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  1/*
  2 * arch/score/kernel/signal.c
  3 *
  4 * Score Processor version.
  5 *
  6 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
  7 *  Chen Liqin <liqin.chen@sunplusct.com>
  8 *  Lennox Wu <lennox.wu@sunplusct.com>
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of the GNU General Public License as published by
 12 * the Free Software Foundation; either version 2 of the License, or
 13 * (at your option) any later version.
 14 *
 15 * This program is distributed in the hope that it will be useful,
 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 18 * GNU General Public License for more details.
 19 *
 20 * You should have received a copy of the GNU General Public License
 21 * along with this program; if not, see the file COPYING, or write
 22 * to the Free Software Foundation, Inc.,
 23 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 24 */
 25
 26#include <linux/errno.h>
 27#include <linux/signal.h>
 28#include <linux/ptrace.h>
 29#include <linux/unistd.h>
 30#include <linux/uaccess.h>
 31#include <linux/tracehook.h>
 32
 33#include <asm/cacheflush.h>
 34#include <asm/syscalls.h>
 35#include <asm/ucontext.h>
 36
 37struct rt_sigframe {
 38	u32 rs_ass[4];		/* argument save space */
 39	u32 rs_code[2];		/* signal trampoline */
 40	struct siginfo rs_info;
 41	struct ucontext rs_uc;
 42};
 43
 44static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 45{
 46	int err = 0;
 47	unsigned long reg;
 48
 49	reg = regs->cp0_epc; err |= __put_user(reg, &sc->sc_pc);
 50	err |= __put_user(regs->cp0_psr, &sc->sc_psr);
 51	err |= __put_user(regs->cp0_condition, &sc->sc_condition);
 52
 53
 54#define save_gp_reg(i) {				\
 55	reg = regs->regs[i];				\
 56	err |= __put_user(reg, &sc->sc_regs[i]);	\
 57} while (0)
 58	save_gp_reg(0); save_gp_reg(1); save_gp_reg(2);
 59	save_gp_reg(3); save_gp_reg(4); save_gp_reg(5);
 60	save_gp_reg(6);	save_gp_reg(7); save_gp_reg(8);
 61	save_gp_reg(9); save_gp_reg(10); save_gp_reg(11);
 62	save_gp_reg(12); save_gp_reg(13); save_gp_reg(14);
 63	save_gp_reg(15); save_gp_reg(16); save_gp_reg(17);
 64	save_gp_reg(18); save_gp_reg(19); save_gp_reg(20);
 65	save_gp_reg(21); save_gp_reg(22); save_gp_reg(23);
 66	save_gp_reg(24); save_gp_reg(25); save_gp_reg(26);
 67	save_gp_reg(27); save_gp_reg(28); save_gp_reg(29);
 68#undef save_gp_reg
 69
 70	reg = regs->ceh; err |= __put_user(reg, &sc->sc_mdceh);
 71	reg = regs->cel; err |= __put_user(reg, &sc->sc_mdcel);
 72	err |= __put_user(regs->cp0_ecr, &sc->sc_ecr);
 73	err |= __put_user(regs->cp0_ema, &sc->sc_ema);
 74
 75	return err;
 76}
 77
 78static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 79{
 80	int err = 0;
 81	u32 reg;
 82
 83	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 84	err |= __get_user(regs->cp0_condition, &sc->sc_condition);
 85
 86	err |= __get_user(reg, &sc->sc_mdceh);
 87	regs->ceh = (int) reg;
 88	err |= __get_user(reg, &sc->sc_mdcel);
 89	regs->cel = (int) reg;
 90
 91	err |= __get_user(reg, &sc->sc_psr);
 92	regs->cp0_psr = (int) reg;
 93	err |= __get_user(reg, &sc->sc_ecr);
 94	regs->cp0_ecr = (int) reg;
 95	err |= __get_user(reg, &sc->sc_ema);
 96	regs->cp0_ema = (int) reg;
 97
 98#define restore_gp_reg(i) do {				\
 99	err |= __get_user(reg, &sc->sc_regs[i]);	\
100	regs->regs[i] = reg;				\
101} while (0)
102	restore_gp_reg(0); restore_gp_reg(1); restore_gp_reg(2);
103	restore_gp_reg(3); restore_gp_reg(4); restore_gp_reg(5);
104	restore_gp_reg(6); restore_gp_reg(7); restore_gp_reg(8);
105	restore_gp_reg(9); restore_gp_reg(10); restore_gp_reg(11);
106	restore_gp_reg(12); restore_gp_reg(13); restore_gp_reg(14);
107	restore_gp_reg(15); restore_gp_reg(16); restore_gp_reg(17);
108	restore_gp_reg(18); restore_gp_reg(19);	restore_gp_reg(20);
109	restore_gp_reg(21); restore_gp_reg(22); restore_gp_reg(23);
110	restore_gp_reg(24); restore_gp_reg(25); restore_gp_reg(26);
111	restore_gp_reg(27); restore_gp_reg(28); restore_gp_reg(29);
112#undef restore_gp_reg
113
114	return err;
115}
116
117/*
118 * Determine which stack to use..
119 */
120static void __user *get_sigframe(struct k_sigaction *ka,
121			struct pt_regs *regs, size_t frame_size)
122{
123	unsigned long sp;
124
125	/* Default to using normal stack */
126	sp = regs->regs[0];
127	sp -= 32;
128
129	/* This is the X/Open sanctioned signal stack switching.  */
130	if ((ka->sa.sa_flags & SA_ONSTACK) && (!on_sig_stack(sp)))
131		sp = current->sas_ss_sp + current->sas_ss_size;
132
133	return (void __user*)((sp - frame_size) & ~7);
134}
135
136asmlinkage long
137score_rt_sigreturn(struct pt_regs *regs)
138{
139	struct rt_sigframe __user *frame;
140	sigset_t set;
141	int sig;
142
143	/* Always make any pending restarted system calls return -EINTR */
144	current_thread_info()->restart_block.fn = do_no_restart_syscall;
145
146	frame = (struct rt_sigframe __user *) regs->regs[0];
147	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
148		goto badframe;
149	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
150		goto badframe;
151
152	set_current_blocked(&set);
153
154	sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
155	if (sig < 0)
156		goto badframe;
157	else if (sig)
158		force_sig(sig, current);
159
160	if (restore_altstack(&frame->rs_uc.uc_stack))
161		goto badframe;
162	regs->is_syscall = 0;
163
164	__asm__ __volatile__(
165		"mv\tr0, %0\n\t"
166		"la\tr8, syscall_exit\n\t"
167		"br\tr8\n\t"
168		: : "r" (regs) : "r8");
169
170badframe:
171	force_sig(SIGSEGV, current);
172
173	return 0;
174}
175
176static int setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
177		int signr, sigset_t *set, siginfo_t *info)
178{
179	struct rt_sigframe __user *frame;
180	int err = 0;
181
182	frame = get_sigframe(ka, regs, sizeof(*frame));
183	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
184		goto give_sigsegv;
185
186	/*
187	 * Set up the return code ...
188	 *
189	 *         li      v0, __NR_rt_sigreturn
190	 *         syscall
191	 */
192	err |= __put_user(0x87788000 + __NR_rt_sigreturn*2,
193			frame->rs_code + 0);
194	err |= __put_user(0x80008002, frame->rs_code + 1);
195	flush_cache_sigtramp((unsigned long) frame->rs_code);
196
197	err |= copy_siginfo_to_user(&frame->rs_info, info);
198	err |= __put_user(0, &frame->rs_uc.uc_flags);
199	err |= __put_user(NULL, &frame->rs_uc.uc_link);
200	err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[0]);
201	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
202	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
203
204	if (err)
205		goto give_sigsegv;
206
207	regs->regs[0] = (unsigned long) frame;
208	regs->regs[3] = (unsigned long) frame->rs_code;
209	regs->regs[4] = signr;
210	regs->regs[5] = (unsigned long) &frame->rs_info;
211	regs->regs[6] = (unsigned long) &frame->rs_uc;
212	regs->regs[29] = (unsigned long) ka->sa.sa_handler;
213	regs->cp0_epc = (unsigned long) ka->sa.sa_handler;
214
215	return 0;
216
217give_sigsegv:
218	force_sigsegv(signr, current);
219	return -EFAULT;
220}
221
222static void handle_signal(unsigned long sig, siginfo_t *info,
223	struct k_sigaction *ka, struct pt_regs *regs)
224{
225	if (regs->is_syscall) {
226		switch (regs->regs[4]) {
227		case ERESTART_RESTARTBLOCK:
228		case ERESTARTNOHAND:
229			regs->regs[4] = EINTR;
230			break;
231		case ERESTARTSYS:
232			if (!(ka->sa.sa_flags & SA_RESTART)) {
233				regs->regs[4] = EINTR;
234				break;
235			}
236		case ERESTARTNOINTR:
237			regs->regs[4] = regs->orig_r4;
238			regs->regs[7] = regs->orig_r7;
239			regs->cp0_epc -= 8;
240		}
241
242		regs->is_syscall = 0;
243	}
244
245	/*
246	 * Set up the stack frame
247	 */
248	if (setup_rt_frame(ka, regs, sig, sigmask_to_save(), info) < 0)
249		return;
250
251	signal_delivered(sig, info, ka, regs, 0);
252}
253
254static void do_signal(struct pt_regs *regs)
255{
256	struct k_sigaction ka;
257	siginfo_t info;
258	int signr;
259
260	/*
261	 * We want the common case to go fast, which is why we may in certain
262	 * cases get here from kernel mode. Just return without doing anything
263	 * if so.
264	 */
265	if (!user_mode(regs))
266		return;
267
268	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
269	if (signr > 0) {
270		/* Actually deliver the signal.  */
271		handle_signal(signr, &info, &ka, regs);
272		return;
273	}
274
275	if (regs->is_syscall) {
276		if (regs->regs[4] == ERESTARTNOHAND ||
277		    regs->regs[4] == ERESTARTSYS ||
278		    regs->regs[4] == ERESTARTNOINTR) {
279			regs->regs[4] = regs->orig_r4;
280			regs->regs[7] = regs->orig_r7;
281			regs->cp0_epc -= 8;
282		}
283
284		if (regs->regs[4] == ERESTART_RESTARTBLOCK) {
285			regs->regs[27] = __NR_restart_syscall;
286			regs->regs[4] = regs->orig_r4;
287			regs->regs[7] = regs->orig_r7;
288			regs->cp0_epc -= 8;
289		}
290
291		regs->is_syscall = 0;	/* Don't deal with this again.  */
292	}
293
294	/*
295	 * If there's no signal to deliver, we just put the saved sigmask
296	 * back
297	 */
298	restore_saved_sigmask();
299}
300
301/*
302 * notification of userspace execution resumption
303 * - triggered by the TIF_WORK_MASK flags
304 */
305asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
306				__u32 thread_info_flags)
307{
308	/* deal with pending signal delivery */
309	if (thread_info_flags & _TIF_SIGPENDING)
310		do_signal(regs);
311	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
312		clear_thread_flag(TIF_NOTIFY_RESUME);
313		tracehook_notify_resume(regs);
314	}
315}