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
13 static inline bool is_lowcore_addr(void *addr)
14 {
15 return addr >= (void *)get_lowcore() &&
16 addr < (void *)(get_lowcore() + 1);
17 }
18
19 static 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
36 static 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 */
60
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