1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <private/bionic_asm.h>
30#include <private/bionic_constants.h>
31
32// According to AARCH64 PCS document we need to save the following
33// registers:
34//
35// Core     x19 - x30, sp (see section 5.1.1)
36// VFP      d8 - d15 (see section 5.1.2)
37//
38// NOTE: All the registers saved here will have 64 bit vales.
39//       AAPCS mandates that the higher part of q registers do not need to
40//       be saved by the callee.
41//
42// The internal structure of a jmp_buf is totally private.
43// Current layout (changes from release to release):
44//
45// word   name            description
46// 0      sigflag/cookie  setjmp cookie in top 31 bits, signal mask flag in low bit
47// 1      sigmask         signal mask (not used with _setjmp / _longjmp)
48// 2      core_base       base of core registers (x18-x30, sp)
49// 16     float_base      base of float registers (d8-d15)
50// 24     checksum        checksum of core registers
51// 25     reserved        reserved entries (room to grow)
52// 32
53
54#define _JB_SIGFLAG     0
55#define _JB_SIGMASK     (_JB_SIGFLAG + 1)
56#define _JB_X30_SP      (_JB_SIGMASK + 1)
57#define _JB_X28_X29     (_JB_X30_SP  + 2)
58#define _JB_X26_X27     (_JB_X28_X29 + 2)
59#define _JB_X24_X25     (_JB_X26_X27 + 2)
60#define _JB_X22_X23     (_JB_X24_X25 + 2)
61#define _JB_X20_X21     (_JB_X22_X23 + 2)
62#define _JB_SCS_X19     (_JB_X20_X21 + 2)
63#define _JB_D14_D15     (_JB_SCS_X19 + 2)
64#define _JB_D12_D13     (_JB_D14_D15 + 2)
65#define _JB_D10_D11     (_JB_D12_D13 + 2)
66#define _JB_D8_D9       (_JB_D10_D11 + 2)
67#define _JB_CHECKSUM    (_JB_D8_D9 + 2)
68
69.macro m_mangle_registers reg, sp_reg
70  eor x3, x3, \reg
71  eor x19, x19, \reg
72  eor x20, x20, \reg
73  eor x21, x21, \reg
74  eor x22, x22, \reg
75  eor x23, x23, \reg
76  eor x24, x24, \reg
77  eor x25, x25, \reg
78  eor x26, x26, \reg
79  eor x27, x27, \reg
80  eor x28, x28, \reg
81  eor x29, x29, \reg
82  eor x30, x30, \reg
83  eor \sp_reg, \sp_reg, \reg
84.endm
85
86.macro m_calculate_checksum dst, src, scratch
87  mov \dst, #0
88  .irp i,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23
89    ldr \scratch, [\src, #(\i * 8)]
90    eor \dst, \dst, \scratch
91  .endr
92.endm
93
94.macro m_unmangle_registers reg, sp_reg
95  m_mangle_registers \reg, sp_reg=\sp_reg
96.endm
97
98ENTRY_WEAK_FOR_NATIVE_BRIDGE(setjmp)
99  mov w1, #1
100  b sigsetjmp
101END(setjmp)
102
103ENTRY_WEAK_FOR_NATIVE_BRIDGE(_setjmp)
104  mov w1, #0
105  b sigsetjmp
106END(_setjmp)
107
108// int sigsetjmp(sigjmp_buf env, int save_signal_mask);
109ENTRY_WEAK_FOR_NATIVE_BRIDGE(sigsetjmp)
110  paciasp
111  .cfi_negate_ra_state
112  stp x0, x30, [sp, #-16]!
113  .cfi_def_cfa_offset 16
114  .cfi_rel_offset x0, 0
115  .cfi_rel_offset x30, 8
116
117  // Get the cookie and store it along with the signal flag.
118  mov x0, x1
119  bl __bionic_setjmp_cookie_get
120  mov x1, x0
121  ldr x0, [sp, #0]
122  str x1, [x0, #(_JB_SIGFLAG * 8)]
123
124  // Do we need to save the signal mask?
125  tbz w1, #0, 1f
126
127  // Save the cookie for later.
128  stp x1, xzr, [sp, #-16]!
129  .cfi_adjust_cfa_offset 16
130
131  // Save current signal mask.
132  // The 'how' argument is ignored if new_mask is NULL.
133  mov x1, #0 // NULL.
134  add x2, x0, #(_JB_SIGMASK * 8) // old_mask.
135  bl sigprocmask
136
137  ldp x1, xzr, [sp], #16
138  .cfi_adjust_cfa_offset -16
139
1401:
141  // Restore original x0 and lr.
142  ldp x0, x30, [sp], #16
143  .cfi_adjust_cfa_offset -16
144  .cfi_restore x0
145  .cfi_restore x30
146
147  // Mask off the signal flag bit.
148  bic x1, x1, #1
149
150  // Mask off the high bits of the shadow call stack pointer.
151  // We only store the low bits of x18 to avoid leaking the
152  // shadow call stack address into memory.
153  // See the SCS commentary in pthread_internal.h for more detail.
154  and x3, x18, #SCS_MASK
155
156  // Save core registers.
157  mov x10, sp
158  m_mangle_registers x1, sp_reg=x10
159  stp x30, x10, [x0, #(_JB_X30_SP  * 8)]
160  stp x28, x29, [x0, #(_JB_X28_X29 * 8)]
161  stp x26, x27, [x0, #(_JB_X26_X27 * 8)]
162  stp x24, x25, [x0, #(_JB_X24_X25 * 8)]
163  stp x22, x23, [x0, #(_JB_X22_X23 * 8)]
164  stp x20, x21, [x0, #(_JB_X20_X21 * 8)]
165  stp x3,  x19, [x0, #(_JB_SCS_X19 * 8)]
166  m_unmangle_registers x1, sp_reg=x10
167
168  // Save floating point registers.
169  stp d14, d15, [x0, #(_JB_D14_D15 * 8)]
170  stp d12, d13, [x0, #(_JB_D12_D13 * 8)]
171  stp d10, d11, [x0, #(_JB_D10_D11 * 8)]
172  stp d8,  d9,  [x0, #(_JB_D8_D9   * 8)]
173
174  // Calculate the checksum.
175  m_calculate_checksum x12, x0, x2
176  str x12, [x0, #(_JB_CHECKSUM * 8)]
177
178  mov w0, #0
179  autiasp
180  .cfi_negate_ra_state
181  ret
182END(sigsetjmp)
183
184// void siglongjmp(sigjmp_buf env, int value);
185ENTRY_WEAK_FOR_NATIVE_BRIDGE(siglongjmp)
186  // Check the checksum before doing anything.
187  m_calculate_checksum x12, x0, x2
188  ldr x2, [x0, #(_JB_CHECKSUM * 8)]
189  cmp x2, x12
190  bne __bionic_setjmp_checksum_mismatch
191
192  // Update stack memory tags (MTE + hwasan).
193  stp x0, x30, [sp, #-16]!
194  .cfi_adjust_cfa_offset 16
195  .cfi_rel_offset x0, 0
196  .cfi_rel_offset x30, 8
197  mov x19, x1 // Save 'value'.
198
199  // load and unmangle destination SP
200  ldr x2, [x0, #(_JB_SIGFLAG * 8)]
201  bic x2, x2, #1
202  ldr x0, [x0, #(_JB_X30_SP  * 8 + 8)]
203  eor x0, x0, x2
204  add x1, sp, #16
205  bl memtag_handle_longjmp
206
207  mov x1, x19 // Restore 'value'.
208  // Restore original x0 and lr.
209  ldp x0, x30, [sp], #16
210  .cfi_adjust_cfa_offset -16
211  .cfi_restore x0
212  .cfi_restore x30
213
214  // Do we need to restore the signal mask?
215  ldr x2, [x0, #(_JB_SIGFLAG * 8)]
216  tbz w2, #0, 1f
217
218  stp x0, x30, [sp, #-16]!
219  .cfi_adjust_cfa_offset 16
220  .cfi_rel_offset x0, 0
221  .cfi_rel_offset x30, 8
222
223  // Restore signal mask.
224  mov x19, x1 // Save 'value'.
225
226  mov x2, x0
227  mov x0, #2 // SIG_SETMASK
228  add x1, x2, #(_JB_SIGMASK * 8) // new_mask.
229  mov x2, #0 // NULL.
230  bl sigprocmask
231  mov x1, x19 // Restore 'value'.
232
233  // Restore original x0 and lr.
234  ldp x0, x30, [sp], #16
235  .cfi_adjust_cfa_offset -16
236  .cfi_restore x0
237  .cfi_restore x30
238
239  ldr x2, [x0, #(_JB_SIGFLAG * 8)]
2401:
241  // Restore core registers.
242  bic x2, x2, #1
243  // x30 was saved with PAC to jmp_buf in sigsetjmp().
244  ldp x30, x10, [x0, #(_JB_X30_SP  * 8)]
245  .cfi_negate_ra_state
246  ldp x28, x29, [x0, #(_JB_X28_X29 * 8)]
247  ldp x26, x27, [x0, #(_JB_X26_X27 * 8)]
248  ldp x24, x25, [x0, #(_JB_X24_X25 * 8)]
249  ldp x22, x23, [x0, #(_JB_X22_X23 * 8)]
250  ldp x20, x21, [x0, #(_JB_X20_X21 * 8)]
251  ldp x3,  x19, [x0, #(_JB_SCS_X19 * 8)]
252  m_unmangle_registers x2, sp_reg=x10
253  mov sp, x10
254
255  // Restore the low bits of the shadow call stack pointer.
256  and x18, x18, #~SCS_MASK
257  orr x18, x3, x18
258
259  stp x0, x1, [sp, #-16]!
260  .cfi_adjust_cfa_offset 16
261  .cfi_rel_offset x0, 0
262  .cfi_rel_offset x1, 8
263  stp x30, xzr, [sp, #-16]!
264  .cfi_adjust_cfa_offset 16
265  .cfi_rel_offset x30, 0
266  ldr x0, [x0, #(_JB_SIGFLAG * 8)]
267  bl __bionic_setjmp_cookie_check
268  ldp x30, xzr, [sp], #16
269  .cfi_adjust_cfa_offset -16
270  .cfi_restore x30
271  ldp x0, x1, [sp], #16
272  .cfi_adjust_cfa_offset -16
273  .cfi_restore x0
274  .cfi_restore x1
275
276  // Restore floating point registers.
277  ldp d14, d15, [x0, #(_JB_D14_D15 * 8)]
278  ldp d12, d13, [x0, #(_JB_D12_D13 * 8)]
279  ldp d10, d11, [x0, #(_JB_D10_D11 * 8)]
280  ldp d8,  d9,  [x0, #(_JB_D8_D9   * 8)]
281
282  // Set return value.
283  cmp w1, wzr
284  csinc w0, w1, wzr, ne
285  autiasp
286  .cfi_negate_ra_state
287  ret
288END(siglongjmp)
289
290ALIAS_SYMBOL_WEAK_FOR_NATIVE_BRIDGE(longjmp, siglongjmp)
291ALIAS_SYMBOL_WEAK_FOR_NATIVE_BRIDGE(_longjmp, siglongjmp)
292
293NOTE_GNU_PROPERTY()
294