2 * Common signal handling code for both 32 and 64 bits
4 * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Corporation
5 * Extracted from signal_32.c and signal_64.c
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License. See the file README.legal in the main directory of
9 * this archive for more details.
12 #include <linux/tracehook.h>
13 #include <linux/signal.h>
14 #include <linux/uprobes.h>
15 #include <linux/key.h>
16 #include <linux/context_tracking.h>
17 #include <linux/livepatch.h>
18 #include <linux/syscalls.h>
19 #include <asm/hw_breakpoint.h>
20 #include <linux/uaccess.h>
21 #include <asm/switch_to.h>
22 #include <asm/unistd.h>
23 #include <asm/debug.h>
29 unsigned long copy_fpr_to_user(void __user *to,
30 struct task_struct *task)
35 /* save FPR copy to local buffer then write to the thread_struct */
36 for (i = 0; i < (ELF_NFPREG - 1) ; i++)
37 buf[i] = task->thread.TS_FPR(i);
38 buf[i] = task->thread.fp_state.fpscr;
39 return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
42 unsigned long copy_fpr_from_user(struct task_struct *task,
48 if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
50 for (i = 0; i < (ELF_NFPREG - 1) ; i++)
51 task->thread.TS_FPR(i) = buf[i];
52 task->thread.fp_state.fpscr = buf[i];
57 unsigned long copy_vsx_to_user(void __user *to,
58 struct task_struct *task)
60 u64 buf[ELF_NVSRHALFREG];
63 /* save FPR copy to local buffer then write to the thread_struct */
64 for (i = 0; i < ELF_NVSRHALFREG; i++)
65 buf[i] = task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
66 return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
69 unsigned long copy_vsx_from_user(struct task_struct *task,
72 u64 buf[ELF_NVSRHALFREG];
75 if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
77 for (i = 0; i < ELF_NVSRHALFREG ; i++)
78 task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
82 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
83 unsigned long copy_ckfpr_to_user(void __user *to,
84 struct task_struct *task)
89 /* save FPR copy to local buffer then write to the thread_struct */
90 for (i = 0; i < (ELF_NFPREG - 1) ; i++)
91 buf[i] = task->thread.TS_CKFPR(i);
92 buf[i] = task->thread.ckfp_state.fpscr;
93 return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
96 unsigned long copy_ckfpr_from_user(struct task_struct *task,
102 if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
104 for (i = 0; i < (ELF_NFPREG - 1) ; i++)
105 task->thread.TS_CKFPR(i) = buf[i];
106 task->thread.ckfp_state.fpscr = buf[i];
111 unsigned long copy_ckvsx_to_user(void __user *to,
112 struct task_struct *task)
114 u64 buf[ELF_NVSRHALFREG];
117 /* save FPR copy to local buffer then write to the thread_struct */
118 for (i = 0; i < ELF_NVSRHALFREG; i++)
119 buf[i] = task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET];
120 return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
123 unsigned long copy_ckvsx_from_user(struct task_struct *task,
126 u64 buf[ELF_NVSRHALFREG];
129 if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
131 for (i = 0; i < ELF_NVSRHALFREG ; i++)
132 task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
135 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
138 /* Log an error when sending an unhandled signal to a process. Controlled
139 * through debug.exception-trace sysctl.
142 int show_unhandled_signals = 1;
145 * Allocate space for the signal frame
147 static unsigned long get_tm_stackpointer(struct task_struct *tsk);
149 void __user *get_sigframe(struct ksignal *ksig, struct task_struct *tsk,
150 size_t frame_size, int is_32)
152 unsigned long oldsp, newsp;
153 unsigned long sp = get_tm_stackpointer(tsk);
155 /* Default to using normal stack */
157 oldsp = sp & 0x0ffffffffUL;
160 oldsp = sigsp(oldsp, ksig);
161 newsp = (oldsp - frame_size) & ~0xFUL;
163 return (void __user *)newsp;
166 static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
169 unsigned long ret = regs->gpr[3];
173 if (!trap_is_syscall(regs))
176 if (trap_norestart(regs))
179 /* error signalled ? */
180 if (trap_is_scv(regs)) {
181 /* 32-bit compat mode sign extend? */
182 if (!IS_ERR_VALUE(ret))
185 } else if (!(regs->ccr & 0x10000000)) {
190 case ERESTART_RESTARTBLOCK:
192 /* ERESTARTNOHAND means that the syscall should only be
193 * restarted if there was no handler for the signal, and since
194 * we only get here if there is a handler, we dont restart.
196 restart = !has_handler;
199 /* ERESTARTSYS means to restart the syscall if there is no
200 * handler or the handler was registered with SA_RESTART
202 restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
205 /* ERESTARTNOINTR means that the syscall should be
206 * called again after the signal handler returns.
213 if (ret == ERESTART_RESTARTBLOCK)
214 regs->gpr[0] = __NR_restart_syscall;
216 regs->gpr[3] = regs->orig_gpr3;
217 regs_add_return_ip(regs, -4);
220 if (trap_is_scv(regs)) {
221 regs->result = -EINTR;
222 regs->gpr[3] = -EINTR;
224 regs->result = -EINTR;
225 regs->gpr[3] = EINTR;
226 regs->ccr |= 0x10000000;
231 static void do_signal(struct task_struct *tsk)
233 sigset_t *oldset = sigmask_to_save();
234 struct ksignal ksig = { .sig = 0 };
237 BUG_ON(tsk != current);
241 /* Is there any syscall restart business here ? */
242 check_syscall_restart(tsk->thread.regs, &ksig.ka, ksig.sig > 0);
245 /* No signal to deliver -- put the saved sigmask back */
246 restore_saved_sigmask();
247 set_trap_norestart(tsk->thread.regs);
248 return; /* no signals delivered */
252 * Reenable the DABR before delivering the signal to
253 * user space. The DABR will have been cleared if it
254 * triggered inside the kernel.
256 if (!IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) {
259 for (i = 0; i < nr_wp_slots(); i++) {
260 if (tsk->thread.hw_brk[i].address && tsk->thread.hw_brk[i].type)
261 __set_breakpoint(i, &tsk->thread.hw_brk[i]);
265 /* Re-enable the breakpoints for the signal stack */
266 thread_change_pc(tsk, tsk->thread.regs);
268 rseq_signal_deliver(&ksig, tsk->thread.regs);
270 if (is_32bit_task()) {
271 if (ksig.ka.sa.sa_flags & SA_SIGINFO)
272 ret = handle_rt_signal32(&ksig, oldset, tsk);
274 ret = handle_signal32(&ksig, oldset, tsk);
276 ret = handle_rt_signal64(&ksig, oldset, tsk);
279 set_trap_norestart(tsk->thread.regs);
280 signal_setup_done(ret, &ksig, test_thread_flag(TIF_SINGLESTEP));
283 void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
285 if (thread_info_flags & _TIF_UPROBE)
286 uprobe_notify_resume(regs);
288 if (thread_info_flags & _TIF_PATCH_PENDING)
289 klp_update_patch_state(current);
291 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
292 BUG_ON(regs != current->thread.regs);
296 if (thread_info_flags & _TIF_NOTIFY_RESUME)
297 tracehook_notify_resume(regs);
300 static unsigned long get_tm_stackpointer(struct task_struct *tsk)
302 /* When in an active transaction that takes a signal, we need to be
303 * careful with the stack. It's possible that the stack has moved back
304 * up after the tbegin. The obvious case here is when the tbegin is
305 * called inside a function that returns before a tend. In this case,
306 * the stack is part of the checkpointed transactional memory state.
307 * If we write over this non transactionally or in suspend, we are in
308 * trouble because if we get a tm abort, the program counter and stack
309 * pointer will be back at the tbegin but our in memory stack won't be
312 * To avoid this, when taking a signal in an active transaction, we
313 * need to use the stack pointer from the checkpointed state, rather
314 * than the speculated state. This ensures that the signal context
315 * (written tm suspended) will be written below the stack required for
316 * the rollback. The transaction is aborted because of the treclaim,
317 * so any memory written between the tbegin and the signal will be
318 * rolled back anyway.
320 * For signals taken in non-TM or suspended mode, we use the
321 * normal/non-checkpointed stack pointer.
323 struct pt_regs *regs = tsk->thread.regs;
324 unsigned long ret = regs->gpr[1];
326 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
327 BUG_ON(tsk != current);
329 if (MSR_TM_ACTIVE(regs->msr)) {
331 tm_reclaim_current(TM_CAUSE_SIGNAL);
332 if (MSR_TM_TRANSACTIONAL(regs->msr))
333 ret = tsk->thread.ckpt_regs.gpr[1];
336 * If we treclaim, we must clear the current thread's TM bits
337 * before re-enabling preemption. Otherwise we might be
338 * preempted and have the live MSR[TS] changed behind our back
339 * (tm_recheckpoint_new_task() would recheckpoint). Besides, we
340 * enter the signal handler in non-transactional state.
342 regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK);
349 static const char fm32[] = KERN_INFO "%s[%d]: bad frame in %s: %p nip %08lx lr %08lx\n";
350 static const char fm64[] = KERN_INFO "%s[%d]: bad frame in %s: %p nip %016lx lr %016lx\n";
352 void signal_fault(struct task_struct *tsk, struct pt_regs *regs,
353 const char *where, void __user *ptr)
355 if (show_unhandled_signals)
356 printk_ratelimited(regs->msr & MSR_64BIT ? fm64 : fm32, tsk->comm,
357 task_pid_nr(tsk), where, ptr, regs->nip, regs->link);