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
47extern const char *cloudabi32_syscallnames[];
48extern struct sysent cloudabi32_sysent[];
49
50static int
51cloudabi32_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
78static void
79cloudabi32_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
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
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
115static void
116cloudabi32_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
141static void
142cloudabi32_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
151int
152cloudabi32_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
181static 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
199INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec);
200
201Elf32_Brandinfo cloudabi32_brand = {
202	.brand		= ELFOSABI_CLOUDABI,
203	.machine	= EM_386,
204	.sysvec		= &cloudabi32_elf_sysvec,
205	.flags		= BI_BRAND_ONLY_STATIC,
206};
207