[lttng-modules.git] / src / wrapper / page_alloc.c

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 * wrapper/page_alloc.c
 *
 * wrapper around get_pfnblock_flags_mask and Ubuntu
 * get_pageblock_flags_mask. Using KALLSYMS to get their address when
 * available, else we need to have a kernel that exports this function
 * to GPL modules.
 *
 * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#ifdef CONFIG_KALLSYMS

#include <linux/kallsyms.h>
#include <linux/mm_types.h>
#include <linux/module.h>
#include <wrapper/kallsyms.h>
#include <wrapper/page_alloc.h>

static
unsigned long (*get_pfnblock_flags_mask_sym)(struct page *page,
		unsigned long pfn,
		unsigned long end_bitidx,
		unsigned long mask);

unsigned long wrapper_get_pfnblock_flags_mask(struct page *page,
		unsigned long pfn,
		unsigned long end_bitidx,
		unsigned long mask)
{
	WARN_ON_ONCE(!get_pfnblock_flags_mask_sym);
	if (get_pfnblock_flags_mask_sym) {
		return get_pfnblock_flags_mask_sym(page, pfn, end_bitidx, mask);
	} else {
		return -ENOSYS;
	}
}
EXPORT_SYMBOL_GPL(wrapper_get_pfnblock_flags_mask);

int wrapper_get_pfnblock_flags_mask_init(void)
{
	get_pfnblock_flags_mask_sym =
		(void *) kallsyms_lookup_funcptr("get_pfnblock_flags_mask");
	if (!get_pfnblock_flags_mask_sym)
		return -1;
	return 0;
}
EXPORT_SYMBOL_GPL(wrapper_get_pfnblock_flags_mask_init);

/*
 * Canary function to check for 'get_pfnblock_flags_mask()' at compile time.
 *
 * From 'include/linux/pageblock-flags.h':
 *
 *   unsigned long get_pfnblock_flags_mask(struct page *page,
 *                                         unsigned long pfn,
 *                                         unsigned long end_bitidx,
 *                                         unsigned long mask);
 */
__attribute__((unused)) static
unsigned long __canary__get_pfnblock_flags_mask(struct page *page,
						unsigned long pfn,
						unsigned long end_bitidx,
						unsigned long mask)
{
	return get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
}

#else

#include <linux/pageblock-flags.h>

#endif
Commit	Line	Data
	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
	2	* wrapper/page_alloc.c
	3	*
	4	* wrapper around get_pfnblock_flags_mask and Ubuntu
	5	* get_pageblock_flags_mask. Using KALLSYMS to get their address when
	6	* available, else we need to have a kernel that exports this function
	7	* to GPL modules.
	8	*
	9	* Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	10	*/
	11
	12	#ifdef CONFIG_KALLSYMS
	13
	14	#include <linux/kallsyms.h>
	15	#include <linux/mm_types.h>
	16	#include <linux/module.h>
	17	#include <wrapper/kallsyms.h>
	18	#include <wrapper/page_alloc.h>
	19
	20	static
	21	unsigned long (get_pfnblock_flags_mask_sym)(struct page page,
	22	unsigned long pfn,
	23	unsigned long end_bitidx,
	24	unsigned long mask);
	25
	26	unsigned long wrapper_get_pfnblock_flags_mask(struct page *page,
	27	unsigned long pfn,
	28	unsigned long end_bitidx,
	29	unsigned long mask)
	30	{
	31	WARN_ON_ONCE(!get_pfnblock_flags_mask_sym);
	32	if (get_pfnblock_flags_mask_sym) {
	33	return get_pfnblock_flags_mask_sym(page, pfn, end_bitidx, mask);
	34	} else {
	35	return -ENOSYS;
	36	}
	37	}
	38	EXPORT_SYMBOL_GPL(wrapper_get_pfnblock_flags_mask);
	39
	40	int wrapper_get_pfnblock_flags_mask_init(void)
	41	{
	42	get_pfnblock_flags_mask_sym =
	43	(void *) kallsyms_lookup_funcptr("get_pfnblock_flags_mask");
	44	if (!get_pfnblock_flags_mask_sym)
	45	return -1;
	46	return 0;
	47	}
	48	EXPORT_SYMBOL_GPL(wrapper_get_pfnblock_flags_mask_init);
	49
	50	/*
	51	* Canary function to check for 'get_pfnblock_flags_mask()' at compile time.
	52	*
	53	* From 'include/linux/pageblock-flags.h':
	54	*
	55	* unsigned long get_pfnblock_flags_mask(struct page *page,
	56	* unsigned long pfn,
	57	* unsigned long end_bitidx,
	58	* unsigned long mask);
	59	*/
	60	__attribute__((unused)) static
	61	unsigned long __canary__get_pfnblock_flags_mask(struct page *page,
	62	unsigned long pfn,
	63	unsigned long end_bitidx,
	64	unsigned long mask)
	65	{
	66	return get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
	67	}
	68
	69	#else
	70
	71	#include <linux/pageblock-flags.h>
	72
	73	#endif