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1
2/*--------------------------------------------------------------------*/
3/*--- Support for doing system calls.         syscall-x86-darwin.S ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7  This file is part of Valgrind, a dynamic binary instrumentation
8  framework.
9
10  Copyright (C) 2000-2017 Julian Seward
11     jseward@acm.org
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#include "pub_core_basics_asm.h"
32
33#if defined(VGP_x86_darwin)
34
35#include "pub_core_vkiscnums_asm.h"
36#include "libvex_guest_offsets.h"
37
38
39/*----------------------------------------------------------------*/
40/*
41	Perform a syscall for the client.  This will run a syscall
42	with the client's specific per-thread signal mask.
43
44	The structure of this function is such that, if the syscall is
45	interrupted by a signal, we can determine exactly what
46	execution state we were in with respect to the execution of
47	the syscall by examining the value of %eip in the signal
48	handler.  This means that we can always do the appropriate
49	thing to precisely emulate the kernel's signal/syscall
50	interactions.
51
52	The syscall number is taken from the argument, even though it
53	should also be in regs->m_eax.  The syscall result is written
54	back to regs->m_eax on completion.
55
56	Returns 0 if the syscall was successfully called (even if the
57	syscall itself failed), or a -ve error code if one of the
58	sigprocmasks failed (there's no way to determine which one
59	failed).
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	Int ML_(do_syscall_for_client_WRK)(
68	                          Int syscallno,		// ebp+8
69				  void* guest_state,		// ebp+12
70				  const vki_sigset_t *sysmask,	// ebp+16
71				  const vki_sigset_t *postmask,	// ebp+20
72				  Int sigsetSzB)		// ebp+24
73
74        Note that sigsetSzB is totally ignored (and irrelevant).
75*/
76
77/* from vki-darwin.h, checked at startup by m_vki.c */
78#define VKI_SIG_SETMASK	3
79
80/* DO_SYSCALL MACH|MDEP|UNIX */
81#define MACH 1
82#define MDEP 2
83#define UNIX 3
84
85.macro DO_SYSCALL
86	/* establish stack frame */
87	push	%ebp
88	mov	%esp, %ebp
89	subl	$$8, %esp	/* 16-byte align stack */
90
91L_$0_1:	/* Even though we can't take a signal until the
92           __pthread_sigmask completes, start the range early.
93           If eip is in the range [1,2), the syscall hasn't been started yet */
94
95        /* Set the signal mask which should be current during the syscall. */
96        /* Set up for __pthread_sigmask(SIG_SETMASK, sysmask, postmask) */
97        pushl   20(%ebp)
98        pushl   16(%ebp)
99        pushl   $$VKI_SIG_SETMASK
100        pushl   $$0xcafebabe    /* totally fake return address */
101        movl    $$__NR___pthread_sigmask, %eax
102        int     $$0x80  /* should be sysenter? */
103        jc      L_$0_7  /* __pthread_sigmask failed */
104        addl    $$16,%esp
105
106	/* Copy syscall parameters to the stack - assume no more than 8
107	 * plus the return address */
108	/* do_syscall8 */
109	/* stack is currently aligned assuming 8 parameters */
110	movl	12(%ebp), %edx
111	movl	OFFSET_x86_ESP(%edx), %edx	/* edx = simulated ESP */
112	movl	28+4(%edx), %eax
113	pushl	%eax
114	movl	24+4(%edx), %eax
115	pushl	%eax
116	movl	20+4(%edx), %eax
117	pushl	%eax
118	movl	16+4(%edx), %eax
119	pushl	%eax
120	movl	12+4(%edx), %eax
121	pushl	%eax
122	movl	8+4(%edx), %eax
123	pushl	%eax
124	movl	4+4(%edx), %eax
125	pushl	%eax
126	movl	0+4(%edx), %eax
127	pushl	%eax
128	/* return address */
129	movl	0(%edx), %eax
130	pushl	%eax
131
132	/* Put syscall number in eax */
133	movl	8(%ebp), %eax
134
135	/* If eip==2, then the syscall was either just about to start,
136	   or was interrupted and the kernel was restarting it. */
137L_$0_2:
138.if $0 == UNIX
139	int	$$0x80		/* UNIX (GrP fixme should be sysenter?) */
140.elseif $0 == MACH
141	int	$$0x81
142.elseif $0 == MDEP
143	int	$$0x82
144.else
145	error$0 x
146.endif
147
148L_$0_3:	/* In the range [3, 4), the syscall result is in %eax and %edx and C,
149           but hasn't been committed to the thread state. */
150	setc	0(%esp)				/* stash returned carry flag */
151	movl	12(%ebp), %ecx
152	movl	%eax, OFFSET_x86_EAX(%ecx)	/* save EAX to vex */
153	movl	%edx, OFFSET_x86_EDX(%ecx)	/* save EDX to vex */
154.if $0 == UNIX
155	/* UNIX: save carry flag to vex */
156	subl	$$12, %esp
157	movl	%ecx, 4(%esp)
158	movl	$$0, 0(%esp)
159	movb	12(%esp), %al
160	movb	%al, 0(%esp)
161	call	_LibVEX_GuestX86_put_eflag_c
162	addl	$$12, %esp
163.endif
164
165L_$0_4:	/* Re-block signals.  If eip is in [4,5), then the syscall is
166           complete and we needn't worry about it. */
167        /* Set up for __pthread_sigmask(SIG_SETMASK, postmask, NULL) */
168        pushl   $$0
169        pushl   20(%ebp)
170        pushl   $$VKI_SIG_SETMASK
171        pushl   $$0xcafef00d    /* totally fake return address */
172        movl    $$__NR___pthread_sigmask, %eax
173        int     $$0x80  /* should be sysenter? */
174        jc      L_$0_7  /* __pthread_sigmask failed */
175        addl    $$16,%esp
176
177L_$0_5:	/* now safe from signals */
178	movl	$$0, %eax       /* SUCCESS */
179	movl	%ebp, %esp
180	popl	%ebp
181	ret
182
183L_$0_7: /* failure: return 0x8000 | error code */
184        /* Note that we enter here with %esp being 16 too low
185           (4 extra words on the stack).  But because we're nuking
186           the stack frame now, that doesn't matter. */
187        andl    $$0x7FFF, %eax
188        orl     $$0x8000, %eax
189	movl	%ebp, %esp
190	popl	%ebp
191	ret
192
193.endmacro
194
195
196.globl ML_(do_syscall_for_client_unix_WRK)
197ML_(do_syscall_for_client_unix_WRK):
198	DO_SYSCALL UNIX
199
200.globl ML_(do_syscall_for_client_mach_WRK)
201ML_(do_syscall_for_client_mach_WRK):
202	DO_SYSCALL MACH
203
204.globl ML_(do_syscall_for_client_mdep_WRK)
205ML_(do_syscall_for_client_mdep_WRK):
206	DO_SYSCALL MDEP
207
208.data
209/* export the ranges so that
210   VG_(fixup_guest_state_after_syscall_interrupted) can do the
211   right thing */
212
213/* eg MK_L_SCLASS_N(UNIX,99) produces L_3_99
214   since UNIX is #defined to 3 at the top of this file */
215#define FOO(scclass,labelno) L_##scclass##_##labelno
216#define MK_L_SCCLASS_N(scclass,labelno) FOO(scclass,labelno)
217
218.globl ML_(blksys_setup_MACH)
219.globl ML_(blksys_restart_MACH)
220.globl ML_(blksys_complete_MACH)
221.globl ML_(blksys_committed_MACH)
222.globl ML_(blksys_finished_MACH)
223ML_(blksys_setup_MACH):	.long MK_L_SCCLASS_N(MACH,1)
224ML_(blksys_restart_MACH):	.long MK_L_SCCLASS_N(MACH,2)
225ML_(blksys_complete_MACH):	.long MK_L_SCCLASS_N(MACH,3)
226ML_(blksys_committed_MACH):	.long MK_L_SCCLASS_N(MACH,4)
227ML_(blksys_finished_MACH):	.long MK_L_SCCLASS_N(MACH,5)
228
229.globl ML_(blksys_setup_MDEP)
230.globl ML_(blksys_restart_MDEP)
231.globl ML_(blksys_complete_MDEP)
232.globl ML_(blksys_committed_MDEP)
233.globl ML_(blksys_finished_MDEP)
234ML_(blksys_setup_MDEP):	.long MK_L_SCCLASS_N(MDEP,1)
235ML_(blksys_restart_MDEP):	.long MK_L_SCCLASS_N(MDEP,2)
236ML_(blksys_complete_MDEP):	.long MK_L_SCCLASS_N(MDEP,3)
237ML_(blksys_committed_MDEP):	.long MK_L_SCCLASS_N(MDEP,4)
238ML_(blksys_finished_MDEP):	.long MK_L_SCCLASS_N(MDEP,5)
239
240.globl ML_(blksys_setup_UNIX)
241.globl ML_(blksys_restart_UNIX)
242.globl ML_(blksys_complete_UNIX)
243.globl ML_(blksys_committed_UNIX)
244.globl ML_(blksys_finished_UNIX)
245ML_(blksys_setup_UNIX):	.long MK_L_SCCLASS_N(UNIX,1)
246ML_(blksys_restart_UNIX):	.long MK_L_SCCLASS_N(UNIX,2)
247ML_(blksys_complete_UNIX):	.long MK_L_SCCLASS_N(UNIX,3)
248ML_(blksys_committed_UNIX):	.long MK_L_SCCLASS_N(UNIX,4)
249ML_(blksys_finished_UNIX):	.long MK_L_SCCLASS_N(UNIX,5)
250
251#endif // defined(VGP_x86_darwin)
252
253/* Let the linker know we don't need an executable stack */
254MARK_STACK_NO_EXEC
255
256/*--------------------------------------------------------------------*/
257/*--- end                                                          ---*/
258/*--------------------------------------------------------------------*/
259