 commits)
  goldfish: Fix build error of missing ioremap on UM
  nvmem: mediatek: Fix later provider initialization
  nvmem: imx-ocotp: Fix return value of imx_ocotp_read
  nvmem: Fix dependencies for !HAS_IOMEM archs
  char: genrtc: replace blacklist with whitelist
  drivers/hwtracing: make coresight-etm-perf.c explicitly non-modular
  drivers: char: mem: fix IS_ERROR_VALUE usage
  char: xillybus: Fix internal data structure initialization
  pch_phub: return -ENODATA if ROM can't be mapped
  Drivers: hv: vmbus: Support kexec on ws2012 r2 and above
  Drivers: hv: vmbus: Support handling messages on multiple CPUs
  Drivers: hv: utils: Remove util transport handler from list if registration fails
  Drivers: hv: util: Pass the channel information during the init call
  Drivers: hv: vmbus: avoid unneeded compiler optimizations in vmbus_wait_for_unload()
  Drivers: hv: vmbus: remove code duplication in message handling
  Drivers: hv: vmbus: avoid wait_for_completion() on crash
  Drivers: hv: vmbus: don't loose HVMSG_TIMER_EXPIRED messages
  misc: at24: replace memory_accessor with nvmem_device_read
  eeprom: 93xx46: extend driver to plug into the NVMEM framework
  eeprom: at25: extend driver to plug into the NVMEM framework
  ...

13 files changed, 243 insertions, 32 deletions

diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h
index 9006c4e75cf7..3d8dcdd1aeae 100644
--- a/include/linux/amba/bus.h
+++ b/include/linux/amba/bus.h
@@ -163,4 +163,13 @@ struct amba_device name##_device = {				\
 #define module_amba_driver(__amba_drv) \
 	module_driver(__amba_drv, amba_driver_register, amba_driver_unregister)
 
+/*
+ * builtin_amba_driver() - Helper macro for drivers that don't do anything
+ * special in driver initcall.  This eliminates a lot of boilerplate.  Each
+ * driver may only use this macro once, and calling it replaces the instance
+ * device_initcall().
+ */
+#define builtin_amba_driver(__amba_drv) \
+	builtin_driver(__amba_drv, amba_driver_register)
+
 #endif
diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
new file mode 100644
index 000000000000..7d410260661b
--- /dev/null
+++ b/include/linux/coresight-pmu.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright(C) 2015 Linaro Limited. All rights reserved.
+ * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _LINUX_CORESIGHT_PMU_H
+#define _LINUX_CORESIGHT_PMU_H
+
+#define CORESIGHT_ETM_PMU_NAME "cs_etm"
+#define CORESIGHT_ETM_PMU_SEED  0x10
+
+/* ETMv3.5/PTM's ETMCR config bit */
+#define ETM_OPT_CYCACC  12
+#define ETM_OPT_TS      28
+
+static inline int coresight_get_trace_id(int cpu)
+{
+	/*
+	 * A trace ID of value 0 is invalid, so let's start at some
+	 * random value that fits in 7 bits and go from there.  Since
+	 * the common convention is to have data trace IDs be I(N) + 1,
+	 * set instruction trace IDs as a function of the CPU number.
+	 */
+	return (CORESIGHT_ETM_PMU_SEED + (cpu * 2));
+}
+
+#endif
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index a7cabfa23b55..385d62e64abb 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -14,6 +14,7 @@
 #define _LINUX_CORESIGHT_H
 
 #include <linux/device.h>
+#include <linux/perf_event.h>
 #include <linux/sched.h>
 
 /* Peripheral id registers (0xFD0-0xFEC) */
@@ -152,7 +153,6 @@ struct coresight_connection {
 		by @coresight_ops.
  * @dev:	The device entity associated to this component.
  * @refcnt:	keep track of what is in use.
- * @path_link:	link of current component into the path being enabled.
  * @orphan:	true if the component has connections that haven't been linked.
  * @enable:	'true' if component is currently part of an active path.
  * @activated:	'true' only if a _sink_ has been activated.  A sink can be
@@ -168,7 +168,6 @@ struct coresight_device {
 	const struct coresight_ops *ops;
 	struct device dev;
 	atomic_t *refcnt;
-	struct list_head path_link;
 	bool orphan;
 	bool enable;	/* true only if configured as part of a path */
 	bool activated;	/* true only if a sink is part of a path */
@@ -183,12 +182,29 @@ struct coresight_device {
 /**
  * struct coresight_ops_sink - basic operations for a sink
  * Operations available for sinks
- * @enable:	enables the sink.
- * @disable:	disables the sink.
+ * @enable:		enables the sink.
+ * @disable:		disables the sink.
+ * @alloc_buffer:	initialises perf's ring buffer for trace collection.
+ * @free_buffer:	release memory allocated in @get_config.
+ * @set_buffer:		initialises buffer mechanic before a trace session.
+ * @reset_buffer:	finalises buffer mechanic after a trace session.
+ * @update_buffer:	update buffer pointers after a trace session.
  */
 struct coresight_ops_sink {
-	int (*enable)(struct coresight_device *csdev);
+	int (*enable)(struct coresight_device *csdev, u32 mode);
 	void (*disable)(struct coresight_device *csdev);
+	void *(*alloc_buffer)(struct coresight_device *csdev, int cpu,
+			      void **pages, int nr_pages, bool overwrite);
+	void (*free_buffer)(void *config);
+	int (*set_buffer)(struct coresight_device *csdev,
+			  struct perf_output_handle *handle,
+			  void *sink_config);
+	unsigned long (*reset_buffer)(struct coresight_device *csdev,
+				      struct perf_output_handle *handle,
+				      void *sink_config, bool *lost);
+	void (*update_buffer)(struct coresight_device *csdev,
+			      struct perf_output_handle *handle,
+			      void *sink_config);
 };
 
 /**
@@ -205,14 +221,18 @@ struct coresight_ops_link {
 /**
  * struct coresight_ops_source - basic operations for a source
  * Operations available for sources.
+ * @cpu_id:	returns the value of the CPU number this component
+ *		is associated to.
  * @trace_id:	returns the value of the component's trace ID as known
-		to the HW.
+ *		to the HW.
  * @enable:	enables tracing for a source.
  * @disable:	disables tracing for a source.
  */
 struct coresight_ops_source {
+	int (*cpu_id)(struct coresight_device *csdev);
 	int (*trace_id)(struct coresight_device *csdev);
-	int (*enable)(struct coresight_device *csdev);
+	int (*enable)(struct coresight_device *csdev,
+		      struct perf_event_attr *attr,  u32 mode);
 	void (*disable)(struct coresight_device *csdev);
 };
 
diff --git a/include/linux/davinci_emac.h b/include/linux/davinci_emac.h
index 542888504994..05b97144d342 100644
--- a/include/linux/davinci_emac.h
+++ b/include/linux/davinci_emac.h
@@ -12,7 +12,7 @@
 #define _LINUX_DAVINCI_EMAC_H
 
 #include <linux/if_ether.h>
-#include <linux/memory.h>
+#include <linux/nvmem-consumer.h>
 
 struct mdio_platform_data {
 	unsigned long		bus_freq;
@@ -46,5 +46,5 @@ enum {
 	EMAC_VERSION_2,	/* DM646x */
 };
 
-void davinci_get_mac_addr(struct memory_accessor *mem_acc, void *context);
+void davinci_get_mac_addr(struct nvmem_device *nvmem, void *context);
 #endif
diff --git a/include/linux/eeprom_93xx46.h b/include/linux/eeprom_93xx46.h
index 06791811e49d..885f587a3555 100644
--- a/include/linux/eeprom_93xx46.h
+++ b/include/linux/eeprom_93xx46.h
@@ -3,16 +3,25 @@
  * platform description for 93xx46 EEPROMs.
  */
 
+struct gpio_desc;
+
 struct eeprom_93xx46_platform_data {
 	unsigned char	flags;
 #define EE_ADDR8	0x01		/*  8 bit addr. cfg */
 #define EE_ADDR16	0x02		/* 16 bit addr. cfg */
 #define EE_READONLY	0x08		/* forbid writing */
 
+	unsigned int	quirks;
+/* Single word read transfers only; no sequential read. */
+#define EEPROM_93XX46_QUIRK_SINGLE_WORD_READ		(1 << 0)
+/* Instructions such as EWEN are (addrlen + 2) in length. */
+#define EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH		(1 << 1)
+
 	/*
 	 * optional hooks to control additional logic
 	 * before and after spi transfer.
 	 */
 	void (*prepare)(void *);
 	void (*finish)(void *);
+	struct gpio_desc *select;
 };
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 753dbad0bf94..aa0fadce9308 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -235,6 +235,7 @@ struct vmbus_channel_offer {
 #define VMBUS_CHANNEL_LOOPBACK_OFFER			0x100
 #define VMBUS_CHANNEL_PARENT_OFFER			0x200
 #define VMBUS_CHANNEL_REQUEST_MONITORED_NOTIFICATION	0x400
+#define VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER		0x2000
 
 struct vmpacket_descriptor {
 	u16 type;
@@ -391,6 +392,10 @@ enum vmbus_channel_message_type {
 	CHANNELMSG_VERSION_RESPONSE		= 15,
 	CHANNELMSG_UNLOAD			= 16,
 	CHANNELMSG_UNLOAD_RESPONSE		= 17,
+	CHANNELMSG_18				= 18,
+	CHANNELMSG_19				= 19,
+	CHANNELMSG_20				= 20,
+	CHANNELMSG_TL_CONNECT_REQUEST		= 21,
 	CHANNELMSG_COUNT
 };
 
@@ -561,6 +566,13 @@ struct vmbus_channel_initiate_contact {
 	u64 monitor_page2;
 } __packed;
 
+/* Hyper-V socket: guest's connect()-ing to host */
+struct vmbus_channel_tl_connect_request {
+	struct vmbus_channel_message_header header;
+	uuid_le guest_endpoint_id;
+	uuid_le host_service_id;
+} __packed;
+
 struct vmbus_channel_version_response {
 	struct vmbus_channel_message_header header;
 	u8 version_supported;
@@ -633,6 +645,32 @@ enum hv_signal_policy {
 	HV_SIGNAL_POLICY_EXPLICIT,
 };
 
+enum vmbus_device_type {
+	HV_IDE = 0,
+	HV_SCSI,
+	HV_FC,
+	HV_NIC,
+	HV_ND,
+	HV_PCIE,
+	HV_FB,
+	HV_KBD,
+	HV_MOUSE,
+	HV_KVP,
+	HV_TS,
+	HV_HB,
+	HV_SHUTDOWN,
+	HV_FCOPY,
+	HV_BACKUP,
+	HV_DM,
+	HV_UNKOWN,
+};
+
+struct vmbus_device {
+	u16  dev_type;
+	uuid_le guid;
+	bool perf_device;
+};
+
 struct vmbus_channel {
 	/* Unique channel id */
 	int id;
@@ -728,6 +766,12 @@ struct vmbus_channel {
 	void (*sc_creation_callback)(struct vmbus_channel *new_sc);
 
 	/*
+	 * Channel rescind callback. Some channels (the hvsock ones), need to
+	 * register a callback which is invoked in vmbus_onoffer_rescind().
+	 */
+	void (*chn_rescind_callback)(struct vmbus_channel *channel);
+
+	/*
 	 * The spinlock to protect the structure. It is being used to protect
 	 * test-and-set access to various attributes of the structure as well
 	 * as all sc_list operations.
@@ -767,8 +811,30 @@ struct vmbus_channel {
 	 * signaling control.
 	 */
 	enum hv_signal_policy  signal_policy;
+	/*
+	 * On the channel send side, many of the VMBUS
+	 * device drivers explicity serialize access to the
+	 * outgoing ring buffer. Give more control to the
+	 * VMBUS device drivers in terms how to serialize
+	 * accesss to the outgoing ring buffer.
+	 * The default behavior will be to aquire the
+	 * ring lock to preserve the current behavior.
+	 */
+	bool acquire_ring_lock;
+
 };
 
+static inline void set_channel_lock_state(struct vmbus_channel *c, bool state)
+{
+	c->acquire_ring_lock = state;
+}
+
+static inline bool is_hvsock_channel(const struct vmbus_channel *c)
+{
+	return !!(c->offermsg.offer.chn_flags &
+		  VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER);
+}
+
 static inline void set_channel_signal_state(struct vmbus_channel *c,
 					    enum hv_signal_policy policy)
 {
@@ -790,6 +856,12 @@ static inline void *get_per_channel_state(struct vmbus_channel *c)
 	return c->per_channel_state;
 }
 
+static inline void set_channel_pending_send_size(struct vmbus_channel *c,
+						 u32 size)
+{
+	c->outbound.ring_buffer->pending_send_sz = size;
+}
+
 void vmbus_onmessage(void *context);
 
 int vmbus_request_offers(void);
@@ -801,6 +873,9 @@ int vmbus_request_offers(void);
 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 			void (*sc_cr_cb)(struct vmbus_channel *new_sc));
 
+void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
+		void (*chn_rescind_cb)(struct vmbus_channel *));
+
 /*
  * Retrieve the (sub) channel on which to send an outgoing request.
  * When a primary channel has multiple sub-channels, we choose a
@@ -940,6 +1015,20 @@ extern void vmbus_ontimer(unsigned long data);
 struct hv_driver {
 	const char *name;
 
+	/*
+	 * A hvsock offer, which has a VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER
+	 * channel flag, actually doesn't mean a synthetic device because the
+	 * offer's if_type/if_instance can change for every new hvsock
+	 * connection.
+	 *
+	 * However, to facilitate the notification of new-offer/rescind-offer
+	 * from vmbus driver to hvsock driver, we can handle hvsock offer as
+	 * a special vmbus device, and hence we need the below flag to
+	 * indicate if the driver is the hvsock driver or not: we need to
+	 * specially treat the hvosck offer & driver in vmbus_match().
+	 */
+	bool hvsock;
+
 	/* the device type supported by this driver */
 	uuid_le dev_type;
 	const struct hv_vmbus_device_id *id_table;
@@ -959,6 +1048,8 @@ struct hv_device {
 
 	/* the device instance id of this device */
 	uuid_le dev_instance;
+	u16 vendor_id;
+	u16 device_id;
 
 	struct device device;
 
@@ -994,6 +1085,8 @@ int __must_check __vmbus_driver_register(struct hv_driver *hv_driver,
 					 const char *mod_name);
 void vmbus_driver_unregister(struct hv_driver *hv_driver);
 
+void vmbus_hvsock_device_unregister(struct vmbus_channel *channel);
+
 int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 			resource_size_t min, resource_size_t max,
 			resource_size_t size, resource_size_t align,
@@ -1158,6 +1251,7 @@ u64 hv_do_hypercall(u64 control, void *input, void *output);
 
 struct hv_util_service {
 	u8 *recv_buffer;
+	void *channel;
 	void (*util_cb)(void *);
 	int (*util_init)(struct hv_util_service *);
 	void (*util_deinit)(void);
@@ -1242,4 +1336,6 @@ void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid);
 
 extern __u32 vmbus_proto_version;
 
+int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
+				  const uuid_le *shv_host_servie_id);
 #endif /* _HYPERV_H */
diff --git a/include/linux/memory.h b/include/linux/memory.h
index 82730adba950..093607f90b91 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -140,17 +140,6 @@ extern struct memory_block *find_memory_block(struct mem_section *);
 #endif
 
 /*
- * 'struct memory_accessor' is a generic interface to provide
- * in-kernel access to persistent memory such as i2c or SPI EEPROMs
- */
-struct memory_accessor {
-	ssize_t (*read)(struct memory_accessor *, char *buf, off_t offset,
-			size_t count);
-	ssize_t (*write)(struct memory_accessor *, const char *buf,
-			 off_t offset, size_t count);
-};
-
-/*
  * Kernel text modification mutex, used for code patching. Users of this lock
  * can sleep.
  */
diff --git a/include/linux/mfd/palmas.h b/include/linux/mfd/palmas.h
index c800dbc42079..5c9a1d44c125 100644
--- a/include/linux/mfd/palmas.h
+++ b/include/linux/mfd/palmas.h
@@ -580,7 +580,9 @@ struct palmas_usb {
 	int vbus_irq;
 
 	int gpio_id_irq;
+	int gpio_vbus_irq;
 	struct gpio_desc *id_gpiod;
+	struct gpio_desc *vbus_gpiod;
 	unsigned long sw_debounce_jiffies;
 	struct delayed_work wq_detectid;
 
@@ -589,6 +591,7 @@ struct palmas_usb {
 	bool enable_vbus_detection;
 	bool enable_id_detection;
 	bool enable_gpio_id_detection;
+	bool enable_gpio_vbus_detection;
 };
 
 #define comparator_to_palmas(x) container_of((x), struct palmas_usb, comparator)
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 0b68caff1b3c..a4fcc90b0f20 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -23,6 +23,10 @@ struct nvmem_config {
 	const struct nvmem_cell_info	*cells;
 	int			ncells;
 	bool			read_only;
+	bool			root_only;
+	/* To be only used by old driver/misc/eeprom drivers */
+	bool			compat;
+	struct device		*base_dev;
 };
 
 #if IS_ENABLED(CONFIG_NVMEM)
@@ -43,5 +47,4 @@ static inline int nvmem_unregister(struct nvmem_device *nvmem)
 }
 
 #endif /* CONFIG_NVMEM */
-
 #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */
diff --git a/include/linux/platform_data/at24.h b/include/linux/platform_data/at24.h
index c42aa89d34ee..dc9a13e5acda 100644
--- a/include/linux/platform_data/at24.h
+++ b/include/linux/platform_data/at24.h
@@ -9,7 +9,7 @@
 #define _LINUX_AT24_H
 
 #include <linux/types.h>
-#include <linux/memory.h>
+#include <linux/nvmem-consumer.h>
 
 /**
  * struct at24_platform_data - data to set up at24 (generic eeprom) driver
@@ -17,7 +17,7 @@
  * @page_size: number of byte which can be written in one go
  * @flags: tunable options, check AT24_FLAG_* defines
  * @setup: an optional callback invoked after eeprom is probed; enables kernel
-	code to access eeprom via memory_accessor, see example
+	code to access eeprom via nvmem, see example
  * @context: optional parameter passed to setup()
  *
  * If you set up a custom eeprom type, please double-check the parameters.
@@ -26,13 +26,13 @@
  *
  * An example in pseudo code for a setup() callback:
  *
- * void get_mac_addr(struct memory_accessor *mem_acc, void *context)
+ * void get_mac_addr(struct mvmem_device *nvmem, void *context)
  * {
  *	u8 *mac_addr = ethernet_pdata->mac_addr;
  *	off_t offset = context;
  *
  *	// Read MAC addr from EEPROM
- *	if (mem_acc->read(mem_acc, mac_addr, offset, ETH_ALEN) == ETH_ALEN)
+ *	if (nvmem_device_read(nvmem, offset, ETH_ALEN, mac_addr) == ETH_ALEN)
  *		pr_info("Read MAC addr from EEPROM: %pM\n", mac_addr);
  * }
  *
@@ -48,7 +48,7 @@ struct at24_platform_data {
 #define AT24_FLAG_IRUGO		0x20	/* sysfs-entry will be world-readable */
 #define AT24_FLAG_TAKE8ADDR	0x10	/* take always 8 addresses (24c00) */
 
-	void		(*setup)(struct memory_accessor *, void *context);
+	void		(*setup)(struct nvmem_device *nvmem, void *context);
 	void		*context;
 };
 
diff --git a/include/linux/spi/eeprom.h b/include/linux/spi/eeprom.h
index 403e007aef68..e34e169f9dcb 100644
--- a/include/linux/spi/eeprom.h
+++ b/include/linux/spi/eeprom.h
@@ -30,8 +30,6 @@ struct spi_eeprom {
 	 */
 #define EE_INSTR_BIT3_IS_ADDR	0x0010
 
-	/* for exporting this chip's data to other kernel code */
-	void (*setup)(struct memory_accessor *mem, void *context);
 	void *context;
 };
 
diff --git a/include/linux/stm.h b/include/linux/stm.h
index 9d0083d364e6..1a79ed8e43da 100644
--- a/include/linux/stm.h
+++ b/include/linux/stm.h
@@ -67,6 +67,16 @@ struct stm_device;
  * description. That is, the lowest master that can be allocated to software
  * writers is @sw_start and data from this writer will appear is @sw_start
  * master in the STP stream.
+ *
+ * The @packet callback should adhere to the following rules:
+ *   1) it must return the number of bytes it consumed from the payload;
+ *   2) therefore, if it sent a packet that does not have payload (like FLAG),
+ *      it must return zero;
+ *   3) if it does not support the requested packet type/flag combination,
+ *      it must return -ENOTSUPP.
+ *
+ * The @unlink callback is called when there are no more active writers so
+ * that the master/channel can be quiesced.
  */
 struct stm_data {
 	const char		*name;
diff --git a/include/linux/vmw_vmci_defs.h b/include/linux/vmw_vmci_defs.h
index 65ac54c61c18..1bd31a38c51e 100644
--- a/include/linux/vmw_vmci_defs.h
+++ b/include/linux/vmw_vmci_defs.h
@@ -734,6 +734,41 @@ static inline void *vmci_event_data_payload(struct vmci_event_data *ev_data)
 }
 
 /*
+ * Helper to read a value from a head or tail pointer. For X86_32, the
+ * pointer is treated as a 32bit value, since the pointer value
+ * never exceeds a 32bit value in this case. Also, doing an
+ * atomic64_read on X86_32 uniprocessor systems may be implemented
+ * as a non locked cmpxchg8b, that may end up overwriting updates done
+ * by the VMCI device to the memory location. On 32bit SMP, the lock
+ * prefix will be used, so correctness isn't an issue, but using a
+ * 64bit operation still adds unnecessary overhead.
+ */
+static inline u64 vmci_q_read_pointer(atomic64_t *var)
+{
+#if defined(CONFIG_X86_32)
+	return atomic_read((atomic_t *)var);
+#else
+	return atomic64_read(var);
+#endif
+}
+
+/*
+ * Helper to set the value of a head or tail pointer. For X86_32, the
+ * pointer is treated as a 32bit value, since the pointer value
+ * never exceeds a 32bit value in this case. On 32bit SMP, using a
+ * locked cmpxchg8b adds unnecessary overhead.
+ */
+static inline void vmci_q_set_pointer(atomic64_t *var,
+				      u64 new_val)
+{
+#if defined(CONFIG_X86_32)
+	return atomic_set((atomic_t *)var, (u32)new_val);
+#else
+	return atomic64_set(var, new_val);
+#endif
+}
+
+/*
  * Helper to add a given offset to a head or tail pointer. Wraps the
  * value of the pointer around the max size of the queue.
  */
@@ -741,14 +776,14 @@ static inline void vmci_qp_add_pointer(atomic64_t *var,
 				       size_t add,
 				       u64 size)
 {
-	u64 new_val = atomic64_read(var);
+	u64 new_val = vmci_q_read_pointer(var);
 
 	if (new_val >= size - add)
 		new_val -= size;
 
 	new_val += add;
 
-	atomic64_set(var, new_val);
+	vmci_q_set_pointer(var, new_val);
 }
 
 /*
@@ -758,7 +793,7 @@ static inline u64
 vmci_q_header_producer_tail(const struct vmci_queue_header *q_header)
 {
 	struct vmci_queue_header *qh = (struct vmci_queue_header *)q_header;
-	return atomic64_read(&qh->producer_tail);
+	return vmci_q_read_pointer(&qh->producer_tail);
 }
 
 /*
@@ -768,7 +803,7 @@ static inline u64
 vmci_q_header_consumer_head(const struct vmci_queue_header *q_header)
 {
 	struct vmci_queue_header *qh = (struct vmci_queue_header *)q_header;
-	return atomic64_read(&qh->consumer_head);
+	return vmci_q_read_pointer(&qh->consumer_head);
 }
 
 /*