From 7759efd0cb4dc0d3d66f629e9ab3344962aa5a48 Mon Sep 17 00:00:00 2001
From: Bjarne von Horn <vh@igh.de>
Date: Wed, 15 Jan 2025 09:56:44 +0100
Subject: [PATCH] bbapi: Add Compile time check for Linux >= 5.8

__vmalloc_node_range has become a macro in 6.10,
so the workaround does no longer work.
This check reveals that at compile time.
---
 Makefile        |  3 +++
 api.c           |  6 ++----
 api_internals.h | 17 +++++++++++++++++
 compile_test.c  | 18 ++++++++++++++++++
 4 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 api_internals.h
 create mode 100644 compile_test.c

diff --git a/Makefile b/Makefile
index 4c96b3d..73e07a6 100644
--- a/Makefile
+++ b/Makefile
@@ -12,6 +12,9 @@ SUDO := ${SUDO_${OS}}
 ccflags-y := -DBIOSAPIERR_OFFSET=0
 ccflags-y := -DUNAME_S=\"${OS}\"
 
+# compile test for vmalloc workaround check for Linux >= 5.8
+always-y += compile_test.o
+
 all:
 	make -C $(KDIR) M=$(PWD) modules
 	make -C $(KDIR) M=$(PWD)/button modules
diff --git a/api.c b/api.c
index 0d2ffb2..8860282 100644
--- a/api.c
+++ b/api.c
@@ -192,10 +192,8 @@ static struct kprobe kp = {
 typedef unsigned long (*kallsyms_lookup_name_t)(const char *name);
 kallsyms_lookup_name_t fcn_kallsyms_lookup_name;
 
-typedef void *(*fcn_vmalloc_node_range_t)(unsigned long size, unsigned long align,
-		unsigned long start, unsigned long end, gfp_t gfp_mask,
-		pgprot_t prot, unsigned long vm_flags, int node,
-		const void *caller);
+#include "api_internals.h"
+
 fcn_vmalloc_node_range_t fcn_vmalloc_node_range;
 #endif
 
diff --git a/api_internals.h b/api_internals.h
new file mode 100644
index 0000000..3d905af
--- /dev/null
+++ b/api_internals.h
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: MIT
+/**
+    Author:     Bjarne von Horn <vh@igh.de>
+    Copyright (C) 2024 IgH GmbH
+*/
+#ifndef __API_INTERNALS_H
+#define __API_INTERNALS_H
+
+#include <linux/vmalloc.h>
+
+typedef void *(*fcn_vmalloc_node_range_t)(unsigned long size, unsigned long align,
+		unsigned long start, unsigned long end, gfp_t gfp_mask,
+		pgprot_t prot, unsigned long vm_flags, int node,
+		const void *caller);
+
+#endif
+
diff --git a/compile_test.c b/compile_test.c
new file mode 100644
index 0000000..84dd026
--- /dev/null
+++ b/compile_test.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MIT
+/**
+    Compile test to ensure __vmalloc_node_range is a symbol and its arguments
+    Author: 	Bjarne von Horn <vh@igh.de>
+    Copyright (C) 2024 IgH GmbH
+*/
+
+#include <linux/version.h>
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 8, 0)
+
+#include "api_internals.h"
+#include <linux/vmalloc.h>
+
+
+__attribute__((__used__)) fcn_vmalloc_node_range_t fcn_vmalloc_node_range_test = &__vmalloc_node_range;
+
+#endif