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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __ASMARM_TLS_H
3#define __ASMARM_TLS_H
4
5#include <linux/compiler.h>
6#include <asm/thread_info.h>
7
8#ifdef __ASSEMBLY__
9#include <asm/asm-offsets.h>
10 .macro switch_tls_none, base, tp, tpuser, tmp1, tmp2
11 .endm
12
13 .macro switch_tls_v6k, base, tp, tpuser, tmp1, tmp2
14 mrc p15, 0, \tmp2, c13, c0, 2 @ get the user r/w register
15 @ TLS register update is deferred until return to user space
16 mcr p15, 0, \tpuser, c13, c0, 2 @ set the user r/w register
17 str \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
18 .endm
19
20 .macro switch_tls_v6, base, tp, tpuser, tmp1, tmp2
21#ifdef CONFIG_SMP
22ALT_SMP(nop)
23ALT_UP_B(.L0_\@)
24 .subsection 1
25#endif
26.L0_\@:
27 ldr_va \tmp1, elf_hwcap
28 mov \tmp2, #0xffff0fff
29 tst \tmp1, #HWCAP_TLS @ hardware TLS available?
30 streq \tp, [\tmp2, #-15] @ set TLS value at 0xffff0ff0
31 beq .L2_\@
32 mcr p15, 0, \tp, c13, c0, 3 @ yes, set TLS register
33#ifdef CONFIG_SMP
34 b .L1_\@
35 .previous
36#endif
37.L1_\@: switch_tls_v6k \base, \tp, \tpuser, \tmp1, \tmp2
38.L2_\@:
39 .endm
40
41 .macro switch_tls_software, base, tp, tpuser, tmp1, tmp2
42 mov \tmp1, #0xffff0fff
43 str \tp, [\tmp1, #-15] @ set TLS value at 0xffff0ff0
44 .endm
45#else
46#include <asm/smp_plat.h>
47#endif
48
49#ifdef CONFIG_TLS_REG_EMUL
50#define tls_emu 1
51#define has_tls_reg 1
52#define defer_tls_reg_update 0
53#define switch_tls switch_tls_none
54#elif defined(CONFIG_CPU_V6)
55#define tls_emu 0
56#define has_tls_reg (elf_hwcap & HWCAP_TLS)
57#define defer_tls_reg_update is_smp()
58#define switch_tls switch_tls_v6
59#elif defined(CONFIG_CPU_32v6K)
60#define tls_emu 0
61#define has_tls_reg 1
62#define defer_tls_reg_update 1
63#define switch_tls switch_tls_v6k
64#else
65#define tls_emu 0
66#define has_tls_reg 0
67#define defer_tls_reg_update 0
68#define switch_tls switch_tls_software
69#endif
70
71#ifndef __ASSEMBLY__
72
73static inline void set_tls(unsigned long val)
74{
75 struct thread_info *thread;
76
77 thread = current_thread_info();
78
79 thread->tp_value[0] = val;
80
81 /*
82 * This code runs with preemption enabled and therefore must
83 * be reentrant with respect to switch_tls.
84 *
85 * We need to ensure ordering between the shadow state and the
86 * hardware state, so that we don't corrupt the hardware state
87 * with a stale shadow state during context switch.
88 *
89 * If we're preempted here, switch_tls will load TPIDRURO from
90 * thread_info upon resuming execution and the following mcr
91 * is merely redundant.
92 */
93 barrier();
94
95 if (!tls_emu) {
96 if (has_tls_reg && !defer_tls_reg_update) {
97 asm("mcr p15, 0, %0, c13, c0, 3"
98 : : "r" (val));
99 } else if (!has_tls_reg) {
100#ifdef CONFIG_KUSER_HELPERS
101 /*
102 * User space must never try to access this
103 * directly. Expect your app to break
104 * eventually if you do so. The user helper
105 * at 0xffff0fe0 must be used instead. (see
106 * entry-armv.S for details)
107 */
108 *((unsigned int *)0xffff0ff0) = val;
109#endif
110 }
111
112 }
113}
114
115static inline unsigned long get_tpuser(void)
116{
117 unsigned long reg = 0;
118
119 if (has_tls_reg && !tls_emu)
120 __asm__("mrc p15, 0, %0, c13, c0, 2" : "=r" (reg));
121
122 return reg;
123}
124
125static inline void set_tpuser(unsigned long val)
126{
127 /* Since TPIDRURW is fully context-switched (unlike TPIDRURO),
128 * we need not update thread_info.
129 */
130 if (has_tls_reg && !tls_emu) {
131 asm("mcr p15, 0, %0, c13, c0, 2"
132 : : "r" (val));
133 }
134}
135
136static inline void flush_tls(void)
137{
138 set_tls(0);
139 set_tpuser(0);
140}
141
142#endif
143#endif /* __ASMARM_TLS_H */
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __ASMARM_TLS_H
3#define __ASMARM_TLS_H
4
5#include <linux/compiler.h>
6#include <asm/thread_info.h>
7
8#ifdef __ASSEMBLY__
9#include <asm/asm-offsets.h>
10 .macro switch_tls_none, base, tp, tpuser, tmp1, tmp2
11 .endm
12
13 .macro switch_tls_v6k, base, tp, tpuser, tmp1, tmp2
14 mrc p15, 0, \tmp2, c13, c0, 2 @ get the user r/w register
15 mcr p15, 0, \tp, c13, c0, 3 @ set TLS register
16 mcr p15, 0, \tpuser, c13, c0, 2 @ and the user r/w register
17 str \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
18 .endm
19
20 .macro switch_tls_v6, base, tp, tpuser, tmp1, tmp2
21 ldr \tmp1, =elf_hwcap
22 ldr \tmp1, [\tmp1, #0]
23 mov \tmp2, #0xffff0fff
24 tst \tmp1, #HWCAP_TLS @ hardware TLS available?
25 streq \tp, [\tmp2, #-15] @ set TLS value at 0xffff0ff0
26 mrcne p15, 0, \tmp2, c13, c0, 2 @ get the user r/w register
27 mcrne p15, 0, \tp, c13, c0, 3 @ yes, set TLS register
28 mcrne p15, 0, \tpuser, c13, c0, 2 @ set user r/w register
29 strne \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
30 .endm
31
32 .macro switch_tls_software, base, tp, tpuser, tmp1, tmp2
33 mov \tmp1, #0xffff0fff
34 str \tp, [\tmp1, #-15] @ set TLS value at 0xffff0ff0
35 .endm
36#endif
37
38#ifdef CONFIG_TLS_REG_EMUL
39#define tls_emu 1
40#define has_tls_reg 1
41#define switch_tls switch_tls_none
42#elif defined(CONFIG_CPU_V6)
43#define tls_emu 0
44#define has_tls_reg (elf_hwcap & HWCAP_TLS)
45#define switch_tls switch_tls_v6
46#elif defined(CONFIG_CPU_32v6K)
47#define tls_emu 0
48#define has_tls_reg 1
49#define switch_tls switch_tls_v6k
50#else
51#define tls_emu 0
52#define has_tls_reg 0
53#define switch_tls switch_tls_software
54#endif
55
56#ifndef __ASSEMBLY__
57
58static inline void set_tls(unsigned long val)
59{
60 struct thread_info *thread;
61
62 thread = current_thread_info();
63
64 thread->tp_value[0] = val;
65
66 /*
67 * This code runs with preemption enabled and therefore must
68 * be reentrant with respect to switch_tls.
69 *
70 * We need to ensure ordering between the shadow state and the
71 * hardware state, so that we don't corrupt the hardware state
72 * with a stale shadow state during context switch.
73 *
74 * If we're preempted here, switch_tls will load TPIDRURO from
75 * thread_info upon resuming execution and the following mcr
76 * is merely redundant.
77 */
78 barrier();
79
80 if (!tls_emu) {
81 if (has_tls_reg) {
82 asm("mcr p15, 0, %0, c13, c0, 3"
83 : : "r" (val));
84 } else {
85#ifdef CONFIG_KUSER_HELPERS
86 /*
87 * User space must never try to access this
88 * directly. Expect your app to break
89 * eventually if you do so. The user helper
90 * at 0xffff0fe0 must be used instead. (see
91 * entry-armv.S for details)
92 */
93 *((unsigned int *)0xffff0ff0) = val;
94#endif
95 }
96
97 }
98}
99
100static inline unsigned long get_tpuser(void)
101{
102 unsigned long reg = 0;
103
104 if (has_tls_reg && !tls_emu)
105 __asm__("mrc p15, 0, %0, c13, c0, 2" : "=r" (reg));
106
107 return reg;
108}
109
110static inline void set_tpuser(unsigned long val)
111{
112 /* Since TPIDRURW is fully context-switched (unlike TPIDRURO),
113 * we need not update thread_info.
114 */
115 if (has_tls_reg && !tls_emu) {
116 asm("mcr p15, 0, %0, c13, c0, 2"
117 : : "r" (val));
118 }
119}
120
121static inline void flush_tls(void)
122{
123 set_tls(0);
124 set_tpuser(0);
125}
126
127#endif
128#endif /* __ASMARM_TLS_H */