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
36struct 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
44struct 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
51asmlinkage 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
86badframe:
87	force_sig(SIGSEGV);
88}
89
90static 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
137struct 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