1 /* Machine-dependent details of interruptible RPC messaging. i386 version.
2 Copyright (C) 1995-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19
20 /* Note that we must mark OPTION and TIMEOUT as outputs of this operation,
21 to indicate that the signal thread might mutate them as part
22 of sending us to a signal handler. */
23
24 #define INTR_MSG_TRAP(msg, option, send_size, rcv_size, rcv_name, timeout, notify, cancel_p, intr_port_p) \
25 ({ \
26 error_t err; \
27 asm (".globl _hurd_intr_rpc_msg_about_to\n" \
28 ".globl _hurd_intr_rpc_msg_setup_done\n" \
29 ".globl _hurd_intr_rpc_msg_in_trap\n" \
30 /* Clear eax before we do the check for cancel below. This is to
31 detect eax being set to non-zero (actually MACH_SEND_INTERRUPTED)
32 from the outside (namely, _hurdsig_abort_rpcs), which signals us
33 to skip the trap we were about to enter. */ \
34 " xorl %0, %0\n" \
35 "_hurd_intr_rpc_msg_about_to:" \
36 /* We need to make a last check of cancel, in case we got interrupted
37 right before _hurd_intr_rpc_msg_about_to. */ \
38 " cmpl $0, %5\n" \
39 " jz _hurd_intr_rpc_msg_do\n" \
40 /* We got interrupted, note so and return EINTR. */ \
41 " movl $0, %3\n" \
42 " movl %6, %0\n" \
43 " jmp _hurd_intr_rpc_msg_sp_restored\n" \
44 "_hurd_intr_rpc_msg_do:" \
45 /* Ok, push the mach_msg_trap arguments and a fake return address. */ \
46 " pushl 24(%4)\n" \
47 " pushl %2\n" \
48 " pushl 16(%4)\n" \
49 " pushl 12(%4)\n" \
50 " pushl 8(%4)\n" \
51 " pushl %1\n" \
52 " pushl (%4)\n" \
53 " pushl $0\n" \
54 "_hurd_intr_rpc_msg_setup_done:" \
55 /* From here on, it is safe to make us jump over the syscall. Now
56 check if we have been told to skip the syscall while running
57 the above. */ \
58 " test %0, %0\n" \
59 " jnz _hurd_intr_rpc_msg_in_trap\n" \
60 /* Do the actual syscall. */ \
61 " movl $-25, %%eax\n" \
62 "_hurd_intr_rpc_msg_do_trap: lcall $7, $0 # status in %0\n" \
63 "_hurd_intr_rpc_msg_in_trap:" \
64 /* Ok, clean the arguments and update OPTION and TIMEOUT. */ \
65 " addl $8, %%esp\n" \
66 " popl %1\n" \
67 " addl $12, %%esp\n" \
68 " popl %2\n" \
69 " addl $4, %%esp\n" \
70 "_hurd_intr_rpc_msg_sp_restored:" \
71 : "=&a" (err), "+r" (option), "+r" (timeout), "=m" (*intr_port_p) \
72 : "r" (&msg), "m" (*cancel_p), "i" (EINTR)); \
73 err; \
74 })
75
76 #include "hurdfault.h"
77
78 /* This cannot be an inline function because it calls setjmp. */
79 #define SYSCALL_EXAMINE(state, callno) \
80 ({ \
81 struct { unsigned int c[2]; } *p = (void *) ((state)->eip - 7); \
82 int result; \
83 if (_hurdsig_catch_memory_fault (p)) \
84 return 0; \
85 if (result = p->c[0] == 0x0000009a && (p->c[1] & 0x00ffffff) == 0x00000700) \
86 /* The PC is just after an `lcall $7,$0' instruction. \
87 This is a system call in progress; %eax holds the call number. */ \
88 *(callno) = (state)->eax; \
89 _hurdsig_end_catch_fault (); \
90 result; \
91 })
92
93
94 struct mach_msg_trap_args
95 {
96 void *retaddr; /* Address mach_msg_trap will return to. */
97 /* This is the order of arguments to mach_msg_trap. */
98 mach_msg_header_t *msg;
99 mach_msg_option_t option;
100 mach_msg_size_t send_size;
101 mach_msg_size_t rcv_size;
102 mach_port_t rcv_name;
103 mach_msg_timeout_t timeout;
104 mach_port_t notify;
105 };
106
107
108 /* This cannot be an inline function because it calls setjmp. */
109 #define MSG_EXAMINE(state, msgid, rcvname, send_name, opt, tmout) \
110 ({ \
111 const struct mach_msg_trap_args *args = (const void *) (state)->uesp; \
112 mach_msg_header_t *msg; \
113 _hurdsig_catch_memory_fault (args) ? -1 : \
114 ({ \
115 msg = args->msg; \
116 *(opt) = args->option; \
117 *(tmout) = args->timeout; \
118 *(rcvname) = args->rcv_name; \
119 _hurdsig_end_catch_fault (); \
120 if (msg == 0) \
121 { \
122 *(send_name) = MACH_PORT_NULL; \
123 *(msgid) = 0; \
124 } \
125 else \
126 { \
127 if (_hurdsig_catch_memory_fault (msg)) \
128 return -1; \
129 *(send_name) = msg->msgh_remote_port; \
130 *(msgid) = msg->msgh_id; \
131 _hurdsig_end_catch_fault (); \
132 } \
133 0; \
134 }); \
135 })