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acrn-kernel/arch/s390/kernel/signal.c

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/*
* arch/s390/kernel/signal.c
*
* Copyright (C) IBM Corp. 1999,2006
* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
*
* Based on Intel version
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/lowcore.h>
#include "entry.h"
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
typedef struct
{
__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
struct sigcontext sc;
_sigregs sregs;
int signo;
__u8 retcode[S390_SYSCALL_SIZE];
} sigframe;
typedef struct
{
__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
__u8 retcode[S390_SYSCALL_SIZE];
struct siginfo info;
struct ucontext uc;
} rt_sigframe;
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int
sys_sigsuspend(int history0, int history1, old_sigset_t mask)
{
mask &= _BLOCKABLE;
spin_lock_irq(&current->sighand->siglock);
current->saved_sigmask = current->blocked;
siginitset(&current->blocked, mask);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
current->state = TASK_INTERRUPTIBLE;
schedule();
set_thread_flag(TIF_RESTORE_SIGMASK);
return -ERESTARTNOHAND;
}
asmlinkage long
sys_sigaction(int sig, const struct old_sigaction __user *act,
struct old_sigaction __user *oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
if (act) {
old_sigset_t mask;
if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
__get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
__get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
__get_user(mask, &act->sa_mask))
return -EFAULT;
siginitset(&new_ka.sa.sa_mask, mask);
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
__put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
return -EFAULT;
}
return ret;
}
asmlinkage long
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
struct pt_regs *regs = task_pt_regs(current);
return do_sigaltstack(uss, uoss, regs->gprs[15]);
}
/* Returns non-zero on fault. */
static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
_sigregs user_sregs;
save_access_regs(current->thread.acrs);
/* Copy a 'clean' PSW mask to the user to avoid leaking
information about whether PER is currently on. */
user_sregs.regs.psw.mask = PSW_MASK_MERGE(psw_user_bits, regs->psw.mask);
user_sregs.regs.psw.addr = regs->psw.addr;
memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
memcpy(&user_sregs.regs.acrs, current->thread.acrs,
sizeof(sregs->regs.acrs));
/*
* We have to store the fp registers to current->thread.fp_regs
* to merge them with the emulated registers.
*/
save_fp_regs(&current->thread.fp_regs);
memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
sizeof(s390_fp_regs));
return __copy_to_user(sregs, &user_sregs, sizeof(_sigregs));
}
/* Returns positive number on error */
static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
int err;
_sigregs user_sregs;
/* Alwys make any pending restarted system call return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
if (err)
return err;
regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask,
user_sregs.regs.psw.mask);
regs->psw.addr = PSW_ADDR_AMODE | user_sregs.regs.psw.addr;
memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
sizeof(sregs->regs.acrs));
restore_access_regs(current->thread.acrs);
memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
sizeof(s390_fp_regs));
current->thread.fp_regs.fpc &= FPC_VALID_MASK;
restore_fp_regs(&current->thread.fp_regs);
regs->trap = -1; /* disable syscall checks */
return 0;
}
asmlinkage long sys_sigreturn(void)
{
struct pt_regs *regs = task_pt_regs(current);
sigframe __user *frame = (sigframe __user *)regs->gprs[15];
sigset_t set;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (restore_sigregs(regs, &frame->sregs))
goto badframe;
return regs->gprs[2];
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage long sys_rt_sigreturn(void)
{
struct pt_regs *regs = task_pt_regs(current);
rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
sigset_t set;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (restore_sigregs(regs, &frame->uc.uc_mcontext))
goto badframe;
if (do_sigaltstack(&frame->uc.uc_stack, NULL,
regs->gprs[15]) == -EFAULT)
goto badframe;
return regs->gprs[2];
badframe:
force_sig(SIGSEGV, current);
return 0;
}
/*
* Set up a signal frame.
*/
/*
* Determine which stack to use..
*/
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
{
unsigned long sp;
/* Default to using normal stack */
sp = regs->gprs[15];
/* Overflow on alternate signal stack gives SIGSEGV. */
if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
return (void __user *) -1UL;
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (! sas_ss_flags(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
}
/* This is the legacy signal stack switching. */
else if (!user_mode(regs) &&
!(ka->sa.sa_flags & SA_RESTORER) &&
ka->sa.sa_restorer) {
sp = (unsigned long) ka->sa.sa_restorer;
}
return (void __user *)((sp - frame_size) & -8ul);
}
static inline int map_signal(int sig)
{
if (current_thread_info()->exec_domain
&& current_thread_info()->exec_domain->signal_invmap
&& sig < 32)
return current_thread_info()->exec_domain->signal_invmap[sig];
else
return sig;
}
static int setup_frame(int sig, struct k_sigaction *ka,
sigset_t *set, struct pt_regs * regs)
{
sigframe __user *frame;
frame = get_sigframe(ka, regs, sizeof(sigframe));
if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
goto give_sigsegv;
if (frame == (void __user *) -1UL)
goto give_sigsegv;
if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
goto give_sigsegv;
if (save_sigregs(regs, &frame->sregs))
goto give_sigsegv;
if (__put_user(&frame->sregs, &frame->sc.sregs))
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
regs->gprs[14] = (unsigned long)
ka->sa.sa_restorer | PSW_ADDR_AMODE;
} else {
regs->gprs[14] = (unsigned long)
frame->retcode | PSW_ADDR_AMODE;
if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
(u16 __user *)(frame->retcode)))
goto give_sigsegv;
}
/* Set up backchain. */
if (__put_user(regs->gprs[15], (addr_t __user *) frame))
goto give_sigsegv;
/* Set up registers for signal handler */
regs->gprs[15] = (unsigned long) frame;
regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
regs->gprs[2] = map_signal(sig);
regs->gprs[3] = (unsigned long) &frame->sc;
/* We forgot to include these in the sigcontext.
To avoid breaking binary compatibility, they are passed as args. */
regs->gprs[4] = current->thread.trap_no;
regs->gprs[5] = current->thread.prot_addr;
/* Place signal number on stack to allow backtrace from handler. */
if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
goto give_sigsegv;
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return -EFAULT;
}
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs * regs)
{
int err = 0;
rt_sigframe __user *frame;
frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
goto give_sigsegv;
if (frame == (void __user *) -1UL)
goto give_sigsegv;
if (copy_siginfo_to_user(&frame->info, info))
goto give_sigsegv;
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(NULL, &frame->uc.uc_link);
err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->gprs[15]),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= save_sigregs(regs, &frame->uc.uc_mcontext);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
regs->gprs[14] = (unsigned long)
ka->sa.sa_restorer | PSW_ADDR_AMODE;
} else {
regs->gprs[14] = (unsigned long)
frame->retcode | PSW_ADDR_AMODE;
if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
(u16 __user *)(frame->retcode)))
goto give_sigsegv;
}
/* Set up backchain. */
if (__put_user(regs->gprs[15], (addr_t __user *) frame))
goto give_sigsegv;
/* Set up registers for signal handler */
regs->gprs[15] = (unsigned long) frame;
regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
regs->gprs[2] = map_signal(sig);
regs->gprs[3] = (unsigned long) &frame->info;
regs->gprs[4] = (unsigned long) &frame->uc;
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return -EFAULT;
}
/*
* OK, we're invoking a handler
*/
static int
handle_signal(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
{
int ret;
/* Set up the stack frame */
if (ka->sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(sig, ka, info, oldset, regs);
else
ret = setup_frame(sig, ka, oldset, regs);
if (ret == 0) {
spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(&current->blocked,sig);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
}
return ret;
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals that
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
void do_signal(struct pt_regs *regs)
{
unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
siginfo_t info;
int signr;
struct k_sigaction ka;
sigset_t *oldset;
/*
* We want the common case to go fast, which
* is why we may in certain cases get here from
* kernel mode. Just return without doing anything
* if so.
*/
if (!user_mode(regs))
return;
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = &current->saved_sigmask;
else
oldset = &current->blocked;
/* Are we from a system call? */
if (regs->trap == __LC_SVC_OLD_PSW) {
continue_addr = regs->psw.addr;
restart_addr = continue_addr - regs->ilc;
retval = regs->gprs[2];
/* Prepare for system call restart. We do this here so that a
debugger will see the already changed PSW. */
switch (retval) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->gprs[2] = regs->orig_gpr2;
regs->psw.addr = restart_addr;
break;
case -ERESTART_RESTARTBLOCK:
regs->gprs[2] = -EINTR;
}
regs->trap = -1; /* Don't deal with this again. */
}
/* Get signal to deliver. When running under ptrace, at this point
the debugger may change all our registers ... */
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
/* Depending on the signal settings we may need to revert the
decision to restart the system call. */
if (signr > 0 && regs->psw.addr == restart_addr) {
if (retval == -ERESTARTNOHAND
|| (retval == -ERESTARTSYS
&& !(current->sighand->action[signr-1].sa.sa_flags
& SA_RESTART))) {
regs->gprs[2] = -EINTR;
regs->psw.addr = continue_addr;
}
}
if (signr > 0) {
/* Whee! Actually deliver the signal. */
int ret;
#ifdef CONFIG_COMPAT
if (test_thread_flag(TIF_31BIT)) {
ret = handle_signal32(signr, &ka, &info, oldset, regs);
}
else
#endif
ret = handle_signal(signr, &ka, &info, oldset, regs);
if (!ret) {
/*
* A signal was successfully delivered; the saved
* sigmask will have been stored in the signal frame,
* and will be restored by sigreturn, so we can simply
* clear the TIF_RESTORE_SIGMASK flag.
*/
if (test_thread_flag(TIF_RESTORE_SIGMASK))
clear_thread_flag(TIF_RESTORE_SIGMASK);
/*
* If we would have taken a single-step trap
* for a normal instruction, act like we took
* one for the handler setup.
*/
if (current->thread.per_info.single_step)
set_thread_flag(TIF_SINGLE_STEP);
}
return;
}
/*
* If there's no signal to deliver, we just put the saved sigmask back.
*/
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
/* Restart a different system call. */
if (retval == -ERESTART_RESTARTBLOCK
&& regs->psw.addr == continue_addr) {
regs->gprs[2] = __NR_restart_syscall;
set_thread_flag(TIF_RESTART_SVC);
}
}
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