1
2/*--------------------------------------------------------------------*/
3/*--- Support for doing system calls.        syscall-ppc64-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_ppc64_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.align 2
77.globl ML_(do_syscall_for_client_WRK)
78.section ".opd","aw"
79.align 3
80ML_(do_syscall_for_client_WRK):
81.quad .ML_(do_syscall_for_client_WRK),.TOC.@tocbase,0
82.previous
83.type .ML_(do_syscall_for_client_WRK),@function
84.globl .ML_(do_syscall_for_client_WRK)
85.ML_(do_syscall_for_client_WRK):
86        /* make a stack frame */
87        stdu    1,-80(1)
88        std     31,72(1)
89        std     30,64(1)
90        std     29,56(1)
91        std     28,48(1)
92        mr      31,3            /* syscall number */
93        mr      30,4            /* guest_state */
94        mr      29,6            /* postmask */
95        mr      28,7            /* sigsetSzB */
96
97        /* set the signal mask for doing the system call */
98        /* set up for sigprocmask(SIG_SETMASK, sysmask, postmask) */
991:      li      0,__NR_rt_sigprocmask
100        li      3,VKI_SIG_SETMASK
101        mr      4,5
102        mr      5,6
103	mr	6,7
104        sc                      /* set the mask */
105        bso     7f              /* if the sigprocmask fails */
106
107        /* load up syscall args from the threadstate */
108        ld      3,OFFSET_ppc64_GPR3(30)
109        ld      4,OFFSET_ppc64_GPR4(30)
110        ld      5,OFFSET_ppc64_GPR5(30)
111        ld      6,OFFSET_ppc64_GPR6(30)
112        ld      7,OFFSET_ppc64_GPR7(30)
113        ld      8,OFFSET_ppc64_GPR8(30)
114        mr      0,31            /* syscall number */
1152:      sc                      /* do the syscall */
116
117        /* put the result back in the threadstate  */
1183:	std     3,OFFSET_ppc64_GPR3(30)     /* gst->GPR3 = sc result */
119	/* copy cr0.so back to simulated state */
120	mfcr    5                           /* r5 = CR               */
121	rlwinm	5,5,4,31,31                 /* r5 = (CR >> 28) & 1   */
122        stb     5,OFFSET_ppc64_CR0_0(30)    /* gst->CR0.SO = cr0.so  */
123
124        /* block signals again */
125	/* set up for sigprocmask(SIG_SETMASK, postmask, NULL) */
1264:      li      0,__NR_rt_sigprocmask
127        li      3,VKI_SIG_SETMASK
128        mr      4,29
129        li      5,0
130        mr      6,28
131        sc                      /* set the mask */
132        bso     7f              /* if the sigprocmask fails */
133        /* now safe from signals */
134	li	3,0		/* SUCCESS */
135
136        /* pop off stack frame */
1375:      ld      28,48(1)
138        ld      29,56(1)
139        ld      30,64(1)
140        ld      31,72(1)
141        addi    1,1,80
142        blr
143
144	/* failure: return 0x8000 | error code */
1457:	ori	3,3,0x8000	/* FAILURE -- ensure return value is nonzero */
146        b       5b
147
148.section .rodata
149/* export the ranges so that
150   VG_(fixup_guest_state_after_syscall_interrupted) can do the
151   right thing */
152
153.globl ML_(blksys_setup)
154.globl ML_(blksys_restart)
155.globl ML_(blksys_complete)
156.globl ML_(blksys_committed)
157.globl ML_(blksys_finished)
158ML_(blksys_setup):     .quad 1b
159ML_(blksys_restart):   .quad 2b
160ML_(blksys_complete):  .quad 3b
161ML_(blksys_committed): .quad 4b
162ML_(blksys_finished):  .quad 5b
163
164
165/* Let the linker know we don't need an executable stack */
166.section .note.GNU-stack,"",@progbits
167
168#endif // defined(VGP_ppc64_linux)
169
170/*--------------------------------------------------------------------*/
171/*--- end                                                          ---*/
172/*--------------------------------------------------------------------*/
173