1 /* Copyright (C) 1997-2023 Free Software Foundation, Inc.
2
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #ifndef _AARCH64_SYSDEP_H
20 #define _AARCH64_SYSDEP_H
21
22 #include <sysdeps/generic/sysdep.h>
23
24 #ifdef __LP64__
25 # define AARCH64_R(NAME) R_AARCH64_ ## NAME
26 # define PTR_REG(n) x##n
27 # define PTR_LOG_SIZE 3
28 # define PTR_ARG(n)
29 # define SIZE_ARG(n)
30 #else
31 # define AARCH64_R(NAME) R_AARCH64_P32_ ## NAME
32 # define PTR_REG(n) w##n
33 # define PTR_LOG_SIZE 2
34 # define PTR_ARG(n) mov w##n, w##n
35 # define SIZE_ARG(n) mov w##n, w##n
36 #endif
37
38 #define PTR_SIZE (1<<PTR_LOG_SIZE)
39
40 #ifndef __ASSEMBLER__
41 /* Strip pointer authentication code from pointer p. */
42 static inline void *
43 strip_pac (void *p)
44 {
45 register void *ra asm ("x30") = (p);
46 asm ("hint 7 // xpaclri" : "+r"(ra));
47 return ra;
48 }
49
50 /* This is needed when glibc is built with -mbranch-protection=pac-ret
51 with a gcc that is affected by PR target/94891. */
52 # if HAVE_AARCH64_PAC_RET
53 # undef RETURN_ADDRESS
54 # define RETURN_ADDRESS(n) strip_pac (__builtin_return_address (n))
55 # endif
56 #endif
57
58 #ifdef __ASSEMBLER__
59
60 /* Syntactic details of assembler. */
61
62 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name
63
64 /* Branch Target Identitication support. */
65 #if HAVE_AARCH64_BTI
66 # define BTI_C hint 34
67 # define BTI_J hint 36
68 #else
69 # define BTI_C nop
70 # define BTI_J nop
71 #endif
72
73 /* Return address signing support (pac-ret). */
74 #define PACIASP hint 25
75 #define AUTIASP hint 29
76
77 /* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code. */
78 #define FEATURE_1_AND 0xc0000000
79 #define FEATURE_1_BTI 1
80 #define FEATURE_1_PAC 2
81
82 /* Add a NT_GNU_PROPERTY_TYPE_0 note. */
83 #define GNU_PROPERTY(type, value) \
84 .section .note.gnu.property, "a"; \
85 .p2align 3; \
86 .word 4; \
87 .word 16; \
88 .word 5; \
89 .asciz "GNU"; \
90 .word type; \
91 .word 4; \
92 .word value; \
93 .word 0; \
94 .text
95
96 /* Add GNU property note with the supported features to all asm code
97 where sysdep.h is included. */
98 #if HAVE_AARCH64_BTI && HAVE_AARCH64_PAC_RET
99 GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI|FEATURE_1_PAC)
100 #elif HAVE_AARCH64_BTI
101 GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI)
102 #endif
103
104 /* Define an entry point visible from C. */
105 #define ENTRY(name) \
106 .globl C_SYMBOL_NAME(name); \
107 .type C_SYMBOL_NAME(name),%function; \
108 .p2align 6; \
109 C_LABEL(name) \
110 cfi_startproc; \
111 BTI_C; \
112 CALL_MCOUNT
113
114 /* Define an entry point visible from C. */
115 #define ENTRY_ALIGN(name, align) \
116 .globl C_SYMBOL_NAME(name); \
117 .type C_SYMBOL_NAME(name),%function; \
118 .p2align align; \
119 C_LABEL(name) \
120 cfi_startproc; \
121 BTI_C; \
122 CALL_MCOUNT
123
124 /* Define an entry point visible from C with a specified alignment and
125 pre-padding with NOPs. This can be used to ensure that a critical
126 loop within a function is cache line aligned. Note this version
127 does not adjust the padding if CALL_MCOUNT is defined. */
128
129 #define ENTRY_ALIGN_AND_PAD(name, align, padding) \
130 .globl C_SYMBOL_NAME(name); \
131 .type C_SYMBOL_NAME(name),%function; \
132 .p2align align; \
133 .rep padding - 1; /* -1 for bti c. */ \
134 nop; \
135 .endr; \
136 C_LABEL(name) \
137 cfi_startproc; \
138 BTI_C; \
139 CALL_MCOUNT
140
141 #undef END
142 #define END(name) \
143 cfi_endproc; \
144 ASM_SIZE_DIRECTIVE(name)
145
146 /* If compiled for profiling, call `mcount' at the start of each function. */
147 #ifdef PROF
148 # define CALL_MCOUNT \
149 str x30, [sp, #-80]!; \
150 cfi_adjust_cfa_offset (80); \
151 cfi_rel_offset (x30, 0); \
152 stp x0, x1, [sp, #16]; \
153 cfi_rel_offset (x0, 16); \
154 cfi_rel_offset (x1, 24); \
155 stp x2, x3, [sp, #32]; \
156 cfi_rel_offset (x2, 32); \
157 cfi_rel_offset (x3, 40); \
158 stp x4, x5, [sp, #48]; \
159 cfi_rel_offset (x4, 48); \
160 cfi_rel_offset (x5, 56); \
161 stp x6, x7, [sp, #64]; \
162 cfi_rel_offset (x6, 64); \
163 cfi_rel_offset (x7, 72); \
164 mov x0, x30; \
165 bl mcount; \
166 ldp x0, x1, [sp, #16]; \
167 cfi_restore (x0); \
168 cfi_restore (x1); \
169 ldp x2, x3, [sp, #32]; \
170 cfi_restore (x2); \
171 cfi_restore (x3); \
172 ldp x4, x5, [sp, #48]; \
173 cfi_restore (x4); \
174 cfi_restore (x5); \
175 ldp x6, x7, [sp, #64]; \
176 cfi_restore (x6); \
177 cfi_restore (x7); \
178 ldr x30, [sp], #80; \
179 cfi_adjust_cfa_offset (-80); \
180 cfi_restore (x30);
181 #else
182 # define CALL_MCOUNT /* Do nothing. */
183 #endif
184
185 /* Local label name for asm code. */
186 #ifndef L
187 # define L(name) .L##name
188 #endif
189
190 /* Load or store to/from a pc-relative EXPR into/from R, using T.
191 Note R and T are register numbers and not register names. */
192 #define LDST_PCREL(OP, R, T, EXPR) \
193 adrp x##T, EXPR; \
194 OP PTR_REG (R), [x##T, #:lo12:EXPR]; \
195
196 /* Load or store to/from a got-relative EXPR into/from R, using T.
197 Note R and T are register numbers and not register names. */
198 #define LDST_GLOBAL(OP, R, T, EXPR) \
199 adrp x##T, :got:EXPR; \
200 ldr PTR_REG (T), [x##T, #:got_lo12:EXPR]; \
201 OP PTR_REG (R), [x##T];
202
203 /* Load an immediate into R.
204 Note R is a register number and not a register name. */
205 #ifdef __LP64__
206 # define MOVL(R, NAME) \
207 movz PTR_REG (R), #:abs_g3:NAME; \
208 movk PTR_REG (R), #:abs_g2_nc:NAME; \
209 movk PTR_REG (R), #:abs_g1_nc:NAME; \
210 movk PTR_REG (R), #:abs_g0_nc:NAME;
211 #else
212 # define MOVL(R, NAME) \
213 movz PTR_REG (R), #:abs_g1:NAME; \
214 movk PTR_REG (R), #:abs_g0_nc:NAME;
215 #endif
216
217 /* Since C identifiers are not normally prefixed with an underscore
218 on this system, the asm identifier `syscall_error' intrudes on the
219 C name space. Make sure we use an innocuous name. */
220 #define syscall_error __syscall_error
221 #define mcount _mcount
222
223 #endif /* __ASSEMBLER__ */
224
225 #endif /* _AARCH64_SYSDEP_H */