1 /* Machine-dependent details of interruptible RPC messaging. i386 version.
2 Copyright (C) 1995-2022 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_cx_sp\n" \
29 ".globl _hurd_intr_rpc_msg_do_trap\n" \
30 ".globl _hurd_intr_rpc_msg_in_trap\n" \
31 ".globl _hurd_intr_rpc_msg_sp_restored\n" \
32 "_hurd_intr_rpc_msg_about_to:" \
33 /* We need to make a last check of cancel, in case we got interrupted
34 right before _hurd_intr_rpc_msg_about_to. */ \
35 " cmpl $0, %5\n" \
36 " jz _hurd_intr_rpc_msg_do\n" \
37 /* We got interrupted, note so and return EINTR. */ \
38 " movl $0, %3\n" \
39 " movl %6, %%eax\n" \
40 " jmp _hurd_intr_rpc_msg_sp_restored\n" \
41 "_hurd_intr_rpc_msg_do:" \
42 /* Ok, push the mach_msg_trap arguments. */ \
43 " pushl 24(%4)\n" \
44 " .cfi_adjust_cfa_offset 4\n" \
45 " pushl %2\n" \
46 " .cfi_adjust_cfa_offset 4\n" \
47 " pushl 16(%4)\n" \
48 " .cfi_adjust_cfa_offset 4\n" \
49 " pushl 12(%4)\n" \
50 " .cfi_adjust_cfa_offset 4\n" \
51 " pushl 8(%4)\n" \
52 " .cfi_adjust_cfa_offset 4\n" \
53 " pushl %1\n" \
54 " .cfi_adjust_cfa_offset 4\n" \
55 " pushl (%4)\n" \
56 " .cfi_adjust_cfa_offset 4\n" \
57 " pushl $0\n" \
58 " .cfi_adjust_cfa_offset 4\n" \
59 /* TODO: remove this ecx kludge, we don't need it any more */ \
60 " movl %%esp, %%ecx\n" \
61 "_hurd_intr_rpc_msg_cx_sp: 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 " .cfi_adjust_cfa_offset -8\n" \
67 " popl %1\n" \
68 " .cfi_adjust_cfa_offset -4\n" \
69 " addl $12, %%esp\n" \
70 " .cfi_adjust_cfa_offset -12\n" \
71 " popl %2\n" \
72 " .cfi_adjust_cfa_offset -4\n" \
73 " addl $4, %%esp\n" \
74 " .cfi_adjust_cfa_offset -4\n" \
75 "_hurd_intr_rpc_msg_sp_restored:" \
76 : "=a" (err), "+r" (option), "+r" (timeout), "=m" (*intr_port_p) \
77 : "r" (&msg), "m" (*cancel_p), "i" (EINTR) \
78 : "ecx"); \
79 err; \
80 })
81
82
83 static void inline
INTR_MSG_BACK_OUT(struct i386_thread_state * state)84 INTR_MSG_BACK_OUT (struct i386_thread_state *state)
85 {
86 extern const void _hurd_intr_rpc_msg_cx_sp;
87 if (state->eip >= (natural_t) &_hurd_intr_rpc_msg_cx_sp)
88 state->uesp = state->ecx;
89 else
90 state->ecx = state->uesp;
91 }
92
93 #include "hurdfault.h"
94
95 /* This cannot be an inline function because it calls setjmp. */
96 #define SYSCALL_EXAMINE(state, callno) \
97 ({ \
98 struct { unsigned int c[2]; } *p = (void *) ((state)->eip - 7); \
99 int result; \
100 if (_hurdsig_catch_memory_fault (p)) \
101 return 0; \
102 if (result = p->c[0] == 0x0000009a && (p->c[1] & 0x00ffffff) == 0x00000700) \
103 /* The PC is just after an `lcall $7,$0' instruction. \
104 This is a system call in progress; %eax holds the call number. */ \
105 *(callno) = (state)->eax; \
106 _hurdsig_end_catch_fault (); \
107 result; \
108 })
109
110
111 struct mach_msg_trap_args
112 {
113 void *retaddr; /* Address mach_msg_trap will return to. */
114 /* This is the order of arguments to mach_msg_trap. */
115 mach_msg_header_t *msg;
116 mach_msg_option_t option;
117 mach_msg_size_t send_size;
118 mach_msg_size_t rcv_size;
119 mach_port_t rcv_name;
120 mach_msg_timeout_t timeout;
121 mach_port_t notify;
122 };
123
124
125 /* This cannot be an inline function because it calls setjmp. */
126 #define MSG_EXAMINE(state, msgid, rcvname, send_name, opt, tmout) \
127 ({ \
128 const struct mach_msg_trap_args *args = (const void *) (state)->uesp; \
129 mach_msg_header_t *msg; \
130 _hurdsig_catch_memory_fault (args) ? -1 : \
131 ({ \
132 msg = args->msg; \
133 *(opt) = args->option; \
134 *(tmout) = args->timeout; \
135 *(rcvname) = args->rcv_name; \
136 _hurdsig_end_catch_fault (); \
137 if (msg == 0) \
138 { \
139 *(send_name) = MACH_PORT_NULL; \
140 *(msgid) = 0; \
141 } \
142 else \
143 { \
144 if (_hurdsig_catch_memory_fault (msg)) \
145 return -1; \
146 *(send_name) = msg->msgh_remote_port; \
147 *(msgid) = msg->msgh_id; \
148 _hurdsig_end_catch_fault (); \
149 } \
150 0; \
151 }); \
152 })
153