cregit-Linux how code gets into the kernel

Release 4.14 arch/m68k/kernel/ptrace.c

Directory: arch/m68k/kernel
/*
 *  linux/arch/m68k/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
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file COPYING in the main directory of
 * this archive for more details.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/tracehook.h>

#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>

/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/* determines which bits in the SR the user has access to. */
/* 1 = access 0 = no access */

#define SR_MASK 0x001f

/* sets the trace bits. */

#define TRACE_BITS 0xC000

#define T1_BIT 0x8000

#define T0_BIT 0x4000

/* Find the stack offset for a register, relative to thread.esp0. */

#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)

#define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
                         - sizeof(struct switch_stack))
/* 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 const int regoff[] = {
	[0]	= PT_REG(d1),
	[1]	= PT_REG(d2),
	[2]	= PT_REG(d3),
	[3]	= PT_REG(d4),
	[4]	= PT_REG(d5),
	[5]	= SW_REG(d6),
	[6]	= SW_REG(d7),
	[7]	= PT_REG(a0),
	[8]	= PT_REG(a1),
	[9]	= PT_REG(a2),
	[10]	= SW_REG(a3),
	[11]	= SW_REG(a4),
	[12]	= SW_REG(a5),
	[13]	= SW_REG(a6),
	[14]	= PT_REG(d0),
	[15]	= -1,
	[16]	= PT_REG(orig_d0),
	[17]	= PT_REG(sr),
	[18]	= PT_REG(pc),
};

/*
 * Get contents of register REGNO in task TASK.
 */

static inline long get_reg(struct task_struct *task, int regno) { unsigned long *addr; if (regno == PT_USP) addr = &task->thread.usp; else if (regno < ARRAY_SIZE(regoff)) addr = (unsigned long *)(task->thread.esp0 + regoff[regno]); else return 0; /* Need to take stkadj into account. */ if (regno == PT_SR || regno == PT_PC) { long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj)); addr = (unsigned long *) ((unsigned long)addr + stkadj); /* The sr is actually a 16 bit register. */ if (regno == PT_SR) return *(unsigned short *)addr; } return *addr; }

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/* * Write contents of register REGNO in task TASK. */
static inline int put_reg(struct task_struct *task, int regno, unsigned long data) { unsigned long *addr; if (regno == PT_USP) addr = &task->thread.usp; else if (regno < ARRAY_SIZE(regoff)) addr = (unsigned long *)(task->thread.esp0 + regoff[regno]); else return -1; /* Need to take stkadj into account. */ if (regno == PT_SR || regno == PT_PC) { long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj)); addr = (unsigned long *) ((unsigned long)addr + stkadj); /* The sr is actually a 16 bit register. */ if (regno == PT_SR) { *(unsigned short *)addr = data; return 0; } } *addr = data; return 0; }

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/* * Make sure the single step bit is not set. */
static inline void singlestep_disable(struct task_struct *child) { unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS; put_reg(child, PT_SR, tmp); clear_tsk_thread_flag(child, TIF_DELAYED_TRACE); }

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/* * Called by kernel/ptrace.c when detaching.. */
void ptrace_disable(struct task_struct *child) { singlestep_disable(child); }

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void user_enable_single_step(struct task_struct *child) { unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS; put_reg(child, PT_SR, tmp | T1_BIT); set_tsk_thread_flag(child, TIF_DELAYED_TRACE); }

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#ifdef CONFIG_MMU
void user_enable_block_step(struct task_struct *child) { unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS; put_reg(child, PT_SR, tmp | T0_BIT); }

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#endif
void user_disable_single_step(struct task_struct *child) { singlestep_disable(child); }

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long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data) { unsigned long tmp; int i, ret = 0; int regno = addr >> 2; /* temporary hack. */ unsigned long __user *datap = (unsigned long __user *) data; switch (request) { /* read the word at location addr in the USER area. */ case PTRACE_PEEKUSR: if (addr & 3) goto out_eio; if (regno >= 0 && regno < 19) { tmp = get_reg(child, regno); } else if (regno >= 21 && regno < 49) { tmp = child->thread.fp[regno - 21]; /* Convert internal fpu reg representation * into long double format */ if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) tmp = ((tmp & 0xffff0000) << 15) | ((tmp & 0x0000ffff) << 16); #ifndef CONFIG_MMU } else if (regno == 49) { tmp = child->mm->start_code; } else if (regno == 50) { tmp = child->mm->start_data; } else if (regno == 51) { tmp = child->mm->end_code; #endif } else goto out_eio; ret = put_user(tmp, datap); break; case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ if (addr & 3) goto out_eio; if (regno == PT_SR) { data &= SR_MASK; data |= get_reg(child, PT_SR) & ~SR_MASK; } if (regno >= 0 && regno < 19) { if (put_reg(child, regno, data)) goto out_eio; } else if (regno >= 21 && regno < 48) { /* Convert long double format * into internal fpu reg representation */ if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) { data <<= 15; data = (data & 0xffff0000) | ((data & 0x0000ffff) >> 1); } child->thread.fp[regno - 21] = data; } else goto out_eio; break; case PTRACE_GETREGS: /* Get all gp regs from the child. */ for (i = 0; i < 19; i++) { tmp = get_reg(child, i); ret = put_user(tmp, datap); if (ret) break; datap++; } break; case PTRACE_SETREGS: /* Set all gp regs in the child. */ for (i = 0; i < 19; i++) { ret = get_user(tmp, datap); if (ret) break; if (i == PT_SR) { tmp &= SR_MASK; tmp |= get_reg(child, PT_SR) & ~SR_MASK; } put_reg(child, i, tmp); datap++; } break; case PTRACE_GETFPREGS: /* Get the child FPU state. */ if (copy_to_user(datap, &child->thread.fp, sizeof(struct user_m68kfp_struct))) ret = -EFAULT; break; case PTRACE_SETFPREGS: /* Set the child FPU state. */ if (copy_from_user(&child->thread.fp, datap, sizeof(struct user_m68kfp_struct))) ret = -EFAULT; break; case PTRACE_GET_THREAD_AREA: ret = put_user(task_thread_info(child)->tp_value, datap); break; default: ret = ptrace_request(child, request, addr, data); break; } return ret; out_eio: return -EIO; }

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asmlinkage void syscall_trace(void) { 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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Greg Ungerer53100.00%1100.00%
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#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
asmlinkage int syscall_trace_enter(void) { int ret = 0; if (test_thread_flag(TIF_SYSCALL_TRACE)) ret = tracehook_report_syscall_entry(task_pt_regs(current)); return ret; }

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asmlinkage void syscall_trace_leave(void) { if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall_exit(task_pt_regs(current), 0); }

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#endif /* CONFIG_COLDFIRE */

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Greg Ungerer141399.58%350.00%
Ingo Molnar30.21%116.67%
Linus Torvalds (pre-git)20.14%116.67%
Linus Torvalds10.07%116.67%
Total1419100.00%6100.00%
Directory: arch/m68k/kernel
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