1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_POWERPC_KUP_BOOKE_H_
3#define _ASM_POWERPC_KUP_BOOKE_H_
4
5#include <asm/bug.h>
6#include <asm/mmu.h>
7
8#ifdef CONFIG_PPC_KUAP
9
10#ifdef __ASSEMBLY__
11
12.macro kuap_check_amr	gpr1, gpr2
13.endm
14
15#else
16
17#include <linux/sched.h>
18
19#include <asm/reg.h>
20
21static __always_inline void __kuap_lock(void)
22{
23	mtspr(SPRN_PID, 0);
24	isync();
25}
26#define __kuap_lock __kuap_lock
27
28static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
29{
30	regs->kuap = mfspr(SPRN_PID);
31	mtspr(SPRN_PID, 0);
32	isync();
33}
34#define __kuap_save_and_lock __kuap_save_and_lock
35
36static __always_inline void kuap_user_restore(struct pt_regs *regs)
37{
38	if (kuap_is_disabled())
39		return;
40
41	mtspr(SPRN_PID, current->thread.pid);
42
43	/* Context synchronisation is performed by rfi */
44}
45
46static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
47{
48	if (regs->kuap)
49		mtspr(SPRN_PID, current->thread.pid);
50
51	/* Context synchronisation is performed by rfi */
52}
53
54#ifdef CONFIG_PPC_KUAP_DEBUG
55static __always_inline unsigned long __kuap_get_and_assert_locked(void)
56{
57	WARN_ON_ONCE(mfspr(SPRN_PID));
58
59	return 0;
60}
61#define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
62#endif
63
64static __always_inline void uaccess_begin_booke(unsigned long val)
65{
66	asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
67	    "i"(SPRN_PID), "r"(val), "i"(MMU_FTR_KUAP) : "memory");
68}
69
70static __always_inline void uaccess_end_booke(void)
71{
72	asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
73	    "i"(SPRN_PID), "r"(0), "i"(MMU_FTR_KUAP) : "memory");
74}
75
76static __always_inline void allow_user_access(void __user *to, const void __user *from,
77					      unsigned long size, unsigned long dir)
78{
79	uaccess_begin_booke(current->thread.pid);
80}
81
82static __always_inline void prevent_user_access(unsigned long dir)
83{
84	uaccess_end_booke();
85}
86
87static __always_inline unsigned long prevent_user_access_return(void)
88{
89	unsigned long flags = mfspr(SPRN_PID);
90
91	uaccess_end_booke();
92
93	return flags;
94}
95
96static __always_inline void restore_user_access(unsigned long flags)
97{
98	if (flags)
99		uaccess_begin_booke(current->thread.pid);
100}
101
102static __always_inline bool
103__bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
104{
105	return !regs->kuap;
106}
107
108#endif /* !__ASSEMBLY__ */
109
110#endif /* CONFIG_PPC_KUAP */
111
112#endif /* _ASM_POWERPC_KUP_BOOKE_H_ */
113