1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2003 Broadcom Corporation
4 */
5 #include <linux/cache.h>
6 #include <linux/sched.h>
7 #include <linux/mm.h>
8 #include <linux/smp.h>
9 #include <linux/kernel.h>
10 #include <linux/signal.h>
11 #include <linux/errno.h>
12 #include <linux/wait.h>
13 #include <linux/ptrace.h>
14 #include <linux/unistd.h>
15 #include <linux/compat.h>
16 #include <linux/bitops.h>
17
18 #include <asm/abi.h>
19 #include <asm/asm.h>
20 #include <asm/cacheflush.h>
21 #include <asm/compat-signal.h>
22 #include <asm/sim.h>
23 #include <linux/uaccess.h>
24 #include <asm/ucontext.h>
25 #include <asm/fpu.h>
26 #include <asm/cpu-features.h>
27 #include <asm/war.h>
28
29 #include "signal-common.h"
30
31 /*
32 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
33 */
34 #define __NR_N32_restart_syscall 6214
35
36 extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *);
37 extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);
38
39 struct ucontextn32 {
40 u32 uc_flags;
41 s32 uc_link;
42 compat_stack_t uc_stack;
43 struct sigcontext uc_mcontext;
44 compat_sigset_t uc_sigmask; /* mask last for extensibility */
45 };
46
47 struct rt_sigframe_n32 {
48 u32 rs_ass[4]; /* argument save space for o32 */
49 u32 rs_pad[2]; /* Was: signal trampoline */
50 struct compat_siginfo rs_info;
51 struct ucontextn32 rs_uc;
52 };
53
sysn32_rt_sigreturn(void)54 asmlinkage void sysn32_rt_sigreturn(void)
55 {
56 struct rt_sigframe_n32 __user *frame;
57 struct pt_regs *regs;
58 sigset_t set;
59 int sig;
60
61 regs = current_pt_regs();
62 frame = (struct rt_sigframe_n32 __user *)regs->regs[29];
63 if (!access_ok(frame, sizeof(*frame)))
64 goto badframe;
65 if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
66 goto badframe;
67
68 set_current_blocked(&set);
69
70 sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
71 if (sig < 0)
72 goto badframe;
73 else if (sig)
74 force_sig(sig);
75
76 if (compat_restore_altstack(&frame->rs_uc.uc_stack))
77 goto badframe;
78
79 /*
80 * Don't let your children do this ...
81 */
82 __asm__ __volatile__(
83 "move\t$29, %0\n\t"
84 "j\tsyscall_exit"
85 : /* no outputs */
86 : "r" (regs));
87 /* Unreached */
88
89 badframe:
90 force_sig(SIGSEGV);
91 }
92
setup_rt_frame_n32(void * sig_return,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)93 static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
94 struct pt_regs *regs, sigset_t *set)
95 {
96 struct rt_sigframe_n32 __user *frame;
97 int err = 0;
98
99 frame = get_sigframe(ksig, regs, sizeof(*frame));
100 if (!access_ok(frame, sizeof (*frame)))
101 return -EFAULT;
102
103 /* Create siginfo. */
104 err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
105
106 /* Create the ucontext. */
107 err |= __put_user(0, &frame->rs_uc.uc_flags);
108 err |= __put_user(0, &frame->rs_uc.uc_link);
109 err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
110 err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
111 err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
112
113 if (err)
114 return -EFAULT;
115
116 /*
117 * Arguments to signal handler:
118 *
119 * a0 = signal number
120 * a1 = 0 (should be cause)
121 * a2 = pointer to ucontext
122 *
123 * $25 and c0_epc point to the signal handler, $29 points to
124 * the struct rt_sigframe.
125 */
126 regs->regs[ 4] = ksig->sig;
127 regs->regs[ 5] = (unsigned long) &frame->rs_info;
128 regs->regs[ 6] = (unsigned long) &frame->rs_uc;
129 regs->regs[29] = (unsigned long) frame;
130 regs->regs[31] = (unsigned long) sig_return;
131 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
132
133 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
134 current->comm, current->pid,
135 frame, regs->cp0_epc, regs->regs[31]);
136
137 return 0;
138 }
139
140 struct mips_abi mips_abi_n32 = {
141 .setup_rt_frame = setup_rt_frame_n32,
142 .restart = __NR_N32_restart_syscall,
143
144 .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
145 .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
146 .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
147
148 .vdso = &vdso_image_n32,
149 };
150