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