1 files changed, 597 insertions, 0 deletions

diff --git a/arch/cris/arch-v32/kernel/ptrace.c b/arch/cris/arch-v32/kernel/ptrace.c
new file mode 100644
index 0000000..208489d
--- /dev/null
+++ b/arch/cris/arch-v32/kernel/ptrace.c
@@ -0,0 +1,597 @@
+/*
+ * Copyright (C) 2000-2003, Axis Communications AB.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+#include <linux/signal.h>
+#include <linux/security.h>
+
+#include <asm/uaccess.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/processor.h>
+#include <asm/arch/hwregs/supp_reg.h>
+
+/*
+ * Determines which bits in CCS the user has access to.
+ * 1 = access, 0 = no access.
+ */
+#define CCS_MASK 0x00087c00     /* SXNZVC */
+
+#define SBIT_USER (1 << (S_CCS_BITNR + CCS_SHIFT))
+
+static int put_debugreg(long pid, unsigned int regno, long data);
+static long get_debugreg(long pid, unsigned int regno);
+static unsigned long get_pseudo_pc(struct task_struct *child);
+void deconfigure_bp(long pid);
+
+extern unsigned long cris_signal_return_page;
+
+/*
+ * Get contents of register REGNO in task TASK.
+ */
+long get_reg(struct task_struct *task, unsigned int regno)
+{
+	/* USP is a special case, it's not in the pt_regs struct but
+	 * in the tasks thread struct
+	 */
+	unsigned long ret;
+
+	if (regno <= PT_EDA)
+		ret = ((unsigned long *)user_regs(task->thread_info))[regno];
+	else if (regno == PT_USP)
+		ret = task->thread.usp;
+	else if (regno == PT_PPC)
+		ret = get_pseudo_pc(task);
+	else if (regno <= PT_MAX)
+		ret = get_debugreg(task->pid, regno);
+	else
+		ret = 0;
+
+	return ret;
+}
+
+/*
+ * Write contents of register REGNO in task TASK.
+ */
+int put_reg(struct task_struct *task, unsigned int regno, unsigned long data)
+{
+	if (regno <= PT_EDA)
+		((unsigned long *)user_regs(task->thread_info))[regno] = data;
+	else if (regno == PT_USP)
+		task->thread.usp = data;
+	else if (regno == PT_PPC) {
+		/* Write pseudo-PC to ERP only if changed. */
+		if (data != get_pseudo_pc(task))
+			((unsigned long *)user_regs(task->thread_info))[PT_ERP] = data;
+	} else if (regno <= PT_MAX)
+		return put_debugreg(task->pid, regno, data);
+	else
+		return -1;
+	return 0;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching.
+ *
+ * Make sure the single step bit is not set.
+ */
+void
+ptrace_disable(struct task_struct *child)
+{
+	unsigned long tmp;
+
+	/* Deconfigure SPC and S-bit. */
+	tmp = get_reg(child, PT_CCS) & ~SBIT_USER;
+	put_reg(child, PT_CCS, tmp);
+	put_reg(child, PT_SPC, 0);
+
+	/* Deconfigure any watchpoints associated with the child. */
+	deconfigure_bp(child->pid);
+}
+
+
+asmlinkage int
+sys_ptrace(long request, long pid, long addr, long data)
+{
+	struct task_struct *child;
+	int ret;
+	unsigned long __user *datap = (unsigned long __user *)data;
+
+	lock_kernel();
+	ret = -EPERM;
+
+	if (request == PTRACE_TRACEME) {
+		/* are we already being traced? */
+		if (current->ptrace & PT_PTRACED)
+			goto out;
+		ret = security_ptrace(current->parent, current);
+		if (ret)
+			goto out;
+		/* set the ptrace bit in the process flags. */
+		current->ptrace |= PT_PTRACED;
+		ret = 0;
+		goto out;
+	}
+
+	ret = -ESRCH;
+	read_lock(&tasklist_lock);
+	child = find_task_by_pid(pid);
+
+	if (child)
+		get_task_struct(child);
+
+	read_unlock(&tasklist_lock);
+
+	if (!child)
+		goto out;
+
+	ret = -EPERM;
+
+	if (pid == 1)		/* Leave the init process alone! */
+		goto out_tsk;
+
+	if (request == PTRACE_ATTACH) {
+		ret = ptrace_attach(child);
+		goto out_tsk;
+	}
+
+	ret = ptrace_check_attach(child, request == PTRACE_KILL);
+	if (ret < 0)
+		goto out_tsk;
+
+	switch (request) {
+		/* Read word at location address. */
+		case PTRACE_PEEKTEXT:
+		case PTRACE_PEEKDATA: {
+			unsigned long tmp;
+			int copied;
+
+			ret = -EIO;
+
+			/* The signal trampoline page is outside the normal user-addressable
+			 * space but still accessible. This is hack to make it possible to
+			 * access the signal handler code in GDB.
+			 */
+			if ((addr & PAGE_MASK) == cris_signal_return_page) {
+				/* The trampoline page is globally mapped, no page table to traverse.*/
+				tmp = *(unsigned long*)addr;
+			} else {
+				copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
+
+				if (copied != sizeof(tmp))
+					break;
+			}
+
+			ret = put_user(tmp,datap);
+			break;
+		}
+
+		/* Read the word at location address in the USER area. */
+		case PTRACE_PEEKUSR: {
+			unsigned long tmp;
+
+			ret = -EIO;
+			if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
+				break;
+
+			tmp = get_reg(child, addr >> 2);
+			ret = put_user(tmp, datap);
+			break;
+		}
+
+		/* Write the word at location address. */
+		case PTRACE_POKETEXT:
+		case PTRACE_POKEDATA:
+			ret = 0;
+
+			if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
+				break;
+
+			ret = -EIO;
+			break;
+
+ 		/* Write the word at location address in the USER area. */
+		case PTRACE_POKEUSR:
+			ret = -EIO;
+			if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
+				break;
+
+			addr >>= 2;
+
+			if (addr == PT_CCS) {
+				/* don't allow the tracing process to change stuff like
+				 * interrupt enable, kernel/user bit, dma enables etc.
+				 */
+				data &= CCS_MASK;
+				data |= get_reg(child, PT_CCS) & ~CCS_MASK;
+			}
+			if (put_reg(child, addr, data))
+				break;
+			ret = 0;
+			break;
+
+		case PTRACE_SYSCALL:
+		case PTRACE_CONT:
+			ret = -EIO;
+
+			if (!valid_signal(data))
+				break;
+
+			/* Continue means no single-step. */
+			put_reg(child, PT_SPC, 0);
+
+			if (!get_debugreg(child->pid, PT_BP_CTRL)) {
+				unsigned long tmp;
+				/* If no h/w bp configured, disable S bit. */
+				tmp = get_reg(child, PT_CCS) & ~SBIT_USER;
+				put_reg(child, PT_CCS, tmp);
+			}
+
+			if (request == PTRACE_SYSCALL) {
+				set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+			}
+			else {
+				clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+			}
+
+			child->exit_code = data;
+
+			/* TODO: make sure any pending breakpoint is killed */
+			wake_up_process(child);
+			ret = 0;
+
+			break;
+
+ 		/* Make the child exit by sending it a sigkill. */
+		case PTRACE_KILL:
+			ret = 0;
+
+			if (child->exit_state == EXIT_ZOMBIE)
+				break;
+
+			child->exit_code = SIGKILL;
+
+			/* Deconfigure single-step and h/w bp. */
+			ptrace_disable(child);
+
+			/* TODO: make sure any pending breakpoint is killed */
+			wake_up_process(child);
+			break;
+
+		/* Set the trap flag. */
+		case PTRACE_SINGLESTEP:	{
+			unsigned long tmp;
+			ret = -EIO;
+
+			/* Set up SPC if not set already (in which case we have
+			   no other choice but to trust it). */
+			if (!get_reg(child, PT_SPC)) {
+				/* In case we're stopped in a delay slot. */
+				tmp = get_reg(child, PT_ERP) & ~1;
+				put_reg(child, PT_SPC, tmp);
+			}
+			tmp = get_reg(child, PT_CCS) | SBIT_USER;
+			put_reg(child, PT_CCS, tmp);
+
+			if (!valid_signal(data))
+				break;
+
+			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
+			/* TODO: set some clever breakpoint mechanism... */
+
+			child->exit_code = data;
+			wake_up_process(child);
+			ret = 0;
+			break;
+
+		}
+		case PTRACE_DETACH:
+			ret = ptrace_detach(child, data);
+			break;
+
+		/* Get all GP registers from the child. */
+		case PTRACE_GETREGS: {
+		  	int i;
+			unsigned long tmp;
+
+			for (i = 0; i <= PT_MAX; i++) {
+				tmp = get_reg(child, i);
+
+				if (put_user(tmp, datap)) {
+					ret = -EFAULT;
+					goto out_tsk;
+				}
+
+				datap++;
+			}
+
+			ret = 0;
+			break;
+		}
+
+		/* Set all GP registers in the child. */
+		case PTRACE_SETREGS: {
+			int i;
+			unsigned long tmp;
+
+			for (i = 0; i <= PT_MAX; i++) {
+				if (get_user(tmp, datap)) {
+					ret = -EFAULT;
+					goto out_tsk;
+				}
+
+				if (i == PT_CCS) {
+					tmp &= CCS_MASK;
+					tmp |= get_reg(child, PT_CCS) & ~CCS_MASK;
+				}
+
+				put_reg(child, i, tmp);
+				datap++;
+			}
+
+			ret = 0;
+			break;
+		}
+
+		default:
+			ret = ptrace_request(child, request, addr, data);
+			break;
+	}
+out_tsk:
+	put_task_struct(child);
+out:
+	unlock_kernel();
+	return ret;
+}
+
+void do_syscall_trace(void)
+{
+	if (!test_thread_flag(TIF_SYSCALL_TRACE))
+		return;
+
+	if (!(current->ptrace & PT_PTRACED))
+		return;
+
+	/* the 0x80 provides a way for the tracing parent to distinguish
+	   between a syscall stop and SIGTRAP delivery */
+	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+				 ? 0x80 : 0));
+
+	/*
+	 * This isn't the same as continuing with a signal, but it will do for
+	 * normal use.
+	 */
+	if (current->exit_code) {
+		send_sig(current->exit_code, current, 1);
+		current->exit_code = 0;
+	}
+}
+
+/* Returns the size of an instruction that has a delay slot. */
+
+static int insn_size(struct task_struct *child, unsigned long pc)
+{
+  unsigned long opcode;
+  int copied;
+  int opsize = 0;
+
+  /* Read the opcode at pc (do what PTRACE_PEEKTEXT would do). */
+  copied = access_process_vm(child, pc, &opcode, sizeof(opcode), 0);
+  if (copied != sizeof(opcode))
+    return 0;
+
+  switch ((opcode & 0x0f00) >> 8) {
+  case 0x0:
+  case 0x9:
+  case 0xb:
+	  opsize = 2;
+	  break;
+  case 0xe:
+  case 0xf:
+	  opsize = 6;
+	  break;
+  case 0xd:
+	  /* Could be 4 or 6; check more bits. */
+	  if ((opcode & 0xff) == 0xff)
+		  opsize = 4;
+	  else
+		  opsize = 6;
+	  break;
+  default:
+	  panic("ERROR: Couldn't find size of opcode 0x%lx at 0x%lx\n",
+		opcode, pc);
+  }
+
+  return opsize;
+}
+
+static unsigned long get_pseudo_pc(struct task_struct *child)
+{
+	/* Default value for PC is ERP. */
+	unsigned long pc = get_reg(child, PT_ERP);
+
+	if (pc & 0x1) {
+		unsigned long spc = get_reg(child, PT_SPC);
+		/* Delay slot bit set. Report as stopped on proper
+		   instruction. */
+		if (spc) {
+			/* Rely on SPC if set. FIXME: We might want to check
+			   that EXS indicates we stopped due to a single-step
+			   exception. */
+			pc = spc;
+		} else {
+			/* Calculate the PC from the size of the instruction
+			   that the delay slot we're in belongs to. */
+			pc += insn_size(child, pc & ~1) - 1;
+		}
+	}
+	return pc;
+}
+
+static long bp_owner = 0;
+
+/* Reachable from exit_thread in signal.c, so not static. */
+void deconfigure_bp(long pid)
+{
+	int bp;
+
+	/* Only deconfigure if the pid is the owner. */
+	if (bp_owner != pid)
+		return;
+
+	for (bp = 0; bp < 6; bp++) {
+		unsigned long tmp;
+		/* Deconfigure start and end address (also gets rid of ownership). */
+		put_debugreg(pid, PT_BP + 3 + (bp * 2), 0);
+		put_debugreg(pid, PT_BP + 4 + (bp * 2), 0);
+
+		/* Deconfigure relevant bits in control register. */
+		tmp = get_debugreg(pid, PT_BP_CTRL) & ~(3 << (2 + (bp * 4)));
+		put_debugreg(pid, PT_BP_CTRL, tmp);
+	}
+	/* No owner now. */
+	bp_owner = 0;
+}
+
+static int put_debugreg(long pid, unsigned int regno, long data)
+{
+	int ret = 0;
+	register int old_srs;
+
+#ifdef CONFIG_ETRAX_KGDB
+	/* Ignore write, but pretend it was ok if value is 0
+	   (we don't want POKEUSR/SETREGS failing unnessecarily). */
+	return (data == 0) ? ret : -1;
+#endif
+
+	/* Simple owner management. */
+	if (!bp_owner)
+		bp_owner = pid;
+	else if (bp_owner != pid) {
+		/* Ignore write, but pretend it was ok if value is 0
+		   (we don't want POKEUSR/SETREGS failing unnessecarily). */
+		return (data == 0) ? ret : -1;
+	}
+
+	/* Remember old SRS. */
+	SPEC_REG_RD(SPEC_REG_SRS, old_srs);
+	/* Switch to BP bank. */
+	SUPP_BANK_SEL(BANK_BP);
+
+	switch (regno - PT_BP) {
+	case 0:
+		SUPP_REG_WR(0, data); break;
+	case 1:
+	case 2:
+		if (data)
+			ret = -1;
+		break;
+	case 3:
+		SUPP_REG_WR(3, data); break;
+	case 4:
+		SUPP_REG_WR(4, data); break;
+	case 5:
+		SUPP_REG_WR(5, data); break;
+	case 6:
+		SUPP_REG_WR(6, data); break;
+	case 7:
+		SUPP_REG_WR(7, data); break;
+	case 8:
+		SUPP_REG_WR(8, data); break;
+	case 9:
+		SUPP_REG_WR(9, data); break;
+	case 10:
+		SUPP_REG_WR(10, data); break;
+	case 11:
+		SUPP_REG_WR(11, data); break;
+	case 12:
+		SUPP_REG_WR(12, data); break;
+	case 13:
+		SUPP_REG_WR(13, data); break;
+	case 14:
+		SUPP_REG_WR(14, data); break;
+	default:
+		ret = -1;
+		break;
+	}
+
+	/* Restore SRS. */
+	SPEC_REG_WR(SPEC_REG_SRS, old_srs);
+	/* Just for show. */
+	NOP();
+	NOP();
+	NOP();
+
+	return ret;
+}
+
+static long get_debugreg(long pid, unsigned int regno)
+{
+	register int old_srs;
+	register long data;
+
+	if (pid != bp_owner) {
+		return 0;
+	}
+
+	/* Remember old SRS. */
+	SPEC_REG_RD(SPEC_REG_SRS, old_srs);
+	/* Switch to BP bank. */
+	SUPP_BANK_SEL(BANK_BP);
+
+	switch (regno - PT_BP) {
+	case 0:
+		SUPP_REG_RD(0, data); break;
+	case 1:
+	case 2:
+		/* error return value? */
+		data = 0;
+		break;
+	case 3:
+		SUPP_REG_RD(3, data); break;
+	case 4:
+		SUPP_REG_RD(4, data); break;
+	case 5:
+		SUPP_REG_RD(5, data); break;
+	case 6:
+		SUPP_REG_RD(6, data); break;
+	case 7:
+		SUPP_REG_RD(7, data); break;
+	case 8:
+		SUPP_REG_RD(8, data); break;
+	case 9:
+		SUPP_REG_RD(9, data); break;
+	case 10:
+		SUPP_REG_RD(10, data); break;
+	case 11:
+		SUPP_REG_RD(11, data); break;
+	case 12:
+		SUPP_REG_RD(12, data); break;
+	case 13:
+		SUPP_REG_RD(13, data); break;
+	case 14:
+		SUPP_REG_RD(14, data); break;
+	default:
+		/* error return value? */
+		data = 0;
+	}
+
+	/* Restore SRS. */
+	SPEC_REG_WR(SPEC_REG_SRS, old_srs);
+	/* Just for show. */
+	NOP();
+	NOP();
+	NOP();
+
+	return data;
+}