Import of Linux/MIPS 2.1.36

1 files changed, 85 insertions, 41 deletions

diff --git a/arch/ppc/kernel/signal.c b/arch/ppc/kernel/signal.c
index 18a0a10d9..ba8864251 100644
--- a/arch/ppc/kernel/signal.c
+++ b/arch/ppc/kernel/signal.c
@@ -3,16 +3,20 @@
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *  Adapted for PowerPC by Gary Thomas
+ *  Modified by Cort Dougan (cort@cs.nmt.edu) 
  */
 
 #include <linux/sched.h>
 #include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.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 <asm/uaccess.h>
 
 #define _S(nr) (1<<((nr)-1))
 
@@ -26,7 +30,9 @@ asmlinkage int sys_waitpid(pid_t pid,unsigned long * stat_addr, int options);
 asmlinkage int sys_sigsuspend(unsigned long set, int p2, int p3, int p4, int p6, int p7, struct pt_regs *regs)
 {
 	unsigned long mask;
+	int ret = -EINTR;
 
+	lock_kernel();
 	mask = current->blocked;
 	current->blocked = set & _BLOCKABLE;
 	regs->gpr[3] = -EINTR;
@@ -37,25 +43,32 @@ printk("Task: %x[%d] - SIGSUSPEND at %x, Mask: %x\n", current, current->pid, reg
 		current->state = TASK_INTERRUPTIBLE;
 		schedule();
 		if (do_signal(mask,regs))
-			return -EINTR;
+			goto out;
 	}
+out:
+	unlock_kernel();
+	return ret;
 }
 
-/*
- * This sets regs->esp even though we don't actually use sigstacks yet..
- */
 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 {
 	struct sigcontext_struct *sc;
 	struct pt_regs *int_regs;
-	int signo;
+	int signo, ret;
+
+	lock_kernel();
+#if 1 	
+	if (verify_area(VERIFY_READ, (void *) regs->gpr[1], sizeof(sc))
+	    || (regs->gpr[1] >=KERNELBASE))
+		goto badframe;
+#endif	
 	sc = (struct sigcontext_struct *)regs->gpr[1];
 	current->blocked = sc->oldmask & _BLOCKABLE;
 	int_regs = sc->regs;
 	signo = sc->signal;
 	sc++;  /* Pop signal 'context' */
-	if (sc == (struct sigcontext_struct *)(int_regs))
-	{ /* Last stacked signal */
+	if (sc == (struct sigcontext_struct *)(int_regs)) {
+		/* Last stacked signal */
 #if 0	
 		/* This doesn't work - it blows away the return address! */
 		memcpy(regs, int_regs, sizeof(*regs));
@@ -72,16 +85,24 @@ asmlinkage int sys_sigreturn(struct pt_regs *regs)
 			regs->nip -= 4; /* Back up & retry system call */
 			regs->result = 0;
 		}
-		return (regs->result);
-	} else
-	{ /* More signals to go */
+		ret = (regs->result);
+	} else { /* More signals to go */
 		regs->gpr[1] = (unsigned long)sc;
 		regs->gpr[3] = sc->signal;
 		regs->gpr[4] = sc->regs;
 		regs->link = (unsigned long)((sc->regs)+1);
 		regs->nip = sc->handler;
-		return (sc->signal);
+		ret = sc->signal;
 	}
+	goto out;
+
+badframe:
+	/*printk("sys_sigreturn(): badstack regs %x cur %s/%d\n",
+	 regs,current->comm,current->pid);*/
+	do_exit(SIGSEGV);
+out:
+	unlock_kernel();
+	return ret;
 }
 
 
@@ -96,27 +117,24 @@ asmlinkage int sys_sigreturn(struct pt_regs *regs)
  */
 asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
 {
-	unsigned long mask = ~current->blocked;
+	unsigned long mask;
 	unsigned long handler_signal = 0;
 	unsigned long *frame = NULL;
-	unsigned long *trampoline;
-	unsigned long *regs_ptr;
+	unsigned long *trampoline, *regs_ptr;
 	unsigned long nip = 0;
 	unsigned long signr;
-	int bitno;
 	struct sigcontext_struct *sc;
 	struct sigaction * sa;
-	int s = _disable_interrupts();
+	int bitno, s, ret;
+
+	lock_kernel();
+	mask = ~current->blocked;
 	while ((signr = current->signal & mask)) {
-#if 0
-		signr = ffz(~signr);  /* Compute bit # */
-#else
 		for (bitno = 0;  bitno < 32;  bitno++)
-		{
-			if (signr & (1<<bitno)) break;
-		}
+			if (signr & (1<<bitno))
+				break;
 		signr = bitno;
-#endif
+
 		current->signal &= ~(1<<signr);  /* Clear bit */
 		sa = current->sig->action + signr;
 		signr++;
@@ -157,7 +175,7 @@ asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
 				current->state = TASK_STOPPED;
 				current->exit_code = signr;
 				if (!(current->p_pptr->sig->action[SIGCHLD-1].sa_flags &
-						SA_NOCLDSTOP))
+				      SA_NOCLDSTOP))
 					notify_parent(current);
 				schedule();
 				continue;
@@ -174,27 +192,33 @@ asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
 				do_exit(signr);
 			}
 		}
-		/*
-		 * OK, we're invoking a handler
-		 */
+
+		/* handle signal */
 		if ((int)regs->orig_gpr3 >= 0) {
 			if ((int)regs->result == -ERESTARTNOHAND ||
-			   ((int)regs->result == -ERESTARTSYS && !(sa->sa_flags & SA_RESTART)))
+			    ((int)regs->result == -ERESTARTSYS &&
+			     !(sa->sa_flags & SA_RESTART)))
 				(int)regs->result = -EINTR;
 		}
 		handler_signal |= 1 << (signr-1);
 		mask &= ~sa->sa_mask;
 	}
+	ret = 0;
 	if (!handler_signal)		/* no handler will be called - return 0 */
-	{
-		_enable_interrupts(s);
-		return 0;
-	}
+		goto out;
+
 	nip = regs->nip;
 	frame = (unsigned long *) regs->gpr[1];
+
 	/* Build trampoline code on stack */
 	frame -= 2;
 	trampoline = frame;
+#if 1
+	/* verify stack is valid for writing regs struct */
+	if (verify_area(VERIFY_WRITE,(void *)frame, sizeof(long)*2+sizeof(*regs))
+	    || (frame >= KERNELBASE ))
+		goto badframe;
+#endif
 	trampoline[0] = 0x38007777;  /* li r0,0x7777 */
 	trampoline[1] = 0x44000002;  /* sc           */
 	frame -= sizeof(*regs) / sizeof(long);
@@ -202,12 +226,19 @@ asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
 	memcpy(regs_ptr, regs, sizeof(*regs));
 	signr = 1;
 	sa = current->sig->action;
+  
 	for (mask = 1 ; mask ; sa++,signr++,mask += mask) {
 		if (mask > handler_signal)
 			break;
 		if (!(mask & handler_signal))
 			continue;
+
 		frame -= sizeof(struct sigcontext_struct) / sizeof(long);
+#if 1
+		if (verify_area(VERIFY_WRITE,(void *)frame,
+				sizeof(struct sigcontext_struct)/sizeof(long)))
+			goto badframe;
+#endif    
 		sc = (struct sigcontext_struct *)frame;
 		nip = (unsigned long) sa->sa_handler;
 #if 0 /* Old compiler */		
@@ -226,14 +257,27 @@ asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
 	regs->link = (unsigned long)trampoline;
 	regs->nip = nip;
 	regs->gpr[1] = (unsigned long)sc;
-	/* The DATA cache must be flushed here to insure coherency */
-	/* between the DATA & INSTRUCTION caches.  Since we just */
-	/* created an instruction stream using the DATA [cache] space */
-	/* and since the instruction cache will not look in the DATA */
-	/* cache for new data, we have to force the data to go on to */
-	/* memory and flush the instruction cache to force it to look */
-	/* there.  The following function performs this magic */
+
+	/* The DATA cache must be flushed here to insure coherency
+	 * between the DATA & INSTRUCTION caches.  Since we just
+	 * created an instruction stream using the DATA [cache] space
+	 * and since the instruction cache will not look in the DATA
+	 * cache for new data, we have to force the data to go on to
+	 * memory and flush the instruction cache to force it to look
+	 * there.  The following function performs this magic
+	 */
 	flush_instruction_cache();
-	_enable_interrupts(s);
-	return 1;
+	ret = 1;
+	goto out;
+
+badframe:
+#if 0
+	printk("do_signal(): badstack signr %d frame %x regs %x cur %s/%d\n",
+	       signr, frame, regs, current->comm, current->pid);
+#endif
+	do_exit(SIGSEGV);
+
+out:
+	unlock_kernel();
+	return ret;
 }