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OpenCloudOS-Kernel/arch/s390/kernel/signal.c

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/*
* Copyright 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 <linux/tracehook.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/lowcore.h>
#include <asm/switch_to.h>
#include "entry.h"
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;
/* 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_user_bits |
(regs->psw.mask & PSW_MASK_USER);
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;
/* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */
regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
(user_sregs.regs.psw.mask & PSW_MASK_USER);
/* Check for invalid user address space control. */
if ((regs->psw.mask & PSW_MASK_ASC) >= (psw_kernel_bits & PSW_MASK_ASC))
regs->psw.mask = (psw_user_bits & PSW_MASK_ASC) |
(regs->psw.mask & ~PSW_MASK_ASC);
/* Check for invalid amode */
if (regs->psw.mask & PSW_MASK_EA)
regs->psw.mask |= PSW_MASK_BA;
regs->psw.addr = 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);
clear_thread_flag(TIF_SYSCALL); /* No longer in a system call */
return 0;
}
SYSCALL_DEFINE0(sigreturn)
{
struct pt_regs *regs = task_pt_regs(current);
sigframe __user *frame = (sigframe __user *)regs->gprs[15];
sigset_t set;
if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
goto badframe;
set_current_blocked(&set);
if (restore_sigregs(regs, &frame->sregs))
goto badframe;
return regs->gprs[2];
badframe:
force_sig(SIGSEGV, current);
return 0;
}
SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = task_pt_regs(current);
rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
sigset_t set;
if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (restore_sigregs(regs, &frame->uc.uc_mcontext))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
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;
}
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 (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;
/* Force default amode and default user address space control. */
regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
(psw_user_bits & PSW_MASK_ASC) |
(regs->psw.mask & ~PSW_MASK_ASC);
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. */
if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
sig == SIGTRAP || sig == SIGFPE) {
/* set extra registers only for synchronous signals */
regs->gprs[4] = regs->int_code & 127;
regs->gprs[5] = regs->int_parm_long;
regs->gprs[6] = task_thread_info(current)->last_break;
}
/* 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 (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 |= __save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
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;
/* Force default amode and default user address space control. */
regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
(psw_user_bits & PSW_MASK_ASC) |
(regs->psw.mask & ~PSW_MASK_ASC);
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;
regs->gprs[5] = task_thread_info(current)->last_break;
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return -EFAULT;
}
static void 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)
return;
signal_delivered(sig, info, ka, regs,
test_thread_flag(TIF_SINGLE_STEP));
}
/*
* 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)
{
siginfo_t info;
int signr;
struct k_sigaction ka;
sigset_t *oldset = sigmask_to_save();
/*
* Get signal to deliver. When running under ptrace, at this point
* the debugger may change all our registers, including the system
* call information.
*/
current_thread_info()->system_call =
test_thread_flag(TIF_SYSCALL) ? regs->int_code : 0;
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* Whee! Actually deliver the signal. */
if (current_thread_info()->system_call) {
regs->int_code = current_thread_info()->system_call;
/* Check for system call restarting. */
switch (regs->gprs[2]) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->gprs[2] = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka.sa.sa_flags & SA_RESTART)) {
regs->gprs[2] = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->gprs[2] = regs->orig_gpr2;
regs->psw.addr =
__rewind_psw(regs->psw,
regs->int_code >> 16);
break;
}
}
/* No longer in a system call */
clear_thread_flag(TIF_SYSCALL);
if (is_compat_task())
handle_signal32(signr, &ka, &info, oldset, regs);
else
handle_signal(signr, &ka, &info, oldset, regs);
return;
}
/* No handlers present - check for system call restart */
clear_thread_flag(TIF_SYSCALL);
if (current_thread_info()->system_call) {
regs->int_code = current_thread_info()->system_call;
switch (regs->gprs[2]) {
case -ERESTART_RESTARTBLOCK:
/* Restart with sys_restart_syscall */
regs->int_code = __NR_restart_syscall;
/* fallthrough */
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
/* Restart system call with magic TIF bit. */
regs->gprs[2] = regs->orig_gpr2;
set_thread_flag(TIF_SYSCALL);
if (test_thread_flag(TIF_SINGLE_STEP))
set_thread_flag(TIF_PER_TRAP);
break;
}
}
/*
* If there's no signal to deliver, we just put the saved sigmask back.
*/
restore_saved_sigmask();
}
void do_notify_resume(struct pt_regs *regs)
{
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
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