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1
2/*--------------------------------------------------------------------*/
3/*--- Support for doing system calls.        syscall-arm64-linux.S ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7  This file is part of Valgrind, a dynamic binary instrumentation
8  framework.
9
10  Copyright (C) 2013-2015 OpenWorks
11     info@open-works.net
12
13  This program is free software; you can redistribute it and/or
14  modify it under the terms of the GNU General Public License as
15  published by the Free Software Foundation; either version 2 of the
16  License, or (at your option) any later version.
17
18  This program is distributed in the hope that it will be useful, but
19  WITHOUT ANY WARRANTY; without even the implied warranty of
20  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21  General Public License for more details.
22
23  You should have received a copy of the GNU General Public License
24  along with this program; if not, write to the Free Software
25  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26  02111-1307, USA.
27
28  The GNU General Public License is contained in the file COPYING.
29*/
30
31#include "pub_core_basics_asm.h"
32
33#if defined(VGP_arm64_linux)
34
35#include "pub_core_vkiscnums_asm.h"
36#include "libvex_guest_offsets.h"
37
38
39/*----------------------------------------------------------------*/
40/*
41        Perform a syscall for the client.  This will run a syscall
42        with the client's specific per-thread signal mask.
43
44        The structure of this function is such that, if the syscall is
45        interrupted by a signal, we can determine exactly what
46        execution state we were in with respect to the execution of
47        the syscall by examining the value of IP in the signal
48        handler.  This means that we can always do the appropriate
49        thing to precisely emulate the kernel's signal/syscall
50        interactions.
51
52        The syscall number is taken from the argument, even though it
53        should also be in guest_state->guest_X8.  The syscall result
54	is written back to guest_state->guest_X0 on completion.
55
56        Returns 0 if the syscall was successfully called (even if the
57        syscall itself failed), or a nonzero error code in the lowest
58        8 bits if one of the sigprocmasks failed (there's no way to
59        determine which one failed).  And there's no obvious way to
60        recover from that either, but nevertheless we want to know.
61
62        VG_(fixup_guest_state_after_syscall_interrupted) does the
63        thread state fixup in the case where we were interrupted by a
64        signal.
65
66        Prototype:
67
68   UWord ML_(do_syscall_for_client_WRK)(
69              Int syscallno,                 // x0
70              void* guest_state,             // x1
71              const vki_sigset_t *sysmask,   // x2
72              const vki_sigset_t *postmask,  // x3
73              Int nsigwords)                 // x4
74*/
75/* from vki-arm64-linux.h */
76#define VKI_SIG_SETMASK 2
77
78.globl ML_(do_syscall_for_client_WRK)
79ML_(do_syscall_for_client_WRK):
80
81   /* Stash callee-saves and our args on the stack */
82   stp  x29, x30, [sp, #-16]!
83   stp  x27, x28, [sp, #-16]!
84   stp  x25, x26, [sp, #-16]!
85   stp  x23, x24, [sp, #-16]!
86   stp  x21, x22, [sp, #-16]!
87   stp  x19, x20, [sp, #-16]!
88   stp  x4,  x5,  [sp, #-16]!
89   stp  x2,  x3,  [sp, #-16]!
90   stp  x0,  x1,  [sp, #-16]!
91
921:
93
94   mov x8, #__NR_rt_sigprocmask
95   mov x0, #VKI_SIG_SETMASK
96   mov x1, x2 /* sysmask */
97   mov x2, x3 /* postmask */
98   mov x3, x4 /* nsigwords */
99   svc 0x00000000
100
101
102   ldr x5, [sp, #8] /* saved x1 == guest_state */
103
104   ldr x8, [sp, #0] /* saved x0 == syscall# */
105   ldr x0, [x5, #OFFSET_arm64_X0]
106   ldr x1, [x5, #OFFSET_arm64_X1]
107   ldr x2, [x5, #OFFSET_arm64_X2]
108   ldr x3, [x5, #OFFSET_arm64_X3]
109   ldr x4, [x5, #OFFSET_arm64_X4]
110   ldr x5, [x5, #OFFSET_arm64_X5]
111
1122: svc 0x00000000
1133:
114   ldr x5, [sp, #8] /* saved x1 == guest_state */
115   str x0, [x5, #OFFSET_arm64_X0]
116
1174:
118   mov x8, #__NR_rt_sigprocmask
119   mov x0, #VKI_SIG_SETMASK
120   ldr x1, [sp, #24] /* saved x3 == postmask */
121   mov x2, #0
122   ldr x3, [sp, #32] /* saved x4 == nsigwords */
123   svc 0x00000000
124
125   cmp x0, #0
126   blt 7f
127
1285: /* Success: return zero */
129   mov  x0, #0
130   ldp  xzr, x1,  [sp], #16
131   ldp  x2,  x3,  [sp], #16
132   ldp  x4,  x5,  [sp], #16
133   ldp  x19, x20, [sp], #16
134   ldp  x21, x22, [sp], #16
135   ldp  x23, x24, [sp], #16
136   ldp  x25, x26, [sp], #16
137   ldp  x27, x28, [sp], #16
138   ldp  x29, x30, [sp], #16
139   ret
140
1417: /* Failure: return 0x8000 | error code */
142   orr  x0, x0, #0x8000
143   ldp  xzr, x1,  [sp], #16
144   ldp  x2,  x3,  [sp], #16
145   ldp  x4,  x5,  [sp], #16
146   ldp  x19, x20, [sp], #16
147   ldp  x21, x22, [sp], #16
148   ldp  x23, x24, [sp], #16
149   ldp  x25, x26, [sp], #16
150   ldp  x27, x28, [sp], #16
151   ldp  x29, x30, [sp], #16
152   ret
153
154
155
156.section .rodata
157/* export the ranges so that
158   VG_(fixup_guest_state_after_syscall_interrupted) can do the
159   right thing */
160
161.align 3
162.globl ML_(blksys_setup)
163.globl ML_(blksys_restart)
164.globl ML_(blksys_complete)
165.globl ML_(blksys_committed)
166.globl ML_(blksys_finished)
167ML_(blksys_setup):      .quad 1b
168ML_(blksys_restart):    .quad 2b
169ML_(blksys_complete):   .quad 3b
170ML_(blksys_committed):  .quad 4b
171ML_(blksys_finished):   .quad 5b
172
173#endif // defined(VGP_arm_linux)
174
175/* Let the linker know we don't need an executable stack */
176MARK_STACK_NO_EXEC
177
178/*--------------------------------------------------------------------*/
179/*--- end                                                          ---*/
180/*--------------------------------------------------------------------*/
181