Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | /*
* Common signal handling code for both 32 and 64 bits
*
* Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
* Extracted from signal_32.c and signal_64.c
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file README.legal in the main directory of
* this archive for more details.
*/
#include <linux/tracehook.h>
#include <linux/signal.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "signal.h"
/* Log an error when sending an unhandled signal to a process. Controlled
* through debug.exception-trace sysctl.
*/
int show_unhandled_signals = 0;
/*
* Allocate space for the signal frame
*/
void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
size_t frame_size, int is_32)
{
unsigned long oldsp, newsp;
/* Default to using normal stack */
oldsp = get_clean_sp(regs, is_32);
/* Check for alt stack */
if ((ka->sa.sa_flags & SA_ONSTACK) &&
current->sas_ss_size && !on_sig_stack(oldsp))
oldsp = (current->sas_ss_sp + current->sas_ss_size);
/* Get aligned frame */
newsp = (oldsp - frame_size) & ~0xFUL;
/* Check access */
if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp))
return NULL;
return (void __user *)newsp;
}
/*
* Restore the user process's signal mask
*/
void restore_sigmask(sigset_t *set)
{
sigdelsetmask(set, ~_BLOCKABLE);
spin_lock_irq(¤t->sighand->siglock);
current->blocked = *set;
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
}
static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
int has_handler)
{
unsigned long ret = regs->gpr[3];
int restart = 1;
/* syscall ? */
if (TRAP(regs) != 0x0C00)
return;
/* error signalled ? */
if (!(regs->ccr & 0x10000000))
return;
switch (ret) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
/* ERESTARTNOHAND means that the syscall should only be
* restarted if there was no handler for the signal, and since
* we only get here if there is a handler, we dont restart.
*/
restart = !has_handler;
break;
case ERESTARTSYS:
/* ERESTARTSYS means to restart the syscall if there is no
* handler or the handler was registered with SA_RESTART
*/
restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
break;
case ERESTARTNOINTR:
/* ERESTARTNOINTR means that the syscall should be
* called again after the signal handler returns.
*/
break;
default:
return;
}
if (restart) {
if (ret == ERESTART_RESTARTBLOCK)
regs->gpr[0] = __NR_restart_syscall;
else
regs->gpr[3] = regs->orig_gpr3;
regs->nip -= 4;
regs->result = 0;
} else {
regs->result = -EINTR;
regs->gpr[3] = EINTR;
regs->ccr |= 0x10000000;
}
}
static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
{
siginfo_t info;
int signr;
struct k_sigaction ka;
int ret;
int is32 = is_32bit_task();
if (current_thread_info()->local_flags & _TLF_RESTORE_SIGMASK)
oldset = ¤t->saved_sigmask;
else if (!oldset)
oldset = ¤t->blocked;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
/* Is there any syscall restart business here ? */
check_syscall_restart(regs, &ka, signr > 0);
if (signr <= 0) {
struct thread_info *ti = current_thread_info();
/* No signal to deliver -- put the saved sigmask back */
if (ti->local_flags & _TLF_RESTORE_SIGMASK) {
ti->local_flags &= ~_TLF_RESTORE_SIGMASK;
sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
}
return 0; /* no signals delivered */
}
/*
* Reenable the DABR before delivering the signal to
* user space. The DABR will have been cleared if it
* triggered inside the kernel.
*/
if (current->thread.dabr) {
set_dabr(current->thread.dabr);
#if defined(CONFIG_BOOKE)
mtspr(SPRN_DBCR0, current->thread.dbcr0);
#endif
}
if (is32) {
if (ka.sa.sa_flags & SA_SIGINFO)
ret = handle_rt_signal32(signr, &ka, &info, oldset,
regs);
else
ret = handle_signal32(signr, &ka, &info, oldset,
regs);
} else {
ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
}
if (ret) {
spin_lock_irq(¤t->sighand->siglock);
sigorsets(¤t->blocked, ¤t->blocked,
&ka.sa.sa_mask);
if (!(ka.sa.sa_flags & SA_NODEFER))
sigaddset(¤t->blocked, signr);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
/*
* A signal was successfully delivered; the saved sigmask is in
* its frame, and we can clear the TLF_RESTORE_SIGMASK flag.
*/
current_thread_info()->local_flags &= ~_TLF_RESTORE_SIGMASK;
/*
* Let tracing know that we've done the handler setup.
*/
tracehook_signal_handler(signr, &info, &ka, regs,
test_thread_flag(TIF_SINGLESTEP));
}
return ret;
}
void do_signal(struct pt_regs *regs, unsigned long thread_info_flags)
{
if (thread_info_flags & _TIF_SIGPENDING)
do_signal_pending(NULL, regs);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
unsigned long r5, unsigned long r6, unsigned long r7,
unsigned long r8, struct pt_regs *regs)
{
return do_sigaltstack(uss, uoss, regs->gpr[1]);
}
|