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_ppc64le_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#if _CALL_ELF == 2
79.type .ML_(do_syscall_for_client_WRK),@function
80ML_(do_syscall_for_client_WRK):
810:      addis         2,12,.TOC.-0b@ha
82        addi          2,2,.TOC.-0b@l
83        .localentry   ML_(do_syscall_for_client_WRK), .-ML_(do_syscall_for_client_WRK)
84#else
85.section ".opd","aw"
86.align 3
87ML_(do_syscall_for_client_WRK):
88.quad .ML_(do_syscall_for_client_WRK),.TOC.@tocbase,0
89.previous
90#endif
91#if _CALL_ELF == 2
920:      addis        2,12,.TOC.-0b@ha
93        addi         2,2,.TOC.-0b@l
94        .localentry  ML_(do_syscall_for_client_WRK), .-ML_(do_syscall_for_client_WRK)
95#endif
96.type  .ML_(do_syscall_for_client_WRK),@function
97.globl .ML_(do_syscall_for_client_WRK)
98.ML_(do_syscall_for_client_WRK):
99        /* make a stack frame */
100        stdu    1,-80(1)
101        std     31,72(1)
102        std     30,64(1)
103        std     29,56(1)
104        std     28,48(1)
105        mr      31,3            /* syscall number */
106        mr      30,4            /* guest_state */
107        mr      29,6            /* postmask */
108        mr      28,7            /* sigsetSzB */
109
110        /* set the signal mask for doing the system call */
111        /* set up for sigprocmask(SIG_SETMASK, sysmask, postmask) */
1121:      li      0,__NR_rt_sigprocmask
113        li      3,VKI_SIG_SETMASK
114        mr      4,5
115        mr      5,6
116	mr	6,7
117        sc                      /* set the mask */
118        bso     7f              /* if the sigprocmask fails */
119
120        /* load up syscall args from the threadstate */
121        ld      3,OFFSET_ppc64_GPR3(30)
122        ld      4,OFFSET_ppc64_GPR4(30)
123        ld      5,OFFSET_ppc64_GPR5(30)
124        ld      6,OFFSET_ppc64_GPR6(30)
125        ld      7,OFFSET_ppc64_GPR7(30)
126        ld      8,OFFSET_ppc64_GPR8(30)
127        mr      0,31            /* syscall number */
1282:      sc                      /* do the syscall */
129
130        /* put the result back in the threadstate  */
1313:	std     3,OFFSET_ppc64_GPR3(30)     /* gst->GPR3 = sc result */
132	/* copy cr0.so back to simulated state */
133	mfcr    5                           /* r5 = CR               */
134	rlwinm	5,5,4,31,31                 /* r5 = (CR >> 28) & 1   */
135        stb     5,OFFSET_ppc64_CR0_0(30)    /* gst->CR0.SO = cr0.so  */
136
137        /* block signals again */
138	/* set up for sigprocmask(SIG_SETMASK, postmask, NULL) */
1394:      li      0,__NR_rt_sigprocmask
140        li      3,VKI_SIG_SETMASK
141        mr      4,29
142        li      5,0
143        mr      6,28
144        sc                      /* set the mask */
145        bso     7f              /* if the sigprocmask fails */
146        /* now safe from signals */
147	li	3,0		/* SUCCESS */
148
149        /* pop off stack frame */
1505:      ld      28,48(1)
151        ld      29,56(1)
152        ld      30,64(1)
153        ld      31,72(1)
154        addi    1,1,80
155        blr
156
157	/* failure: return 0x8000 | error code */
1587:	ori	3,3,0x8000	/* FAILURE -- ensure return value is nonzero */
159        b       5b
160#if _CALL_ELF == 2
161        .size .ML_(do_syscall_for_client_WRK),.-.ML_(do_syscall_for_client_WRK)
162#else
163        .size .ML_(do_syscall_for_client_WRK),.-.ML_(do_syscall_for_client_WRK)
164#endif
165.section .rodata
166/* export the ranges so that
167   VG_(fixup_guest_state_after_syscall_interrupted) can do the
168   right thing */
169
170.globl ML_(blksys_setup)
171.globl ML_(blksys_restart)
172.globl ML_(blksys_complete)
173.globl ML_(blksys_committed)
174.globl ML_(blksys_finished)
175ML_(blksys_setup):     .quad 1b
176ML_(blksys_restart):   .quad 2b
177ML_(blksys_complete):  .quad 3b
178ML_(blksys_committed): .quad 4b
179ML_(blksys_finished):  .quad 5b
180
181
182/* Let the linker know we don't need an executable stack */
183.section .note.GNU-stack,"",@progbits
184
185#endif // defined(VGP_ppc64le_linux)
186
187/*--------------------------------------------------------------------*/
188/*--- end                                                          ---*/
189/*--------------------------------------------------------------------*/
190