xen: fixes for 5.4-rc3

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Merge tag 'for-linus-5.4-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:

 - correct panic handling when running as a Xen guest

 - cleanup the Xen grant driver to remove printing a pointer being
   always NULL

 - remove a soon to be wrong call of of_dma_configure()

* tag 'for-linus-5.4-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: Stop abusing DT of_dma_configure API
  xen/grant-table: remove unnecessary printing
  x86/xen: Return from panic notifier

Documentation/admin-guide/kernel-parameters.txt

@@ -5302,6 +5302,10 @@
 				the unplug protocol
 			never -- do not unplug even if version check succeeds
 
+	xen_legacy_crash	[X86,XEN]
+			Crash from Xen panic notifier, without executing late
+			panic() code such as dumping handler.
+
 	xen_nopvspin	[X86,XEN]
 			Disables the ticketlock slowpath using Xen PV
 			optimizations.

arch/x86/xen/enlighten.c

@@ -269,19 +269,41 @@ void xen_reboot(int reason)
 		BUG();
 }
 
+static int reboot_reason = SHUTDOWN_reboot;
+static bool xen_legacy_crash;
 void xen_emergency_restart(void)
 {
-	xen_reboot(SHUTDOWN_reboot);
+	xen_reboot(reboot_reason);
 }
 
 static int
 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
-	if (!kexec_crash_loaded())
+	if (!kexec_crash_loaded()) {
-		xen_reboot(SHUTDOWN_crash);
+		if (xen_legacy_crash)
+			xen_reboot(SHUTDOWN_crash);
+
+		reboot_reason = SHUTDOWN_crash;
+
+		/*
+		 * If panic_timeout==0 then we are supposed to wait forever.
+		 * However, to preserve original dom0 behavior we have to drop
+		 * into hypervisor. (domU behavior is controlled by its
+		 * config file)
+		 */
+		if (panic_timeout == 0)
+			panic_timeout = -1;
+	}
 	return NOTIFY_DONE;
 }
 
+static int __init parse_xen_legacy_crash(char *arg)
+{
+	xen_legacy_crash = true;
+	return 0;
+}
+early_param("xen_legacy_crash", parse_xen_legacy_crash);
+
 static struct notifier_block xen_panic_block = {
 	.notifier_call = xen_panic_event,
 	.priority = INT_MIN

drivers/gpu/drm/xen/xen_drm_front.c

@@ -718,17 +718,9 @@ static int xen_drv_probe(struct xenbus_device *xb_dev,
 	struct device *dev = &xb_dev->dev;
 	int ret;
 
-	/*
+	ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64));
-	 * The device is not spawn from a device tree, so arch_setup_dma_ops
-	 * is not called, thus leaving the device with dummy DMA ops.
-	 * This makes the device return error on PRIME buffer import, which
-	 * is not correct: to fix this call of_dma_configure() with a NULL
-	 * node to set default DMA ops.
-	 */
-	dev->coherent_dma_mask = DMA_BIT_MASK(32);
-	ret = of_dma_configure(dev, NULL, true);
 	if (ret < 0) {
-		DRM_ERROR("Cannot setup DMA ops, ret %d", ret);
+		DRM_ERROR("Cannot setup DMA mask, ret %d", ret);
 		return ret;
 	}
 

drivers/xen/gntdev.c

@@ -22,6 +22,7 @@
 
 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
 
+#include <linux/dma-mapping.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
@@ -34,9 +35,6 @@
 #include <linux/slab.h>
 #include <linux/highmem.h>
 #include <linux/refcount.h>
-#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
-#include <linux/of_device.h>
-#endif
 
 #include <xen/xen.h>
 #include <xen/grant_table.h>
@@ -625,14 +623,7 @@ static int gntdev_open(struct inode *inode, struct file *flip)
 	flip->private_data = priv;
 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 	priv->dma_dev = gntdev_miscdev.this_device;
-
+	dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
-	/*
-	 * The device is not spawn from a device tree, so arch_setup_dma_ops
-	 * is not called, thus leaving the device with dummy DMA ops.
-	 * Fix this by calling of_dma_configure() with a NULL node to set
-	 * default DMA ops.
-	 */
-	of_dma_configure(priv->dma_dev, NULL, true);
 #endif
 	pr_debug("priv %p\n", priv);
 

drivers/xen/grant-table.c

@@ -1363,8 +1363,7 @@ static int gnttab_setup(void)
 	if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
 		gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
 		if (gnttab_shared.addr == NULL) {
-			pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
+			pr_warn("gnttab share frames is not mapped!\n");
-				(unsigned long)xen_auto_xlat_grant_frames.vaddr);
 			return -ENOMEM;
 		}
 	}