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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 00:20:36 +0200 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 00:20:36 +0200 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/kernel/ptrace.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/kernel/ptrace.c')
-rw-r--r-- | arch/arm/kernel/ptrace.c | 861 |
1 files changed, 861 insertions, 0 deletions
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c new file mode 100644 index 000000000000..efd7a341614b --- /dev/null +++ b/arch/arm/kernel/ptrace.c @@ -0,0 +1,861 @@ +/* + * linux/arch/arm/kernel/ptrace.c + * + * By Ross Biro 1/23/92 + * edited by Linus Torvalds + * ARM modifications Copyright (C) 2000 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/config.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/smp_lock.h> +#include <linux/ptrace.h> +#include <linux/user.h> +#include <linux/security.h> +#include <linux/init.h> + +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/system.h> +#include <asm/traps.h> + +#include "ptrace.h" + +#define REG_PC 15 +#define REG_PSR 16 +/* + * does not yet catch signals sent when the child dies. + * in exit.c or in signal.c. + */ + +#if 0 +/* + * Breakpoint SWI instruction: SWI &9F0001 + */ +#define BREAKINST_ARM 0xef9f0001 +#define BREAKINST_THUMB 0xdf00 /* fill this in later */ +#else +/* + * New breakpoints - use an undefined instruction. The ARM architecture + * reference manual guarantees that the following instruction space + * will produce an undefined instruction exception on all CPUs: + * + * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx + * Thumb: 1101 1110 xxxx xxxx + */ +#define BREAKINST_ARM 0xe7f001f0 +#define BREAKINST_THUMB 0xde01 +#endif + +/* + * 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 - + 8 - sizeof(struct pt_regs)); +} + +/* + * this routine will get a word off of the processes privileged stack. + * the offset is how far from the base addr as stored in the THREAD. + * this routine assumes that all the privileged stacks are in our + * data space. + */ +static inline long get_user_reg(struct task_struct *task, int offset) +{ + return get_user_regs(task)->uregs[offset]; +} + +/* + * this routine will put a word on the processes privileged stack. + * the offset is how far from the base addr as stored in the THREAD. + * this routine assumes that all the privileged stacks are in our + * data space. + */ +static inline int +put_user_reg(struct task_struct *task, int offset, long data) +{ + struct pt_regs newregs, *regs = get_user_regs(task); + int ret = -EINVAL; + + newregs = *regs; + newregs.uregs[offset] = data; + + if (valid_user_regs(&newregs)) { + regs->uregs[offset] = data; + ret = 0; + } + + return ret; +} + +static inline int +read_u32(struct task_struct *task, unsigned long addr, u32 *res) +{ + int ret; + + ret = access_process_vm(task, addr, res, sizeof(*res), 0); + + return ret == sizeof(*res) ? 0 : -EIO; +} + +static inline int +read_instr(struct task_struct *task, unsigned long addr, u32 *res) +{ + int ret; + + if (addr & 1) { + u16 val; + ret = access_process_vm(task, addr & ~1, &val, sizeof(val), 0); + ret = ret == sizeof(val) ? 0 : -EIO; + *res = val; + } else { + u32 val; + ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0); + ret = ret == sizeof(val) ? 0 : -EIO; + *res = val; + } + return ret; +} + +/* + * Get value of register `rn' (in the instruction) + */ +static unsigned long +ptrace_getrn(struct task_struct *child, unsigned long insn) +{ + unsigned int reg = (insn >> 16) & 15; + unsigned long val; + + val = get_user_reg(child, reg); + if (reg == 15) + val = pc_pointer(val + 8); + + return val; +} + +/* + * Get value of operand 2 (in an ALU instruction) + */ +static unsigned long +ptrace_getaluop2(struct task_struct *child, unsigned long insn) +{ + unsigned long val; + int shift; + int type; + + if (insn & 1 << 25) { + val = insn & 255; + shift = (insn >> 8) & 15; + type = 3; + } else { + val = get_user_reg (child, insn & 15); + + if (insn & (1 << 4)) + shift = (int)get_user_reg (child, (insn >> 8) & 15); + else + shift = (insn >> 7) & 31; + + type = (insn >> 5) & 3; + } + + switch (type) { + case 0: val <<= shift; break; + case 1: val >>= shift; break; + case 2: + val = (((signed long)val) >> shift); + break; + case 3: + val = (val >> shift) | (val << (32 - shift)); + break; + } + return val; +} + +/* + * Get value of operand 2 (in a LDR instruction) + */ +static unsigned long +ptrace_getldrop2(struct task_struct *child, unsigned long insn) +{ + unsigned long val; + int shift; + int type; + + val = get_user_reg(child, insn & 15); + shift = (insn >> 7) & 31; + type = (insn >> 5) & 3; + + switch (type) { + case 0: val <<= shift; break; + case 1: val >>= shift; break; + case 2: + val = (((signed long)val) >> shift); + break; + case 3: + val = (val >> shift) | (val << (32 - shift)); + break; + } + return val; +} + +#define OP_MASK 0x01e00000 +#define OP_AND 0x00000000 +#define OP_EOR 0x00200000 +#define OP_SUB 0x00400000 +#define OP_RSB 0x00600000 +#define OP_ADD 0x00800000 +#define OP_ADC 0x00a00000 +#define OP_SBC 0x00c00000 +#define OP_RSC 0x00e00000 +#define OP_ORR 0x01800000 +#define OP_MOV 0x01a00000 +#define OP_BIC 0x01c00000 +#define OP_MVN 0x01e00000 + +static unsigned long +get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn) +{ + u32 alt = 0; + + switch (insn & 0x0e000000) { + case 0x00000000: + case 0x02000000: { + /* + * data processing + */ + long aluop1, aluop2, ccbit; + + if ((insn & 0xf000) != 0xf000) + break; + + aluop1 = ptrace_getrn(child, insn); + aluop2 = ptrace_getaluop2(child, insn); + ccbit = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0; + + switch (insn & OP_MASK) { + case OP_AND: alt = aluop1 & aluop2; break; + case OP_EOR: alt = aluop1 ^ aluop2; break; + case OP_SUB: alt = aluop1 - aluop2; break; + case OP_RSB: alt = aluop2 - aluop1; break; + case OP_ADD: alt = aluop1 + aluop2; break; + case OP_ADC: alt = aluop1 + aluop2 + ccbit; break; + case OP_SBC: alt = aluop1 - aluop2 + ccbit; break; + case OP_RSC: alt = aluop2 - aluop1 + ccbit; break; + case OP_ORR: alt = aluop1 | aluop2; break; + case OP_MOV: alt = aluop2; break; + case OP_BIC: alt = aluop1 & ~aluop2; break; + case OP_MVN: alt = ~aluop2; break; + } + break; + } + + case 0x04000000: + case 0x06000000: + /* + * ldr + */ + if ((insn & 0x0010f000) == 0x0010f000) { + unsigned long base; + + base = ptrace_getrn(child, insn); + if (insn & 1 << 24) { + long aluop2; + + if (insn & 0x02000000) + aluop2 = ptrace_getldrop2(child, insn); + else + aluop2 = insn & 0xfff; + + if (insn & 1 << 23) + base += aluop2; + else + base -= aluop2; + } + if (read_u32(child, base, &alt) == 0) + alt = pc_pointer(alt); + } + break; + + case 0x08000000: + /* + * ldm + */ + if ((insn & 0x00108000) == 0x00108000) { + unsigned long base; + unsigned int nr_regs; + + if (insn & (1 << 23)) { + nr_regs = hweight16(insn & 65535) << 2; + + if (!(insn & (1 << 24))) + nr_regs -= 4; + } else { + if (insn & (1 << 24)) + nr_regs = -4; + else + nr_regs = 0; + } + + base = ptrace_getrn(child, insn); + + if (read_u32(child, base + nr_regs, &alt) == 0) + alt = pc_pointer(alt); + break; + } + break; + + case 0x0a000000: { + /* + * bl or b + */ + signed long displ; + /* It's a branch/branch link: instead of trying to + * figure out whether the branch will be taken or not, + * we'll put a breakpoint at both locations. This is + * simpler, more reliable, and probably not a whole lot + * slower than the alternative approach of emulating the + * branch. + */ + displ = (insn & 0x00ffffff) << 8; + displ = (displ >> 6) + 8; + if (displ != 0 && displ != 4) + alt = pc + displ; + } + break; + } + + return alt; +} + +static int +swap_insn(struct task_struct *task, unsigned long addr, + void *old_insn, void *new_insn, int size) +{ + int ret; + + ret = access_process_vm(task, addr, old_insn, size, 0); + if (ret == size) + ret = access_process_vm(task, addr, new_insn, size, 1); + return ret; +} + +static void +add_breakpoint(struct task_struct *task, struct debug_info *dbg, unsigned long addr) +{ + int nr = dbg->nsaved; + + if (nr < 2) { + u32 new_insn = BREAKINST_ARM; + int res; + + res = swap_insn(task, addr, &dbg->bp[nr].insn, &new_insn, 4); + + if (res == 4) { + dbg->bp[nr].address = addr; + dbg->nsaved += 1; + } + } else + printk(KERN_ERR "ptrace: too many breakpoints\n"); +} + +/* + * Clear one breakpoint in the user program. We copy what the hardware + * does and use bit 0 of the address to indicate whether this is a Thumb + * breakpoint or an ARM breakpoint. + */ +static void clear_breakpoint(struct task_struct *task, struct debug_entry *bp) +{ + unsigned long addr = bp->address; + union debug_insn old_insn; + int ret; + + if (addr & 1) { + ret = swap_insn(task, addr & ~1, &old_insn.thumb, + &bp->insn.thumb, 2); + + if (ret != 2 || old_insn.thumb != BREAKINST_THUMB) + printk(KERN_ERR "%s:%d: corrupted Thumb breakpoint at " + "0x%08lx (0x%04x)\n", task->comm, task->pid, + addr, old_insn.thumb); + } else { + ret = swap_insn(task, addr & ~3, &old_insn.arm, + &bp->insn.arm, 4); + + if (ret != 4 || old_insn.arm != BREAKINST_ARM) + printk(KERN_ERR "%s:%d: corrupted ARM breakpoint at " + "0x%08lx (0x%08x)\n", task->comm, task->pid, + addr, old_insn.arm); + } +} + +void ptrace_set_bpt(struct task_struct *child) +{ + struct pt_regs *regs; + unsigned long pc; + u32 insn; + int res; + + regs = get_user_regs(child); + pc = instruction_pointer(regs); + + if (thumb_mode(regs)) { + printk(KERN_WARNING "ptrace: can't handle thumb mode\n"); + return; + } + + res = read_instr(child, pc, &insn); + if (!res) { + struct debug_info *dbg = &child->thread.debug; + unsigned long alt; + + dbg->nsaved = 0; + + alt = get_branch_address(child, pc, insn); + if (alt) + add_breakpoint(child, dbg, alt); + + /* + * Note that we ignore the result of setting the above + * breakpoint since it may fail. When it does, this is + * not so much an error, but a forewarning that we may + * be receiving a prefetch abort shortly. + * + * If we don't set this breakpoint here, then we can + * lose control of the thread during single stepping. + */ + if (!alt || predicate(insn) != PREDICATE_ALWAYS) + add_breakpoint(child, dbg, pc + 4); + } +} + +/* + * Ensure no single-step breakpoint is pending. Returns non-zero + * value if child was being single-stepped. + */ +void ptrace_cancel_bpt(struct task_struct *child) +{ + int i, nsaved = child->thread.debug.nsaved; + + child->thread.debug.nsaved = 0; + + if (nsaved > 2) { + printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved); + nsaved = 2; + } + + for (i = 0; i < nsaved; i++) + clear_breakpoint(child, &child->thread.debug.bp[i]); +} + +/* + * Called by kernel/ptrace.c when detaching.. + * + * Make sure the single step bit is not set. + */ +void ptrace_disable(struct task_struct *child) +{ + child->ptrace &= ~PT_SINGLESTEP; + ptrace_cancel_bpt(child); +} + +/* + * Handle hitting a breakpoint. + */ +void ptrace_break(struct task_struct *tsk, struct pt_regs *regs) +{ + siginfo_t info; + + ptrace_cancel_bpt(tsk); + + info.si_signo = SIGTRAP; + info.si_errno = 0; + info.si_code = TRAP_BRKPT; + info.si_addr = (void __user *)instruction_pointer(regs); + + force_sig_info(SIGTRAP, &info, tsk); +} + +static int break_trap(struct pt_regs *regs, unsigned int instr) +{ + ptrace_break(current, regs); + return 0; +} + +static struct undef_hook arm_break_hook = { + .instr_mask = 0x0fffffff, + .instr_val = 0x07f001f0, + .cpsr_mask = PSR_T_BIT, + .cpsr_val = 0, + .fn = break_trap, +}; + +static struct undef_hook thumb_break_hook = { + .instr_mask = 0xffff, + .instr_val = 0xde01, + .cpsr_mask = PSR_T_BIT, + .cpsr_val = PSR_T_BIT, + .fn = break_trap, +}; + +static int __init ptrace_break_init(void) +{ + register_undef_hook(&arm_break_hook); + register_undef_hook(&thumb_break_hook); + return 0; +} + +core_initcall(ptrace_break_init); + +/* + * 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 *ret) +{ + unsigned long tmp; + + if (off & 3 || off >= sizeof(struct user)) + return -EIO; + + tmp = 0; + if (off < sizeof(struct pt_regs)) + tmp = get_user_reg(tsk, off >> 2); + + return put_user(tmp, ret); +} + +/* + * Write the word at offset "off" into "struct user". We + * actually access the pt_regs stored on the kernel stack. + */ +static int ptrace_write_user(struct task_struct *tsk, unsigned long off, + unsigned long val) +{ + if (off & 3 || off >= sizeof(struct user)) + return -EIO; + + if (off >= sizeof(struct pt_regs)) + return 0; + + return put_user_reg(tsk, off >> 2, val); +} + +/* + * Get all user integer registers. + */ +static int ptrace_getregs(struct task_struct *tsk, void __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); + + ret = -EINVAL; + if (valid_user_regs(&newregs)) { + *regs = newregs; + ret = 0; + } + } + + return ret; +} + +/* + * Get the child FPU state. + */ +static int ptrace_getfpregs(struct task_struct *tsk, void __user *ufp) +{ + return copy_to_user(ufp, &tsk->thread_info->fpstate, + sizeof(struct user_fp)) ? -EFAULT : 0; +} + +/* + * Set the child FPU state. + */ +static int ptrace_setfpregs(struct task_struct *tsk, void __user *ufp) +{ + struct thread_info *thread = tsk->thread_info; + thread->used_cp[1] = thread->used_cp[2] = 1; + return copy_from_user(&thread->fpstate, ufp, + sizeof(struct user_fp)) ? -EFAULT : 0; +} + +#ifdef CONFIG_IWMMXT + +/* + * Get the child iWMMXt state. + */ +static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp) +{ + struct thread_info *thread = tsk->thread_info; + void *ptr = &thread->fpstate; + + if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT)) + return -ENODATA; + iwmmxt_task_disable(thread); /* force it to ram */ + /* The iWMMXt state is stored doubleword-aligned. */ + if (((long) ptr) & 4) + ptr += 4; + return copy_to_user(ufp, ptr, 0x98) ? -EFAULT : 0; +} + +/* + * Set the child iWMMXt state. + */ +static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp) +{ + struct thread_info *thread = tsk->thread_info; + void *ptr = &thread->fpstate; + + if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT)) + return -EACCES; + iwmmxt_task_release(thread); /* force a reload */ + /* The iWMMXt state is stored doubleword-aligned. */ + if (((long) ptr) & 4) + ptr += 4; + return copy_from_user(ptr, ufp, 0x98) ? -EFAULT : 0; +} + +#endif + +static int do_ptrace(int request, struct task_struct *child, long addr, long data) +{ + unsigned long tmp; + int ret; + + switch (request) { + /* + * read word at location "addr" in the child process. + */ + case PTRACE_PEEKTEXT: + case PTRACE_PEEKDATA: + ret = access_process_vm(child, addr, &tmp, + sizeof(unsigned long), 0); + if (ret == sizeof(unsigned long)) + ret = put_user(tmp, (unsigned long __user *) data); + else + ret = -EIO; + break; + + 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(unsigned long), 1); + if (ret == sizeof(unsigned long)) + ret = 0; + else + ret = -EIO; + break; + + case PTRACE_POKEUSR: + ret = ptrace_write_user(child, addr, data); + break; + + /* + * continue/restart and stop at next (return from) syscall + */ + case PTRACE_SYSCALL: + case PTRACE_CONT: + ret = -EIO; + if ((unsigned long) data > _NSIG) + break; + if (request == PTRACE_SYSCALL) + set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + else + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + child->exit_code = data; + /* make sure single-step breakpoint is gone. */ + child->ptrace &= ~PT_SINGLESTEP; + ptrace_cancel_bpt(child); + wake_up_process(child); + ret = 0; + break; + + /* + * make the child exit. Best I can do is send it a sigkill. + * perhaps it should be put in the status that it wants to + * exit. + */ + case PTRACE_KILL: + /* make sure single-step breakpoint is gone. */ + child->ptrace &= ~PT_SINGLESTEP; + ptrace_cancel_bpt(child); + if (child->exit_state != EXIT_ZOMBIE) { + child->exit_code = SIGKILL; + wake_up_process(child); + } + ret = 0; + break; + + /* + * execute single instruction. + */ + case PTRACE_SINGLESTEP: + ret = -EIO; + if ((unsigned long) data > _NSIG) + break; + child->ptrace |= PT_SINGLESTEP; + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + child->exit_code = data; + /* give it a chance to run. */ + wake_up_process(child); + ret = 0; + break; + + case PTRACE_DETACH: + ret = ptrace_detach(child, data); + break; + + case PTRACE_GETREGS: + ret = ptrace_getregs(child, (void __user *)data); + break; + + case PTRACE_SETREGS: + ret = ptrace_setregs(child, (void __user *)data); + break; + + case PTRACE_GETFPREGS: + ret = ptrace_getfpregs(child, (void __user *)data); + break; + + case PTRACE_SETFPREGS: + ret = ptrace_setfpregs(child, (void __user *)data); + break; + +#ifdef CONFIG_IWMMXT + case PTRACE_GETWMMXREGS: + ret = ptrace_getwmmxregs(child, (void __user *)data); + break; + + case PTRACE_SETWMMXREGS: + ret = ptrace_setwmmxregs(child, (void __user *)data); + break; +#endif + + case PTRACE_GET_THREAD_AREA: + ret = put_user(child->thread_info->tp_value, + (unsigned long __user *) data); + break; + + default: + ret = ptrace_request(child, request, addr, data); + break; + } + + return ret; +} + +asmlinkage int sys_ptrace(long request, long pid, long addr, long data) +{ + struct task_struct *child; + int ret; + + lock_kernel(); + ret = -EPERM; + if (request == PTRACE_TRACEME) { + /* are we already being traced? */ + if (current->ptrace & PT_PTRACED) + goto out; + ret = security_ptrace(current->parent, current); + if (ret) + goto out; + /* set the ptrace bit in the process flags. */ + current->ptrace |= PT_PTRACED; + ret = 0; + goto out; + } + ret = -ESRCH; + read_lock(&tasklist_lock); + child = find_task_by_pid(pid); + if (child) + get_task_struct(child); + read_unlock(&tasklist_lock); + if (!child) + goto out; + + ret = -EPERM; + if (pid == 1) /* you may not mess with init */ + goto out_tsk; + + if (request == PTRACE_ATTACH) { + ret = ptrace_attach(child); + goto out_tsk; + } + ret = ptrace_check_attach(child, request == PTRACE_KILL); + if (ret == 0) + ret = do_ptrace(request, child, addr, data); + +out_tsk: + put_task_struct(child); +out: + unlock_kernel(); + return ret; +} + +asmlinkage void syscall_trace(int why, struct pt_regs *regs) +{ + unsigned long ip; + + if (!test_thread_flag(TIF_SYSCALL_TRACE)) + return; + if (!(current->ptrace & PT_PTRACED)) + return; + + /* + * Save IP. IP is used to denote syscall entry/exit: + * IP = 0 -> entry, = 1 -> exit + */ + ip = regs->ARM_ip; + regs->ARM_ip = why; + + /* the 0x80 provides a way for the tracing parent to distinguish + between a syscall stop and SIGTRAP delivery */ + ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) + ? 0x80 : 0)); + /* + * this isn't the same as continuing with a signal, but it will do + * for normal use. strace only continues with a signal if the + * stopping signal is not SIGTRAP. -brl + */ + if (current->exit_code) { + send_sig(current->exit_code, current, 1); + current->exit_code = 0; + } + regs->ARM_ip = ip; +} |