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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [ppc/] [kernel/] [ptrace.c] - Blame information for rev 1782

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/*
 *  linux/arch/ppc/kernel/ptrace.c
 *
 *  Copyright (C) 1994 by Hamish Macdonald
 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
 *
 * Adapted from 'linux/arch/m68k/kernel/ptrace.c'
 * PowerPC version by Gary Thomas (gdt@linuxppc.org)
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file README.legal in the main directory of
 * this archive for more details.
 */
 
#include <stddef.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/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
 
/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */
 
/* Find the stack offset for a register, relative to tss.ksp. */
#define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
/* Mapping from PT_xxx to the stack offset at which the register is
   saved.  Notice that usp has no stack-slot and needs to be treated
   specially (see get_reg/put_reg below). */
static int regoff[] = {
};
 
/* 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;
}
 
/*
 * Get contents of register REGNO in task TASK.
 */
static inline long get_reg(struct task_struct *task, int regno)
{
        struct pt_regs *regs = task->tss.regs;
        if (regno <= PT_R31)
        {
                return (regs->gpr[regno]);
        } else
        if (regno == PT_NIP)
        {
                return (regs->nip);
        } else
        if (regno == PT_MSR)
        {
                return (regs->msr);
        } else
        if (regno == PT_ORIG_R3)
        {
                return (regs->orig_gpr3);
        } else
        if (regno == PT_CTR)
        {
                return (regs->ctr);
        } else
        if (regno == PT_LNK)
        {
                return (regs->link);
        } else
        if (regno == PT_XER)
        {
                return (regs->xer);
        } else
        if (regno == PT_CCR)
        {
                return (regs->ccr);
        }
        return (0);
}
 
/*
 * Write contents of register REGNO in task TASK.
 */
static inline int put_reg(struct task_struct *task, int regno,
                          unsigned long data)
{
        struct pt_regs *regs = task->tss.regs;
        if (regno <= PT_R31)
        {
                regs->gpr[regno] = data;
        } else
        if (regno == PT_NIP)
        {
                regs->nip = data;
        } else
        if (regno == PT_MSR)
        {
                regs->msr = data;
        } else
        if (regno == PT_CTR)
        {
                regs->ctr = data;
        } else
        if (regno == PT_LNK)
        {
                regs->link = data;
        } else
        if (regno == PT_XER)
        {
                regs->xer = data;
        } else
        if (regno == PT_CCR)
        {
                regs->ccr = data;
        } else
        { /* Invalid register */
                return (-1);
        }
        return (0);
}
 
static inline
set_single_step(struct task_struct *task)
{
        struct pt_regs *regs = task->tss.regs;
printk("Set single step - Task: %x, Regs: %x", task, regs);
printk(", MSR: %x/", regs->msr);
        regs->msr |= MSR_SE;
printk("%x\n", regs->msr);
}
 
static inline
clear_single_step(struct task_struct *task)
{
        struct pt_regs *regs = task->tss.regs;
        regs->msr &= ~MSR_SE;
}
 
/*
 * 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 task_struct * tsk,
        struct vm_area_struct * vma, unsigned long addr)
{
        pgd_t * pgdir;
        pmd_t * pgmiddle;
        pte_t * pgtable;
        unsigned long page;
 
repeat:
        pgdir = pgd_offset(vma->vm_mm, addr);
        if (pgd_none(*pgdir)) {
                do_no_page(tsk, vma, addr, 0);
                goto repeat;
        }
        if (pgd_bad(*pgdir)) {
                printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
                pgd_clear(pgdir);
                return 0;
        }
        pgmiddle = pmd_offset(pgdir,addr);
        if (pmd_none(*pgmiddle)) {
                do_no_page(tsk, vma, addr, 0);
                goto repeat;
        }
        if (pmd_bad(*pgmiddle)) {
                printk("ptrace: bad page directory %08lx\n",
                       pmd_val(*pgmiddle));
                pmd_clear(pgmiddle);
                return 0;
        }
        pgtable = pte_offset(pgmiddle, addr);
        if (!pte_present(*pgtable)) {
                do_no_page(tsk, vma, addr, 0);
                goto repeat;
        }
        page = pte_page(*pgtable);
/* this is a hack for non-kernel-mapped video buffers and similar */
        if (page >= high_memory)
                return 0;
        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 task_struct * tsk, struct vm_area_struct * vma, unsigned long addr,
        unsigned long data)
{
        pgd_t *pgdir;
        pmd_t *pgmiddle;
        pte_t *pgtable;
        unsigned long page;
 
repeat:
        pgdir = pgd_offset(vma->vm_mm, addr);
        if (!pgd_present(*pgdir)) {
                do_no_page(tsk, vma, addr, 1);
                goto repeat;
        }
        if (pgd_bad(*pgdir)) {
                printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
                pgd_clear(pgdir);
                return;
        }
        pgmiddle = pmd_offset(pgdir,addr);
        if (pmd_none(*pgmiddle)) {
                do_no_page(tsk, vma, addr, 1);
                goto repeat;
        }
        if (pmd_bad(*pgmiddle)) {
                printk("ptrace: bad page directory %08lx\n",
                       pmd_val(*pgmiddle));
                pmd_clear(pgmiddle);
                return;
        }
        pgtable = pte_offset(pgmiddle, addr);
        if (!pte_present(*pgtable)) {
                do_no_page(tsk, vma, addr, 1);
                goto repeat;
        }
        page = pte_page(*pgtable);
        if (!pte_write(*pgtable)) {
                do_wp_page(tsk, vma, addr, 2);
                goto repeat;
        }
/* this is a hack for non-kernel-mapped video buffers and similar */
        if (page < high_memory) {
                *(unsigned long *) (page + (addr & ~PAGE_MASK)) = data;
        }
/* we're bypassing pagetables, so we have to set the dirty bit ourselves */
/* this should also re-instate whatever read-only mode there was before */
        *pgtable = pte_mkdirty(mk_pte(page, vma->vm_page_prot));
        flush_tlb_all();
}
 
static struct vm_area_struct * find_extend_vma(struct task_struct * tsk, unsigned long addr)
{
        struct vm_area_struct * vma;
 
        addr &= PAGE_MASK;
        vma = find_vma(tsk,addr);
        if (!vma)
                return NULL;
        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_extend_vma(tsk, addr);
 
        if (!vma)
                return -EIO;
        if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
                unsigned long low,high;
                struct vm_area_struct * vma_low = vma;
 
                if (addr + sizeof(long) >= vma->vm_end) {
                        vma_low = vma->vm_next;
                        if (!vma_low || vma_low->vm_start != vma->vm_end)
                                return -EIO;
                }
                high = get_long(tsk, vma,addr & ~(sizeof(long)-1));
                low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));
                switch (addr & (sizeof(long)-1)) {
                        case 3:
                                low >>= 8;
                                low |= high << 24;
                                break;
                        case 2:
                                low >>= 16;
                                low |= high << 16;
                                break;
                        case 1:
                                low >>= 24;
                                low |= high << 8;
                                break;
                }
                *result = low;
        } else
                *result = get_long(tsk, 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_extend_vma(tsk, addr);
 
        if (!vma)
                return -EIO;
        if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
                unsigned long low,high;
                struct vm_area_struct * vma_low = vma;
 
                if (addr + sizeof(long) >= vma->vm_end) {
                        vma_low = vma->vm_next;
                        if (!vma_low || vma_low->vm_start != vma->vm_end)
                                return -EIO;
                }
                high = get_long(tsk, vma,addr & ~(sizeof(long)-1));
                low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));
                switch (addr & (sizeof(long)-1)) {
                        case 0: /* shouldn't happen, but safety first */
                                high = data;
                                break;
                        case 3:
                                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 1:
                                low &= 0x00ffffff;
                                low |= data << 24;
                                high &= ~0xffffff;
                                high |= data >> 8;
                                break;
                }
                put_long(tsk, vma,addr & ~(sizeof(long)-1),high);
                put_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1),low);
        } else
                put_long(tsk, vma,addr,data);
        return 0;
}
 
asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
{
        struct task_struct *child;
        struct user * dummy;
 
        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) {
        /* If 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_user(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))
                                return -EIO;
 
                        res = verify_area(VERIFY_WRITE, (void *) data,
                                          sizeof(long));
                        if (res)
                                return res;
                        tmp = 0;  /* Default return condition */
                        addr = addr >> 2; /* temporary hack. */
                        if (addr < PT_FPR0) {
                                tmp = get_reg(child, addr);
                        }
#if 0                   
                        else if (addr >= PT_FPR0 && addr < PT_FPR31)
                                tmp = child->tss.fpr[addr - PT_FPR0];
#endif                          
                        else
                                return -EIO;
                        put_user(tmp,(unsigned long *) data);
                        return 0;
                }
 
      /* If 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))
                                return -EIO;
 
                        addr = addr >> 2; /* temporary hack. */
 
                        if (addr == PT_ORIG_R3)
                                return -EIO;
#if 0 /* Let this check be in 'put_reg' */                              
                        if (addr == PT_SR) {
                                data &= SR_MASK;
                                data <<= 16;
                                data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
                        }
#endif                  
                        if (addr < PT_FPR0) {
                                if (put_reg(child, addr, data))
                                        return -EIO;
                                return 0;
                        }
#if 0                   
                        if (addr >= 21 && addr < 48)
                        {
                                child->tss.fp[addr - 21] = data;
                                return 0;
                        }
#endif                  
                        return -EIO;
 
                case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
                case PTRACE_CONT: { /* restart after signal. */
                        if ((unsigned long) data >= NSIG)
                                return -EIO;
                        if (request == PTRACE_SYSCALL)
                                child->flags |= PF_TRACESYS;
                        else
                                child->flags &= ~PF_TRACESYS;
                        child->exit_code = data;
                        wake_up_process(child);
                        /* make sure the single step bit is not set. */
                        clear_single_step(child);
                        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: {
                        if (child->state == TASK_ZOMBIE) /* already dead */
                                return 0;
                        wake_up_process(child);
                        child->exit_code = SIGKILL;
                        /* make sure the single step bit is not set. */
                        clear_single_step(child);
                        return 0;
                }
 
                case PTRACE_SINGLESTEP: {  /* set the trap flag. */
                        if ((unsigned long) data >= NSIG)
                                return -EIO;
                        child->flags &= ~PF_TRACESYS;
                        set_single_step(child);
                        wake_up_process(child);
                        child->exit_code = data;
                        /* give it a chance to run. */
                        return 0;
                }
 
                case PTRACE_DETACH: { /* detach a process that was attached. */
                        if ((unsigned long) data >= NSIG)
                                return -EIO;
                        child->flags &= ~(PF_PTRACED|PF_TRACESYS);
                        wake_up_process(child);
                        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. */
                        clear_single_step(child);
                        return 0;
                }
 
                default:
                        return -EIO;
        }
}
 
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;
        return;
}

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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [ppc/] [kernel/] [ptrace.c] - Blame information for rev 1782

Line No.	Rev	Author	Line
1	1624	jcastillo	`/*`
2			`* linux/arch/ppc/kernel/ptrace.c`
3			`*`
4			`* Copyright (C) 1994 by Hamish Macdonald`
5			`* Taken from linux/kernel/ptrace.c and modified for M680x0.`
6			`* linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds`
7			`*`
8			`* Adapted from 'linux/arch/m68k/kernel/ptrace.c'`
9			`* PowerPC version by Gary Thomas (gdt@linuxppc.org)`
10			`*`
11			`* This file is subject to the terms and conditions of the GNU General`
12			`* Public License. See the file README.legal in the main directory of`
13			`* this archive for more details.`
14			`*/`
15
16			`#include <stddef.h>`
17			`#include <linux/kernel.h>`
18			`#include <linux/sched.h>`
19			`#include <linux/mm.h>`
20			`#include <linux/errno.h>`
21			`#include <linux/ptrace.h>`
22			`#include <linux/user.h>`
23
24			`#include <asm/segment.h>`
25			`#include <asm/page.h>`
26			`#include <asm/pgtable.h>`
27			`#include <asm/system.h>`
28
29			`/*`
30			`* does not yet catch signals sent when the child dies.`
31			`* in exit.c or in signal.c.`
32			`*/`
33
34			`/* Find the stack offset for a register, relative to tss.ksp. */`
35			`#define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)`
36			`/* Mapping from PT_xxx to the stack offset at which the register is`
37			`saved. Notice that usp has no stack-slot and needs to be treated`
38			`specially (see get_reg/put_reg below). */`
39			`static int regoff[] = {`
40			`};`
41
42			`/* change a pid into a task struct. */`
43			`static inline struct task_struct * get_task(int pid)`
44			`{`
45			`int i;`
46
47			`for (i = 1; i < NR_TASKS; i++) {`
48			`if (task[i] != NULL && (task[i]->pid == pid))`
49			`return task[i];`
50			`}`
51			`return NULL;`
52			`}`
53
54			`/*`
55			`* Get contents of register REGNO in task TASK.`
56			`*/`
57			`static inline long get_reg(struct task_struct *task, int regno)`
58			`{`
59			`struct pt_regs *regs = task->tss.regs;`
60			`if (regno <= PT_R31)`
61			`{`
62			`return (regs->gpr[regno]);`
63			`} else`
64			`if (regno == PT_NIP)`
65			`{`
66			`return (regs->nip);`
67			`} else`
68			`if (regno == PT_MSR)`
69			`{`
70			`return (regs->msr);`
71			`} else`
72			`if (regno == PT_ORIG_R3)`
73			`{`
74			`return (regs->orig_gpr3);`
75			`} else`
76			`if (regno == PT_CTR)`
77			`{`
78			`return (regs->ctr);`
79			`} else`
80			`if (regno == PT_LNK)`
81			`{`
82			`return (regs->link);`
83			`} else`
84			`if (regno == PT_XER)`
85			`{`
86			`return (regs->xer);`
87			`} else`
88			`if (regno == PT_CCR)`
89			`{`
90			`return (regs->ccr);`
91			`}`
92			`return (0);`
93			`}`
94
95			`/*`
96			`* Write contents of register REGNO in task TASK.`
97			`*/`
98			`static inline int put_reg(struct task_struct *task, int regno,`
99			`unsigned long data)`
100			`{`
101			`struct pt_regs *regs = task->tss.regs;`
102			`if (regno <= PT_R31)`
103			`{`
104			`regs->gpr[regno] = data;`
105			`} else`
106			`if (regno == PT_NIP)`
107			`{`
108			`regs->nip = data;`
109			`} else`
110			`if (regno == PT_MSR)`
111			`{`
112			`regs->msr = data;`
113			`} else`
114			`if (regno == PT_CTR)`
115			`{`
116			`regs->ctr = data;`
117			`} else`
118			`if (regno == PT_LNK)`
119			`{`
120			`regs->link = data;`
121			`} else`
122			`if (regno == PT_XER)`
123			`{`
124			`regs->xer = data;`
125			`} else`
126			`if (regno == PT_CCR)`
127			`{`
128			`regs->ccr = data;`
129			`} else`
130			`{ /* Invalid register */`
131			`return (-1);`
132			`}`
133			`return (0);`
134			`}`
135
136			`static inline`
137			`set_single_step(struct task_struct *task)`
138			`{`
139			`struct pt_regs *regs = task->tss.regs;`
140			`printk("Set single step - Task: %x, Regs: %x", task, regs);`
141			`printk(", MSR: %x/", regs->msr);`
142			`regs->msr \|= MSR_SE;`
143			`printk("%x\n", regs->msr);`
144			`}`
145
146			`static inline`
147			`clear_single_step(struct task_struct *task)`
148			`{`
149			`struct pt_regs *regs = task->tss.regs;`
150			`regs->msr &= ~MSR_SE;`
151			`}`
152
153			`/*`
154			`* This routine gets a long from any process space by following the page`
155			`* tables. NOTE! You should check that the long isn't on a page boundary,`
156			`* and that it is in the task area before calling this: this routine does`
157			`* no checking.`
158			`*`
159			`*/`
160			`static unsigned long get_long(struct task_struct * tsk,`
161			`struct vm_area_struct * vma, unsigned long addr)`
162			`{`
163			`pgd_t * pgdir;`
164			`pmd_t * pgmiddle;`
165			`pte_t * pgtable;`
166			`unsigned long page;`
167
168			`repeat:`
169			`pgdir = pgd_offset(vma->vm_mm, addr);`
170			`if (pgd_none(*pgdir)) {`
171			`do_no_page(tsk, vma, addr, 0);`
172			`goto repeat;`
173			`}`
174			`if (pgd_bad(*pgdir)) {`
175			`printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));`
176			`pgd_clear(pgdir);`
177			`return 0;`
178			`}`
179			`pgmiddle = pmd_offset(pgdir,addr);`
180			`if (pmd_none(*pgmiddle)) {`
181			`do_no_page(tsk, vma, addr, 0);`
182			`goto repeat;`
183			`}`
184			`if (pmd_bad(*pgmiddle)) {`
185			`printk("ptrace: bad page directory %08lx\n",`
186			`pmd_val(*pgmiddle));`
187			`pmd_clear(pgmiddle);`
188			`return 0;`
189			`}`
190			`pgtable = pte_offset(pgmiddle, addr);`
191			`if (!pte_present(*pgtable)) {`
192			`do_no_page(tsk, vma, addr, 0);`
193			`goto repeat;`
194			`}`
195			`page = pte_page(*pgtable);`
196			`/* this is a hack for non-kernel-mapped video buffers and similar */`
197			`if (page >= high_memory)`
198			`return 0;`
199			`page += addr & ~PAGE_MASK;`
200			`return (unsigned long ) page;`
201			`}`
202
203			`/*`
204			`* This routine puts a long into any process space by following the page`
205			`* tables. NOTE! You should check that the long isn't on a page boundary,`
206			`* and that it is in the task area before calling this: this routine does`
207			`* no checking.`
208			`*`
209			`* Now keeps R/W state of page so that a text page stays readonly`
210			`* even if a debugger scribbles breakpoints into it. -M.U-`
211			`*/`
212			`static void put_long(struct task_struct * tsk, struct vm_area_struct * vma, unsigned long addr,`
213			`unsigned long data)`
214			`{`
215			`pgd_t *pgdir;`
216			`pmd_t *pgmiddle;`
217			`pte_t *pgtable;`
218			`unsigned long page;`
219
220			`repeat:`
221			`pgdir = pgd_offset(vma->vm_mm, addr);`
222			`if (!pgd_present(*pgdir)) {`
223			`do_no_page(tsk, vma, addr, 1);`
224			`goto repeat;`
225			`}`
226			`if (pgd_bad(*pgdir)) {`
227			`printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));`
228			`pgd_clear(pgdir);`
229			`return;`
230			`}`
231			`pgmiddle = pmd_offset(pgdir,addr);`
232			`if (pmd_none(*pgmiddle)) {`
233			`do_no_page(tsk, vma, addr, 1);`
234			`goto repeat;`
235			`}`
236			`if (pmd_bad(*pgmiddle)) {`
237			`printk("ptrace: bad page directory %08lx\n",`
238			`pmd_val(*pgmiddle));`
239			`pmd_clear(pgmiddle);`
240			`return;`
241			`}`
242			`pgtable = pte_offset(pgmiddle, addr);`
243			`if (!pte_present(*pgtable)) {`
244			`do_no_page(tsk, vma, addr, 1);`
245			`goto repeat;`
246			`}`
247			`page = pte_page(*pgtable);`
248			`if (!pte_write(*pgtable)) {`
249			`do_wp_page(tsk, vma, addr, 2);`
250			`goto repeat;`
251			`}`
252			`/* this is a hack for non-kernel-mapped video buffers and similar */`
253			`if (page < high_memory) {`
254			`(unsigned long ) (page + (addr & ~PAGE_MASK)) = data;`
255			`}`
256			`/* we're bypassing pagetables, so we have to set the dirty bit ourselves */`
257			`/* this should also re-instate whatever read-only mode there was before */`
258			`*pgtable = pte_mkdirty(mk_pte(page, vma->vm_page_prot));`
259			`flush_tlb_all();`
260			`}`
261
262			`static struct vm_area_struct * find_extend_vma(struct task_struct * tsk, unsigned long addr)`
263			`{`
264			`struct vm_area_struct * vma;`
265
266			`addr &= PAGE_MASK;`
267			`vma = find_vma(tsk,addr);`
268			`if (!vma)`
269			`return NULL;`
270			`if (vma->vm_start <= addr)`
271			`return vma;`
272			`if (!(vma->vm_flags & VM_GROWSDOWN))`
273			`return NULL;`
274			`if (vma->vm_end - addr > tsk->rlim[RLIMIT_STACK].rlim_cur)`
275			`return NULL;`
276			`vma->vm_offset -= vma->vm_start - addr;`
277			`vma->vm_start = addr;`
278			`return vma;`
279			`}`
280
281			`/*`
282			`* This routine checks the page boundaries, and that the offset is`
283			`* within the task area. It then calls get_long() to read a long.`
284			`*/`
285			`static int read_long(struct task_struct * tsk, unsigned long addr,`
286			`unsigned long * result)`
287			`{`
288			`struct vm_area_struct * vma = find_extend_vma(tsk, addr);`
289
290			`if (!vma)`
291			`return -EIO;`
292			`if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {`
293			`unsigned long low,high;`
294			`struct vm_area_struct * vma_low = vma;`
295
296			`if (addr + sizeof(long) >= vma->vm_end) {`
297			`vma_low = vma->vm_next;`
298			`if (!vma_low \|\| vma_low->vm_start != vma->vm_end)`
299			`return -EIO;`
300			`}`
301			`high = get_long(tsk, vma,addr & ~(sizeof(long)-1));`
302			`low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));`
303			`switch (addr & (sizeof(long)-1)) {`
304			`case 3:`
305			`low >>= 8;`
306			`low \|= high << 24;`
307			`break;`
308			`case 2:`
309			`low >>= 16;`
310			`low \|= high << 16;`
311			`break;`
312			`case 1:`
313			`low >>= 24;`
314			`low \|= high << 8;`
315			`break;`
316			`}`
317			`*result = low;`
318			`} else`
319			`*result = get_long(tsk, vma,addr);`
320			`return 0;`
321			`}`
322
323			`/*`
324			`* This routine checks the page boundaries, and that the offset is`
325			`* within the task area. It then calls put_long() to write a long.`
326			`*/`
327			`static int write_long(struct task_struct * tsk, unsigned long addr,`
328			`unsigned long data)`
329			`{`
330			`struct vm_area_struct * vma = find_extend_vma(tsk, addr);`
331
332			`if (!vma)`
333			`return -EIO;`
334			`if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {`
335			`unsigned long low,high;`
336			`struct vm_area_struct * vma_low = vma;`
337
338			`if (addr + sizeof(long) >= vma->vm_end) {`
339			`vma_low = vma->vm_next;`
340			`if (!vma_low \|\| vma_low->vm_start != vma->vm_end)`
341			`return -EIO;`
342			`}`
343			`high = get_long(tsk, vma,addr & ~(sizeof(long)-1));`
344			`low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));`
345			`switch (addr & (sizeof(long)-1)) {`
346			`case 0: /* shouldn't happen, but safety first */`
347			`high = data;`
348			`break;`
349			`case 3:`
350			`low &= 0x000000ff;`
351			`low \|= data << 8;`
352			`high &= ~0xff;`
353			`high \|= data >> 24;`
354			`break;`
355			`case 2:`
356			`low &= 0x0000ffff;`
357			`low \|= data << 16;`
358			`high &= ~0xffff;`
359			`high \|= data >> 16;`
360			`break;`
361			`case 1:`
362			`low &= 0x00ffffff;`
363			`low \|= data << 24;`
364			`high &= ~0xffffff;`
365			`high \|= data >> 8;`
366			`break;`
367			`}`
368			`put_long(tsk, vma,addr & ~(sizeof(long)-1),high);`
369			`put_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1),low);`
370			`} else`
371			`put_long(tsk, vma,addr,data);`
372			`return 0;`
373			`}`
374
375			`asmlinkage int sys_ptrace(long request, long pid, long addr, long data)`
376			`{`
377			`struct task_struct *child;`
378			`struct user * dummy;`
379
380			`dummy = NULL;`
381
382			`if (request == PTRACE_TRACEME) {`
383			`/* are we already being traced? */`
384			`if (current->flags & PF_PTRACED)`
385			`return -EPERM;`
386			`/* set the ptrace bit in the process flags. */`
387			`current->flags \|= PF_PTRACED;`
388			`return 0;`
389			`}`
390			`if (pid == 1) /* you may not mess with init */`
391			`return -EPERM;`
392			`if (!(child = get_task(pid)))`
393			`return -ESRCH;`
394			`if (request == PTRACE_ATTACH) {`
395			`if (child == current)`
396			`return -EPERM;`
397			`if ((!child->dumpable \|\|`
398			`(current->uid != child->euid) \|\|`
399			`(current->uid != child->uid) \|\|`
400			`(current->gid != child->egid) \|\|`
401			`(current->gid != child->gid)) && !suser())`
402			`return -EPERM;`
403			`/* the same process cannot be attached many times */`
404			`if (child->flags & PF_PTRACED)`
405			`return -EPERM;`
406			`child->flags \|= PF_PTRACED;`
407			`if (child->p_pptr != current) {`
408			`REMOVE_LINKS(child);`
409			`child->p_pptr = current;`
410			`SET_LINKS(child);`
411			`}`
412			`send_sig(SIGSTOP, child, 1);`
413			`return 0;`
414			`}`
415			`if (!(child->flags & PF_PTRACED))`
416			`return -ESRCH;`
417			`if (child->state != TASK_STOPPED) {`
418			`if (request != PTRACE_KILL)`
419			`return -ESRCH;`
420			`}`
421			`if (child->p_pptr != current)`
422			`return -ESRCH;`
423
424			`switch (request) {`
425			`/* If I and D space are separate, these will need to be fixed. */`
426			`case PTRACE_PEEKTEXT: /* read word at location addr. */`
427			`case PTRACE_PEEKDATA: {`
428			`unsigned long tmp;`
429			`int res;`
430
431			`res = read_long(child, addr, &tmp);`
432			`if (res < 0)`
433			`return res;`
434			`res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));`
435			`if (!res)`
436			`put_user(tmp, (unsigned long *) data);`
437			`return res;`
438			`}`
439
440			`/* read the word at location addr in the USER area. */`
441			`case PTRACE_PEEKUSR: {`
442			`unsigned long tmp;`
443			`int res;`
444
445			`if ((addr & 3) \|\| addr < 0 \|\| addr >= sizeof(struct user))`
446			`return -EIO;`
447
448			`res = verify_area(VERIFY_WRITE, (void *) data,`
449			`sizeof(long));`
450			`if (res)`
451			`return res;`
452			`tmp = 0; /* Default return condition */`
453			`addr = addr >> 2; /* temporary hack. */`
454			`if (addr < PT_FPR0) {`
455			`tmp = get_reg(child, addr);`
456			`}`
457			`#if 0`
458			`else if (addr >= PT_FPR0 && addr < PT_FPR31)`
459			`tmp = child->tss.fpr[addr - PT_FPR0];`
460			`#endif`
461			`else`
462			`return -EIO;`
463			`put_user(tmp,(unsigned long *) data);`
464			`return 0;`
465			`}`
466
467			`/* If I and D space are separate, this will have to be fixed. */`
468			`case PTRACE_POKETEXT: /* write the word at location addr. */`
469			`case PTRACE_POKEDATA:`
470			`return write_long(child,addr,data);`
471
472			`case PTRACE_POKEUSR: /* write the word at location addr in the USER area */`
473			`if ((addr & 3) \|\| addr < 0 \|\| addr >= sizeof(struct user))`
474			`return -EIO;`
475
476			`addr = addr >> 2; /* temporary hack. */`
477
478			`if (addr == PT_ORIG_R3)`
479			`return -EIO;`
480			`#if 0 /* Let this check be in 'put_reg' */`
481			`if (addr == PT_SR) {`
482			`data &= SR_MASK;`
483			`data <<= 16;`
484			`data \|= get_reg(child, PT_SR) & ~(SR_MASK << 16);`
485			`}`
486			`#endif`
487			`if (addr < PT_FPR0) {`
488			`if (put_reg(child, addr, data))`
489			`return -EIO;`
490			`return 0;`
491			`}`
492			`#if 0`
493			`if (addr >= 21 && addr < 48)`
494			`{`
495			`child->tss.fp[addr - 21] = data;`
496			`return 0;`
497			`}`
498			`#endif`
499			`return -EIO;`
500
501			`case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */`
502			`case PTRACE_CONT: { /* restart after signal. */`
503			`if ((unsigned long) data >= NSIG)`
504			`return -EIO;`
505			`if (request == PTRACE_SYSCALL)`
506			`child->flags \|= PF_TRACESYS;`
507			`else`
508			`child->flags &= ~PF_TRACESYS;`
509			`child->exit_code = data;`
510			`wake_up_process(child);`
511			`/* make sure the single step bit is not set. */`
512			`clear_single_step(child);`
513			`return 0;`
514			`}`
515
516			`/*`
517			`* make the child exit. Best I can do is send it a sigkill.`
518			`* perhaps it should be put in the status that it wants to`
519			`* exit.`
520			`*/`
521			`case PTRACE_KILL: {`
522			`if (child->state == TASK_ZOMBIE) /* already dead */`
523			`return 0;`
524			`wake_up_process(child);`
525			`child->exit_code = SIGKILL;`
526			`/* make sure the single step bit is not set. */`
527			`clear_single_step(child);`
528			`return 0;`
529			`}`
530
531			`case PTRACE_SINGLESTEP: { /* set the trap flag. */`
532			`if ((unsigned long) data >= NSIG)`
533			`return -EIO;`
534			`child->flags &= ~PF_TRACESYS;`
535			`set_single_step(child);`
536			`wake_up_process(child);`
537			`child->exit_code = data;`
538			`/* give it a chance to run. */`
539			`return 0;`
540			`}`
541
542			`case PTRACE_DETACH: { /* detach a process that was attached. */`
543			`if ((unsigned long) data >= NSIG)`
544			`return -EIO;`
545			`child->flags &= ~(PF_PTRACED\|PF_TRACESYS);`
546			`wake_up_process(child);`
547			`child->exit_code = data;`
548			`REMOVE_LINKS(child);`
549			`child->p_pptr = child->p_opptr;`
550			`SET_LINKS(child);`
551			`/* make sure the single step bit is not set. */`
552			`clear_single_step(child);`
553			`return 0;`
554			`}`
555
556			`default:`
557			`return -EIO;`
558			`}`
559			`}`
560
561			`asmlinkage void syscall_trace(void)`
562			`{`
563			`if ((current->flags & (PF_PTRACED\|PF_TRACESYS))`
564			`!= (PF_PTRACED\|PF_TRACESYS))`
565			`return;`
566			`current->exit_code = SIGTRAP;`
567			`current->state = TASK_STOPPED;`
568			`notify_parent(current);`
569			`schedule();`
570			`/*`
571			`* this isn't the same as continuing with a signal, but it will do`
572			`* for normal use. strace only continues with a signal if the`
573			`* stopping signal is not SIGTRAP. -brl`
574			`*/`
575			`if (current->exit_code)`
576			`current->signal \|= (1 << (current->exit_code - 1));`
577			`current->exit_code = 0;`
578			`return;`
579			`}`