1/*-
2 * Copyright (c) 2015-2017 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 void
51cloudabi32_proc_setregs(struct thread *td, struct image_params *imgp,
52    unsigned long stack)
53{
54	struct trapframe *regs;
55
56	regs = td->td_frame;
57	memset(regs, 0, sizeof(*regs));
58	regs->tf_x[0] =
59	    stack + roundup(sizeof(cloudabi32_tcb_t), sizeof(register_t));
60	regs->tf_x[13] = STACKALIGN(stack);
61	regs->tf_elr = imgp->entry_addr;
62	regs->tf_spsr |= PSR_AARCH32;
63	(void)cpu_set_user_tls(td, TO_PTR(stack));
64}
65
66static int
67cloudabi32_fetch_syscall_args(struct thread *td)
68{
69	struct trapframe *frame;
70	struct syscall_args *sa;
71	int error;
72
73	frame = td->td_frame;
74	sa = &td->td_sa;
75
76	/* Obtain system call number. */
77	sa->code = frame->tf_x[0];
78	if (sa->code >= CLOUDABI32_SYS_MAXSYSCALL)
79		return (ENOSYS);
80	sa->callp = &cloudabi32_sysent[sa->code];
81	sa->narg = sa->callp->sy_narg;
82
83	/*
84	 * Fetch system call arguments.
85	 *
86	 * The vDSO has already made sure that the arguments are
87	 * eight-byte aligned. Pointers and size_t parameters are
88	 * zero-extended. This makes it possible to copy in the
89	 * arguments directly. As long as the call doesn't use 32-bit
90	 * data structures, we can just invoke the same system call
91	 * implementation used by 64-bit processes.
92	 */
93	error = copyin((void *)frame->tf_x[2], sa->args,
94	    sa->narg * sizeof(sa->args[0]));
95	if (error != 0)
96		return (error);
97
98	/* Default system call return values. */
99	td->td_retval[0] = 0;
100	td->td_retval[1] = 0;
101	return (0);
102}
103
104static void
105cloudabi32_set_syscall_retval(struct thread *td, int error)
106{
107	struct trapframe *frame = td->td_frame;
108
109	switch (error) {
110	case 0:
111		/*
112		 * System call succeeded.
113		 *
114		 * Simply copy out the 64-bit return values into the
115		 * same buffer provided for system call arguments. The
116		 * vDSO will copy them to the right spot, truncating
117		 * pointers and size_t values to 32 bits.
118		 */
119		if (copyout(td->td_retval, (void *)frame->tf_x[2],
120		    sizeof(td->td_retval)) == 0) {
121			frame->tf_x[0] = 0;
122			frame->tf_spsr &= ~PSR_C;
123		} else {
124			frame->tf_x[0] = CLOUDABI_EFAULT;
125			frame->tf_spsr |= PSR_C;
126		}
127		break;
128	case ERESTART:
129		/* Restart system call. */
130		frame->tf_elr -= 4;
131		break;
132	case EJUSTRETURN:
133		break;
134	default:
135		/* System call returned an error. */
136		frame->tf_x[0] = cloudabi_convert_errno(error);
137		frame->tf_spsr |= PSR_C;
138		break;
139	}
140}
141
142static void
143cloudabi32_schedtail(struct thread *td)
144{
145	struct trapframe *frame = td->td_frame;
146	register_t retval[2];
147
148	/* Return values for processes returning from fork. */
149	if ((td->td_pflags & TDP_FORKING) != 0) {
150		retval[0] = CLOUDABI_PROCESS_CHILD;
151		retval[1] = td->td_tid;
152		copyout(retval, (void *)frame->tf_x[2], sizeof(retval));
153	}
154	frame->tf_spsr |= PSR_AARCH32;
155}
156
157int
158cloudabi32_thread_setregs(struct thread *td,
159    const cloudabi32_threadattr_t *attr, uint32_t tcb)
160{
161	struct trapframe *frame;
162
163	/*
164	 * Pass in the thread ID of the new thread and the argument
165	 * pointer provided by the parent thread in as arguments to the
166	 * entry point.
167	 */
168	frame = td->td_frame;
169	memset(frame, 0, sizeof(*frame));
170	frame->tf_x[0] = td->td_tid;
171	frame->tf_x[1] = attr->argument;
172	frame->tf_x[13] = STACKALIGN(attr->stack + attr->stack_len);
173	frame->tf_elr = attr->entry_point;
174
175	/* Set up TLS. */
176	return (cpu_set_user_tls(td, TO_PTR(tcb)));
177}
178
179static struct sysentvec cloudabi32_elf_sysvec = {
180	.sv_size		= CLOUDABI32_SYS_MAXSYSCALL,
181	.sv_table		= cloudabi32_sysent,
182	.sv_fixup		= cloudabi32_fixup,
183	.sv_name		= "CloudABI ELF32",
184	.sv_coredump		= elf32_coredump,
185	.sv_minuser		= VM_MIN_ADDRESS,
186	.sv_maxuser		= (uintmax_t)1 << 32,
187	.sv_stackprot		= VM_PROT_READ | VM_PROT_WRITE,
188	.sv_copyout_strings	= cloudabi32_copyout_strings,
189	.sv_setregs		= cloudabi32_proc_setregs,
190	.sv_flags		= SV_ABI_CLOUDABI | SV_CAPSICUM | SV_ILP32,
191	.sv_set_syscall_retval	= cloudabi32_set_syscall_retval,
192	.sv_fetch_syscall_args	= cloudabi32_fetch_syscall_args,
193	.sv_syscallnames	= cloudabi32_syscallnames,
194	.sv_schedtail		= cloudabi32_schedtail,
195};
196
197INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec);
198
199Elf32_Brandinfo cloudabi32_brand = {
200	.brand		= ELFOSABI_CLOUDABI,
201	.machine	= EM_ARM,
202	.sysvec		= &cloudabi32_elf_sysvec,
203	.flags		= BI_BRAND_ONLY_STATIC,
204};
205