1 files changed, 95 insertions, 33 deletions

diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
index 98749fa817da..bde6c9e59166 100644
--- a/drivers/s390/char/vmcp.c
+++ b/drivers/s390/char/vmcp.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright IBM Corp. 2004, 2010
  * Interface implementation for communication with the z/VM control program
@@ -13,19 +14,89 @@
 
 #include <linux/fs.h>
 #include <linux/init.h>
-#include <linux/compat.h>
 #include <linux/kernel.h>
 #include <linux/miscdevice.h>
 #include <linux/slab.h>
-#include <linux/export.h>
-#include <asm/compat.h>
+#include <linux/uaccess.h>
+#include <linux/mutex.h>
+#include <linux/cma.h>
+#include <linux/mm.h>
+#include <asm/machine.h>
 #include <asm/cpcmd.h>
 #include <asm/debug.h>
-#include <linux/uaccess.h>
-#include "vmcp.h"
+#include <asm/vmcp.h>
+
+struct vmcp_session {
+	char *response;
+	unsigned int bufsize;
+	unsigned int cma_alloc : 1;
+	int resp_size;
+	int resp_code;
+	struct mutex mutex;
+};
 
 static debug_info_t *vmcp_debug;
 
+static unsigned long vmcp_cma_size __initdata = CONFIG_VMCP_CMA_SIZE * 1024 * 1024;
+static struct cma *vmcp_cma;
+
+static int __init early_parse_vmcp_cma(char *p)
+{
+	if (!p)
+		return 1;
+	vmcp_cma_size = ALIGN(memparse(p, NULL), PAGE_SIZE);
+	return 0;
+}
+early_param("vmcp_cma", early_parse_vmcp_cma);
+
+void __init vmcp_cma_reserve(void)
+{
+	if (!machine_is_vm())
+		return;
+	cma_declare_contiguous(0, vmcp_cma_size, 0, 0, 0, false, "vmcp", &vmcp_cma);
+}
+
+static void vmcp_response_alloc(struct vmcp_session *session)
+{
+	struct page *page = NULL;
+	int nr_pages, order;
+
+	order = get_order(session->bufsize);
+	nr_pages = ALIGN(session->bufsize, PAGE_SIZE) >> PAGE_SHIFT;
+	/*
+	 * For anything below order 3 allocations rely on the buddy
+	 * allocator. If such low-order allocations can't be handled
+	 * anymore the system won't work anyway.
+	 */
+	if (order > 2)
+		page = cma_alloc(vmcp_cma, nr_pages, 0, false);
+	if (page) {
+		session->response = (char *)page_to_virt(page);
+		session->cma_alloc = 1;
+		return;
+	}
+	session->response = (char *)__get_free_pages(GFP_KERNEL | __GFP_RETRY_MAYFAIL, order);
+}
+
+static void vmcp_response_free(struct vmcp_session *session)
+{
+	int nr_pages, order;
+	struct page *page;
+
+	if (!session->response)
+		return;
+	order = get_order(session->bufsize);
+	nr_pages = ALIGN(session->bufsize, PAGE_SIZE) >> PAGE_SHIFT;
+	if (session->cma_alloc) {
+		page = virt_to_page(session->response);
+		cma_release(vmcp_cma, page, nr_pages);
+		session->cma_alloc = 0;
+	} else {
+		free_pages((unsigned long)session->response, order);
+	}
+	session->response = NULL;
+}
+
 static int vmcp_open(struct inode *inode, struct file *file)
 {
 	struct vmcp_session *session;
@@ -51,7 +122,7 @@ static int vmcp_release(struct inode *inode, struct file *file)
 
 	session = file->private_data;
 	file->private_data = NULL;
-	free_pages((unsigned long)session->response, get_order(session->bufsize));
+	vmcp_response_free(session);
 	kfree(session);
 	return 0;
 }
@@ -97,9 +168,7 @@ vmcp_write(struct file *file, const char __user *buff, size_t count,
 		return -ERESTARTSYS;
 	}
 	if (!session->response)
-		session->response = (char *)__get_free_pages(GFP_KERNEL
-						| __GFP_RETRY_MAYFAIL | GFP_DMA,
-						get_order(session->bufsize));
+		vmcp_response_alloc(session);
 	if (!session->response) {
 		mutex_unlock(&session->mutex);
 		kfree(cmd);
@@ -130,40 +199,35 @@ vmcp_write(struct file *file, const char __user *buff, size_t count,
 static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct vmcp_session *session;
+	int ret = -ENOTTY;
 	int __user *argp;
-	int temp;
 
 	session = file->private_data;
-	if (is_compat_task())
-		argp = compat_ptr(arg);
-	else
-		argp = (int __user *)arg;
+	argp = (int __user *)arg;
 	if (mutex_lock_interruptible(&session->mutex))
 		return -ERESTARTSYS;
 	switch (cmd) {
 	case VMCP_GETCODE:
-		temp = session->resp_code;
-		mutex_unlock(&session->mutex);
-		return put_user(temp, argp);
+		ret = put_user(session->resp_code, argp);
+		break;
 	case VMCP_SETBUF:
-		free_pages((unsigned long)session->response,
-				get_order(session->bufsize));
-		session->response=NULL;
-		temp = get_user(session->bufsize, argp);
-		if (get_order(session->bufsize) > 8) {
+		vmcp_response_free(session);
+		ret = get_user(session->bufsize, argp);
+		if (ret)
+			session->bufsize = PAGE_SIZE;
+		if (!session->bufsize || get_order(session->bufsize) > 8) {
 			session->bufsize = PAGE_SIZE;
-			temp = -EINVAL;
+			ret = -EINVAL;
 		}
-		mutex_unlock(&session->mutex);
-		return temp;
+		break;
 	case VMCP_GETSIZE:
-		temp = session->resp_size;
-		mutex_unlock(&session->mutex);
-		return put_user(temp, argp);
+		ret = put_user(session->resp_size, argp);
+		break;
 	default:
-		mutex_unlock(&session->mutex);
-		return -ENOIOCTLCMD;
+		break;
 	}
+	mutex_unlock(&session->mutex);
+	return ret;
 }
 
 static const struct file_operations vmcp_fops = {
@@ -173,8 +237,6 @@ static const struct file_operations vmcp_fops = {
 	.read		= vmcp_read,
 	.write		= vmcp_write,
 	.unlocked_ioctl	= vmcp_ioctl,
-	.compat_ioctl	= vmcp_ioctl,
-	.llseek		= no_llseek,
 };
 
 static struct miscdevice vmcp_dev = {
@@ -187,7 +249,7 @@ static int __init vmcp_init(void)
 {
 	int ret;
 
-	if (!MACHINE_IS_VM)
+	if (!machine_is_vm())
 		return 0;
 
 	vmcp_debug = debug_register("vmcp", 1, 1, 240);