Update of /cvsroot/linux-vax/kernel-2.4/arch/vax/kernel
In directory usw-pr-cvs1:/tmp/cvs-serv5459
Modified Files:
ptrace.c
Log Message:
DA: ptrace fixes for segfault
Index: ptrace.c
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/arch/vax/kernel/ptrace.c,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- ptrace.c 2001/11/09 23:48:40 1.4
+++ ptrace.c 2001/11/13 23:31:16 1.5
@@ -28,17 +28,49 @@
#include <asm/system.h>
#include <asm/uaccess.h>
+#define VAX_MAX_DIST_BETWEEN_PC 20
+/*
+ * search out does damn regs.. that variable length exception info is evil I
+ * tell you evil.
+ */
+static struct pt_regs *ptrace_find_vax_regs(struct task_struct *child)
+{
+ struct pt_regs *regs_ptr;
+ unsigned long *pc1, *pc2;
+ void *stack_top;
+
+ stack_top = ((union task_union *)child)+1;
+ stack_top -= 4;
+
+
+ pc1 = (unsigned long *)stack_top - 2;
+ pc2 = pc1;
+
+ //printk("pc1 is %8lX at %8lX\n", *pc1, pc1);
+ /* back step looking for second copy of PC */
+ do {
+ pc2 -= 1;
+ } while (*pc1!=*pc2 && pc1-pc2<VAX_MAX_DIST_BETWEEN_PC);
+
+ //printk("difference is %d\n", pc1-pc2);
+
+ if (pc1-pc2>=VAX_MAX_DIST_BETWEEN_PC)
+ return NULL;
+
+ regs_ptr = ((void *)pc2) + 8 - sizeof(struct pt_regs);
+
+ return regs_ptr;
+}
+
static int putreg(struct task_struct *child,
unsigned long regno, unsigned long value)
{
unsigned long retval = ~0UL;
- void *stack_top;
struct pt_regs *regs_ptr;
-
- stack_top = ((union task_union *)child)+1;
- stack_top -= 4;
- regs_ptr = stack_top - 16 - sizeof(struct pt_regs);
+ regs_ptr = ptrace_find_vax_regs(child);
+ if (!regs_ptr)
+ return 0;
switch(regno >> 2) {
case 0 ... 16:
@@ -59,18 +91,12 @@
unsigned long regno)
{
unsigned long retval = ~0UL;
- void *stack_top;
struct pt_regs *regs_ptr;
- stack_top = ((union task_union *)child)+1;
- stack_top -= 4;
-
- /* get the registers from where we shoved them on the stack at the last
- exception for this process.. not sure if this is always correct but
- will do for now - 4 longwords back from end of stack is end of regs */
-
- regs_ptr = stack_top - 16 - sizeof(struct pt_regs);
-
+ /* call helper function to get registers for the VAX */
+ regs_ptr = ptrace_find_vax_regs(child);
+ if (!regs_ptr)
+ return 0;
switch(regno >> 2) {
case 0 ... 16:
@@ -81,6 +107,7 @@
retval=0;
break;
}
+// printk("getreg for %d returned %8lX\n", regno>>2, retval);
return retval;
}
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