Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull fw_cfg, vhost updates from Michael Tsirkin:
 "This cleans up the qemu fw cfg device driver.

  On top of this, vmcore is dumped there on crash to help debugging
  with kASLR enabled.

  Also included are some fixes in vhost"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: add vsock compat ioctl
  vhost: fix vhost ioctl signature to build with clang
  fw_cfg: write vmcoreinfo details
  crash: export paddr_vmcoreinfo_note()
  fw_cfg: add DMA register
  fw_cfg: add a public uapi header
  fw_cfg: handle fw_cfg_read_blob() error
  fw_cfg: remove inline from fw_cfg_read_blob()
  fw_cfg: fix sparse warnings around FW_CFG_FILE_DIR read
  fw_cfg: fix sparse warning reading FW_CFG_ID
  fw_cfg: fix sparse warnings with fw_cfg_file
  fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()
  ptr_ring: fix build

1 files changed, 230 insertions, 61 deletions

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index a41b572eeeb1..14fedbeca724 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -10,20 +10,21 @@
  * and select subsets of aarch64), a Device Tree node (on arm), or using
  * a kernel module (or command line) parameter with the following syntax:
  *
- *      [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>]
+ *      [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
  * or
- *      [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>]
+ *      [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
  *
  * where:
  *      <size>     := size of ioport or mmio range
  *      <base>     := physical base address of ioport or mmio range
  *      <ctrl_off> := (optional) offset of control register
  *      <data_off> := (optional) offset of data register
+ *      <dma_off> := (optional) offset of dma register
  *
  * e.g.:
- *      qemu_fw_cfg.ioport=2@0x510:0:1		(the default on x86)
+ *      qemu_fw_cfg.ioport=12@0x510:0:1:4	(the default on x86)
  * or
- *      qemu_fw_cfg.mmio=0xA@0x9020000:8:0	(the default on arm)
+ *      qemu_fw_cfg.mmio=16@0x9020000:8:0:16	(the default on arm)
  */
 
 #include <linux/module.h>
@@ -32,29 +33,17 @@
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
+#include <uapi/linux/qemu_fw_cfg.h>
+#include <linux/delay.h>
+#include <linux/crash_dump.h>
+#include <linux/crash_core.h>
 
 MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
 MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
 MODULE_LICENSE("GPL");
 
-/* selector key values for "well-known" fw_cfg entries */
-#define FW_CFG_SIGNATURE  0x00
-#define FW_CFG_ID         0x01
-#define FW_CFG_FILE_DIR   0x19
-
-/* size in bytes of fw_cfg signature */
-#define FW_CFG_SIG_SIZE 4
-
-/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
-#define FW_CFG_MAX_FILE_PATH 56
-
-/* fw_cfg file directory entry type */
-struct fw_cfg_file {
-	u32 size;
-	u16 select;
-	u16 reserved;
-	char name[FW_CFG_MAX_FILE_PATH];
-};
+/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
+static u32 fw_cfg_rev;
 
 /* fw_cfg device i/o register addresses */
 static bool fw_cfg_is_mmio;
@@ -63,19 +52,83 @@ static resource_size_t fw_cfg_p_size;
 static void __iomem *fw_cfg_dev_base;
 static void __iomem *fw_cfg_reg_ctrl;
 static void __iomem *fw_cfg_reg_data;
+static void __iomem *fw_cfg_reg_dma;
 
 /* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
 static DEFINE_MUTEX(fw_cfg_dev_lock);
 
 /* pick appropriate endianness for selector key */
-static inline u16 fw_cfg_sel_endianness(u16 key)
+static void fw_cfg_sel_endianness(u16 key)
+{
+	if (fw_cfg_is_mmio)
+		iowrite16be(key, fw_cfg_reg_ctrl);
+	else
+		iowrite16(key, fw_cfg_reg_ctrl);
+}
+
+#ifdef CONFIG_CRASH_CORE
+static inline bool fw_cfg_dma_enabled(void)
+{
+	return (fw_cfg_rev & FW_CFG_VERSION_DMA) && fw_cfg_reg_dma;
+}
+
+/* qemu fw_cfg device is sync today, but spec says it may become async */
+static void fw_cfg_wait_for_control(struct fw_cfg_dma_access *d)
 {
-	return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
+	for (;;) {
+		u32 ctrl = be32_to_cpu(READ_ONCE(d->control));
+
+		/* do not reorder the read to d->control */
+		rmb();
+		if ((ctrl & ~FW_CFG_DMA_CTL_ERROR) == 0)
+			return;
+
+		cpu_relax();
+	}
+}
+
+static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control)
+{
+	phys_addr_t dma;
+	struct fw_cfg_dma_access *d = NULL;
+	ssize_t ret = length;
+
+	d = kmalloc(sizeof(*d), GFP_KERNEL);
+	if (!d) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	/* fw_cfg device does not need IOMMU protection, so use physical addresses */
+	*d = (struct fw_cfg_dma_access) {
+		.address = cpu_to_be64(address ? virt_to_phys(address) : 0),
+		.length = cpu_to_be32(length),
+		.control = cpu_to_be32(control)
+	};
+
+	dma = virt_to_phys(d);
+
+	iowrite32be((u64)dma >> 32, fw_cfg_reg_dma);
+	/* force memory to sync before notifying device via MMIO */
+	wmb();
+	iowrite32be(dma, fw_cfg_reg_dma + 4);
+
+	fw_cfg_wait_for_control(d);
+
+	if (be32_to_cpu(READ_ONCE(d->control)) & FW_CFG_DMA_CTL_ERROR) {
+		ret = -EIO;
+	}
+
+end:
+	kfree(d);
+
+	return ret;
 }
+#endif
 
 /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
-static inline void fw_cfg_read_blob(u16 key,
-				    void *buf, loff_t pos, size_t count)
+static ssize_t fw_cfg_read_blob(u16 key,
+				void *buf, loff_t pos, size_t count)
 {
 	u32 glk = -1U;
 	acpi_status status;
@@ -88,18 +141,60 @@ static inline void fw_cfg_read_blob(u16 key,
 		/* Should never get here */
 		WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");
 		memset(buf, 0, count);
-		return;
+		return -EINVAL;
 	}
 
 	mutex_lock(&fw_cfg_dev_lock);
-	iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
+	fw_cfg_sel_endianness(key);
 	while (pos-- > 0)
 		ioread8(fw_cfg_reg_data);
 	ioread8_rep(fw_cfg_reg_data, buf, count);
 	mutex_unlock(&fw_cfg_dev_lock);
 
 	acpi_release_global_lock(glk);
+	return count;
+}
+
+#ifdef CONFIG_CRASH_CORE
+/* write chunk of given fw_cfg blob (caller responsible for sanity-check) */
+static ssize_t fw_cfg_write_blob(u16 key,
+				 void *buf, loff_t pos, size_t count)
+{
+	u32 glk = -1U;
+	acpi_status status;
+	ssize_t ret = count;
+
+	/* If we have ACPI, ensure mutual exclusion against any potential
+	 * device access by the firmware, e.g. via AML methods:
+	 */
+	status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
+	if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
+		/* Should never get here */
+		WARN(1, "%s: Failed to lock ACPI!\n", __func__);
+		return -EINVAL;
+	}
+
+	mutex_lock(&fw_cfg_dev_lock);
+	if (pos == 0) {
+		ret = fw_cfg_dma_transfer(buf, count, key << 16
+					  | FW_CFG_DMA_CTL_SELECT
+					  | FW_CFG_DMA_CTL_WRITE);
+	} else {
+		fw_cfg_sel_endianness(key);
+		ret = fw_cfg_dma_transfer(NULL, pos, FW_CFG_DMA_CTL_SKIP);
+		if (ret < 0)
+			goto end;
+		ret = fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE);
+	}
+
+end:
+	mutex_unlock(&fw_cfg_dev_lock);
+
+	acpi_release_global_lock(glk);
+
+	return ret;
 }
+#endif /* CONFIG_CRASH_CORE */
 
 /* clean up fw_cfg device i/o */
 static void fw_cfg_io_cleanup(void)
@@ -118,12 +213,14 @@ static void fw_cfg_io_cleanup(void)
 # if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
 #  define FW_CFG_CTRL_OFF 0x08
 #  define FW_CFG_DATA_OFF 0x00
+#  define FW_CFG_DMA_OFF 0x10
 # elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
 #  define FW_CFG_CTRL_OFF 0x00
 #  define FW_CFG_DATA_OFF 0x02
 # elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
 #  define FW_CFG_CTRL_OFF 0x00
 #  define FW_CFG_DATA_OFF 0x01
+#  define FW_CFG_DMA_OFF 0x04
 # else
 #  error "QEMU FW_CFG not available on this architecture!"
 # endif
@@ -133,7 +230,7 @@ static void fw_cfg_io_cleanup(void)
 static int fw_cfg_do_platform_probe(struct platform_device *pdev)
 {
 	char sig[FW_CFG_SIG_SIZE];
-	struct resource *range, *ctrl, *data;
+	struct resource *range, *ctrl, *data, *dma;
 
 	/* acquire i/o range details */
 	fw_cfg_is_mmio = false;
@@ -170,6 +267,7 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
 	/* were custom register offsets provided (e.g. on the command line)? */
 	ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
 	data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
+	dma = platform_get_resource_byname(pdev, IORESOURCE_REG, "dma");
 	if (ctrl && data) {
 		fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
 		fw_cfg_reg_data = fw_cfg_dev_base + data->start;
@@ -179,9 +277,17 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
 		fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
 	}
 
+	if (dma)
+		fw_cfg_reg_dma = fw_cfg_dev_base + dma->start;
+#ifdef FW_CFG_DMA_OFF
+	else
+		fw_cfg_reg_dma = fw_cfg_dev_base + FW_CFG_DMA_OFF;
+#endif
+
 	/* verify fw_cfg device signature */
-	fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);
-	if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
+	if (fw_cfg_read_blob(FW_CFG_SIGNATURE, sig,
+				0, FW_CFG_SIG_SIZE) < 0 ||
+		memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
 		fw_cfg_io_cleanup();
 		return -ENODEV;
 	}
@@ -189,9 +295,6 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
 	return 0;
 }
 
-/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
-static u32 fw_cfg_rev;
-
 static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
 {
 	return sprintf(buf, "%u\n", fw_cfg_rev);
@@ -208,10 +311,38 @@ static const struct {
 /* fw_cfg_sysfs_entry type */
 struct fw_cfg_sysfs_entry {
 	struct kobject kobj;
-	struct fw_cfg_file f;
+	u32 size;
+	u16 select;
+	char name[FW_CFG_MAX_FILE_PATH];
 	struct list_head list;
 };
 
+#ifdef CONFIG_CRASH_CORE
+static ssize_t fw_cfg_write_vmcoreinfo(const struct fw_cfg_file *f)
+{
+	static struct fw_cfg_vmcoreinfo *data;
+	ssize_t ret;
+
+	data = kmalloc(sizeof(struct fw_cfg_vmcoreinfo), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	*data = (struct fw_cfg_vmcoreinfo) {
+		.guest_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF),
+		.size = cpu_to_le32(VMCOREINFO_NOTE_SIZE),
+		.paddr = cpu_to_le64(paddr_vmcoreinfo_note())
+	};
+	/* spare ourself reading host format support for now since we
+	 * don't know what else to format - host may ignore ours
+	 */
+	ret = fw_cfg_write_blob(be16_to_cpu(f->select), data,
+				0, sizeof(struct fw_cfg_vmcoreinfo));
+
+	kfree(data);
+	return ret;
+}
+#endif /* CONFIG_CRASH_CORE */
+
 /* get fw_cfg_sysfs_entry from kobject member */
 static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
 {
@@ -272,17 +403,17 @@ struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \
 
 static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf)
 {
-	return sprintf(buf, "%u\n", e->f.size);
+	return sprintf(buf, "%u\n", e->size);
 }
 
 static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
 {
-	return sprintf(buf, "%u\n", e->f.select);
+	return sprintf(buf, "%u\n", e->select);
 }
 
 static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
 {
-	return sprintf(buf, "%s\n", e->f.name);
+	return sprintf(buf, "%s\n", e->name);
 }
 
 static FW_CFG_SYSFS_ATTR(size);
@@ -333,14 +464,13 @@ static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
 {
 	struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
 
-	if (pos > entry->f.size)
+	if (pos > entry->size)
 		return -EINVAL;
 
-	if (count > entry->f.size - pos)
-		count = entry->f.size - pos;
+	if (count > entry->size - pos)
+		count = entry->size - pos;
 
-	fw_cfg_read_blob(entry->f.select, buf, pos, count);
-	return count;
+	return fw_cfg_read_blob(entry->select, buf, pos, count);
 }
 
 static struct bin_attribute fw_cfg_sysfs_attr_raw = {
@@ -452,17 +582,28 @@ static int fw_cfg_register_file(const struct fw_cfg_file *f)
 	int err;
 	struct fw_cfg_sysfs_entry *entry;
 
+#ifdef CONFIG_CRASH_CORE
+	if (fw_cfg_dma_enabled() &&
+		strcmp(f->name, FW_CFG_VMCOREINFO_FILENAME) == 0 &&
+		!is_kdump_kernel()) {
+		if (fw_cfg_write_vmcoreinfo(f) < 0)
+			pr_warn("fw_cfg: failed to write vmcoreinfo");
+	}
+#endif
+
 	/* allocate new entry */
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry)
 		return -ENOMEM;
 
 	/* set file entry information */
-	memcpy(&entry->f, f, sizeof(struct fw_cfg_file));
+	entry->size = be32_to_cpu(f->size);
+	entry->select = be16_to_cpu(f->select);
+	memcpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH);
 
 	/* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
 	err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
-				   fw_cfg_sel_ko, "%d", entry->f.select);
+				   fw_cfg_sel_ko, "%d", entry->select);
 	if (err)
 		goto err_register;
 
@@ -472,7 +613,7 @@ static int fw_cfg_register_file(const struct fw_cfg_file *f)
 		goto err_add_raw;
 
 	/* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */
-	fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->f.name);
+	fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->name);
 
 	/* success, add entry to global cache */
 	fw_cfg_sysfs_cache_enlist(entry);
@@ -489,28 +630,35 @@ err_register:
 static int fw_cfg_register_dir_entries(void)
 {
 	int ret = 0;
+	__be32 files_count;
 	u32 count, i;
 	struct fw_cfg_file *dir;
 	size_t dir_size;
 
-	fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count));
-	count = be32_to_cpu(count);
+	ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count,
+			0, sizeof(files_count));
+	if (ret < 0)
+		return ret;
+
+	count = be32_to_cpu(files_count);
 	dir_size = count * sizeof(struct fw_cfg_file);
 
 	dir = kmalloc(dir_size, GFP_KERNEL);
 	if (!dir)
 		return -ENOMEM;
 
-	fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size);
+	ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, dir,
+			sizeof(files_count), dir_size);
+	if (ret < 0)
+		goto end;
 
 	for (i = 0; i < count; i++) {
-		dir[i].size = be32_to_cpu(dir[i].size);
-		dir[i].select = be16_to_cpu(dir[i].select);
 		ret = fw_cfg_register_file(&dir[i]);
 		if (ret)
 			break;
 	}
 
+end:
 	kfree(dir);
 	return ret;
 }
@@ -525,6 +673,7 @@ static inline void fw_cfg_kobj_cleanup(struct kobject *kobj)
 static int fw_cfg_sysfs_probe(struct platform_device *pdev)
 {
 	int err;
+	__le32 rev;
 
 	/* NOTE: If we supported multiple fw_cfg devices, we'd first create
 	 * a subdirectory named after e.g. pdev->id, then hang per-device
@@ -550,8 +699,11 @@ static int fw_cfg_sysfs_probe(struct platform_device *pdev)
 		goto err_probe;
 
 	/* get revision number, add matching top-level attribute */
-	fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev));
-	fw_cfg_rev = le32_to_cpu(fw_cfg_rev);
+	err = fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev));
+	if (err < 0)
+		goto err_probe;
+
+	fw_cfg_rev = le32_to_cpu(rev);
 	err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
 	if (err)
 		goto err_rev;
@@ -597,7 +749,7 @@ MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
 
 #ifdef CONFIG_ACPI
 static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
-	{ "QEMU0002", },
+	{ FW_CFG_ACPI_DEVICE_ID, },
 	{},
 };
 MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
@@ -629,6 +781,7 @@ static struct platform_device *fw_cfg_cmdline_dev;
 /* use special scanf/printf modifier for phys_addr_t, resource_size_t */
 #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
 			 ":%" __PHYS_ADDR_PREFIX "i" \
+			 ":%" __PHYS_ADDR_PREFIX "i%n" \
 			 ":%" __PHYS_ADDR_PREFIX "i%n"
 
 #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
@@ -638,12 +791,15 @@ static struct platform_device *fw_cfg_cmdline_dev;
 			 ":%" __PHYS_ADDR_PREFIX "u" \
 			 ":%" __PHYS_ADDR_PREFIX "u"
 
+#define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \
+			 ":%" __PHYS_ADDR_PREFIX "u"
+
 static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
 {
-	struct resource res[3] = {};
+	struct resource res[4] = {};
 	char *str;
 	phys_addr_t base;
-	resource_size_t size, ctrl_off, data_off;
+	resource_size_t size, ctrl_off, data_off, dma_off;
 	int processed, consumed = 0;
 
 	/* only one fw_cfg device can exist system-wide, so if one
@@ -659,19 +815,20 @@ static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
 	/* consume "<size>" portion of command line argument */
 	size = memparse(arg, &str);
 
-	/* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
+	/* get "@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]" chunks */
 	processed = sscanf(str, PH_ADDR_SCAN_FMT,
 			   &base, &consumed,
-			   &ctrl_off, &data_off, &consumed);
+			   &ctrl_off, &data_off, &consumed,
+			   &dma_off, &consumed);
 
-	/* sscanf() must process precisely 1 or 3 chunks:
+	/* sscanf() must process precisely 1, 3 or 4 chunks:
 	 * <base> is mandatory, optionally followed by <ctrl_off>
-	 * and <data_off>;
+	 * and <data_off>, and <dma_off>;
 	 * there must be no extra characters after the last chunk,
 	 * so str[consumed] must be '\0'.
 	 */
 	if (str[consumed] ||
-	    (processed != 1 && processed != 3))
+	    (processed != 1 && processed != 3 && processed != 4))
 		return -EINVAL;
 
 	res[0].start = base;
@@ -688,6 +845,11 @@ static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
 		res[2].start = data_off;
 		res[2].flags = IORESOURCE_REG;
 	}
+	if (processed > 3) {
+		res[3].name = "dma";
+		res[3].start = dma_off;
+		res[3].flags = IORESOURCE_REG;
+	}
 
 	/* "processed" happens to nicely match the number of resources
 	 * we need to pass in to this platform device.
@@ -720,6 +882,13 @@ static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
 				fw_cfg_cmdline_dev->resource[0].start,
 				fw_cfg_cmdline_dev->resource[1].start,
 				fw_cfg_cmdline_dev->resource[2].start);
+	case 4:
+		return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_FMT,
+				resource_size(&fw_cfg_cmdline_dev->resource[0]),
+				fw_cfg_cmdline_dev->resource[0].start,
+				fw_cfg_cmdline_dev->resource[1].start,
+				fw_cfg_cmdline_dev->resource[2].start,
+				fw_cfg_cmdline_dev->resource[3].start);
 	}
 
 	/* Should never get here */