1
2/*--------------------------------------------------------------------*/
3/*--- Support for doing system calls.        syscall-s390x-linux.S ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7   This file is part of Valgrind, a dynamic binary instrumentation
8   framework.
9
10   Copyright IBM Corp. 2010-2015
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/* Contributed by Christian Borntraeger */
31
32#include "pub_core_basics_asm.h"
33#include "pub_core_vkiscnums_asm.h"
34#include "libvex_guest_offsets.h"
35
36#if defined(VGA_s390x)
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 NIP 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, since the syscall
52        number can be encoded in the svc instruction itself.
53        The syscall result is written back to guest register r2.
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,		// r2
69				  void* guest_state,		// r3
70				  const vki_sigset_t *sysmask,	// r4
71				  const vki_sigset_t *postmask,	// r5
72				  Int nsigwords)		// r6
73*/
74/* from vki_arch.h */
75#define VKI_SIG_SETMASK 2
76
77#define SP_SAVE 16
78#define SP_R2	SP_SAVE + 0*8
79#define SP_R3	SP_SAVE + 1*8
80#define SP_R4	SP_SAVE + 2*8
81#define SP_R5	SP_SAVE + 3*8
82#define SP_R6	SP_SAVE + 4*8
83#define SP_R7	SP_SAVE + 5*8
84#define SP_R8	SP_SAVE + 6*8
85#define SP_R9	SP_SAVE + 7*8
86
87.align 4
88.globl ML_(do_syscall_for_client_WRK)
89ML_(do_syscall_for_client_WRK):
901:	/* Even though we can't take a signal until the sigprocmask completes,
91	start the range early.
92	If IA is in the range [1,2), the syscall hasn't been started yet */
93
94	/* Set the signal mask which should be current during the syscall. */
95	/* Save and restore all the parameters and all the registers that
96	   we clobber (r6-r9) */
97	stmg	%r2,%r9, SP_R2(%r15)
98
99	lghi	%r2, VKI_SIG_SETMASK		/* how */
100	lgr	%r3, %r4			/* sysmask */
101	lgr	%r4, %r5			/* postmask */
102	lgr	%r5, %r6			/* nsigwords */
103	svc	__NR_rt_sigprocmask
104	cghi	%r2, 0x0
105	jne	7f				/* sigprocmask failed */
106
107	/* OK, that worked.  Now do the syscall proper. */
108	lg	%r9, SP_R3(%r15)		/* guest state --> r9 */
109	lg	%r2, OFFSET_s390x_r2(%r9)	/* guest r2 --> real r2 */
110	lg	%r3, OFFSET_s390x_r3(%r9)	/* guest r3 --> real r3 */
111	lg	%r4, OFFSET_s390x_r4(%r9)	/* guest r4 --> real r4 */
112	lg	%r5, OFFSET_s390x_r5(%r9)	/* guest r5 --> real r5 */
113	lg	%r6, OFFSET_s390x_r6(%r9)	/* guest r6 --> real r6 */
114	lg	%r7, OFFSET_s390x_r7(%r9)	/* guest r7 --> real r7 */
115	lg	%r1, SP_R2(%r15)		/* syscallno -> r1 */
116
1172:	svc	0
118
1193:
120	stg	%r2, OFFSET_s390x_r2(%r9)
121
1224:	/* Re-block signals.  If IA is in [4,5), then the syscall
123	   is complete and we needn't worry about it. */
124	lghi	%r2, VKI_SIG_SETMASK		/* how */
125	lg	%r3, SP_R5(%r15)		/* postmask */
126	lghi	%r4, 0x0			/* NULL */
127	lg	%r5, SP_R6(%r15)		/* nsigwords */
128	svc	__NR_rt_sigprocmask
129	cghi	%r2, 0x0
130	jne	7f				/* sigprocmask failed */
131
1325:	/* Everyting ok. Return 0 and restore the call-saved
133	   registers, that we have clobbered */
134	lghi	%r2, 0x0
135	lmg	%r6,%r9, SP_R6(%r15)
136	br	%r14
137
1387:	/* Some problem. Return 0x8000 | error and restore the call-saved
139	   registers we have clobbered. */
140	nill	%r2, 0x7fff
141	oill	%r2, 0x8000
142	lmg	%r6,%r9, SP_R6(%r15)
143	br	%r14
144
145.section .rodata
146/* Export the ranges so that
147   VG_(fixup_guest_state_after_syscall_interrupted) can do the
148   right thing */
149
150.globl ML_(blksys_setup)
151.globl ML_(blksys_restart)
152.globl ML_(blksys_complete)
153.globl ML_(blksys_committed)
154.globl ML_(blksys_finished)
155
156/* The compiler can assume that 8 byte data elements are aligned on 8 byte */
157.align 8
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.previous
164
165#endif /* VGA_s390x */
166
167/* Let the linker know we don't need an executable stack */
168MARK_STACK_NO_EXEC
169
170/*--------------------------------------------------------------------*/
171/*--- end                                                          ---*/
172/*--------------------------------------------------------------------*/
173