1
2/*--------------------------------------------------------------------*/
3/*--- Support for doing system calls.        syscall-ppc32-linux.S ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7  This file is part of Valgrind, a dynamic binary instrumentation
8  framework.
9
10  Copyright (C) 2005-2013 Paul Mackerras (paulus@samba.org)
11
12  This program is free software; you can redistribute it and/or
13  modify it under the terms of the GNU General Public License as
14  published by the Free Software Foundation; either version 2 of the
15  License, or (at your option) any later version.
16
17  This program is distributed in the hope that it will be useful, but
18  WITHOUT ANY WARRANTY; without even the implied warranty of
19  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20  General Public License for more details.
21
22  You should have received a copy of the GNU General Public License
23  along with this program; if not, write to the Free Software
24  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
25  02111-1307, USA.
26
27  The GNU General Public License is contained in the file COPYING.
28*/
29
30#if defined(VGP_ppc32_linux)
31
32#include "pub_core_basics_asm.h"
33#include "pub_core_vkiscnums_asm.h"
34#include "libvex_guest_offsets.h"
35
36
37/*----------------------------------------------------------------*/
38/*
39        Perform a syscall for the client.  This will run a syscall
40        with the client's specific per-thread signal mask.
41
42        The structure of this function is such that, if the syscall is
43        interrupted by a signal, we can determine exactly what
44        execution state we were in with respect to the execution of
45        the syscall by examining the value of NIP in the signal
46        handler.  This means that we can always do the appropriate
47        thing to precisely emulate the kernel's signal/syscall
48        interactions.
49
50        The syscall number is taken from the argument, even though it
51        should also be in regs->m_gpr[0].  The syscall result is written
52        back to regs->m_gpr[3]/m_xer/m_result on completion.
53
54        Returns 0 if the syscall was successfully called (even if the
55        syscall itself failed), or a nonzero error code in the lowest
56	8 bits if one of the sigprocmasks failed (there's no way to
57	determine which one failed).  And there's no obvious way to
58	recover from that either, but nevertheless we want to know.
59
60        VG_(fixup_guest_state_after_syscall_interrupted) does the
61	thread state fixup in the case where we were interrupted by a
62	signal.
63
64        Prototype:
65
66	UWord ML_(do_syscall_for_client_WRK)(
67				  Int syscallno,		// r3
68				  void* guest_state,		// r4
69				  const vki_sigset_t *sysmask,	// r5
70				  const vki_sigset_t *postmask,	// r6
71				  Int sigsetSzB)		// r7
72*/
73/* from vki_arch.h */
74#define VKI_SIG_SETMASK 2
75
76.globl ML_(do_syscall_for_client_WRK)
77ML_(do_syscall_for_client_WRK):
78        /* make a stack frame */
79        stwu    1,-32(1)
80        stw     31,28(1)
81        stw     30,24(1)
82        stw     29,20(1)
83        stw     28,16(1)
84        mr      31,3            /* syscall number */
85        mr      30,4            /* guest_state */
86        mr      29,6            /* postmask */
87        mr      28,7            /* sigsetSzB */
88
89        /* set the signal mask for doing the system call */
90        /* set up for sigprocmask(SIG_SETMASK, sysmask, postmask) */
911:      li      0,__NR_rt_sigprocmask
92        li      3,VKI_SIG_SETMASK
93        mr      4,5
94        mr      5,6
95	mr	6,7
96        sc                      /* set the mask */
97        bso     7f              /* if the sigprocmask fails */
98
99        /* load up syscall args from the threadstate */
100        lwz     3,OFFSET_ppc32_GPR3(30)
101        lwz     4,OFFSET_ppc32_GPR4(30)
102        lwz     5,OFFSET_ppc32_GPR5(30)
103        lwz     6,OFFSET_ppc32_GPR6(30)
104        lwz     7,OFFSET_ppc32_GPR7(30)
105        lwz     8,OFFSET_ppc32_GPR8(30)
106        mr      0,31            /* syscall number */
1072:      sc                      /* do the syscall */
108
109        /* put the result back in the threadstate  */
1103:	stw     3,OFFSET_ppc32_GPR3(30)     /* gst->GPR3 = sc result */
111	/* copy cr0.so back to simulated state */
112	mfcr    5                           /* r5 = CR               */
113	rlwinm	5,5,4,31,31                 /* r5 = (CR >> 28) & 1   */
114        stb     5,OFFSET_ppc32_CR0_0(30)    /* gst->CR0.SO = cr0.so  */
115
116        /* block signals again */
117	/* set up for sigprocmask(SIG_SETMASK, postmask, NULL) */
1184:      li      0,__NR_rt_sigprocmask
119        li      3,VKI_SIG_SETMASK
120        mr      4,29
121        li      5,0
122        mr      6,28
123        sc                      /* set the mask */
124        bso     7f              /* if the sigprocmask fails */
125        /* now safe from signals */
126	li	3,0		/* SUCCESS */
127
128        /* pop off stack frame */
1295:      lwz     28,16(1)
130        lwz     29,20(1)
131        lwz     30,24(1)
132        lwz     31,28(1)
133        addi    1,1,32
134        blr
135
136	/* failure: return 0x8000 | error code */
1377:      ori	3,3,0x8000	/* FAILURE -- ensure return value is nonzero */
138        b       5b
139
140.section .rodata
141/* export the ranges so that
142   VG_(fixup_guest_state_after_syscall_interrupted) can do the
143   right thing */
144
145.globl ML_(blksys_setup)
146.globl ML_(blksys_restart)
147.globl ML_(blksys_complete)
148.globl ML_(blksys_committed)
149.globl ML_(blksys_finished)
150ML_(blksys_setup):     .long 1b
151ML_(blksys_restart):   .long 2b
152ML_(blksys_complete):  .long 3b
153ML_(blksys_committed): .long 4b
154ML_(blksys_finished):  .long 5b
155
156.previous
157
158/* Let the linker know we don't need an executable stack */
159.section .note.GNU-stack,"",@progbits
160
161#endif // defined(VGP_ppc32_linux)
162
163/*--------------------------------------------------------------------*/
164/*--- end                                                          ---*/
165/*--------------------------------------------------------------------*/
166