xref: /openbmc/linux/arch/mips/kernel/signal_n32.c (revision 2209fda3)
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 <linux/uaccess.h>
37 #include <asm/ucontext.h>
38 #include <asm/fpu.h>
39 #include <asm/cpu-features.h>
40 #include <asm/war.h>
41 
42 #include "signal-common.h"
43 
44 /*
45  * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
46  */
47 #define __NR_N32_restart_syscall	6214
48 
49 extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *);
50 extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);
51 
52 struct ucontextn32 {
53 	u32		    uc_flags;
54 	s32		    uc_link;
55 	compat_stack_t      uc_stack;
56 	struct sigcontext   uc_mcontext;
57 	compat_sigset_t	    uc_sigmask;	  /* mask last for extensibility */
58 };
59 
60 struct rt_sigframe_n32 {
61 	u32 rs_ass[4];			/* argument save space for o32 */
62 	u32 rs_pad[2];			/* Was: signal trampoline */
63 	struct compat_siginfo rs_info;
64 	struct ucontextn32 rs_uc;
65 };
66 
67 asmlinkage void sysn32_rt_sigreturn(void)
68 {
69 	struct rt_sigframe_n32 __user *frame;
70 	struct pt_regs *regs;
71 	sigset_t set;
72 	int sig;
73 
74 	regs = current_pt_regs();
75 	frame = (struct rt_sigframe_n32 __user *)regs->regs[29];
76 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
77 		goto badframe;
78 	if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
79 		goto badframe;
80 
81 	set_current_blocked(&set);
82 
83 	sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
84 	if (sig < 0)
85 		goto badframe;
86 	else if (sig)
87 		force_sig(sig, current);
88 
89 	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
90 		goto badframe;
91 
92 	/*
93 	 * Don't let your children do this ...
94 	 */
95 	__asm__ __volatile__(
96 		"move\t$29, %0\n\t"
97 		"j\tsyscall_exit"
98 		: /* no outputs */
99 		: "r" (regs));
100 	/* Unreached */
101 
102 badframe:
103 	force_sig(SIGSEGV, current);
104 }
105 
106 static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
107 			      struct pt_regs *regs, sigset_t *set)
108 {
109 	struct rt_sigframe_n32 __user *frame;
110 	int err = 0;
111 
112 	frame = get_sigframe(ksig, regs, sizeof(*frame));
113 	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
114 		return -EFAULT;
115 
116 	/* Create siginfo.  */
117 	err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
118 
119 	/* Create the ucontext.	 */
120 	err |= __put_user(0, &frame->rs_uc.uc_flags);
121 	err |= __put_user(0, &frame->rs_uc.uc_link);
122 	err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
123 	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
124 	err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
125 
126 	if (err)
127 		return -EFAULT;
128 
129 	/*
130 	 * Arguments to signal handler:
131 	 *
132 	 *   a0 = signal number
133 	 *   a1 = 0 (should be cause)
134 	 *   a2 = pointer to ucontext
135 	 *
136 	 * $25 and c0_epc point to the signal handler, $29 points to
137 	 * the struct rt_sigframe.
138 	 */
139 	regs->regs[ 4] = ksig->sig;
140 	regs->regs[ 5] = (unsigned long) &frame->rs_info;
141 	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
142 	regs->regs[29] = (unsigned long) frame;
143 	regs->regs[31] = (unsigned long) sig_return;
144 	regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
145 
146 	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
147 	       current->comm, current->pid,
148 	       frame, regs->cp0_epc, regs->regs[31]);
149 
150 	return 0;
151 }
152 
153 struct mips_abi mips_abi_n32 = {
154 	.setup_rt_frame = setup_rt_frame_n32,
155 	.restart	= __NR_N32_restart_syscall,
156 
157 	.off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
158 	.off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
159 	.off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
160 
161 	.vdso		= &vdso_image_n32,
162 };
163