android_kernel_motorola_sm6225/arch/s390/kernel/signal.c
Heiko Carstens a806170e29 [S390] Fix a lot of sparse warnings.
Most noteable part of this commit is the new local header file entry.h
which contains all the function declarations of functions that get only
called from asm code or are arch internal. That way we can avoid extern
declarations in C files.
This is more or less the same that was done for sparc64.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-17 07:47:06 +02:00

528 lines
14 KiB
C

/*
* 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);
}
}