Import of Linux/MIPS 1.1.68

1 files changed, 523 insertions, 0 deletions

diff --git a/arch/mips/ptrace.c b/arch/mips/ptrace.c
new file mode 100644
index 000000000..0a42b9c38
--- /dev/null
+++ b/arch/mips/ptrace.c
@@ -0,0 +1,523 @@
+/* ptrace.c */
+/* By Ross Biro 1/23/92 */
+/* edited by Linus Torvalds */
+
+#include <linux/head.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+
+#include <asm/segment.h>
+#include <asm/system.h>
+
+#if 0
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+/* determines which flags the user has access to. */
+/* 1 = access 0 = no access */
+#define FLAG_MASK 0x00044dd5
+
+/* set's the trap flag. */
+#define TRAP_FLAG 0x100
+
+/*
+ * this is the number to subtract from the top of the stack. To find
+ * the local frame.
+ */
+#define MAGICNUMBER 68
+
+/* change a pid into a task struct. */
+static inline struct task_struct * get_task(int pid)
+{
+	int i;
+
+	for (i = 1; i < NR_TASKS; i++) {
+		if (task[i] != NULL && (task[i]->pid == pid))
+			return task[i];
+	}
+	return NULL;
+}
+
+/*
+ * this routine will get a word off of the processes privileged stack. 
+ * the offset is how far from the base addr as stored in the TSS.  
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */   
+static inline int get_stack_long(struct task_struct *task, int offset)
+{
+	unsigned char *stack;
+
+	stack = (unsigned char *)task->tss.esp0;
+	stack += offset;
+	return (*((int *)stack));
+}
+
+/*
+ * this routine will put a word on the processes privileged stack. 
+ * the offset is how far from the base addr as stored in the TSS.  
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline int put_stack_long(struct task_struct *task, int offset,
+	unsigned long data)
+{
+	unsigned char * stack;
+
+	stack = (unsigned char *) task->tss.esp0;
+	stack += offset;
+	*(unsigned long *) stack = data;
+	return 0;
+}
+
+/*
+ * This routine gets a long from any process space by following the page
+ * tables. NOTE! You should check that the long isn't on a page boundary,
+ * and that it is in the task area before calling this: this routine does
+ * no checking.
+ */
+static unsigned long get_long(struct vm_area_struct * vma, unsigned long addr)
+{
+	unsigned long page;
+
+repeat:
+	page = *PAGE_DIR_OFFSET(vma->vm_task->tss.cr3, addr);
+	if (page & PAGE_PRESENT) {
+		page &= PAGE_MASK;
+		page += PAGE_PTR(addr);
+		page = *((unsigned long *) page);
+	}
+	if (!(page & PAGE_PRESENT)) {
+		do_no_page(vma, addr, 0);
+		goto repeat;
+	}
+/* this is a hack for non-kernel-mapped video buffers and similar */
+	if (page >= high_memory)
+		return 0;
+	page &= PAGE_MASK;
+	page += addr & ~PAGE_MASK;
+	return *(unsigned long *) page;
+}
+
+/*
+ * This routine puts a long into any process space by following the page
+ * tables. NOTE! You should check that the long isn't on a page boundary,
+ * and that it is in the task area before calling this: this routine does
+ * no checking.
+ *
+ * Now keeps R/W state of page so that a text page stays readonly
+ * even if a debugger scribbles breakpoints into it.  -M.U-
+ */
+static void put_long(struct vm_area_struct * vma, unsigned long addr,
+	unsigned long data)
+{
+	unsigned long page, pte = 0;
+	int readonly = 0;
+
+repeat:
+	page = *PAGE_DIR_OFFSET(vma->vm_task->tss.cr3, addr);
+	if (page & PAGE_PRESENT) {
+		page &= PAGE_MASK;
+		page += PAGE_PTR(addr);
+		pte = page;
+		page = *((unsigned long *) page);
+	}
+	if (!(page & PAGE_PRESENT)) {
+		do_no_page(vma, addr, 0 /* PAGE_RW */);
+		goto repeat;
+	}
+	if (!(page & PAGE_RW)) {
+		if (!(page & PAGE_COW))
+			readonly = 1;
+		do_wp_page(vma, addr, PAGE_RW | PAGE_PRESENT);
+		goto repeat;
+	}
+/* this is a hack for non-kernel-mapped video buffers and similar */
+	if (page >= high_memory)
+		return;
+/* we're bypassing pagetables, so we have to set the dirty bit ourselves */
+	*(unsigned long *) pte |= (PAGE_DIRTY|PAGE_COW);
+	page &= PAGE_MASK;
+	page += addr & ~PAGE_MASK;
+	*(unsigned long *) page = data;
+	if (readonly) {
+		*(unsigned long *) pte &=~ (PAGE_RW|PAGE_COW);
+		invalidate();
+	} 
+}
+
+static struct vm_area_struct * find_vma(struct task_struct * tsk, unsigned long addr)
+{
+	struct vm_area_struct * vma;
+
+	addr &= PAGE_MASK;
+	for (vma = tsk->mm->mmap ; ; vma = vma->vm_next) {
+		if (!vma)
+			return NULL;
+		if (vma->vm_end > addr)
+			break;
+	}
+	if (vma->vm_start <= addr)
+		return vma;
+	if (!(vma->vm_flags & VM_GROWSDOWN))
+		return NULL;
+	if (vma->vm_end - addr > tsk->rlim[RLIMIT_STACK].rlim_cur)
+		return NULL;
+	vma->vm_offset -= vma->vm_start - addr;
+	vma->vm_start = addr;
+	return vma;
+}
+
+/*
+ * This routine checks the page boundaries, and that the offset is
+ * within the task area. It then calls get_long() to read a long.
+ */
+static int read_long(struct task_struct * tsk, unsigned long addr,
+	unsigned long * result)
+{
+	struct vm_area_struct * vma = find_vma(tsk, addr);
+
+	if (!vma)
+		return -EIO;
+	if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
+		unsigned long low,high;
+		struct vm_area_struct * vma_high = vma;
+
+		if (addr + sizeof(long) >= vma->vm_end) {
+			vma_high = vma->vm_next;
+			if (!vma_high || vma_high->vm_start != vma->vm_end)
+				return -EIO;
+		}
+		low = get_long(vma, addr & ~(sizeof(long)-1));
+		high = get_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1));
+		switch (addr & (sizeof(long)-1)) {
+			case 1:
+				low >>= 8;
+				low |= high << 24;
+				break;
+			case 2:
+				low >>= 16;
+				low |= high << 16;
+				break;
+			case 3:
+				low >>= 24;
+				low |= high << 8;
+				break;
+		}
+		*result = low;
+	} else
+		*result = get_long(vma, addr);
+	return 0;
+}
+
+/*
+ * This routine checks the page boundaries, and that the offset is
+ * within the task area. It then calls put_long() to write a long.
+ */
+static int write_long(struct task_struct * tsk, unsigned long addr,
+	unsigned long data)
+{
+	struct vm_area_struct * vma = find_vma(tsk, addr);
+
+	if (!vma)
+		return -EIO;
+	if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
+		unsigned long low,high;
+		struct vm_area_struct * vma_high = vma;
+
+		if (addr + sizeof(long) >= vma->vm_end) {
+			vma_high = vma->vm_next;
+			if (!vma_high || vma_high->vm_start != vma->vm_end)
+				return -EIO;
+		}
+		low = get_long(vma, addr & ~(sizeof(long)-1));
+		high = get_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1));
+		switch (addr & (sizeof(long)-1)) {
+			case 0: /* shouldn't happen, but safety first */
+				low = data;
+				break;
+			case 1:
+				low &= 0x000000ff;
+				low |= data << 8;
+				high &= ~0xff;
+				high |= data >> 24;
+				break;
+			case 2:
+				low &= 0x0000ffff;
+				low |= data << 16;
+				high &= ~0xffff;
+				high |= data >> 16;
+				break;
+			case 3:
+				low &= 0x00ffffff;
+				low |= data << 24;
+				high &= ~0xffffff;
+				high |= data >> 8;
+				break;
+		}
+		put_long(vma, addr & ~(sizeof(long)-1),low);
+		put_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1),high);
+	} else
+		put_long(vma, addr, data);
+	return 0;
+}
+#endif
+
+asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
+{
+#if 1
+	return -ENOSYS;
+#else
+	struct task_struct *child;
+	struct user * dummy;
+	int i;
+
+
+	dummy = NULL;
+
+	if (request == PTRACE_TRACEME) {
+		/* are we already being traced? */
+		if (current->flags & PF_PTRACED)
+			return -EPERM;
+		/* set the ptrace bit in the process flags. */
+		current->flags |= PF_PTRACED;
+		return 0;
+	}
+	if (pid == 1)		/* you may not mess with init */
+		return -EPERM;
+	if (!(child = get_task(pid)))
+		return -ESRCH;
+	if (request == PTRACE_ATTACH) {
+		if (child == current)
+			return -EPERM;
+		if ((!child->dumpable ||
+		    (current->uid != child->euid) ||
+		    (current->uid != child->uid) ||
+	 	    (current->gid != child->egid) ||
+	 	    (current->gid != child->gid)) && !suser())
+			return -EPERM;
+		/* the same process cannot be attached many times */
+		if (child->flags & PF_PTRACED)
+			return -EPERM;
+		child->flags |= PF_PTRACED;
+		if (child->p_pptr != current) {
+			REMOVE_LINKS(child);
+			child->p_pptr = current;
+			SET_LINKS(child);
+		}
+		send_sig(SIGSTOP, child, 1);
+		return 0;
+	}
+	if (!(child->flags & PF_PTRACED))
+		return -ESRCH;
+	if (child->state != TASK_STOPPED) {
+		if (request != PTRACE_KILL)
+			return -ESRCH;
+	}
+	if (child->p_pptr != current)
+		return -ESRCH;
+
+	switch (request) {
+	/* when I and D space are separate, these will need to be fixed. */
+		case PTRACE_PEEKTEXT: /* read word at location addr. */ 
+		case PTRACE_PEEKDATA: {
+			unsigned long tmp;
+			int res;
+
+			res = read_long(child, addr, &tmp);
+			if (res < 0)
+				return res;
+			res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
+			if (!res)
+				put_fs_long(tmp,(unsigned long *) data);
+			return res;
+		}
+
+	/* read the word at location addr in the USER area. */
+		case PTRACE_PEEKUSR: {
+			unsigned long tmp;
+			int res;
+
+			if ((addr & 3) || addr < 0 || 
+			    addr > sizeof(struct user) - 3)
+				return -EIO;
+
+			res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
+			if (res)
+				return res;
+			tmp = 0;  /* Default return condition */
+			if(addr < 17*sizeof(long)) {
+			  addr = addr >> 2; /* temporary hack. */
+
+			  tmp = get_stack_long(child, sizeof(long)*addr - MAGICNUMBER);
+			  if (addr == DS || addr == ES ||
+			      addr == FS || addr == GS ||
+			      addr == CS || addr == SS)
+			    tmp &= 0xffff;
+			};
+			if(addr >= (long) &dummy->u_debugreg[0] &&
+			   addr <= (long) &dummy->u_debugreg[7]){
+				addr -= (long) &dummy->u_debugreg[0];
+				addr = addr >> 2;
+				tmp = child->debugreg[addr];
+			};
+			put_fs_long(tmp,(unsigned long *) data);
+			return 0;
+		}
+
+      /* when I and D space are separate, this will have to be fixed. */
+		case PTRACE_POKETEXT: /* write the word at location addr. */
+		case PTRACE_POKEDATA:
+			return write_long(child,addr,data);
+
+		case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
+			if ((addr & 3) || addr < 0 || 
+			    addr > sizeof(struct user) - 3)
+				return -EIO;
+
+			addr = addr >> 2; /* temporary hack. */
+
+			if (addr == ORIG_EAX)
+				return -EIO;
+			if (addr == DS || addr == ES ||
+			    addr == FS || addr == GS ||
+			    addr == CS || addr == SS) {
+			    	data &= 0xffff;
+			    	if (data && (data & 3) != 3)
+					return -EIO;
+			}
+			if (addr == EFL) {   /* flags. */
+				data &= FLAG_MASK;
+				data |= get_stack_long(child, EFL*sizeof(long)-MAGICNUMBER)  & ~FLAG_MASK;
+			}
+		  /* Do not allow the user to set the debug register for kernel
+		     address space */
+		  if(addr < 17){
+			  if (put_stack_long(child, sizeof(long)*addr-MAGICNUMBER, data))
+				return -EIO;
+			return 0;
+			};
+
+		  /* We need to be very careful here.  We implicitly
+		     want to modify a portion of the task_struct, and we
+		     have to be selective about what portions we allow someone
+		     to modify. */
+
+		  addr = addr << 2;  /* Convert back again */
+		  if(addr >= (long) &dummy->u_debugreg[0] &&
+		     addr <= (long) &dummy->u_debugreg[7]){
+
+			  if(addr == (long) &dummy->u_debugreg[4]) return -EIO;
+			  if(addr == (long) &dummy->u_debugreg[5]) return -EIO;
+			  if(addr < (long) &dummy->u_debugreg[4] &&
+			     ((unsigned long) data) >= 0xbffffffd) return -EIO;
+			  
+			  if(addr == (long) &dummy->u_debugreg[7]) {
+				  data &= ~DR_CONTROL_RESERVED;
+				  for(i=0; i<4; i++)
+					  if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
+						  return -EIO;
+			  };
+
+			  addr -= (long) &dummy->u_debugreg;
+			  addr = addr >> 2;
+			  child->debugreg[addr] = data;
+			  return 0;
+		  };
+		  return -EIO;
+
+		case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
+		case PTRACE_CONT: { /* restart after signal. */
+			long tmp;
+
+			if ((unsigned long) data > NSIG)
+				return -EIO;
+			if (request == PTRACE_SYSCALL)
+				child->flags |= PF_TRACESYS;
+			else
+				child->flags &= ~PF_TRACESYS;
+			child->exit_code = data;
+			child->state = TASK_RUNNING;
+	/* make sure the single step bit is not set. */
+			tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;
+			put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
+			return 0;
+		}
+
+/*
+ * make the child exit.  Best I can do is send it a sigkill. 
+ * perhaps it should be put in the status that it wants to 
+ * exit.
+ */
+		case PTRACE_KILL: {
+			long tmp;
+
+			child->state = TASK_RUNNING;
+			child->exit_code = SIGKILL;
+	/* make sure the single step bit is not set. */
+			tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;
+			put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
+			return 0;
+		}
+
+		case PTRACE_SINGLESTEP: {  /* set the trap flag. */
+			long tmp;
+
+			if ((unsigned long) data > NSIG)
+				return -EIO;
+			child->flags &= ~PF_TRACESYS;
+			tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) | TRAP_FLAG;
+			put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
+			child->state = TASK_RUNNING;
+			child->exit_code = data;
+	/* give it a chance to run. */
+			return 0;
+		}
+
+		case PTRACE_DETACH: { /* detach a process that was attached. */
+			long tmp;
+
+			if ((unsigned long) data > NSIG)
+				return -EIO;
+			child->flags &= ~(PF_PTRACED|PF_TRACESYS);
+			child->state = TASK_RUNNING;
+			child->exit_code = data;
+			REMOVE_LINKS(child);
+			child->p_pptr = child->p_opptr;
+			SET_LINKS(child);
+			/* make sure the single step bit is not set. */
+			tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;
+			put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
+			return 0;
+		}
+
+		default:
+			return -EIO;
+	}
+#endif
+}
+
+asmlinkage void syscall_trace(void)
+{
+	if ((current->flags & (PF_PTRACED|PF_TRACESYS))
+			!= (PF_PTRACED|PF_TRACESYS))
+		return;
+	current->exit_code = SIGTRAP;
+	current->state = TASK_STOPPED;
+	notify_parent(current);
+	schedule();
+	/*
+	 * this isn't the same as continuing with a signal, but it will do
+	 * for normal use.  strace only continues with a signal if the
+	 * stopping signal is not SIGTRAP.  -brl
+	 */
+	if (current->exit_code)
+		current->signal |= (1 << (current->exit_code - 1));
+	current->exit_code = 0;
+}