Change to kcompat system

.gitignore

@@ -64,6 +64,9 @@ __pycache__/
 *.pyc
 .venv/
 
+# Kernel module kcompat probe scratch (driver/kcompat/probe.sh)
+driver/kcompat/.scratch/
+
 # Build files for package
 /pbuild/
 /rpmbuild/

driver/Makefile

@@ -44,6 +44,14 @@ endif
 
 SLASH_QDMA_OP_DEBUG ?= 0
 
+# Kcompat feature flags. Defaults are "n"; the all: recipe runs
+# driver/kcompat/probe.sh against $(KDIR) to detect the actual values
+# and passes them into the kbuild recursion. Each pair (modern API +
+# legacy fallback) is covered by one probe — if the modern form is
+# absent, the legacy form is the unconditional fallback in slash_compat.h.
+SLASH_HAVE_VM_FLAGS_SET ?= n
+SLASH_HAVE_MODULE_IMPORT_NS_TOKEN ?= n
+
 # Set GCOV=1 to instrument the module for kernel gcov coverage.
 # Not set by default — never enable this in production builds.
 ifdef GCOV
@@ -66,6 +74,14 @@ ccflags-y += \
 	-DSLASH_QDMA_OP_DEBUG=$(SLASH_QDMA_OP_DEBUG) \
 	-DSLASH_VERSION_STR=\"$(SLASH_VERSION)\"
 
+ifeq ($(SLASH_HAVE_VM_FLAGS_SET),y)
+ccflags-y += -DSLASH_HAVE_VM_FLAGS_SET
+endif
+
+ifeq ($(SLASH_HAVE_MODULE_IMPORT_NS_TOKEN),y)
+ccflags-y += -DSLASH_HAVE_MODULE_IMPORT_NS_TOKEN
+endif
+
 
 LIBQDMA_OBJS := \
 	$(LIBQDMA_PATH)/qdma_mbox.o \
@@ -102,11 +118,16 @@ QDMA_ACCESS_OBJS := \
 $(MODULE)-objs += $(LIBQDMA_OBJS) $(QDMA_ACCESS_OBJS)
 
 
+KCOMPAT := "$(SHELL)" "$(PWD)/kcompat/probe.sh"
+
 all:
-	$(MAKE) -C $(KDIR) M=$(PWD) modules
+	@flags="$$($(KCOMPAT) "$(KDIR)" | tr '\n' ' ')"; \
+	echo "slash: kcompat: $$flags"; \
+	$(MAKE) -C "$(KDIR)" M="$(PWD)" $$flags modules
 
 clean:
-	$(MAKE) -C $(KDIR) M=$(PWD) clean
+	$(MAKE) -C "$(KDIR)" M="$(PWD)" clean
+	rm -rf "$(PWD)/kcompat/.scratch"
 
 install: all
 	sudo install -d -m 755 /lib/modules/$(shell uname -r)/extra

driver/kcompat/module_import_ns_token.c

@@ -0,0 +1,44 @@
+/**
+ * Copyright (C) 2026 Advanced Micro Devices, Inc. All rights reserved.
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; version 2.
+ *
+ * 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/*
+ * Token-form MODULE_IMPORT_NS probe.
+ *
+ * Pre-6.13:  MODULE_IMPORT_NS(ns) = MODULE_INFO(import_ns, __stringify(ns))
+ *            -> token form is the documented usage.
+ * 6.13+:     MODULE_IMPORT_NS(ns) = MODULE_INFO(import_ns, ns)
+ *            -> token form fails to compile (DMA_BUF undefined).
+ *
+ * So this probe succeeds iff the token form is the right one to use.
+ * Compile success on a pre-6.13 kernel that still accepts the string
+ * form silently produces the wrong namespace string at runtime, which
+ * is why we probe the token form (precise) instead of the string form
+ * (ambiguous on older kernels).
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+
+static int __init conftest_init(void)
+{
+    return 0;
+}
+
+static void __exit conftest_exit(void)
+{
+}
+
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(DMA_BUF);
+module_init(conftest_init);
+module_exit(conftest_exit);

driver/kcompat/probe.sh

@@ -0,0 +1,67 @@
+#!/bin/sh
+#/**
+# * Copyright (C) 2026 Advanced Micro Devices, Inc. All rights reserved.
+# * This program is free software; you can redistribute it and/or modify it under the terms of the
+# * GNU General Public License as published by the Free Software Foundation; version 2.
+# *
+# * 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# * 02110-1301, USA.
+# */
+
+# Probe the kernel build at $1 for SLASH API compatibility features.
+#
+# Each *.c file in this directory is built as a tiny standalone module
+# against the target kernel headers; a successful build means the
+# feature is available. One make-style assignment per feature is
+# printed to stdout, e.g.:
+#
+#     SLASH_HAVE_VM_FLAGS_SET=y
+#     SLASH_HAVE_MODULE_IMPORT_NS_STRING=n
+#
+# To add a new probe, drop another conftest .c file into this directory.
+# The macro name is derived from the file basename (uppercased).
+
+set -eu
+
+if [ "$#" -ne 1 ]; then
+    echo "Usage: $0 <kernel-build-dir>" >&2
+    exit 2
+fi
+
+kdir="$1"
+here="$(cd "$(dirname "$0")" && pwd)"
+
+if [ ! -d "$kdir" ]; then
+    echo "$0: kernel build dir '$kdir' not found" >&2
+    exit 1
+fi
+
+scratch="$here/.scratch"
+cleanup() { rm -rf "$scratch"; }
+trap cleanup EXIT HUP INT TERM
+
+# Conftest builds must actually compile to be meaningful. Drop any
+# flags the parent make may have set (notably -n / --dry-run, which
+# would make every probe look successful but produce no real result).
+unset MAKEFLAGS MFLAGS MAKEOVERRIDES
+
+rm -rf "$scratch"
+mkdir -p "$scratch"
+printf 'obj-m := conftest.o\n' > "$scratch/Makefile"
+
+for src in "$here"/*.c; do
+    [ -f "$src" ] || continue
+    feat=$(basename "$src" .c)
+    cp "$src" "$scratch/conftest.c"
+    if "${MAKE:-make}" -s -C "$kdir" M="$scratch" modules >/dev/null 2>&1; then
+        ans=y
+    else
+        ans=n
+    fi
+    printf 'SLASH_HAVE_%s=%s\n' "$(printf '%s' "$feat" | tr '[:lower:]' '[:upper:]')" "$ans"
+done

driver/kcompat/vm_flags_set.c

@@ -0,0 +1,33 @@
+/**
+ * Copyright (C) 2026 Advanced Micro Devices, Inc. All rights reserved.
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; version 2.
+ *
+ * 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+
+static int __init conftest_init(void)
+{
+    struct vm_area_struct *vma = NULL;
+
+    vm_flags_set(vma, (vm_flags_t)0);
+    return 0;
+}
+
+static void __exit conftest_exit(void)
+{
+}
+
+MODULE_LICENSE("GPL");
+module_init(conftest_init);
+module_exit(conftest_exit);

driver/slash_compat.h

@@ -0,0 +1,56 @@
+/**
+ * Copyright (C) 2026 Advanced Micro Devices, Inc. All rights reserved.
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; version 2.
+ *
+ * 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef SLASH_COMPAT_H
+#define SLASH_COMPAT_H
+
+#include <linux/mm.h>
+#include <linux/module.h>
+
+/*
+ * Compat shims selected by the kcompat probes in driver/kcompat/.
+ * If the modern form is detected (SLASH_HAVE_*), use it; otherwise
+ * fall back to the legacy form. The probes are exhaustive, so no
+ * #error path is needed.
+ */
+
+static inline void slash_vm_flags_set(struct vm_area_struct *vma, vm_flags_t flags)
+{
+#if defined(SLASH_HAVE_VM_FLAGS_SET)
+    vm_flags_set(vma, flags);
+#else
+    vma->vm_flags |= flags;
+#endif
+}
+
+/*
+ * MODULE_IMPORT_NS argument form.
+ *
+ * Pre-6.13: bare token, e.g. MODULE_IMPORT_NS(DMA_BUF). The kernel
+ *           macro internally __stringify()s the argument, so passing a
+ *           string literal would produce a runtime namespace mismatch.
+ * 6.13+:    string literal, e.g. MODULE_IMPORT_NS("DMA_BUF"). The
+ *           kernel macro stopped stringifying, so passing a bare token
+ *           fails to compile.
+ *
+ * We probe the token form (precise cutover at 6.13) and stringify here
+ * when it's no longer accepted.
+ */
+#if defined(SLASH_HAVE_MODULE_IMPORT_NS_TOKEN)
+#define SLASH_MODULE_IMPORT_NS(ns) MODULE_IMPORT_NS(ns)
+#else
+#define SLASH_MODULE_IMPORT_NS(ns) MODULE_IMPORT_NS(#ns)
+#endif
+
+#endif /* SLASH_COMPAT_H */

driver/slash_ctldev.c

@@ -41,7 +41,6 @@
 #include <linux/stddef.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
-#include <linux/version.h>
 
 #include "slash.h"
 #include "slash_dmabuf.h"

driver/slash_dmabuf.c

@@ -39,13 +39,13 @@
 #include "slash_dmabuf.h"
 
 #include "slash.h"
+#include "slash_compat.h"
 
 #include <linux/err.h>
 #include <linux/mm.h>
 #include <linux/pci.h>
 #include <linux/printk.h>
 #include <linux/slab.h>
-#include <linux/version.h>
 
 /**
  * struct slash_bar_dmabuf_data - Private data attached to each BAR dma-buf.
@@ -181,13 +181,8 @@ static int slash_bar_dmabuf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *
      * VM_DONTCOPY  — do not inherit across fork(); BAR register
      *                mappings should not be silently shared with children.
      */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
-    vm_flags_set(vma, VM_PFNMAP | VM_IO | VM_DONTDUMP |
-                      VM_DONTEXPAND | VM_DONTCOPY);
-#else
-    vma->vm_flags |= VM_PFNMAP | VM_IO | VM_DONTDUMP |
-                     VM_DONTEXPAND | VM_DONTCOPY;
-#endif
+    slash_vm_flags_set(vma, VM_PFNMAP | VM_IO | VM_DONTDUMP |
+                            VM_DONTEXPAND | VM_DONTCOPY);
 
     wc = !!(pci_resource_flags(priv->pdev, priv->bar_number) & IORESOURCE_PREFETCH);
     vma->vm_page_prot = wc ? pgprot_writecombine(vma->vm_page_prot)

driver/slash_main.c

@@ -44,12 +44,12 @@
  */
 
 #include "slash.h"
+#include "slash_compat.h"
 
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/printk.h>
-#include <linux/version.h>
 
 #include "slash_pcie.h"
 #include "slash_hotplug_driver.h"
@@ -131,8 +131,4 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("AMD Inc.");
 MODULE_DESCRIPTION("SLASH/VRT module");
 MODULE_VERSION(SLASH_VERSION_STR);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 13, 0)
-MODULE_IMPORT_NS("DMA_BUF");
-#else
-MODULE_IMPORT_NS(DMA_BUF);
-#endif
+SLASH_MODULE_IMPORT_NS(DMA_BUF);

packaging/debian/slash-dkms.install

@@ -21,6 +21,7 @@
 driver/*.c            usr/src/slash-@VERSION@/driver/
 driver/*.h            usr/src/slash-@VERSION@/driver/
 driver/Makefile       usr/src/slash-@VERSION@/driver/
+driver/kcompat        usr/src/slash-@VERSION@/driver/
 driver/libslash/include/slash/uapi  usr/src/slash-@VERSION@/driver/libslash/include/slash/
 
 submodules/qdma_drv/QDMA/linux-kernel/driver/libqdma/   usr/src/slash-@VERSION@/driver/

packaging/rpm/slash.spec

@@ -209,6 +209,8 @@ install -m 0644 driver/*.c      %{buildroot}%{_usrsrc}/%{dkms_name}-%{dkms_versi
 install -m 0644 driver/*.h      %{buildroot}%{_usrsrc}/%{dkms_name}-%{dkms_version}/driver/
 install -m 0644 driver/Makefile %{buildroot}%{_usrsrc}/%{dkms_name}-%{dkms_version}/driver/
 
+cp -a driver/kcompat %{buildroot}%{_usrsrc}/%{dkms_name}-%{dkms_version}/driver/
+
 cp -a driver/libslash/include/slash/uapi \
     %{buildroot}%{_usrsrc}/%{dkms_name}-%{dkms_version}/driver/libslash/include/slash/