1 /*
2 * Copyright (c) 2014 Travis Geiselbrecht
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files
6 * (the "Software"), to deal in the Software without restriction,
7 * including without limitation the rights to use, copy, modify, merge,
8 * publish, distribute, sublicense, and/or sell copies of the Software,
9 * and to permit persons to whom the Software is furnished to do so,
10 * subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23 #pragma once
24
25 #include <stdbool.h>
26 #include <sys/types.h>
27 #include <compiler.h>
28
29 __BEGIN_CDECLS
30
31 #define DSB __asm__ volatile("dsb sy" ::: "memory")
32 #define ISB __asm__ volatile("isb" ::: "memory")
33
34 #define STRINGIFY(x) #x
35 #define TOSTRING(x) STRINGIFY(x)
36
37 #define ARM64_READ_SYSREG(reg) \
38 ({ \
39 uint64_t _val; \
40 __asm__ volatile("mrs %0," TOSTRING(reg) : "=r" (_val)); \
41 _val; \
42 })
43
44 #define ARM64_WRITE_SYSREG_RAW(reg, val) \
45 ({ \
46 __asm__ volatile("msr " TOSTRING(reg) ", %0" :: "r" (val)); \
47 })
48
49 #define ARM64_WRITE_SYSREG(reg, val) \
50 ({ \
51 ARM64_WRITE_SYSREG_RAW(reg, val); \
52 ISB; \
53 })
54
55 void arm64_context_switch(vaddr_t *old_sp, vaddr_t new_sp);
56
57 /* exception handling */
58 struct arm64_iframe_long {
59 uint64_t r[29];
60 uint64_t lr;
61 uint64_t sp;
62 uint64_t spsr;
63 uint64_t fp;
64 uint64_t elr;
65 };
66
67 struct arm64_iframe_short {
68 uint64_t r[19];
69 uint64_t lr;
70 uint64_t sp;
71 uint64_t spsr;
72 uint64_t fp;
73 uint64_t elr;
74 };
75
76 struct thread;
77 struct fpstate;
78
79 /*
80 * This declaration is made to avoid issues with CFI while setting
81 * vector base, with CFI enabled VBAR_EL1 was set wrong, so instead
82 * of jumping to the correct exception entrypoint it was jumping into
83 * the middle of an unrelated function
84 */
85 extern uint32_t arm64_exception_base[];
86
87 void arm64_el3_to_el1(void);
88 void arm64_fpu_exception(struct arm64_iframe_long *iframe);
89 void arm64_fpu_save_state(struct thread *thread);
90
91 /**
92 * arm64_fpu_load_fpstate() - Load the FP state from memory.
93 * @fpstate: Pointer to a &struct fpstate containing the new
94 * values of the FP registers.
95 * @force: Force the load operation even if the @fpstate pointer
96 * is the same as the previous operation.
97 *
98 * Return:
99 * * %true if the load is performed successfully
100 * * %false if the register values are already present in the registers
101 *
102 * This function will copy the pointer from @fpstate into some internal
103 * storage. For this reason, the pointer should not point
104 * into the stack.
105 */
106 bool arm64_fpu_load_fpstate(struct fpstate *fpstate, bool force);
107
108 /**
109 * arm64_fpu_save_fpstate() - Save the current values of the FP registers.
110 * @fpstate: Pointer to a &struct fpstate to store the registers into.
111 */
112 void arm64_fpu_save_fpstate(struct fpstate *fpstate);
113
arm64_fpu_pre_context_switch(struct thread * thread)114 static inline void arm64_fpu_pre_context_switch(struct thread *thread)
115 {
116 uint64_t cpacr = ARM64_READ_SYSREG(cpacr_el1);
117 if ((cpacr >> 20) & 3) {
118 arm64_fpu_save_state(thread);
119 cpacr &= ~(3U << 20);
120 ARM64_WRITE_SYSREG(cpacr_el1, cpacr);
121 }
122 }
123
124 /* overridable syscall handler */
125 void arm64_syscall(struct arm64_iframe_long *iframe, bool is_64bit);
126
127 /* Macro to remove PAC protection from a function */
128 #if defined(KERNEL_PAC_ENABLED) && defined(KERNEL_BTI_ENABLED)
129 #define __ARM64_NO_PAC __attribute__((target("branch-protection=bti")))
130 #else
131 #define __ARM64_NO_PAC __attribute__((target("branch-protection=none")))
132 #endif
133
134 __END_CDECLS
135
136