[LV-kern-commit] CVS: kernel-2.4/arch/vax/kernel syscall.c,1.4,1.5 signal.c,1.3,1.4

[Andy P. <at...@us...>]

Update of /cvsroot/linux-vax/kernel-2.4/arch/vax/kernel
In directory usw-pr-cvs1:/tmp/cvs-serv18613/kernel

Modified Files:
	syscall.c signal.c 
Log Message:
Signals implementation. First attempt.


Index: syscall.c
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/arch/vax/kernel/syscall.c,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- syscall.c	2001/07/31 17:28:26	1.4
+++ syscall.c	2001/08/17 20:20:41	1.5
@@ -95,6 +95,7 @@
 	   by the user.
 
 	   We'll sort this out later... - KPH 2000-10-16 */
+        /* atp aug 2001, FIXME: ptrace/strace syscall stuff */
 
 	__asm__("  pushl %1             \n
 		   subl2 %2,sp          \n
@@ -115,8 +116,21 @@
 			"g"(-EFAULT)
 		: "r0","r1","r2","r3","r4","r5" /* clobbers*/ );
 
-/*	printk("syscall %d returned %ld (0x%08lx)\n", chmk_arg, regs->r0, regs->r0);*/
+//	printk("syscall %d returned %ld (0x%08lx)\n", chmk_arg, regs->r0, regs->r0);
 
+	/* now we check for softirqs ready to be run */
+        /* This is the equivalent of ENTRY(ret_from_syscall) on other ports */
+        if ( (softirq_active(smp_processor_id()) & softirq_mask(smp_processor_id())) !=0 ) do_softirq();
+	
+	/* check for need_reschedule */
+	if (current->need_resched !=0) schedule();
+        
+	/* check for pending signals */
+	if (current->sigpending != 0) {
+	   /* FIXME: do we need to check the IPL here (i386 does a sti here) */
+	   do_signal();
+	}
+	
 	return;
 }
 

Index: signal.c
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/arch/vax/kernel/signal.c,v
retrieving revision 1.3
retrieving revision 1.4
diff -u -r1.3 -r1.4
--- signal.c	2001/07/31 17:28:26	1.3
+++ signal.c	2001/08/17 20:20:41	1.4
@@ -1,14 +1,20 @@
-/* 
-   $Id$
-
-   This file contains the standard functions that the arch-independent
-   kernel expects for signal handling
-   
-   Copyright, 1998-2001 atp, kenn, airlied. 
- 
-   atp Jul 2001, signal handling, based on S390/Intel version. 
-
-*/
+/*
+ *  linux/arch/vax/kernel/signal.c
+ *
+ *  From arch/cris/kernel/signal.c
+ * 
+ *  Based on arch/i386/kernel/signal.c by
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *     1997-11-28  Modified for POSIX.1b signals by Richard Henderson *
+ *
+ *  Ideas also taken from arch/arm.
+ *
+ *  Copyright (C) 2000 Axis Communications AB
+ *
+ *  Authors:  Bjorn Wesen (bj...@ax...)
+ *            VAX port at...@pe....
+ * 	      See syscall.c for details of the call stack layout etc... 
+ */
 
 #include <linux/sched.h>
 #include <linux/mm.h>
@@ -21,12 +27,20 @@
 #include <linux/ptrace.h>
 #include <linux/unistd.h>
 #include <linux/stddef.h>
+
+#include <asm/processor.h>
 #include <asm/ucontext.h>
 #include <asm/uaccess.h>
 
+#define DEBUG_SIG 0
+
+/* FIXME: Check this & fixup other regs, like r0 */
+#define RESTART_VAX_SYSCALL(regs) { (regs)->pc -= 4; } 
+
+
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
-asmlinkage int FASTCALL(do_signal(struct pt_regs *regs, sigset_t *oldset));
+int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs);
 
 int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
 {
@@ -66,8 +80,8 @@
 /*
  * Atomically swap in the new signal mask, and wait for a signal.
  */
-asmlinkage int
-sys_sigsuspend(struct pt_regs * regs,int history0, int history1, old_sigset_t mask)
+int
+sys_sigsuspend(struct pt_regs *regs, old_sigset_t mask)
 {
 	sigset_t saveset;
 
@@ -77,18 +91,22 @@
 	siginitset(&current->blocked, mask);
 	recalc_sigpending(current);
 	spin_unlock_irq(&current->sigmask_lock);
-	regs->r2 = -EINTR;
 
+	regs->r0 = -EINTR;
 	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
+		current->state = TASK_INTERRUPTIBLE;
 		schedule();
-		if (do_signal(regs, &saveset))
+		if (do_signal(0, &saveset, regs))
 			return -EINTR;
 	}
 }
 
-asmlinkage int
-sys_rt_sigsuspend(struct pt_regs * regs,sigset_t *unewset, size_t sigsetsize)
+/*
+ * atp - it is a little confusing, looking at other ports, as to what the arguments to 
+ * this function are. I'm assuming two args, plus our pushed pt_regs set up by syscall 
+ */
+int
+sys_rt_sigsuspend(struct pt_regs *regs,sigset_t *unewset, size_t sigsetsize)
 {
 	sigset_t saveset, newset;
 
@@ -105,17 +123,17 @@
 	current->blocked = newset;
 	recalc_sigpending(current);
 	spin_unlock_irq(&current->sigmask_lock);
-	regs->r2 = -EINTR;
 
+	regs->r0 = -EINTR;
 	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
+		current->state = TASK_INTERRUPTIBLE;
 		schedule();
-		if (do_signal(regs, &saveset))
+		if (do_signal(0, &saveset, regs))
 			return -EINTR;
 	}
 }
 
-asmlinkage int 
+int 
 sys_sigaction(int sig, const struct old_sigaction *act,
 	      struct old_sigaction *oact)
 {
@@ -146,10 +164,12 @@
 
 	return ret;
 }
-asmlinkage int
-sys_sigaltstack(const stack_t *uss, stack_t *uoss, struct pt_regs *regs)
+
+int
+sys_sigaltstack(const stack_t *uss, stack_t *uoss)
 {
-	return do_sigaltstack(uss, uoss, regs->sp); /* is ->sp the right one FIXME: check */
+	struct pt_regs *regs = (struct pt_regs *) &uss;
+	return do_sigaltstack(uss, uoss, regs->sp );
 }
 
 
@@ -158,12 +178,14 @@
  */
 
 struct sigframe {
+   	char *pretcode;
 	struct sigcontext sc;
 	unsigned long extramask[_NSIG_WORDS-1];
 	unsigned char retcode[8];  /* trampoline code */
 };
 
 struct rt_sigframe {
+   	char *pretcode;
 	struct siginfo *pinfo;
 	void *puc;
 	struct siginfo info;
@@ -171,16 +193,462 @@
 	unsigned char retcode[8];  /* trampoline code */
 };
 
+
+static int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
+{
+	unsigned int err = 0;
+	unsigned long old_usp;
+
+	/* restore the regs from &sc->regs (same as sc, since regs is first)
+	 * (sc is already checked for VERIFY_READ since the sigframe was
+	 *  checked in sys_sigreturn previously)
+	 */
+
+	if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
+                goto badframe;
+
+	/* FIXME: check user mode flag in restored regs PSW */
+	
+	/* restore the old USP as it was before we stacked the sc etc.
+	 * (we cannot just pop the sigcontext since we aligned the sp and
+	 *  stuff after pushing it)
+	 */
+	
+   	/* FIXME: check process stack */
+   
+	/* TODO: the other ports use regs->orig_XX to disable syscall checks
+	 * after this completes, but we don't use that mechanism. maybe we can
+	 * use it now ? 
+	 */
+
+	return err;
+
+badframe:
+	return 1;
+}
+
+asmlinkage int sys_sigreturn(struct pt_regs *regs)
+{
+	struct sigframe *frame = (struct sigframe *)(regs->sp);
+	sigset_t set;
+
+        /*
+         * Since we stacked the signal on a dword boundary,
+         * then frame should be dword aligned here.  If it's
+         * not, then the user is trying to mess with us.
+         */
+        if (((long)frame) & 3)
+                goto badframe;
+
+	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__get_user(set.sig[0], &frame->sc.oldmask)
+	    || (_NSIG_WORDS > 1
+		&& __copy_from_user(&set.sig[1], &frame->extramask,
+				    sizeof(frame->extramask))))
+		goto badframe;
+
+	sigdelsetmask(&set, ~_BLOCKABLE);
+	spin_lock_irq(&current->sigmask_lock);
+	current->blocked = set;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+	
+	if (restore_sigcontext(regs, &frame->sc))
+		goto badframe;
+
+	/* TODO: SIGTRAP when single-stepping as in arm ? */
+
+	return regs->r0;
+
+badframe:
+	force_sig(SIGSEGV, current);
+	return 0;
+}	
+
+asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
+{
+	struct rt_sigframe *frame = (struct rt_sigframe *)(regs->sp);
+	sigset_t set;
+	stack_t st;
+
+        /*
+         * Since we stacked the signal on a dword boundary,
+         * then frame should be dword aligned here.  If it's
+         * not, then the user is trying to mess with us.
+         */
+        if (((long)frame) & 3)
+                goto badframe;
+
+	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+		goto badframe;
+
+	sigdelsetmask(&set, ~_BLOCKABLE);
+	spin_lock_irq(&current->sigmask_lock);
+	current->blocked = set;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+	
+	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
+		goto badframe;
+
+	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
+		goto badframe;
+	/* It is more difficult to avoid calling this function than to
+	   call it and ignore errors.  */
+	do_sigaltstack(&st, NULL, (regs->sp));
+
+	return regs->r0;
+
+badframe:
+	force_sig(SIGSEGV, current);
+	return 0;
+}	
+
+/*
+ * Set up a signal frame.
+ */
+
+static int
+setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs, unsigned long mask)
+{
+	int err = 0;
+
+	/* copy the regs. they are first in sc so we can use sc directly */
+
+	err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
+
+	/* then some other stuff */
+
+	err |= __put_user(mask, &sc->oldmask);
+
+	return err;
+}
+
+/* figure out where we want to put the new signal frame - usually on the stack */
 
-int sys_sigreturn(void)
+static inline void *
+get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 {
-	return -ENOSYS;
+	unsigned long sp = regs->sp;
+
+	/* This is the X/Open sanctioned signal stack switching.  */
+	if (ka->sa.sa_flags & SA_ONSTACK) {
+		if (! on_sig_stack(sp))
+			sp = current->sas_ss_sp + current->sas_ss_size;
+	}
+
+	/* make sure the frame is dword-aligned */
+
+	sp &= ~3;
+
+	return (void *)(sp - frame_size);
 }
+
+/* grab and setup a signal frame.
+ * 
+ * basically we stack a lot of state info, and arrange for the
+ * user-mode program to return to the kernel using either a
+ * trampoline which performs the syscall sigreturn, or a provided
+ * user-mode trampoline.
+ */
 
-int sys_rt_sigreturn(void)
+static void setup_frame(int sig, struct k_sigaction *ka,
+			sigset_t *set, struct pt_regs * regs)
 {
-	return -ENOSYS;
+	struct sigframe *frame;
+	unsigned long return_ip;
+	int err = 0;
+
+	frame = get_sigframe(ka, regs, sizeof(*frame));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto give_sigsegv;
+
+	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
+	if (err)
+		goto give_sigsegv;
+
+	if (_NSIG_WORDS > 1) {
+		err |= __copy_to_user(frame->extramask, &set->sig[1],
+				      sizeof(frame->extramask));
+	}
+	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) {
+		return_ip = (unsigned long)ka->sa.sa_restorer;
+	} else {
+		/* trampoline - the desired return ip is the retcode itself */
+		return_ip = (unsigned long)&frame->retcode;
+		/* This is chmk __NR_sigreturn; */
+		/* TODO: check byteorder */
+		err |= __put_user(0xbc8f,         (short *)(frame->retcode+0));
+		err |= __put_user(__NR_sigreturn, (short *)(frame->retcode+2));
+	}
+
+        err |= __put_user(return_ip, &frame->pretcode);
+			  
+	if (err)
+		goto give_sigsegv;
+
+	/* Set up registers for signal handler */
+
+	regs->pc = (unsigned long) ka->sa.sa_handler;  /* what we enter NOW   */
+	regs->sp = frame;                          
+
+	return;
+
+give_sigsegv:
+	if (sig == SIGSEGV)
+		ka->sa.sa_handler = SIG_DFL;
+	force_sig(SIGSEGV, current);
 }
 
+static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+			   sigset_t *set, struct pt_regs * regs)
+{
+	struct rt_sigframe *frame;
+	unsigned long return_ip;
+	int err = 0;
+
+	frame = get_sigframe(ka, regs, sizeof(*frame));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto give_sigsegv;
+
+	err |= __put_user(&frame->info, &frame->pinfo);
+	err |= __put_user(&frame->uc, &frame->puc);
+	err |= copy_siginfo_to_user(&frame->info, info);
+	if (err)
+		goto give_sigsegv;
+
+	/* Clear all the bits of the ucontext we don't use.  */
+        err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
+
+	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
+
+	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) {
+		return_ip = (unsigned long)ka->sa.sa_restorer;
+	} else {
+		/* trampoline - the desired return ip is the retcode itself */
+		return_ip = (unsigned long)&frame->retcode;
+		/* TODO: check byteorder */
+		err |= __put_user(0xbc8f,         (short *)(frame->retcode+0));
+		err |= __put_user(__NR_sigreturn, (short *)(frame->retcode+2));
+	}
+
+        err |= __put_user(return_ip, &frame->pretcode);
+	if (err)
+		goto give_sigsegv;
+
+	/* TODO what is the current->exec_domain stuff and invmap ? */
+
+	/* Set up registers for signal handler */
+
+	regs->pc = (unsigned long) ka->sa.sa_handler;  /* what we enter NOW   */
+	regs->sp = frame;                          /* what we enter LATER */
+
+	return;
 
+give_sigsegv:
+	if (sig == SIGSEGV)
+		ka->sa.sa_handler = SIG_DFL;
+	force_sig(SIGSEGV, current);
+}
+
+/*
+ * OK, we're invoking a handler
+ */	
 
+static inline void
+handle_signal(int canrestart, unsigned long sig, struct k_sigaction *ka,
+	      siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
+{
+	/* Are we from a system call? */
+	if (canrestart) {
+		/* If so, check system call restarting.. */
+		switch (regs->r0) {
+			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 */
+				regs->r0 = -EINTR;
+				break;
+
+			case -ERESTARTSYS:
+				/* ERESTARTSYS means to restart the syscall if there is no
+				   handler or the handler was registered with SA_RESTART */
+				if (!(ka->sa.sa_flags & SA_RESTART)) {
+					regs->r0 = -EINTR;
+					break;
+				}
+			/* fallthrough */
+			case -ERESTARTNOINTR:
+				/* ERESTARTNOINTR means that the syscall should be called again
+				   after the signal handler returns. */
+		   		RESTART_VAX_SYSCALL(regs);
+		}
+	}
+
+	/* Set up the stack frame */
+	if (ka->sa.sa_flags & SA_SIGINFO)
+		setup_rt_frame(sig, ka, info, oldset, regs);
+	else
+		setup_frame(sig, ka, oldset, regs);
+
+	if (ka->sa.sa_flags & SA_ONESHOT)
+		ka->sa.sa_handler = SIG_DFL;
+
+	if (!(ka->sa.sa_flags & SA_NODEFER)) {
+		spin_lock_irq(&current->sigmask_lock);
+		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
+		sigaddset(&current->blocked,sig);
+		recalc_sigpending(current);
+		spin_unlock_irq(&current->sigmask_lock);
+	}
+}
+
+/*
+ * 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.
+ */
+int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs)
+{
+	siginfo_t info;
+	struct k_sigaction *ka;
+
+	/*
+	 * 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 1;
+
+	if (!oldset)
+		oldset = &current->blocked;
+
+	for (;;) {
+		unsigned long signr;
+
+		spin_lock_irq(&current->sigmask_lock);
+		signr = dequeue_signal(&current->blocked, &info);
+		spin_unlock_irq(&current->sigmask_lock);
+
+		if (!signr)
+			break;
+
+		if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
+			/* Let the debugger run.  */
+			current->exit_code = signr;
+			current->state = TASK_STOPPED;
+			notify_parent(current, SIGCHLD);
+			schedule();
+
+			/* We're back.  Did the debugger cancel the sig?  */
+			if (!(signr = current->exit_code))
+				continue;
+			current->exit_code = 0;
+
+			/* The debugger continued.  Ignore SIGSTOP.  */
+			if (signr == SIGSTOP)
+				continue;
+
+			/* Update the siginfo structure.  Is this good?  */
+			if (signr != info.si_signo) {
+				info.si_signo = signr;
+				info.si_errno = 0;
+				info.si_code = SI_USER;
+				info.si_pid = current->p_pptr->pid;
+				info.si_uid = current->p_pptr->uid;
+			}
+
+			/* If the (new) signal is now blocked, requeue it.  */
+			if (sigismember(&current->blocked, signr)) {
+				send_sig_info(signr, &info, current);
+				continue;
+			}
+		}
+
+		ka = &current->sig->action[signr-1];
+		if (ka->sa.sa_handler == SIG_IGN) {
+			if (signr != SIGCHLD)
+				continue;
+			/* Check for SIGCHLD: it's special.  */
+			while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
+				/* nothing */;
+			continue;
+		}
+
+		if (ka->sa.sa_handler == SIG_DFL) {
+			int exit_code = signr;
+
+			/* Init gets no signals it doesn't want.  */
+			if (current->pid == 1)
+				continue;
+
+			switch (signr) {
+			case SIGCONT: case SIGCHLD: case SIGWINCH:
+				continue;
+
+			case SIGTSTP: case SIGTTIN: case SIGTTOU:
+				if (is_orphaned_pgrp(current->pgrp))
+					continue;
+				/* FALLTHRU */
+
+			case SIGSTOP:
+				current->state = TASK_STOPPED;
+				current->exit_code = signr;
+				if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
+					notify_parent(current, SIGCHLD);
+				schedule();
+				continue;
+
+			case SIGQUIT: case SIGILL: case SIGTRAP:
+			case SIGABRT: case SIGFPE: case SIGSEGV:
+			case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
+				if (do_coredump(signr, regs))
+					exit_code |= 0x80;
+				/* FALLTHRU */
+
+			default:
+				lock_kernel();
+				sigaddset(&current->pending.signal, signr);
+				recalc_sigpending(current);
+				current->flags |= PF_SIGNALED;
+				do_exit(exit_code);
+				/* NOTREACHED */
+			}
+		}
+
+		/* Whee!  Actually deliver the signal.  */
+		handle_signal(canrestart, signr, ka, &info, oldset, regs);
+		return 1;
+	}
+
+	/* Did we come from a system call? */
+	if (canrestart) {
+		/* Restart the system call - no handlers present */
+		if (regs->r0 == -ERESTARTNOHAND ||
+		    regs->r0 == -ERESTARTSYS ||
+		    regs->r0 == -ERESTARTNOINTR) {
+			RESTART_VAX_SYSCALL(regs);
+		}
+	}
+	return 0;
+}