15f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen/* 25f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * Copyright (C) 2004-2006 Atmel Corporation 35f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * 45f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * This program is free software; you can redistribute it and/or modify 55f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * it under the terms of the GNU General Public License version 2 as 65f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * published by the Free Software Foundation. 75f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen */ 85f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#undef DEBUG 95f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/kernel.h> 105f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/sched.h> 115f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/mm.h> 125f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/ptrace.h> 135f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/errno.h> 145f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/user.h> 155f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/security.h> 165f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/unistd.h> 175f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <linux/notifier.h> 185f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 195f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <asm/traps.h> 205f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <asm/uaccess.h> 215f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <asm/ocd.h> 225f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen#include <asm/mmu_context.h> 231eeb66a1bb973534dc3d064920a5ca683823372eChristoph Hellwig#include <linux/kdebug.h> 245f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 255f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoenstatic struct pt_regs *get_user_regs(struct task_struct *tsk) 265f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 27c9f4f06d3191bd91c1a081b54a6c8e913e7b8a83Roman Zippel return (struct pt_regs *)((unsigned long)task_stack_page(tsk) + 285f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen THREAD_SIZE - sizeof(struct pt_regs)); 295f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 305f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 319e584fbbd9fd4f0f10b8aafc9982df8d0b553e35Peter Huewevoid user_enable_single_step(struct task_struct *tsk) 325f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 331d8393171b1f6c30a889fd7cb16fc193f689923cChristoph Hellwig pr_debug("user_enable_single_step: pid=%u, PC=0x%08lx, SR=0x%08lx\n", 342507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen tsk->pid, task_pt_regs(tsk)->pc, task_pt_regs(tsk)->sr); 355f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 362507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen /* 372507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * We can't schedule in Debug mode, so when TIF_BREAKPOINT is 382507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * set, the system call or exception handler will do a 392507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * breakpoint to enter monitor mode before returning to 402507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * userspace. 412507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * 422507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * The monitor code will then notice that TIF_SINGLE_STEP is 432507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * set and return to userspace with single stepping enabled. 442507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * The CPU will then enter monitor mode again after exactly 452507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * one instruction has been executed, and the monitor code 462507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * will then send a SIGTRAP to the process. 472507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen */ 482507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen set_tsk_thread_flag(tsk, TIF_BREAKPOINT); 495f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen set_tsk_thread_flag(tsk, TIF_SINGLE_STEP); 505f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 515f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 521d8393171b1f6c30a889fd7cb16fc193f689923cChristoph Hellwigvoid user_disable_single_step(struct task_struct *child) 531d8393171b1f6c30a889fd7cb16fc193f689923cChristoph Hellwig{ 541d8393171b1f6c30a889fd7cb16fc193f689923cChristoph Hellwig /* XXX(hch): a no-op here seems wrong.. */ 551d8393171b1f6c30a889fd7cb16fc193f689923cChristoph Hellwig} 561d8393171b1f6c30a889fd7cb16fc193f689923cChristoph Hellwig 575f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen/* 585f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * Called by kernel/ptrace.c when detaching 595f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * 605f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * Make sure any single step bits, etc. are not set 615f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen */ 625f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoenvoid ptrace_disable(struct task_struct *child) 635f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 645f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen clear_tsk_thread_flag(child, TIF_SINGLE_STEP); 652507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen clear_tsk_thread_flag(child, TIF_BREAKPOINT); 6613b54a50525a9685065684e1e11258d27dd27bdfHaavard Skinnemoen ocd_disable(child); 675f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 685f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 695f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen/* 705f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * Read the word at offset "offset" into the task's "struct user". We 715f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * actually access the pt_regs struct stored on the kernel stack. 725f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen */ 735f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoenstatic int ptrace_read_user(struct task_struct *tsk, unsigned long offset, 745f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen unsigned long __user *data) 755f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 765f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen unsigned long *regs; 775f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen unsigned long value; 785f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 795f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (offset & 3 || offset >= sizeof(struct user)) { 805f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen printk("ptrace_read_user: invalid offset 0x%08lx\n", offset); 815f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return -EIO; 825f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen } 835f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 845f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen regs = (unsigned long *)get_user_regs(tsk); 855f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 865f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen value = 0; 875f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (offset < sizeof(struct pt_regs)) 885f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen value = regs[offset / sizeof(regs[0])]; 895f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 902507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("ptrace_read_user(%s[%u], %#lx, %p) -> %#lx\n", 912507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen tsk->comm, tsk->pid, offset, data, value); 922507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 935f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return put_user(value, data); 945f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 955f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 965f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen/* 975f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * Write the word "value" to offset "offset" into the task's "struct 985f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * user". We actually access the pt_regs struct stored on the kernel 995f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * stack. 1005f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen */ 1015f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoenstatic int ptrace_write_user(struct task_struct *tsk, unsigned long offset, 1025f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen unsigned long value) 1035f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 1045f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen unsigned long *regs; 1055f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1062507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("ptrace_write_user(%s[%u], %#lx, %#lx)\n", 1072507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen tsk->comm, tsk->pid, offset, value); 1082507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 1095f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (offset & 3 || offset >= sizeof(struct user)) { 1102507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug(" invalid offset 0x%08lx\n", offset); 1115f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return -EIO; 1125f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen } 1135f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1145f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (offset >= sizeof(struct pt_regs)) 1155f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return 0; 1165f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1175f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen regs = (unsigned long *)get_user_regs(tsk); 1185f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen regs[offset / sizeof(regs[0])] = value; 1195f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1205f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return 0; 1215f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 1225f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1235f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoenstatic int ptrace_getregs(struct task_struct *tsk, void __user *uregs) 1245f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 1255f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen struct pt_regs *regs = get_user_regs(tsk); 1265f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1275f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0; 1285f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 1295f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1305f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoenstatic int ptrace_setregs(struct task_struct *tsk, const void __user *uregs) 1315f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 1325f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen struct pt_regs newregs; 1335f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen int ret; 1345f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1355f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen ret = -EFAULT; 1365f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) { 1375f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen struct pt_regs *regs = get_user_regs(tsk); 1385f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1395f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen ret = -EINVAL; 1405f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (valid_user_regs(&newregs)) { 1415f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen *regs = newregs; 1425f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen ret = 0; 1435f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen } 1445f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen } 1455f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1465f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return ret; 1475f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 1485f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1499b05a69e0534ec70bc94921936ffa05b330507cbNamhyung Kimlong arch_ptrace(struct task_struct *child, long request, 1509b05a69e0534ec70bc94921936ffa05b330507cbNamhyung Kim unsigned long addr, unsigned long data) 1515f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 1525f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen int ret; 1539f29b8fb416a0ad49d5077ab10ed780efdfcb126Namhyung Kim void __user *datap = (void __user *) data; 1545f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1555f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen switch (request) { 1565f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen /* Read the word at location addr in the child process */ 1575f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_PEEKTEXT: 1585f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_PEEKDATA: 1597664732315c97f48dba9d1e7339ad16fc5a320acAlexey Dobriyan ret = generic_ptrace_peekdata(child, addr, data); 1605f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen break; 1615f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1625f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_PEEKUSR: 1639f29b8fb416a0ad49d5077ab10ed780efdfcb126Namhyung Kim ret = ptrace_read_user(child, addr, datap); 1645f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen break; 1655f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1665f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen /* Write the word in data at location addr */ 1675f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_POKETEXT: 1685f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_POKEDATA: 169f284ce7269031947326bac6bb19a977705276222Alexey Dobriyan ret = generic_ptrace_pokedata(child, addr, data); 1705f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen break; 1715f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1725f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_POKEUSR: 1735f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen ret = ptrace_write_user(child, addr, data); 1745f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen break; 1755f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1765f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_GETREGS: 1779f29b8fb416a0ad49d5077ab10ed780efdfcb126Namhyung Kim ret = ptrace_getregs(child, datap); 1785f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen break; 1795f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1805f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen case PTRACE_SETREGS: 1819f29b8fb416a0ad49d5077ab10ed780efdfcb126Namhyung Kim ret = ptrace_setregs(child, datap); 1825f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen break; 1835f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1845f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen default: 1855f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen ret = ptrace_request(child, request, addr, data); 1865f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen break; 1875f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen } 1885f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1895f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return ret; 1905f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 1915f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1925f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoenasmlinkage void syscall_trace(void) 1935f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen{ 1945f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (!test_thread_flag(TIF_SYSCALL_TRACE)) 1955f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return; 1965f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (!(current->ptrace & PT_PTRACED)) 1975f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen return; 1985f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 1995f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen /* The 0x80 provides a way for the tracing parent to 2005f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * distinguish between a syscall stop and SIGTRAP delivery */ 2015f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 2025f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen ? 0x80 : 0)); 2035f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 2045f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen /* 2055f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * this isn't the same as continuing with a signal, but it 2065f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * will do for normal use. strace only continues with a 2075f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen * signal if the stopping signal is not SIGTRAP. -brl 2085f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen */ 2095f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen if (current->exit_code) { 2105f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen pr_debug("syscall_trace: sending signal %d to PID %u\n", 2115f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen current->exit_code, current->pid); 2125f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen send_sig(current->exit_code, current, 1); 2135f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen current->exit_code = 0; 2145f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen } 2155f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 2165f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 2175f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen/* 2182507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * debug_trampoline() is an assembly stub which will store all user 2192507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * registers on the stack and execute a breakpoint instruction. 2202507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * 2212507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * If we single-step into an exception handler which runs with 2222507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * interrupts disabled the whole time so it doesn't have to check for 2232507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * pending work, its return address will be modified so that it ends 2242507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * up returning to debug_trampoline. 2252507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * 2262507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * If the exception handler decides to store the user context and 2272507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * enable interrupts after all, it will restore the original return 2282507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * address and status register value. Before it returns, it will 2292507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * notice that TIF_BREAKPOINT is set and execute a breakpoint 2302507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * instruction. 2315f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen */ 2322507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoenextern void debug_trampoline(void); 2335f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 2342507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoenasmlinkage struct pt_regs *do_debug(struct pt_regs *regs) 2352507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen{ 2362507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen struct thread_info *ti; 2372507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen unsigned long trampoline_addr; 2382507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen u32 status; 2392507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen u32 ctrl; 2402507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen int code; 2412507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2422507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen status = ocd_read(DS); 2432507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ti = current_thread_info(); 2442507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen code = TRAP_BRKPT; 2452507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2462507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("do_debug: status=0x%08x PC=0x%08lx SR=0x%08lx tif=0x%08lx\n", 2472507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen status, regs->pc, regs->sr, ti->flags); 2482507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2492507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen if (!user_mode(regs)) { 2502507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen unsigned long die_val = DIE_BREAKPOINT; 2512507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2522507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen if (status & (1 << OCD_DS_SSS_BIT)) 2532507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen die_val = DIE_SSTEP; 2542507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2552507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP) 2562507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen == NOTIFY_STOP) 2572507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen return regs; 2582507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2592507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen if ((status & (1 << OCD_DS_SWB_BIT)) 2602507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen && test_and_clear_ti_thread_flag( 2612507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ti, TIF_BREAKPOINT)) { 2622507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen /* 2632507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * Explicit breakpoint from trampoline or 2642507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * exception/syscall/interrupt handler. 2652507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * 2662507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * The real saved regs are on the stack right 2672507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * after the ones we saved on entry. 2682507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen */ 2692507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen regs++; 2702507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug(" -> TIF_BREAKPOINT done, adjusted regs:" 2712507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen "PC=0x%08lx SR=0x%08lx\n", 2722507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen regs->pc, regs->sr); 2732507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen BUG_ON(!user_mode(regs)); 2742507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2752507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen if (test_thread_flag(TIF_SINGLE_STEP)) { 2762507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("Going to do single step...\n"); 2772507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen return regs; 2782507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen } 2792507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2802507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen /* 2812507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * No TIF_SINGLE_STEP means we're done 2822507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * stepping over a syscall. Do the trap now. 2832507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen */ 2842507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen code = TRAP_TRACE; 2852507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen } else if ((status & (1 << OCD_DS_SSS_BIT)) 2862507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen && test_ti_thread_flag(ti, TIF_SINGLE_STEP)) { 2872507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2882507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("Stepped into something, " 2892507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen "setting TIF_BREAKPOINT...\n"); 2902507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen set_ti_thread_flag(ti, TIF_BREAKPOINT); 2912507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 2922507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen /* 2932507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * We stepped into an exception, interrupt or 2942507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * syscall handler. Some exception handlers 2952507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * don't check for pending work, so we need to 2962507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * set up a trampoline just in case. 2972507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * 2982507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * The exception entry code will undo the 2992507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * trampoline stuff if it does a full context 3002507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * save (which also means that it'll check for 3012507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * pending work later.) 3022507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen */ 3032507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen if ((regs->sr & MODE_MASK) == MODE_EXCEPTION) { 3042507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen trampoline_addr 3052507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen = (unsigned long)&debug_trampoline; 3062507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 3072507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("Setting up trampoline...\n"); 3082507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ti->rar_saved = sysreg_read(RAR_EX); 3092507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ti->rsr_saved = sysreg_read(RSR_EX); 3102507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen sysreg_write(RAR_EX, trampoline_addr); 3112507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen sysreg_write(RSR_EX, (MODE_EXCEPTION 3122507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen | SR_EM | SR_GM)); 3132507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen BUG_ON(ti->rsr_saved & MODE_MASK); 3142507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen } 3152507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 3162507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen /* 3172507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * If we stepped into a system call, we 3182507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * shouldn't do a single step after we return 3192507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * since the return address is right after the 3202507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * "scall" instruction we were told to step 3212507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen * over. 3222507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen */ 3232507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen if ((regs->sr & MODE_MASK) == MODE_SUPERVISOR) { 3242507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("Supervisor; no single step\n"); 3252507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen clear_ti_thread_flag(ti, TIF_SINGLE_STEP); 3262507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen } 3272507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 3282507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ctrl = ocd_read(DC); 3292507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ctrl &= ~(1 << OCD_DC_SS_BIT); 3302507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ocd_write(DC, ctrl); 3312507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 3322507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen return regs; 3332507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen } else { 3342507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen printk(KERN_ERR "Unexpected OCD_DS value: 0x%08x\n", 3352507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen status); 3362507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen printk(KERN_ERR "Thread flags: 0x%08lx\n", ti->flags); 3372507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen die("Unhandled debug trap in kernel mode", 3382507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen regs, SIGTRAP); 3392507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen } 3402507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen } else if (status & (1 << OCD_DS_SSS_BIT)) { 3412507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen /* Single step in user mode */ 3422507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen code = TRAP_TRACE; 3435f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 3442507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ctrl = ocd_read(DC); 3452507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ctrl &= ~(1 << OCD_DC_SS_BIT); 3462507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen ocd_write(DC, ctrl); 3475f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen } 3485f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 3492507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen pr_debug("Sending SIGTRAP: code=%d PC=0x%08lx SR=0x%08lx\n", 3502507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen code, regs->pc, regs->sr); 3515f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen 3522507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen clear_thread_flag(TIF_SINGLE_STEP); 3532507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen _exception(SIGTRAP, regs, code, instruction_pointer(regs)); 3542507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen 3552507bc1338e43eadfef5b604d2c47e4f8180718fHaavard Skinnemoen return regs; 3565f97f7f9400de47ae837170bb274e90ad3934386Haavard Skinnemoen} 357