1 files changed, 744 insertions, 0 deletions

diff --git a/arch/arm26/kernel/ptrace.c b/arch/arm26/kernel/ptrace.c
new file mode 100644
index 000000000000..2a137146a77c
--- /dev/null
+++ b/arch/arm26/kernel/ptrace.c
@@ -0,0 +1,744 @@
+/*
+ *  linux/arch/arm26/kernel/ptrace.c
+ *
+ *  By Ross Biro 1/23/92
+ * edited by Linus Torvalds
+ * ARM modifications Copyright (C) 2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+#include <linux/security.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+//#include <asm/processor.h>
+
+#include "ptrace.h"
+
+#define REG_PC  15
+#define REG_PSR 15
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+/*
+ * Breakpoint SWI instruction: SWI &9F0001
+ */
+#define BREAKINST_ARM   0xef9f0001
+
+/*
+ * Get the address of the live pt_regs for the specified task.
+ * These are saved onto the top kernel stack when the process
+ * is not running.
+ *
+ * Note: if a user thread is execve'd from kernel space, the
+ * kernel stack will not be empty on entry to the kernel, so
+ * ptracing these tasks will fail.
+ */
+static inline struct pt_regs *
+get_user_regs(struct task_struct *task)
+{
+        return __get_user_regs(task->thread_info);
+}
+
+/*
+ * 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 THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline long get_user_reg(struct task_struct *task, int offset)
+{
+        return get_user_regs(task)->uregs[offset];
+}
+
+/*
+ * this routine will put a word on the processes privileged stack.
+ * the offset is how far from the base addr as stored in the THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline int
+put_user_reg(struct task_struct *task, int offset, long data)
+{
+        struct pt_regs newregs, *regs = get_user_regs(task);
+        int ret = -EINVAL;
+
+        newregs = *regs;
+        newregs.uregs[offset] = data;
+
+        if (valid_user_regs(&newregs)) {
+                regs->uregs[offset] = data;
+                ret = 0;
+        }
+
+        return ret;
+}
+
+static inline int
+read_u32(struct task_struct *task, unsigned long addr, u32 *res)
+{
+        int ret;
+
+        ret = access_process_vm(task, addr, res, sizeof(*res), 0);
+
+        return ret == sizeof(*res) ? 0 : -EIO;
+}
+
+static inline int
+read_instr(struct task_struct *task, unsigned long addr, u32 *res)
+{
+        int ret;
+        u32 val;
+        ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0);
+        ret = ret == sizeof(val) ? 0 : -EIO;
+        *res = val;
+        return ret;
+}
+
+/*
+ * Get value of register `rn' (in the instruction)
+ */
+static unsigned long
+ptrace_getrn(struct task_struct *child, unsigned long insn)
+{
+        unsigned int reg = (insn >> 16) & 15;
+        unsigned long val;
+
+        val = get_user_reg(child, reg);
+        if (reg == 15)
+                val = pc_pointer(val + 8); //FIXME - correct for arm26?
+
+        return val;
+}
+
+/*
+ * Get value of operand 2 (in an ALU instruction)
+ */
+static unsigned long
+ptrace_getaluop2(struct task_struct *child, unsigned long insn)
+{
+        unsigned long val;
+        int shift;
+        int type;
+
+        if (insn & 1 << 25) {
+                val = insn & 255;
+                shift = (insn >> 8) & 15;
+                type = 3;
+        } else {
+                val = get_user_reg (child, insn & 15);
+
+                if (insn & (1 << 4))
+                        shift = (int)get_user_reg (child, (insn >> 8) & 15);
+                else
+                        shift = (insn >> 7) & 31;
+
+                type = (insn >> 5) & 3;
+        }
+
+        switch (type) {
+        case 0: val <<= shift;  break;
+        case 1: val >>= shift;  break;
+        case 2:
+                val = (((signed long)val) >> shift);
+                break;
+        case 3:
+                val = (val >> shift) | (val << (32 - shift));
+                break;
+        }
+        return val;
+}
+
+/*
+ * Get value of operand 2 (in a LDR instruction)
+ */
+static unsigned long
+ptrace_getldrop2(struct task_struct *child, unsigned long insn)
+{
+        unsigned long val;
+        int shift;
+        int type;
+
+        val = get_user_reg(child, insn & 15);
+        shift = (insn >> 7) & 31;
+        type = (insn >> 5) & 3;
+
+        switch (type) {
+        case 0: val <<= shift;  break;
+        case 1: val >>= shift;  break;
+        case 2:
+                val = (((signed long)val) >> shift);
+                break;
+        case 3:
+                val = (val >> shift) | (val << (32 - shift));
+                break;
+        }
+        return val;
+}
+
+#define OP_MASK 0x01e00000
+#define OP_AND  0x00000000
+#define OP_EOR  0x00200000
+#define OP_SUB  0x00400000
+#define OP_RSB  0x00600000
+#define OP_ADD  0x00800000
+#define OP_ADC  0x00a00000
+#define OP_SBC  0x00c00000
+#define OP_RSC  0x00e00000
+#define OP_ORR  0x01800000
+#define OP_MOV  0x01a00000
+#define OP_BIC  0x01c00000
+#define OP_MVN  0x01e00000
+
+static unsigned long
+get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn)
+{
+        u32 alt = 0;
+
+        switch (insn & 0x0e000000) {
+        case 0x00000000:
+        case 0x02000000: {
+                /*
+                 * data processing
+                 */
+                long aluop1, aluop2, ccbit;
+
+                if ((insn & 0xf000) != 0xf000)
+                        break;
+
+                aluop1 = ptrace_getrn(child, insn);
+                aluop2 = ptrace_getaluop2(child, insn);
+                ccbit  = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0;
+
+                switch (insn & OP_MASK) {
+                case OP_AND: alt = aluop1 & aluop2;             break;
+                case OP_EOR: alt = aluop1 ^ aluop2;             break;
+                case OP_SUB: alt = aluop1 - aluop2;             break;
+                case OP_RSB: alt = aluop2 - aluop1;             break;
+                case OP_ADD: alt = aluop1 + aluop2;             break;
+                case OP_ADC: alt = aluop1 + aluop2 + ccbit;     break;
+                case OP_SBC: alt = aluop1 - aluop2 + ccbit;     break;
+                case OP_RSC: alt = aluop2 - aluop1 + ccbit;     break;
+                case OP_ORR: alt = aluop1 | aluop2;             break;
+                case OP_MOV: alt = aluop2;                      break;
+                case OP_BIC: alt = aluop1 & ~aluop2;            break;
+                case OP_MVN: alt = ~aluop2;                     break;
+                }
+                break;
+        }
+
+        case 0x04000000:
+        case 0x06000000:
+                /*
+                 * ldr
+                 */
+                if ((insn & 0x0010f000) == 0x0010f000) {
+                        unsigned long base;
+
+                        base = ptrace_getrn(child, insn);
+                        if (insn & 1 << 24) {
+                                long aluop2;
+
+                                if (insn & 0x02000000)
+                                        aluop2 = ptrace_getldrop2(child, insn);
+                                else
+                                        aluop2 = insn & 0xfff;
+
+                                if (insn & 1 << 23)
+                                        base += aluop2;
+                                else
+                                        base -= aluop2;
+                        }
+                        if (read_u32(child, base, &alt) == 0)
+                                alt = pc_pointer(alt);
+                }
+                break;
+
+        case 0x08000000:
+                /*
+                 * ldm
+                 */
+                if ((insn & 0x00108000) == 0x00108000) {
+                        unsigned long base;
+                        unsigned int nr_regs;
+
+                        if (insn & (1 << 23)) {
+                                nr_regs = hweight16(insn & 65535) << 2;
+
+                                if (!(insn & (1 << 24)))
+                                        nr_regs -= 4;
+                        } else {
+                                if (insn & (1 << 24))
+                                        nr_regs = -4;
+                                else
+                                        nr_regs = 0;
+                        }
+
+                        base = ptrace_getrn(child, insn);
+
+                        if (read_u32(child, base + nr_regs, &alt) == 0)
+                                alt = pc_pointer(alt);
+                        break;
+                }
+                break;
+
+        case 0x0a000000: {
+                /*
+                 * bl or b
+                 */
+                signed long displ;
+                /* It's a branch/branch link: instead of trying to
+                 * figure out whether the branch will be taken or not,
+                 * we'll put a breakpoint at both locations.  This is
+                 * simpler, more reliable, and probably not a whole lot
+                 * slower than the alternative approach of emulating the
+                 * branch.
+                 */
+                displ = (insn & 0x00ffffff) << 8;
+                displ = (displ >> 6) + 8;
+                if (displ != 0 && displ != 4)
+                        alt = pc + displ;
+            }
+            break;
+        }
+
+        return alt;
+}
+
+static int
+swap_insn(struct task_struct *task, unsigned long addr,
+          void *old_insn, void *new_insn, int size)
+{
+        int ret;
+
+        ret = access_process_vm(task, addr, old_insn, size, 0);
+        if (ret == size)
+                ret = access_process_vm(task, addr, new_insn, size, 1);
+        return ret;
+}
+
+static void
+add_breakpoint(struct task_struct *task, struct debug_info *dbg, unsigned long addr)
+{
+        int nr = dbg->nsaved;
+
+        if (nr < 2) {
+                u32 new_insn = BREAKINST_ARM;
+                int res;
+
+                res = swap_insn(task, addr, &dbg->bp[nr].insn, &new_insn, 4);
+
+                if (res == 4) {
+                        dbg->bp[nr].address = addr;
+                        dbg->nsaved += 1;
+                }
+        } else
+                printk(KERN_ERR "ptrace: too many breakpoints\n");
+}
+
+/*
+ * Clear one breakpoint in the user program.  We copy what the hardware
+ * does and use bit 0 of the address to indicate whether this is a Thumb
+ * breakpoint or an ARM breakpoint.
+ */
+static void clear_breakpoint(struct task_struct *task, struct debug_entry *bp)
+{
+        unsigned long addr = bp->address;
+        u32 old_insn;
+        int ret;
+
+        ret = swap_insn(task, addr & ~3, &old_insn,
+                        &bp->insn, 4);
+
+        if (ret != 4 || old_insn != BREAKINST_ARM)
+                printk(KERN_ERR "%s:%d: corrupted ARM breakpoint at "
+                        "0x%08lx (0x%08x)\n", task->comm, task->pid,
+                        addr, old_insn);
+}
+
+void ptrace_set_bpt(struct task_struct *child)
+{
+        struct pt_regs *regs;
+        unsigned long pc;
+        u32 insn;
+        int res;
+
+        regs = get_user_regs(child);
+        pc = instruction_pointer(regs);
+
+        res = read_instr(child, pc, &insn);
+        if (!res) {
+                struct debug_info *dbg = &child->thread.debug;
+                unsigned long alt;
+
+                dbg->nsaved = 0;
+
+                alt = get_branch_address(child, pc, insn);
+                if (alt)
+                        add_breakpoint(child, dbg, alt);
+
+                /*
+                 * Note that we ignore the result of setting the above
+                 * breakpoint since it may fail.  When it does, this is
+                 * not so much an error, but a forewarning that we may
+                 * be receiving a prefetch abort shortly.
+                 *
+                 * If we don't set this breakpoint here, then we can
+                 * lose control of the thread during single stepping.
+                 */
+                if (!alt || predicate(insn) != PREDICATE_ALWAYS)
+                        add_breakpoint(child, dbg, pc + 4);
+        }
+}
+
+/*
+ * Ensure no single-step breakpoint is pending.  Returns non-zero
+ * value if child was being single-stepped.
+ */
+void ptrace_cancel_bpt(struct task_struct *child)
+{
+        int i, nsaved = child->thread.debug.nsaved;
+
+        child->thread.debug.nsaved = 0;
+
+        if (nsaved > 2) {
+                printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved);
+                nsaved = 2;
+        }
+
+        for (i = 0; i < nsaved; i++)
+                clear_breakpoint(child, &child->thread.debug.bp[i]);
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure the single step bit is not set.
+ */
+void ptrace_disable(struct task_struct *child)
+{
+        child->ptrace &= ~PT_SINGLESTEP;
+        ptrace_cancel_bpt(child);
+}
+
+/*
+ * Handle hitting a breakpoint.
+ */
+void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
+{
+        siginfo_t info;
+
+        /*
+         * The PC is always left pointing at the next instruction.  Fix this.
+         */
+        regs->ARM_pc -= 4;
+
+        if (tsk->thread.debug.nsaved == 0)
+                printk(KERN_ERR "ptrace: bogus breakpoint trap\n");
+
+        ptrace_cancel_bpt(tsk);
+
+        info.si_signo = SIGTRAP;
+        info.si_errno = 0;
+        info.si_code  = TRAP_BRKPT;
+        info.si_addr  = (void *)instruction_pointer(regs) - 4;
+
+        force_sig_info(SIGTRAP, &info, tsk);
+}
+
+/*
+ * Read the word at offset "off" into the "struct user".  We
+ * actually access the pt_regs stored on the kernel stack.
+ */
+static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
+                            unsigned long *ret)
+{
+        unsigned long tmp;
+
+        if (off & 3 || off >= sizeof(struct user))
+                return -EIO;
+
+        tmp = 0;
+        if (off < sizeof(struct pt_regs))
+                tmp = get_user_reg(tsk, off >> 2);
+
+        return put_user(tmp, ret);
+}
+
+/*
+ * Write the word at offset "off" into "struct user".  We
+ * actually access the pt_regs stored on the kernel stack.
+ */
+static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
+                             unsigned long val)
+{
+        if (off & 3 || off >= sizeof(struct user))
+                return -EIO;
+
+        if (off >= sizeof(struct pt_regs))
+                return 0;
+
+        return put_user_reg(tsk, off >> 2, val);
+}
+
+/*
+ * Get all user integer registers.
+ */
+static int ptrace_getregs(struct task_struct *tsk, void *uregs)
+{
+        struct pt_regs *regs = get_user_regs(tsk);
+
+        return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
+}
+
+/*
+ * Set all user integer registers.
+ */
+static int ptrace_setregs(struct task_struct *tsk, void *uregs)
+{
+        struct pt_regs newregs;
+        int ret;
+
+        ret = -EFAULT;
+        if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
+                struct pt_regs *regs = get_user_regs(tsk);
+
+                ret = -EINVAL;
+                if (valid_user_regs(&newregs)) {
+                        *regs = newregs;
+                        ret = 0;
+                }
+        }
+
+        return ret;
+}
+
+/*
+ * Get the child FPU state.
+ */
+static int ptrace_getfpregs(struct task_struct *tsk, void *ufp)
+{
+        return copy_to_user(ufp, &tsk->thread_info->fpstate,
+                            sizeof(struct user_fp)) ? -EFAULT : 0;
+}
+
+/*
+ * Set the child FPU state.
+ */
+static int ptrace_setfpregs(struct task_struct *tsk, void *ufp)
+{
+        set_stopped_child_used_math(tsk);
+        return copy_from_user(&tsk->thread_info->fpstate, ufp,
+                              sizeof(struct user_fp)) ? -EFAULT : 0;
+}
+
+static int do_ptrace(int request, struct task_struct *child, long addr, long data)
+{
+        unsigned long tmp;
+        int ret;
+
+        switch (request) {
+                /*
+                 * read word at location "addr" in the child process.
+                 */
+                case PTRACE_PEEKTEXT:
+                case PTRACE_PEEKDATA:
+                        ret = access_process_vm(child, addr, &tmp,
+                                                sizeof(unsigned long), 0);
+                        if (ret == sizeof(unsigned long))
+                                ret = put_user(tmp, (unsigned long *) data);
+                        else
+                                ret = -EIO;
+                        break;
+
+                case PTRACE_PEEKUSR:
+                        ret = ptrace_read_user(child, addr, (unsigned long *)data);
+                        break;
+
+                /*
+                 * write the word at location addr.
+                 */
+                case PTRACE_POKETEXT:
+                case PTRACE_POKEDATA:
+                        ret = access_process_vm(child, addr, &data,
+                                                sizeof(unsigned long), 1);
+                        if (ret == sizeof(unsigned long))
+                                ret = 0;
+                        else
+                                ret = -EIO;
+                        break;
+
+                case PTRACE_POKEUSR:
+                        ret = ptrace_write_user(child, addr, data);
+                        break;
+
+                /*
+                 * continue/restart and stop at next (return from) syscall
+                 */
+                case PTRACE_SYSCALL:
+                case PTRACE_CONT:
+                        ret = -EIO;
+                        if ((unsigned long) data > _NSIG)
+                                break;
+                        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;
+                        /* make sure single-step breakpoint is gone. */
+                        child->ptrace &= ~PT_SINGLESTEP;
+                        ptrace_cancel_bpt(child);
+                        wake_up_process(child);
+                        ret = 0;
+                        break;
+
+                /*
+                 * 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:
+                        /* make sure single-step breakpoint is gone. */
+                        child->ptrace &= ~PT_SINGLESTEP;
+                        ptrace_cancel_bpt(child);
+                        if (child->exit_state != EXIT_ZOMBIE) {
+                                child->exit_code = SIGKILL;
+                                wake_up_process(child);
+                        }
+                        ret = 0;
+                        break;
+
+                /*
+                 * execute single instruction.
+                 */
+                case PTRACE_SINGLESTEP:
+                        ret = -EIO;
+                        if ((unsigned long) data > _NSIG)
+                                break;
+                        child->ptrace |= PT_SINGLESTEP;
+                        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+                        child->exit_code = data;
+                        /* give it a chance to run. */
+                        wake_up_process(child);
+                        ret = 0;
+                        break;
+
+                case PTRACE_DETACH:
+                        ret = ptrace_detach(child, data);
+                        break;
+
+                case PTRACE_GETREGS:
+                        ret = ptrace_getregs(child, (void *)data);
+                        break;
+
+                case PTRACE_SETREGS:
+                        ret = ptrace_setregs(child, (void *)data);
+                        break;
+
+                case PTRACE_GETFPREGS:
+                        ret = ptrace_getfpregs(child, (void *)data);
+                        break;
+                
+                case PTRACE_SETFPREGS:
+                        ret = ptrace_setfpregs(child, (void *)data);
+                        break;
+
+                default:
+                        ret = ptrace_request(child, request, addr, data);
+                        break;
+        }
+
+        return ret;
+}
+
+asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
+{
+        struct task_struct *child;
+        int ret;
+
+        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)           /* you may not mess with init */
+                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)
+                ret = do_ptrace(request, child, addr, data);
+
+out_tsk:
+        put_task_struct(child);
+out:
+        unlock_kernel();
+        return ret;
+}
+
+asmlinkage void syscall_trace(int why, struct pt_regs *regs)
+{
+        unsigned long ip;
+
+        if (!test_thread_flag(TIF_SYSCALL_TRACE))
+                return;
+        if (!(current->ptrace & PT_PTRACED))
+                return;
+
+        /*
+         * Save IP.  IP is used to denote syscall entry/exit:
+         *  IP = 0 -> entry, = 1 -> exit
+         */
+        ip = regs->ARM_ip;
+        regs->ARM_ip = why;
+
+        /* 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.  strace only continues with a signal if the
+         * stopping signal is not SIGTRAP.  -brl
+         */
+        if (current->exit_code) {
+                send_sig(current->exit_code, current, 1);
+                current->exit_code = 0;
+        }
+        regs->ARM_ip = ip;
+}