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linux/arch/m32r/kernel/ptrace.c

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/*
* linux/arch/m32r/kernel/ptrace.c
*
* Copyright (C) 2002 Hirokazu Takata, Takeo Takahashi
* Copyright (C) 2004 Hirokazu Takata, Kei Sakamoto
*
* Original x86 implementation:
* By Ross Biro 1/23/92
* edited by Linus Torvalds
*
* Some code taken from sh version:
* Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
* Some code taken from arm version:
* Copyright (C) 2000 Russell King
*/
#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/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <asm/cacheflush.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
/*
* 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 (struct pt_regs *)
((unsigned long)task->thread_info + THREAD_SIZE
- sizeof(struct pt_regs));
}
/*
* This routine will get a word off of the process kernel stack.
*/
static inline unsigned long int
get_stack_long(struct task_struct *task, int offset)
{
unsigned long *stack;
stack = (unsigned long *)get_user_regs(task);
return stack[offset];
}
/*
* This routine will put a word on the process kernel stack.
*/
static inline int
put_stack_long(struct task_struct *task, int offset, unsigned long data)
{
unsigned long *stack;
stack = (unsigned long *)get_user_regs(task);
stack[offset] = data;
return 0;
}
static int reg_offset[] = {
PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7,
PT_R8, PT_R9, PT_R10, PT_R11, PT_R12, PT_FP, PT_LR, PT_SPU,
};
/*
* 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 __user *data)
{
unsigned long tmp;
#ifndef NO_FPU
struct user * dummy = NULL;
#endif
if ((off & 3) || (off < 0) || (off > sizeof(struct user) - 3))
return -EIO;
off >>= 2;
switch (off) {
case PT_EVB:
__asm__ __volatile__ (
"mvfc %0, cr5 \n\t"
: "=r" (tmp)
);
break;
case PT_CBR: {
unsigned long psw;
psw = get_stack_long(tsk, PT_PSW);
tmp = ((psw >> 8) & 1);
}
break;
case PT_PSW: {
unsigned long psw, bbpsw;
psw = get_stack_long(tsk, PT_PSW);
bbpsw = get_stack_long(tsk, PT_BBPSW);
tmp = ((psw >> 8) & 0xff) | ((bbpsw & 0xff) << 8);
}
break;
case PT_PC:
tmp = get_stack_long(tsk, PT_BPC);
break;
case PT_BPC:
off = PT_BBPC;
/* fall through */
default:
if (off < (sizeof(struct pt_regs) >> 2))
tmp = get_stack_long(tsk, off);
#ifndef NO_FPU
else if (off >= (long)(&dummy->fpu >> 2) &&
off < (long)(&dummy->u_fpvalid >> 2)) {
if (!tsk_used_math(tsk)) {
if (off == (long)(&dummy->fpu.fpscr >> 2))
tmp = FPSCR_INIT;
else
tmp = 0;
} else
tmp = ((long *)(&tsk->thread.fpu >> 2))
[off - (long)&dummy->fpu];
} else if (off == (long)(&dummy->u_fpvalid >> 2))
tmp = !!tsk_used_math(tsk);
#endif /* not NO_FPU */
else
tmp = 0;
}
return put_user(tmp, data);
}
static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
unsigned long data)
{
int ret = -EIO;
#ifndef NO_FPU
struct user * dummy = NULL;
#endif
if ((off & 3) || off < 0 ||
off > sizeof(struct user) - 3)
return -EIO;
off >>= 2;
switch (off) {
case PT_EVB:
case PT_BPC:
case PT_SPI:
/* We don't allow to modify evb. */
ret = 0;
break;
case PT_PSW:
case PT_CBR: {
/* We allow to modify only cbr in psw */
unsigned long psw;
psw = get_stack_long(tsk, PT_PSW);
psw = (psw & ~0x100) | ((data & 1) << 8);
ret = put_stack_long(tsk, PT_PSW, psw);
}
break;
case PT_PC:
off = PT_BPC;
data &= ~1;
/* fall through */
default:
if (off < (sizeof(struct pt_regs) >> 2))
ret = put_stack_long(tsk, off, data);
#ifndef NO_FPU
else if (off >= (long)(&dummy->fpu >> 2) &&
off < (long)(&dummy->u_fpvalid >> 2)) {
set_stopped_child_used_math(tsk);
((long *)&tsk->thread.fpu)
[off - (long)&dummy->fpu] = data;
ret = 0;
} else if (off == (long)(&dummy->u_fpvalid >> 2)) {
conditional_stopped_child_used_math(data, tsk);
ret = 0;
}
#endif /* not NO_FPU */
break;
}
return ret;
}
/*
* Get all user integer registers.
*/
static int ptrace_getregs(struct task_struct *tsk, void __user *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 __user *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);
*regs = newregs;
ret = 0;
}
return ret;
}
static inline int
check_condition_bit(struct task_struct *child)
{
return (int)((get_stack_long(child, PT_PSW) >> 8) & 1);
}
static int
check_condition_src(unsigned long op, unsigned long regno1,
unsigned long regno2, struct task_struct *child)
{
unsigned long reg1, reg2;
reg2 = get_stack_long(child, reg_offset[regno2]);
switch (op) {
case 0x0: /* BEQ */
reg1 = get_stack_long(child, reg_offset[regno1]);
return reg1 == reg2;
case 0x1: /* BNE */
reg1 = get_stack_long(child, reg_offset[regno1]);
return reg1 != reg2;
case 0x8: /* BEQZ */
return reg2 == 0;
case 0x9: /* BNEZ */
return reg2 != 0;
case 0xa: /* BLTZ */
return (int)reg2 < 0;
case 0xb: /* BGEZ */
return (int)reg2 >= 0;
case 0xc: /* BLEZ */
return (int)reg2 <= 0;
case 0xd: /* BGTZ */
return (int)reg2 > 0;
default:
/* never reached */
return 0;
}
}
static void
compute_next_pc_for_16bit_insn(unsigned long insn, unsigned long pc,
unsigned long *next_pc,
struct task_struct *child)
{
unsigned long op, op2, op3;
unsigned long disp;
unsigned long regno;
int parallel = 0;
if (insn & 0x00008000)
parallel = 1;
if (pc & 3)
insn &= 0x7fff; /* right slot */
else
insn >>= 16; /* left slot */
op = (insn >> 12) & 0xf;
op2 = (insn >> 8) & 0xf;
op3 = (insn >> 4) & 0xf;
if (op == 0x7) {
switch (op2) {
case 0xd: /* BNC */
case 0x9: /* BNCL */
if (!check_condition_bit(child)) {
disp = (long)(insn << 24) >> 22;
*next_pc = (pc & ~0x3) + disp;
return;
}
break;
case 0x8: /* BCL */
case 0xc: /* BC */
if (check_condition_bit(child)) {
disp = (long)(insn << 24) >> 22;
*next_pc = (pc & ~0x3) + disp;
return;
}
break;
case 0xe: /* BL */
case 0xf: /* BRA */
disp = (long)(insn << 24) >> 22;
*next_pc = (pc & ~0x3) + disp;
return;
break;
}
} else if (op == 0x1) {
switch (op2) {
case 0x0:
if (op3 == 0xf) { /* TRAP */
#if 1
/* pass through */
#else
/* kernel space is not allowed as next_pc */
unsigned long evb;
unsigned long trapno;
trapno = insn & 0xf;
__asm__ __volatile__ (
"mvfc %0, cr5\n"
:"=r"(evb)
:
);
*next_pc = evb + (trapno << 2);
return;
#endif
} else if (op3 == 0xd) { /* RTE */
*next_pc = get_stack_long(child, PT_BPC);
return;
}
break;
case 0xc: /* JC */
if (op3 == 0xc && check_condition_bit(child)) {
regno = insn & 0xf;
*next_pc = get_stack_long(child,
reg_offset[regno]);
return;
}
break;
case 0xd: /* JNC */
if (op3 == 0xc && !check_condition_bit(child)) {
regno = insn & 0xf;
*next_pc = get_stack_long(child,
reg_offset[regno]);
return;
}
break;
case 0xe: /* JL */
case 0xf: /* JMP */
if (op3 == 0xc) { /* JMP */
regno = insn & 0xf;
*next_pc = get_stack_long(child,
reg_offset[regno]);
return;
}
break;
}
}
if (parallel)
*next_pc = pc + 4;
else
*next_pc = pc + 2;
}
static void
compute_next_pc_for_32bit_insn(unsigned long insn, unsigned long pc,
unsigned long *next_pc,
struct task_struct *child)
{
unsigned long op;
unsigned long op2;
unsigned long disp;
unsigned long regno1, regno2;
op = (insn >> 28) & 0xf;
if (op == 0xf) { /* branch 24-bit relative */
op2 = (insn >> 24) & 0xf;
switch (op2) {
case 0xd: /* BNC */
case 0x9: /* BNCL */
if (!check_condition_bit(child)) {
disp = (long)(insn << 8) >> 6;
*next_pc = (pc & ~0x3) + disp;
return;
}
break;
case 0x8: /* BCL */
case 0xc: /* BC */
if (check_condition_bit(child)) {
disp = (long)(insn << 8) >> 6;
*next_pc = (pc & ~0x3) + disp;
return;
}
break;
case 0xe: /* BL */
case 0xf: /* BRA */
disp = (long)(insn << 8) >> 6;
*next_pc = (pc & ~0x3) + disp;
return;
}
} else if (op == 0xb) { /* branch 16-bit relative */
op2 = (insn >> 20) & 0xf;
switch (op2) {
case 0x0: /* BEQ */
case 0x1: /* BNE */
case 0x8: /* BEQZ */
case 0x9: /* BNEZ */
case 0xa: /* BLTZ */
case 0xb: /* BGEZ */
case 0xc: /* BLEZ */
case 0xd: /* BGTZ */
regno1 = ((insn >> 24) & 0xf);
regno2 = ((insn >> 16) & 0xf);
if (check_condition_src(op2, regno1, regno2, child)) {
disp = (long)(insn << 16) >> 14;
*next_pc = (pc & ~0x3) + disp;
return;
}
break;
}
}
*next_pc = pc + 4;
}
static inline void
compute_next_pc(unsigned long insn, unsigned long pc,
unsigned long *next_pc, struct task_struct *child)
{
if (insn & 0x80000000)
compute_next_pc_for_32bit_insn(insn, pc, next_pc, child);
else
compute_next_pc_for_16bit_insn(insn, pc, next_pc, child);
}
static int
register_debug_trap(struct task_struct *child, unsigned long next_pc,
unsigned long next_insn, unsigned long *code)
{
struct debug_trap *p = &child->thread.debug_trap;
unsigned long addr = next_pc & ~3;
if (p->nr_trap == MAX_TRAPS) {
printk("kernel BUG at %s %d: p->nr_trap = %d\n",
__FILE__, __LINE__, p->nr_trap);
return -1;
}
p->addr[p->nr_trap] = addr;
p->insn[p->nr_trap] = next_insn;
p->nr_trap++;
if (next_pc & 3) {
*code = (next_insn & 0xffff0000) | 0x10f1;
/* xxx --> TRAP1 */
} else {
if ((next_insn & 0x80000000) || (next_insn & 0x8000)) {
*code = 0x10f17000;
/* TRAP1 --> NOP */
} else {
*code = (next_insn & 0xffff) | 0x10f10000;
/* TRAP1 --> xxx */
}
}
return 0;
}
static int
unregister_debug_trap(struct task_struct *child, unsigned long addr,
unsigned long *code)
{
struct debug_trap *p = &child->thread.debug_trap;
int i;
/* Search debug trap entry. */
for (i = 0; i < p->nr_trap; i++) {
if (p->addr[i] == addr)
break;
}
if (i >= p->nr_trap) {
/* The trap may be requested from debugger.
* ptrace should do nothing in this case.
*/
return 0;
}
/* Recover orignal instruction code. */
*code = p->insn[i];
/* Shift debug trap entries. */
while (i < p->nr_trap - 1) {
p->insn[i] = p->insn[i + 1];
p->addr[i] = p->addr[i + 1];
i++;
}
p->nr_trap--;
return 1;
}
static void
unregister_all_debug_traps(struct task_struct *child)
{
struct debug_trap *p = &child->thread.debug_trap;
int i;
for (i = 0; i < p->nr_trap; i++)
access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]), 1);
p->nr_trap = 0;
}
static inline void
invalidate_cache(void)
{
#if defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP)
_flush_cache_copyback_all();
#else /* ! CONFIG_CHIP_M32700 */
/* Invalidate cache */
__asm__ __volatile__ (
"ldi r0, #-1 \n\t"
"ldi r1, #0 \n\t"
"stb r1, @r0 ; cache off \n\t"
"; \n\t"
"ldi r0, #-2 \n\t"
"ldi r1, #1 \n\t"
"stb r1, @r0 ; cache invalidate \n\t"
".fillinsn \n"
"0: \n\t"
"ldb r1, @r0 ; invalidate check \n\t"
"bnez r1, 0b \n\t"
"; \n\t"
"ldi r0, #-1 \n\t"
"ldi r1, #1 \n\t"
"stb r1, @r0 ; cache on \n\t"
: : : "r0", "r1", "memory"
);
/* FIXME: copying-back d-cache and invalidating i-cache are needed.
*/
#endif /* CONFIG_CHIP_M32700 */
}
/* Embed a debug trap (TRAP1) code */
static int
embed_debug_trap(struct task_struct *child, unsigned long next_pc)
{
unsigned long next_insn, code;
unsigned long addr = next_pc & ~3;
if (access_process_vm(child, addr, &next_insn, sizeof(next_insn), 0)
!= sizeof(next_insn)) {
return -1; /* error */
}
/* Set a trap code. */
if (register_debug_trap(child, next_pc, next_insn, &code)) {
return -1; /* error */
}
if (access_process_vm(child, addr, &code, sizeof(code), 1)
!= sizeof(code)) {
return -1; /* error */
}
return 0; /* success */
}
void
withdraw_debug_trap(struct pt_regs *regs)
{
unsigned long addr;
unsigned long code;
addr = (regs->bpc - 2) & ~3;
regs->bpc -= 2;
if (unregister_debug_trap(current, addr, &code)) {
access_process_vm(current, addr, &code, sizeof(code), 1);
invalidate_cache();
}
}
static void
init_debug_traps(struct task_struct *child)
{
struct debug_trap *p = &child->thread.debug_trap;
int i;
p->nr_trap = 0;
for (i = 0; i < MAX_TRAPS; i++) {
p->addr[i] = 0;
p->insn[i] = 0;
}
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *child)
{
/* nothing to do.. */
}
static int
do_ptrace(long 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(tmp), 0);
if (ret == sizeof(tmp))
ret = put_user(tmp,(unsigned long __user *) data);
else
ret = -EIO;
break;
/*
* read the word at location addr in the USER area.
*/
case PTRACE_PEEKUSR:
ret = ptrace_read_user(child, addr,
(unsigned long __user *)data);
break;
/*
* write the word at location addr.
*/
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
ret = access_process_vm(child, addr, &data, sizeof(data), 1);
if (ret == sizeof(data)) {
ret = 0;
if (request == PTRACE_POKETEXT) {
invalidate_cache();
}
} else {
ret = -EIO;
}
break;
/*
* write the word at location addr in the USER area.
*/
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 (!valid_signal(data))
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;
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: {
ret = 0;
unregister_all_debug_traps(child);
invalidate_cache();
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
wake_up_process(child);
break;
}
/*
* execute single instruction.
*/
case PTRACE_SINGLESTEP: {
unsigned long next_pc;
unsigned long pc, insn;
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
if ((child->ptrace & PT_DTRACE) == 0) {
/* Spurious delayed TF traps may occur */
child->ptrace |= PT_DTRACE;
}
/* Compute next pc. */
pc = get_stack_long(child, PT_BPC);
if (access_process_vm(child, pc&~3, &insn, sizeof(insn), 0)
!= sizeof(insn))
break;
compute_next_pc(insn, pc, &next_pc, child);
if (next_pc & 0x80000000)
break;
if (embed_debug_trap(child, next_pc))
break;
invalidate_cache();
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
}
/*
* detach a process that was attached.
*/
case PTRACE_DETACH:
ret = 0;
ret = ptrace_detach(child, data);
break;
case PTRACE_GETREGS:
ret = ptrace_getregs(child, (void __user *)data);
break;
case PTRACE_SETREGS:
ret = ptrace_setregs(child, (void __user *)data);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
asmlinkage long 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;
/* 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;
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
if (ret == 0)
init_debug_traps(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;
}
/* notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
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. 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;
}
}
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