1 /*-
2 * Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28
29 #include <sys/param.h>
30 #include <sys/imgact.h>
31 #include <sys/kernel.h>
32 #include <sys/proc.h>
33 #include <sys/sysent.h>
34
35 #include <vm/vm.h>
36 #include <vm/pmap.h>
37
38 #include <machine/frame.h>
39 #include <machine/pcb.h>
40 #include <machine/vmparam.h>
41
42 #include <compat/cloudabi/cloudabi_util.h>
43
44 #include <compat/cloudabi32/cloudabi32_syscall.h>
45 #include <compat/cloudabi32/cloudabi32_util.h>
46
47 extern const char *cloudabi32_syscallnames[];
48 extern struct sysent cloudabi32_sysent[];
49
50 static int
51 cloudabi32_fixup_tcb(uintptr_t *stack_base, struct image_params *imgp)
52 {
53 int error;
54 uint32_t args[2];
55
56 /* Place auxiliary vector and TCB on the stack. */
57 error = cloudabi32_fixup(stack_base, imgp);
58 if (error != 0)
59 return (error);
60
61 /*
62 * On i386, the TCB is referred to by %gs:0. Reuse the empty
63 * space normally used by the return address (args[0]) to store
64 * a single element array, containing a pointer to the TCB. %gs
65 * base will point to this.
66 *
67 * Also let the first argument of the entry point (args[1])
68 * refer to the auxiliary vector, which is stored right after
69 * the TCB.
70 */
71 args[0] = *stack_base;
72 args[1] = *stack_base +
73 roundup(sizeof(cloudabi32_tcb_t), sizeof(register_t));
74 *stack_base -= roundup(sizeof(args), sizeof(register_t));
75 return (copyout(args, (void *)*stack_base, sizeof(args)));
76 }
77
78 static void
79 cloudabi32_proc_setregs(struct thread *td, struct image_params *imgp,
80 uintptr_t stack)
81 {
82
83 exec_setregs(td, imgp, stack);
84 (void)cpu_set_user_tls(td, TO_PTR(stack));
85 }
86
87 static int
88 cloudabi32_fetch_syscall_args(struct thread *td)
89 {
90 struct trapframe *frame;
91 struct syscall_args *sa;
92 int error;
93
94 frame = td->td_frame;
95 sa = &td->td_sa;
96
97 /* Obtain system call number. */
98 sa->code = frame->tf_eax;
99 if (sa->code >= CLOUDABI32_SYS_MAXSYSCALL)
100 return (ENOSYS);
101 sa->callp = &cloudabi32_sysent[sa->code];
102
103 /* Fetch system call arguments from the stack. */
104 error = copyin((void *)(frame->tf_esp + 4), sa->args,
105 sa->callp->sy_narg * sizeof(sa->args[0]));
106 if (error != 0)
107 return (error);
108
109 /* Default system call return values. */
110 td->td_retval[0] = 0;
111 td->td_retval[1] = frame->tf_edx;
112 return (0);
113 }
114
115 static void
116 cloudabi32_set_syscall_retval(struct thread *td, int error)
117 {
118 struct trapframe *frame = td->td_frame;
119
120 switch (error) {
121 case 0:
122 /* System call succeeded. */
123 frame->tf_eax = td->td_retval[0];
124 frame->tf_edx = td->td_retval[1];
125 frame->tf_eflags &= ~PSL_C;
126 break;
127 case ERESTART:
128 /* Restart system call. */
129 frame->tf_eip -= frame->tf_err;
130 break;
131 case EJUSTRETURN:
132 break;
133 default:
134 /* System call returned an error. */
135 frame->tf_eax = cloudabi_convert_errno(error);
136 frame->tf_eflags |= PSL_C;
137 break;
138 }
139 }
140
141 static void
142 cloudabi32_schedtail(struct thread *td)
143 {
144 struct trapframe *frame = td->td_frame;
145
146 /* Initial register values for processes returning from fork. */
147 frame->tf_eax = CLOUDABI_PROCESS_CHILD;
148 frame->tf_edx = td->td_tid;
149 }
150
151 int
152 cloudabi32_thread_setregs(struct thread *td,
153 const cloudabi32_threadattr_t *attr, uint32_t tcb)
154 {
155 stack_t stack;
156 uint32_t args[3];
157 void *frameptr;
158 int error;
159
160 /* Perform standard register initialization. */
161 stack.ss_sp = TO_PTR(attr->stack);
162 stack.ss_size = attr->stack_len - sizeof(args);
163 cpu_set_upcall(td, TO_PTR(attr->entry_point), NULL, &stack);
164
165 /*
166 * Copy the arguments for the thread entry point onto the stack
167 * (args[1] and args[2]). Similar to process startup, use the
168 * otherwise unused return address (args[0]) for TLS.
169 */
170 args[0] = tcb;
171 args[1] = td->td_tid;
172 args[2] = attr->argument;
173 frameptr = (void *)td->td_frame->tf_esp;
174 error = copyout(args, frameptr, sizeof(args));
175 if (error != 0)
176 return (error);
177
178 return (cpu_set_user_tls(td, frameptr));
179 }
180
181 static struct sysentvec cloudabi32_elf_sysvec = {
182 .sv_size = CLOUDABI32_SYS_MAXSYSCALL,
183 .sv_table = cloudabi32_sysent,
184 .sv_fixup = cloudabi32_fixup_tcb,
185 .sv_name = "CloudABI ELF32",
186 .sv_coredump = elf32_coredump,
187 .sv_minuser = VM_MIN_ADDRESS,
188 .sv_maxuser = VM_MAXUSER_ADDRESS,
189 .sv_stackprot = VM_PROT_READ | VM_PROT_WRITE,
190 .sv_copyout_strings = cloudabi32_copyout_strings,
191 .sv_setregs = cloudabi32_proc_setregs,
192 .sv_flags = SV_ABI_CLOUDABI | SV_CAPSICUM | SV_IA32 | SV_ILP32,
193 .sv_set_syscall_retval = cloudabi32_set_syscall_retval,
194 .sv_fetch_syscall_args = cloudabi32_fetch_syscall_args,
195 .sv_syscallnames = cloudabi32_syscallnames,
196 .sv_schedtail = cloudabi32_schedtail,
197 };
198
199 INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec);
200
201 Elf32_Brandinfo cloudabi32_brand = {
202 .brand = ELFOSABI_CLOUDABI,
203 .machine = EM_386,
204 .sysvec = &cloudabi32_elf_sysvec,
205 .flags = BI_BRAND_ONLY_STATIC,
206 };
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