cloudabi32_sysvec.c revision 321343 
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: stable/11/sys/i386/cloudabi32/cloudabi32_sysvec.c 321343 2017-07-21 18:06:57Z kib $");
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
47extern const char *cloudabi32_syscallnames[];
48extern struct sysent cloudabi32_sysent[];
49
50static int
51cloudabi32_fixup_tcb(register_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] = (uintptr_t)*stack_base;
72	args[1] = (uintptr_t)*stack_base +
73	    roundup(sizeof(cloudabi32_tcb_t), sizeof(register_t));
74	*stack_base -= howmany(sizeof(args), sizeof(register_t));
75	return (copyout(args, *stack_base, sizeof(args)));
76}
77
78static void
79cloudabi32_proc_setregs(struct thread *td, struct image_params *imgp,
80    unsigned long stack)
81{
82
83	exec_setregs(td, imgp, stack);
84	(void)cpu_set_user_tls(td, (void *)stack);
85}
86
87static int
88cloudabi32_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	sa->narg = sa->callp->sy_narg;
103
104	/* Fetch system call arguments from the stack. */
105	error = copyin((void *)(frame->tf_esp + 4), sa->args,
106	    sa->narg * sizeof(sa->args[0]));
107	if (error != 0)
108		return (error);
109
110	/* Default system call return values. */
111	td->td_retval[0] = 0;
112	td->td_retval[1] = frame->tf_edx;
113	return (0);
114}
115
116static void
117cloudabi32_set_syscall_retval(struct thread *td, int error)
118{
119	struct trapframe *frame = td->td_frame;
120
121	switch (error) {
122	case 0:
123		/* System call succeeded. */
124		frame->tf_eax = td->td_retval[0];
125		frame->tf_edx = td->td_retval[1];
126		frame->tf_eflags &= ~PSL_C;
127		break;
128	case ERESTART:
129		/* Restart system call. */
130		frame->tf_eip -= frame->tf_err;
131		break;
132	case EJUSTRETURN:
133		break;
134	default:
135		/* System call returned an error. */
136		frame->tf_eax = cloudabi_convert_errno(error);
137		frame->tf_eflags |= PSL_C;
138		break;
139	}
140}
141
142static void
143cloudabi32_schedtail(struct thread *td)
144{
145	struct trapframe *frame = td->td_frame;
146
147	/* Initial register values for processes returning from fork. */
148	frame->tf_eax = CLOUDABI_PROCESS_CHILD;
149	frame->tf_edx = td->td_tid;
150}
151
152int
153cloudabi32_thread_setregs(struct thread *td,
154    const cloudabi32_threadattr_t *attr, uint32_t tcb)
155{
156	stack_t stack;
157	uint32_t args[3];
158	void *frameptr;
159	int error;
160
161	/* Perform standard register initialization. */
162	stack.ss_sp = TO_PTR(attr->stack);
163	stack.ss_size = attr->stack_len - sizeof(args);
164	cpu_set_upcall(td, TO_PTR(attr->entry_point), NULL, &stack);
165
166	/*
167	 * Copy the arguments for the thread entry point onto the stack
168	 * (args[1] and args[2]). Similar to process startup, use the
169	 * otherwise unused return address (args[0]) for TLS.
170	 */
171	args[0] = tcb;
172	args[1] = td->td_tid;
173	args[2] = attr->argument;
174	frameptr = (void *)td->td_frame->tf_esp;
175	error = copyout(args, frameptr, sizeof(args));
176	if (error != 0)
177		return (error);
178
179	return (cpu_set_user_tls(td, frameptr));
180}
181
182static struct sysentvec cloudabi32_elf_sysvec = {
183	.sv_size		= CLOUDABI32_SYS_MAXSYSCALL,
184	.sv_table		= cloudabi32_sysent,
185	.sv_fixup		= cloudabi32_fixup_tcb,
186	.sv_name		= "CloudABI ELF32",
187	.sv_coredump		= elf32_coredump,
188	.sv_pagesize		= PAGE_SIZE,
189	.sv_minuser		= VM_MIN_ADDRESS,
190	.sv_maxuser		= VM_MAXUSER_ADDRESS,
191	.sv_stackprot		= VM_PROT_READ | VM_PROT_WRITE,
192	.sv_copyout_strings	= cloudabi32_copyout_strings,
193	.sv_setregs		= cloudabi32_proc_setregs,
194	.sv_flags		= SV_ABI_CLOUDABI | SV_CAPSICUM | SV_IA32 | SV_ILP32,
195	.sv_set_syscall_retval	= cloudabi32_set_syscall_retval,
196	.sv_fetch_syscall_args	= cloudabi32_fetch_syscall_args,
197	.sv_syscallnames	= cloudabi32_syscallnames,
198	.sv_schedtail		= cloudabi32_schedtail,
199};
200
201INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec);
202
203Elf32_Brandinfo cloudabi32_brand = {
204	.brand		= ELFOSABI_CLOUDABI,
205	.machine	= EM_386,
206	.sysvec		= &cloudabi32_elf_sysvec,
207	.flags		= BI_BRAND_ONLY_STATIC,
208};
209