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

source code of linux/arch/mips/kernel/signal_n32.c