xref: /openbmc/linux/arch/mips/kernel/signal_n32.c (revision 87c2ce3b)
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/sched.h>
21 #include <linux/mm.h>
22 #include <linux/smp.h>
23 #include <linux/smp_lock.h>
24 #include <linux/kernel.h>
25 #include <linux/signal.h>
26 #include <linux/errno.h>
27 #include <linux/wait.h>
28 #include <linux/ptrace.h>
29 #include <linux/unistd.h>
30 #include <linux/compat.h>
31 #include <linux/bitops.h>
32 
33 #include <asm/asm.h>
34 #include <asm/cacheflush.h>
35 #include <asm/sim.h>
36 #include <asm/uaccess.h>
37 #include <asm/ucontext.h>
38 #include <asm/system.h>
39 #include <asm/fpu.h>
40 #include <asm/cpu-features.h>
41 #include <asm/war.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_rt_sigreturn		6211
49 #define __NR_N32_restart_syscall	6214
50 
51 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
52 
53 /* IRIX compatible stack_t  */
54 typedef struct sigaltstack32 {
55 	s32 ss_sp;
56 	compat_size_t ss_size;
57 	int ss_flags;
58 } stack32_t;
59 
60 struct ucontextn32 {
61 	u32                 uc_flags;
62 	s32                 uc_link;
63 	stack32_t           uc_stack;
64 	struct sigcontext   uc_mcontext;
65 	sigset_t            uc_sigmask;   /* mask last for extensibility */
66 };
67 
68 struct rt_sigframe_n32 {
69 	u32 rs_ass[4];			/* argument save space for o32 */
70 #if ICACHE_REFILLS_WORKAROUND_WAR
71 	u32 rs_pad[2];
72 #else
73 	u32 rs_code[2];			/* signal trampoline */
74 #endif
75 	struct siginfo rs_info;
76 	struct ucontextn32 rs_uc;
77 #if ICACHE_REFILLS_WORKAROUND_WAR
78 	u32 rs_code[8] ____cacheline_aligned;		/* signal trampoline */
79 #endif
80 };
81 
82 save_static_function(sysn32_rt_sigreturn);
83 __attribute_used__ noinline static void
84 _sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
85 {
86 	struct rt_sigframe_n32 *frame;
87 	sigset_t set;
88 	stack_t st;
89 	s32 sp;
90 
91 	frame = (struct rt_sigframe_n32 *) regs.regs[29];
92 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
93 		goto badframe;
94 	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
95 		goto badframe;
96 
97 	sigdelsetmask(&set, ~_BLOCKABLE);
98 	spin_lock_irq(&current->sighand->siglock);
99 	current->blocked = set;
100 	recalc_sigpending();
101 	spin_unlock_irq(&current->sighand->siglock);
102 
103 	if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
104 		goto badframe;
105 
106 	/* The ucontext contains a stack32_t, so we must convert!  */
107 	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
108 		goto badframe;
109 	st.ss_size = (long) sp;
110 	if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
111 		goto badframe;
112 	if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
113 		goto badframe;
114 
115 	/* It is more difficult to avoid calling this function than to
116 	   call it and ignore errors.  */
117 	do_sigaltstack(&st, NULL, regs.regs[29]);
118 
119 	/*
120 	 * Don't let your children do this ...
121 	 */
122 	__asm__ __volatile__(
123 		"move\t$29, %0\n\t"
124 		"j\tsyscall_exit"
125 		:/* no outputs */
126 		:"r" (&regs));
127 	/* Unreached */
128 
129 badframe:
130 	force_sig(SIGSEGV, current);
131 }
132 
133 int setup_rt_frame_n32(struct k_sigaction * ka,
134 	struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info)
135 {
136 	struct rt_sigframe_n32 *frame;
137 	int err = 0;
138 	s32 sp;
139 
140 	frame = get_sigframe(ka, regs, sizeof(*frame));
141 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
142 		goto give_sigsegv;
143 
144 	install_sigtramp(frame->rs_code, __NR_N32_rt_sigreturn);
145 
146 	/* Create siginfo.  */
147 	err |= copy_siginfo_to_user(&frame->rs_info, info);
148 
149 	/* Create the ucontext.  */
150 	err |= __put_user(0, &frame->rs_uc.uc_flags);
151 	err |= __put_user(0, &frame->rs_uc.uc_link);
152         sp = (int) (long) current->sas_ss_sp;
153 	err |= __put_user(sp,
154 	                  &frame->rs_uc.uc_stack.ss_sp);
155 	err |= __put_user(sas_ss_flags(regs->regs[29]),
156 	                  &frame->rs_uc.uc_stack.ss_flags);
157 	err |= __put_user(current->sas_ss_size,
158 	                  &frame->rs_uc.uc_stack.ss_size);
159 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
160 	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
161 
162 	if (err)
163 		goto give_sigsegv;
164 
165 	/*
166 	 * Arguments to signal handler:
167 	 *
168 	 *   a0 = signal number
169 	 *   a1 = 0 (should be cause)
170 	 *   a2 = pointer to ucontext
171 	 *
172 	 * $25 and c0_epc point to the signal handler, $29 points to
173 	 * the struct rt_sigframe.
174 	 */
175 	regs->regs[ 4] = signr;
176 	regs->regs[ 5] = (unsigned long) &frame->rs_info;
177 	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
178 	regs->regs[29] = (unsigned long) frame;
179 	regs->regs[31] = (unsigned long) frame->rs_code;
180 	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
181 
182 #if DEBUG_SIG
183 	printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
184 	       current->comm, current->pid,
185 	       frame, regs->cp0_epc, regs->regs[31]);
186 #endif
187 	return 1;
188 
189 give_sigsegv:
190 	force_sigsegv(signr, current);
191 	return 0;
192 }
193