1
2/*--------------------------------------------------------------------*/
3/*--- Support for doing system calls.      syscall-mips32-linux.S  ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7   This file is part of Valgrind, a dynamic binary instrumentation
8   framework.
9
10   Copyright (C) 2010-2013 RT-RK
11      mips-valgrind@rt-rk.com
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#if defined(VGP_mips32_linux)
32
33#include "pub_core_basics_asm.h"
34#include "pub_core_vkiscnums_asm.h"
35#include "libvex_guest_offsets.h"
36
37
38/*----------------------------------------------------------------*/
39/*
40        Perform a syscall for the client.  This will run a syscall
41        with the client's specific per-thread signal mask.
42
43        The structure of this function is such that, if the syscall is
44        interrupted by a signal, we can determine exactly what
45        execution state we were in with respect to the execution of
46        the syscall by examining the value of IP in the signal
47        handler.  This means that we can always do the appropriate
48        thing to precisely emulate the kernel's signal/syscall
49        interactions.
50
51        The syscall number is taken from the argument, even though it
52        should also be in regs->v0.  The syscall result is written
53        back to regs->v0 on completion.
54
55        Returns 0 if the syscall was successfully called (even if the
56        syscall itself failed), or a nonzero error code in the lowest
57        8 bits if one of the sigprocmasks failed (there's no way to
58        determine which one failed).  And there's no obvious way to
59        recover from that either, but nevertheless we want to know.
60
61        VG_(fixup_guest_state_after_syscall_interrupted) does the
62        thread state fixup in the case where we were interrupted by a
63        signal.
64
65        Prototype:
66
67   UWord ML_(do_syscall_for_client_WRK)(
68              Int syscallno,                 // $4 - a0
69              void* guest_state,             // $5 - a1
70              const vki_sigset_t *sysmask,   // $6 - a2
71              const vki_sigset_t *postmask,  // $7 - a3
72              Int nsigwords)                 // stack
73*/
74/* from vki_arch.h */
75#define VKI_SIG_SETMASK 3
76
77.globl ML_(do_syscall_for_client_WRK)
78ML_(do_syscall_for_client_WRK):
79
80    subu $29, $29, 56  #set up the steck frame,
81    sw $4, 52($29)
82    sw $5, 48($29)
83    sw $6, 44($29)
84    sw $7, 40($29)
85    sw $31, 36($29)
86    sw $30, 32($29)
87    sw $16, 28($29)
88    sw $17, 24($29)
89    sw $18, 20($29)
90    sw $19, 16($29)
91    sw $20, 12($29)
92    sw $21, 8($29)
93    sw $22, 4($29)
94    sw $23, 0($29)
95    addu $30, $29, 56
96
97
98    /* Set the signal mask which should be current during the syscall. */
99
1001:  li $2, __NR_rt_sigprocmask
101    li $4, VKI_SIG_SETMASK
102    move $5, $6 /* sysmask */
103    move $6, $7 /* postmask */
104    lw $7, 72($29) /* nsigwords */
105    syscall
106    nop
107
108# TODO: this should remain, keep it just for now
109    bnez $7, 7f
110    nop
111
112    lw $8, 48($29)    /* t0 == ThreadState */
113
114    lw $2, 52($29) /* v0 == syscallno */
115    lw $4, OFFSET_mips32_r4($8)
116    lw $5, OFFSET_mips32_r5($8)
117    lw $6, OFFSET_mips32_r6($8)
118    lw $7, OFFSET_mips32_r7($8)
119    subu $29, $29, 24  #set up the steck frame,
120    lw $9, OFFSET_mips32_r29($8)
121    lw $10, 16($9)
122    sw $10, 16($29)
123    lw $10, 20($9)
124    sw $10, 20($29)
125
1262:  syscall
127
1283:  addu $29, $29, 24  #set up the steck frame,
129
130    lw $8, 48($29) /* t0 == ThreadState */
131    sw $2, OFFSET_mips32_r2($8)
132    sw $3, OFFSET_mips32_r3($8)
133    sw $7, OFFSET_mips32_r7($8)
134
1354:  li $2, __NR_rt_sigprocmask
136    li $4, VKI_SIG_SETMASK
137    lw $5, 40($29)
138    li $6, 0
139    lw $7, 72($29) /* nsigwords */
140    syscall
141    nop
142
143    bnez $7, 7f
144    nop
145
146    /* Success */
147    li $2, 0
148
1495:  lw $4, 52($29)
150    lw $5, 48($29)
151    lw $6, 44($29)
152    lw $7, 40($29)
153    lw $31, 36($29)
154    lw $30, 32($29)
155    lw $16, 28($29)
156    lw $17, 24($29)
157    lw $18, 20($29)
158    lw $19, 16($29)
159    lw $20, 12($29)
160    lw $21, 8($29)
161    lw $22, 4($29)
162    lw $23, 0($29)
163    addu $29, $29, 56 #release the stack frame.
164
165    jr $31
166    nop
167
1687:  /* Failure: return 0x8000 | error code */
169    li $2, 0x8000
170
171    lw $4, 52($29)
172    lw $5, 48($29)
173    lw $6, 44($29)
174    lw $7, 40($29)
175    lw $31, 36($29)
176    lw $30, 32($29)
177    lw $16, 28($29)
178    lw $17, 24($29)
179    lw $18, 20($29)
180    lw $19, 16($29)
181    lw $20, 12($29)
182    lw $21, 8($29)
183    lw $22, 4($29)
184    lw $23, 0($29)
185    addu $29, $29, 56 #release the stack frame.
186
187    jr $31
188    nop
189
190.section .rodata
191/* export the ranges so that
192   VG_(fixup_guest_state_after_syscall_interrupted) can do the
193   right thing */
194
195.globl ML_(blksys_setup)
196.globl ML_(blksys_restart)
197.globl ML_(blksys_complete)
198.globl ML_(blksys_committed)
199.globl ML_(blksys_finished)
200ML_(blksys_setup):      .long 1b
201ML_(blksys_restart):    .long 2b
202ML_(blksys_complete):   .long 3b
203ML_(blksys_committed):  .long 4b
204ML_(blksys_finished):   .long 5b
205.previous
206/* Let the linker know we don't need an executable stack */
207.section .note.GNU-stack,"",%progbits
208
209
210
211#endif // defined(VGP_mips32_linux)
212
213/*--------------------------------------------------------------------*/
214/*--- end                                                          ---*/
215/*--------------------------------------------------------------------*/
216