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 #include <compat/ia32/ia32_signal.h>
48 #include <compat/ia32/ia32_util.h>
49
50 extern const char *cloudabi32_syscallnames[];
51 extern struct sysent cloudabi32_sysent[];
52
53 extern unsigned long ia32_maxssiz;
54
55 static int
cloudabi32_fixup_tcb(register_t ** stack_base,struct image_params * imgp)56 cloudabi32_fixup_tcb(register_t **stack_base, struct image_params *imgp)
57 {
58 int error;
59 uint32_t args[2];
60
61 /* Place auxiliary vector and TCB on the stack. */
62 error = cloudabi32_fixup(stack_base, imgp);
63 if (error != 0)
64 return (error);
65
66 /*
67 * On i386, the TCB is referred to by %gs:0. Reuse the empty
68 * space normally used by the return address (args[0]) to store
69 * a single element array, containing a pointer to the TCB. %gs
70 * base will point to this.
71 *
72 * Also let the first argument of the entry point (args[1])
73 * refer to the auxiliary vector, which is stored right after
74 * the TCB.
75 */
76 args[0] = (uintptr_t)*stack_base;
77 args[1] = (uintptr_t)*stack_base +
78 roundup(sizeof(cloudabi32_tcb_t), sizeof(register_t));
79 *stack_base -= howmany(sizeof(args), sizeof(register_t));
80 return (copyout(args, *stack_base, sizeof(args)));
81 }
82
83 static void
cloudabi32_proc_setregs(struct thread * td,struct image_params * imgp,unsigned long stack)84 cloudabi32_proc_setregs(struct thread *td, struct image_params *imgp,
85 unsigned long stack)
86 {
87
88 ia32_setregs(td, imgp, stack);
89 (void)cpu_set_user_tls(td, TO_PTR(stack));
90 }
91
92 static int
cloudabi32_fetch_syscall_args(struct thread * td)93 cloudabi32_fetch_syscall_args(struct thread *td)
94 {
95 struct trapframe *frame;
96 struct syscall_args *sa;
97 int error;
98
99 frame = td->td_frame;
100 sa = &td->td_sa;
101
102 /* Obtain system call number. */
103 sa->code = frame->tf_rax;
104 if (sa->code >= CLOUDABI32_SYS_MAXSYSCALL)
105 return (ENOSYS);
106 sa->callp = &cloudabi32_sysent[sa->code];
107 sa->narg = sa->callp->sy_narg;
108
109 /*
110 * Fetch system call arguments.
111 *
112 * The vDSO has already made sure that the arguments are
113 * eight-byte aligned. Pointers and size_t parameters are
114 * zero-extended. This makes it possible to copy in the
115 * arguments directly. As long as the call doesn't use 32-bit
116 * data structures, we can just invoke the same system call
117 * implementation used by 64-bit processes.
118 */
119 error = copyin((void *)frame->tf_rcx, sa->args,
120 sa->narg * sizeof(sa->args[0]));
121 if (error != 0)
122 return (error);
123
124 /* Default system call return values. */
125 td->td_retval[0] = 0;
126 td->td_retval[1] = 0;
127 return (0);
128 }
129
130 static void
cloudabi32_set_syscall_retval(struct thread * td,int error)131 cloudabi32_set_syscall_retval(struct thread *td, int error)
132 {
133 struct trapframe *frame = td->td_frame;
134
135 switch (error) {
136 case 0:
137 /*
138 * System call succeeded.
139 *
140 * Simply copy out the 64-bit return values into the
141 * same buffer provided for system call arguments. The
142 * vDSO will copy them to the right spot, truncating
143 * pointers and size_t values to 32 bits.
144 */
145 frame->tf_rax = copyout(td->td_retval, (void *)frame->tf_rcx,
146 sizeof(td->td_retval)) == 0 ? 0 : CLOUDABI_EFAULT;
147 break;
148 case ERESTART:
149 /* Restart system call. */
150 frame->tf_rip -= frame->tf_err;
151 frame->tf_r10 = frame->tf_rcx;
152 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
153 break;
154 case EJUSTRETURN:
155 break;
156 default:
157 /* System call returned an error. */
158 frame->tf_rax = cloudabi_convert_errno(error);
159 break;
160 }
161 }
162
163 static void
cloudabi32_schedtail(struct thread * td)164 cloudabi32_schedtail(struct thread *td)
165 {
166 struct trapframe *frame = td->td_frame;
167 register_t retval[2];
168
169 /* Return values for processes returning from fork. */
170 if ((td->td_pflags & TDP_FORKING) != 0) {
171 retval[0] = CLOUDABI_PROCESS_CHILD;
172 retval[1] = td->td_tid;
173 copyout(retval, (void *)frame->tf_rcx, sizeof(retval));
174 }
175 }
176
177 int
cloudabi32_thread_setregs(struct thread * td,const cloudabi32_threadattr_t * attr,uint32_t tcb)178 cloudabi32_thread_setregs(struct thread *td,
179 const cloudabi32_threadattr_t *attr, uint32_t tcb)
180 {
181 stack_t stack;
182 uint32_t args[3];
183 void *frameptr;
184 int error;
185
186 /* Perform standard register initialization. */
187 stack.ss_sp = TO_PTR(attr->stack);
188 stack.ss_size = attr->stack_len - sizeof(args);
189 cpu_set_upcall(td, TO_PTR(attr->entry_point), NULL, &stack);
190
191 /*
192 * Copy the arguments for the thread entry point onto the stack
193 * (args[1] and args[2]). Similar to process startup, use the
194 * otherwise unused return address (args[0]) for TLS.
195 */
196 args[0] = tcb;
197 args[1] = td->td_tid;
198 args[2] = attr->argument;
199 frameptr = (void *)td->td_frame->tf_rsp;
200 error = copyout(args, frameptr, sizeof(args));
201 if (error != 0)
202 return (error);
203
204 return (cpu_set_user_tls(td, frameptr));
205 }
206
207 static struct sysentvec cloudabi32_elf_sysvec = {
208 .sv_size = CLOUDABI32_SYS_MAXSYSCALL,
209 .sv_table = cloudabi32_sysent,
210 .sv_fixup = cloudabi32_fixup_tcb,
211 .sv_name = "CloudABI ELF32",
212 .sv_coredump = elf32_coredump,
213 .sv_minuser = FREEBSD32_MINUSER,
214 .sv_maxuser = FREEBSD32_MAXUSER,
215 .sv_stackprot = VM_PROT_READ | VM_PROT_WRITE,
216 .sv_copyout_strings = cloudabi32_copyout_strings,
217 .sv_setregs = cloudabi32_proc_setregs,
218 .sv_fixlimit = ia32_fixlimit,
219 .sv_maxssiz = &ia32_maxssiz,
220 .sv_flags = SV_ABI_CLOUDABI | SV_CAPSICUM | SV_IA32 | SV_ILP32,
221 .sv_set_syscall_retval = cloudabi32_set_syscall_retval,
222 .sv_fetch_syscall_args = cloudabi32_fetch_syscall_args,
223 .sv_syscallnames = cloudabi32_syscallnames,
224 .sv_schedtail = cloudabi32_schedtail,
225 };
226
227 INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec);
228
229 Elf32_Brandinfo cloudabi32_brand = {
230 .brand = ELFOSABI_CLOUDABI,
231 .machine = EM_386,
232 .sysvec = &cloudabi32_elf_sysvec,
233 .flags = BI_BRAND_ONLY_STATIC,
234 };
235