Initial file dump from open source releaseHEADmaster

1 files changed, 420 insertions, 0 deletions

diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
new file mode 100644
index 00000000..c45becf8
--- /dev/null
+++ b/arch/s390/kernel/signal.c
@@ -0,0 +1,420 @@
+/*
+ *    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);
+}