xref: /openbmc/linux/arch/mips/kernel/signal_n32.c (revision 05bcf503)
1 /*
2  * Copyright (C) 2003 Broadcom Corporation
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version 2
7  * of the License, or (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
17  */
18 #include <linux/cache.h>
19 #include <linux/sched.h>
20 #include <linux/mm.h>
21 #include <linux/smp.h>
22 #include <linux/kernel.h>
23 #include <linux/signal.h>
24 #include <linux/errno.h>
25 #include <linux/wait.h>
26 #include <linux/ptrace.h>
27 #include <linux/unistd.h>
28 #include <linux/compat.h>
29 #include <linux/bitops.h>
30 
31 #include <asm/abi.h>
32 #include <asm/asm.h>
33 #include <asm/cacheflush.h>
34 #include <asm/compat-signal.h>
35 #include <asm/sim.h>
36 #include <asm/uaccess.h>
37 #include <asm/ucontext.h>
38 #include <asm/fpu.h>
39 #include <asm/cpu-features.h>
40 #include <asm/war.h>
41 #include <asm/vdso.h>
42 
43 #include "signal-common.h"
44 
45 /*
46  * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
47  */
48 #define __NR_N32_restart_syscall	6214
49 
50 extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *);
51 extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);
52 
53 
54 /* IRIX compatible stack_t  */
55 typedef struct sigaltstack32 {
56 	s32 ss_sp;
57 	compat_size_t ss_size;
58 	int ss_flags;
59 } stack32_t;
60 
61 struct ucontextn32 {
62 	u32                 uc_flags;
63 	s32                 uc_link;
64 	stack32_t           uc_stack;
65 	struct sigcontext   uc_mcontext;
66 	compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
67 };
68 
69 struct rt_sigframe_n32 {
70 	u32 rs_ass[4];			/* argument save space for o32 */
71 	u32 rs_pad[2];			/* Was: signal trampoline */
72 	struct compat_siginfo rs_info;
73 	struct ucontextn32 rs_uc;
74 };
75 
76 extern void sigset_from_compat(sigset_t *set, compat_sigset_t *compat);
77 
78 asmlinkage int sysn32_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
79 {
80 	compat_sigset_t __user *unewset;
81 	compat_sigset_t uset;
82 	size_t sigsetsize;
83 	sigset_t newset;
84 
85 	/* XXX Don't preclude handling different sized sigset_t's.  */
86 	sigsetsize = regs.regs[5];
87 	if (sigsetsize != sizeof(sigset_t))
88 		return -EINVAL;
89 
90 	unewset = (compat_sigset_t __user *) regs.regs[4];
91 	if (copy_from_user(&uset, unewset, sizeof(uset)))
92 		return -EFAULT;
93 	sigset_from_compat(&newset, &uset);
94 	return sigsuspend(&newset);
95 }
96 
97 asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
98 {
99 	struct rt_sigframe_n32 __user *frame;
100 	mm_segment_t old_fs;
101 	sigset_t set;
102 	stack_t st;
103 	s32 sp;
104 	int sig;
105 
106 	frame = (struct rt_sigframe_n32 __user *) regs.regs[29];
107 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
108 		goto badframe;
109 	if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
110 		goto badframe;
111 
112 	set_current_blocked(&set);
113 
114 	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
115 	if (sig < 0)
116 		goto badframe;
117 	else if (sig)
118 		force_sig(sig, current);
119 
120 	/* The ucontext contains a stack32_t, so we must convert!  */
121 	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
122 		goto badframe;
123 	st.ss_sp = (void __user *)(long) sp;
124 	if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
125 		goto badframe;
126 	if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
127 		goto badframe;
128 
129 	/* It is more difficult to avoid calling this function than to
130 	   call it and ignore errors.  */
131 	old_fs = get_fs();
132 	set_fs(KERNEL_DS);
133 	do_sigaltstack((stack_t __user *)&st, NULL, regs.regs[29]);
134 	set_fs(old_fs);
135 
136 
137 	/*
138 	 * Don't let your children do this ...
139 	 */
140 	__asm__ __volatile__(
141 		"move\t$29, %0\n\t"
142 		"j\tsyscall_exit"
143 		:/* no outputs */
144 		:"r" (&regs));
145 	/* Unreached */
146 
147 badframe:
148 	force_sig(SIGSEGV, current);
149 }
150 
151 static int setup_rt_frame_n32(void *sig_return, struct k_sigaction *ka,
152 	struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info)
153 {
154 	struct rt_sigframe_n32 __user *frame;
155 	int err = 0;
156 	s32 sp;
157 
158 	frame = get_sigframe(ka, regs, sizeof(*frame));
159 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
160 		goto give_sigsegv;
161 
162 	/* Create siginfo.  */
163 	err |= copy_siginfo_to_user32(&frame->rs_info, info);
164 
165 	/* Create the ucontext.  */
166 	err |= __put_user(0, &frame->rs_uc.uc_flags);
167 	err |= __put_user(0, &frame->rs_uc.uc_link);
168 	sp = (int) (long) current->sas_ss_sp;
169 	err |= __put_user(sp,
170 	                  &frame->rs_uc.uc_stack.ss_sp);
171 	err |= __put_user(sas_ss_flags(regs->regs[29]),
172 	                  &frame->rs_uc.uc_stack.ss_flags);
173 	err |= __put_user(current->sas_ss_size,
174 	                  &frame->rs_uc.uc_stack.ss_size);
175 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
176 	err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
177 
178 	if (err)
179 		goto give_sigsegv;
180 
181 	/*
182 	 * Arguments to signal handler:
183 	 *
184 	 *   a0 = signal number
185 	 *   a1 = 0 (should be cause)
186 	 *   a2 = pointer to ucontext
187 	 *
188 	 * $25 and c0_epc point to the signal handler, $29 points to
189 	 * the struct rt_sigframe.
190 	 */
191 	regs->regs[ 4] = signr;
192 	regs->regs[ 5] = (unsigned long) &frame->rs_info;
193 	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
194 	regs->regs[29] = (unsigned long) frame;
195 	regs->regs[31] = (unsigned long) sig_return;
196 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
197 
198 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
199 	       current->comm, current->pid,
200 	       frame, regs->cp0_epc, regs->regs[31]);
201 
202 	return 0;
203 
204 give_sigsegv:
205 	force_sigsegv(signr, current);
206 	return -EFAULT;
207 }
208 
209 struct mips_abi mips_abi_n32 = {
210 	.setup_rt_frame	= setup_rt_frame_n32,
211 	.rt_signal_return_offset =
212 		offsetof(struct mips_vdso, n32_rt_signal_trampoline),
213 	.restart	= __NR_N32_restart_syscall
214 };
215