kmsan.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _ASM_S390_KMSAN_H
 3#define _ASM_S390_KMSAN_H
 4
 5#include <asm/lowcore.h>
 6#include <asm/page.h>
 7#include <linux/kmsan.h>
 8#include <linux/mmzone.h>
 9#include <linux/stddef.h>
10
11#ifndef MODULE
12
13static inline bool is_lowcore_addr(void *addr)
14{
15	return addr >= (void *)get_lowcore() &&
16	       addr < (void *)(get_lowcore() + 1);
17}
18
19static inline void *arch_kmsan_get_meta_or_null(void *addr, bool is_origin)
20{
21	if (is_lowcore_addr(addr)) {
22		/*
23		 * Different lowcores accessed via S390_lowcore are described
24		 * by the same struct page. Resolve the prefix manually in
25		 * order to get a distinct struct page.
26		 */
27		addr += (void *)lowcore_ptr[raw_smp_processor_id()] -
28			(void *)get_lowcore();
29		if (KMSAN_WARN_ON(is_lowcore_addr(addr)))
30			return NULL;
31		return kmsan_get_metadata(addr, is_origin);
32	}
33	return NULL;
34}
35
36static inline bool kmsan_virt_addr_valid(void *addr)
37{
38	bool ret;
39
40	/*
41	 * pfn_valid() relies on RCU, and may call into the scheduler on exiting
42	 * the critical section. However, this would result in recursion with
43	 * KMSAN. Therefore, disable preemption here, and re-enable preemption
44	 * below while suppressing reschedules to avoid recursion.
45	 *
46	 * Note, this sacrifices occasionally breaking scheduling guarantees.
47	 * Although, a kernel compiled with KMSAN has already given up on any
48	 * performance guarantees due to being heavily instrumented.
49	 */
50	preempt_disable();
51	ret = virt_addr_valid(addr);
52	preempt_enable_no_resched();
53
54	return ret;
55}
56
57#endif /* !MODULE */
58
59#endif /* _ASM_S390_KMSAN_H */