support/mem: add driverkit operations

Within DriverKit we cannot use malloc/free but have to use the DriverKit
specific IOMallocZero and IOFree.

Signed-off-by: Mads Ynddal <[email protected]>
[k.jensen: allowed more generic functions to be retained]
Signed-off-by: Klaus Jensen <[email protected]>

docs/api/support/mem.rst

@@ -3,4 +3,4 @@
 Memory Allocation Helpers
 =========================
 
-.. kernel-doc:: include/vfn/support/mem.h
+.. kernel-doc:: include/vfn/support/platform/posix/mem.h

include/vfn/support/mem.h

@@ -40,41 +40,11 @@ static inline size_t __abort_on_overflow(unsigned int n, size_t sz)
 	return n * sz;
 }
 
-/**
- * xmalloc - version of malloc that cannot fail
- * @sz: number of bytes to allocate
- *
- * Call malloc, but only return NULL when @sz is zero. Otherwise, abort.
- *
- * Return: pointer to allocated memory
- */
-static inline void *xmalloc(size_t sz)
-{
-	void *mem;
-
-	if (unlikely(!sz))
-		return NULL;
-
-	mem = malloc(sz);
-	if (unlikely(!mem))
-		backtrace_abort();
-
-	return mem;
-}
-
-static inline void *zmalloc(size_t sz)
-{
-	void *mem;
-
-	if (unlikely(!sz))
-		return NULL;
-
-	mem = calloc(1, sz);
-	if (unlikely(!mem))
-		backtrace_abort();
-
-	return mem;
-}
+#ifdef __APPLE__
+# include "vfn/support/platform/driverkit/mem.h"
+#else
+# include "vfn/support/platform/posix/mem.h"
+#endif
 
 static inline void *mallocn(unsigned int n, size_t sz)
 {
@@ -98,17 +68,6 @@ static inline void *zmallocn(unsigned int n, size_t sz)
 	return zmalloc(n * sz);
 }
 
-static inline void *reallocn(void *mem, unsigned int n, size_t sz)
-{
-	if (would_overflow(n, sz)) {
-		fprintf(stderr, "allocation of %d * %zu bytes would overflow\n", n, sz);
-
-		backtrace_abort();
-	}
-
-	return realloc(mem, n * sz);
-}
-
 #define _new_t(t, n, f) \
 	((t *) f(n, sizeof(t)))
 

include/vfn/support/platform/driverkit/mem.h

@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later or MIT */
+
+/*
+ * This file is part of libvfn.
+ *
+ * Copyright (C) 2024 The libvfn Authors. All Rights Reserved.
+ *
+ * This library (libvfn) is dual licensed under the GNU Lesser General
+ * Public License version 2.1 or later or the MIT license. See the
+ * COPYING and LICENSE files for more information.
+ */
+
+#ifndef LIBVFN_SUPPORT_PLATFORM_DRIVERKIT_MEM_H
+#define LIBVFN_SUPPORT_PLATFORM_DRIVERKIT_MEM_H
+
+#include <DriverKit/IOLib.h>
+#include <DriverKit/IOBufferMemoryDescriptor.h>
+
+static inline void *xmalloc(size_t sz)
+{
+	void *mem;
+
+	if (unlikely(!sz))
+		return NULL;
+
+	sz += sizeof(uint64_t);
+
+	mem = IOMalloc(sz);
+	if (unlikely(!mem))
+		backtrace_abort();
+
+	/* prepend length of allocationl (we need it on free) */
+	*(uint64_t *)mem = sz;
+
+	return (void *)(((char *)mem) + sizeof(uint64_t));
+}
+
+static inline void *zmalloc(size_t sz)
+{
+	void *mem;
+
+	if (unlikely(!sz))
+		return NULL;
+
+	sz += sizeof(uint64_t);
+
+	mem = IOMallocZero(sz);
+	if (unlikely(!mem))
+		backtrace_abort();
+
+	/* prepend length of allocationl (we need it on free) */
+	*(uint64_t *)mem = sz;
+
+	return (void *)(((char *)mem) + sizeof(uint64_t));
+}
+
+static inline void free(void *ptr)
+{
+	void *real_ptr = (void *)(((uint8_t *)ptr) - sizeof(uint64_t));
+	uint64_t len = *(uint64_t *)real_ptr;
+
+	IOFree(real_ptr, len);
+}
+
+#endif /* LIBVFN_SUPPORT_PLATFORM_DRIVERKIT_MEM_H */

include/vfn/support/platform/posix/mem.h

@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later or MIT */
+
+/*
+ * This file is part of libvfn.
+ *
+ * Copyright (C) 2022 The libvfn Authors. All Rights Reserved.
+ *
+ * This library (libvfn) is dual licensed under the GNU Lesser General
+ * Public License version 2.1 or later or the MIT license. See the
+ * COPYING and LICENSE files for more information.
+ */
+
+#ifndef LIBVFN_SUPPORT_PLATFORM_POSIX_MEM_H
+#define LIBVFN_SUPPORT_PLATFORM_POSIX_MEM_H
+
+/**
+ * xmalloc - version of malloc that cannot fail
+ * @sz: number of bytes to allocate
+ *
+ * Call malloc, but only return NULL when @sz is zero. Otherwise, abort.
+ *
+ * Return: pointer to allocated memory
+ */
+static inline void *xmalloc(size_t sz)
+{
+	void *mem;
+
+	if (unlikely(!sz))
+		return NULL;
+
+	mem = malloc(sz);
+	if (unlikely(!mem))
+		backtrace_abort();
+
+	return mem;
+}
+
+static inline void *zmalloc(size_t sz)
+{
+	void *mem;
+
+	if (unlikely(!sz))
+		return NULL;
+
+	mem = calloc(1, sz);
+	if (unlikely(!mem))
+		backtrace_abort();
+
+	return mem;
+}
+
+static inline void *reallocn(void *mem, unsigned int n, size_t sz)
+{
+	if (would_overflow(n, sz)) {
+		fprintf(stderr, "allocation of %d * %zu bytes would overflow\n", n, sz);
+
+		backtrace_abort();
+	}
+
+	return realloc(mem, n * sz);
+}
+
+#endif /* LIBVFN_SUPPORT_PLATFORM_POSIX_MEM_H */