diff options
Diffstat (limited to 'arch/parisc/kernel/ptrace.c')
| -rw-r--r-- | arch/parisc/kernel/ptrace.c | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c new file mode 100644 index 000000000000..2937a9236384 --- /dev/null +++ b/arch/parisc/kernel/ptrace.c @@ -0,0 +1,423 @@ +/* + * Kernel support for the ptrace() and syscall tracing interfaces. + * + * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc. + * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx> + * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org> + */ + +#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/personality.h> +#include <linux/security.h> +#include <linux/compat.h> + +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/system.h> +#include <asm/processor.h> +#include <asm/offsets.h> + +/* PSW bits we allow the debugger to modify */ +#define USER_PSW_BITS (PSW_N | PSW_V | PSW_CB) + +#undef DEBUG_PTRACE + +#ifdef DEBUG_PTRACE +#define DBG(x...) printk(x) +#else +#define DBG(x...) +#endif + +#ifdef __LP64__ + +/* This function is needed to translate 32 bit pt_regs offsets in to + * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel + * will request offset 12 if it wants gr3, but the lower 32 bits of + * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4). + * This code relies on a 32 bit pt_regs being comprised of 32 bit values + * except for the fp registers which (a) are 64 bits, and (b) follow + * the gr registers at the start of pt_regs. The 32 bit pt_regs should + * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[] + * being 64 bit in both cases. + */ + +static long translate_usr_offset(long offset) +{ + if (offset < 0) + return -1; + else if (offset <= 32*4) /* gr[0..31] */ + return offset * 2 + 4; + else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */ + return offset + 32*4; + else if (offset < sizeof(struct pt_regs)/2 + 32*4) + return offset * 2 + 4 - 32*8; + else + return -1; +} +#endif + +/* + * Called by kernel/ptrace.c when detaching.. + * + * Make sure single step bits etc are not set. + */ +void ptrace_disable(struct task_struct *child) +{ + /* make sure the trap bits are not set */ + pa_psw(child)->r = 0; + pa_psw(child)->t = 0; + pa_psw(child)->h = 0; + pa_psw(child)->l = 0; +} + +long sys_ptrace(long request, pid_t pid, long addr, long data) +{ + struct task_struct *child; + long ret; +#ifdef DEBUG_PTRACE + long oaddr=addr, odata=data; +#endif + + 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) /* no messing around 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) + goto out_tsk; + + switch (request) { + case PTRACE_PEEKTEXT: /* read word at location addr. */ + case PTRACE_PEEKDATA: { + int copied; + +#ifdef __LP64__ + if (is_compat_task(child)) { + unsigned int tmp; + + addr &= 0xffffffffL; + copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); + ret = -EIO; + if (copied != sizeof(tmp)) + goto out_tsk; + ret = put_user(tmp,(unsigned int *) data); + DBG("sys_ptrace(PEEK%s, %d, %lx, %lx) returning %ld, data %x\n", + request == PTRACE_PEEKTEXT ? "TEXT" : "DATA", + pid, oaddr, odata, ret, tmp); + } + else +#endif + { + unsigned long tmp; + + copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); + ret = -EIO; + if (copied != sizeof(tmp)) + goto out_tsk; + ret = put_user(tmp,(unsigned long *) data); + } + goto out_tsk; + } + + /* when I and D space are separate, this will have to be fixed. */ + case PTRACE_POKETEXT: /* write the word at location addr. */ + case PTRACE_POKEDATA: + ret = 0; +#ifdef __LP64__ + if (is_compat_task(child)) { + unsigned int tmp = (unsigned int)data; + DBG("sys_ptrace(POKE%s, %d, %lx, %lx)\n", + request == PTRACE_POKETEXT ? "TEXT" : "DATA", + pid, oaddr, odata); + addr &= 0xffffffffL; + if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1) == sizeof(tmp)) + goto out_tsk; + } + else +#endif + { + if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) + goto out_tsk; + } + ret = -EIO; + goto out_tsk; + + /* Read the word at location addr in the USER area. For ptraced + processes, the kernel saves all regs on a syscall. */ + case PTRACE_PEEKUSR: { + ret = -EIO; +#ifdef __LP64__ + if (is_compat_task(child)) { + unsigned int tmp; + + if (addr & (sizeof(int)-1)) + goto out_tsk; + if ((addr = translate_usr_offset(addr)) < 0) + goto out_tsk; + + tmp = *(unsigned int *) ((char *) task_regs(child) + addr); + ret = put_user(tmp, (unsigned int *) data); + DBG("sys_ptrace(PEEKUSR, %d, %lx, %lx) returning %ld, addr %lx, data %x\n", + pid, oaddr, odata, ret, addr, tmp); + } + else +#endif + { + unsigned long tmp; + + if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) + goto out_tsk; + tmp = *(unsigned long *) ((char *) task_regs(child) + addr); + ret = put_user(tmp, (unsigned long *) data); + } + goto out_tsk; + } + + /* Write the word at location addr in the USER area. This will need + to change when the kernel no longer saves all regs on a syscall. + FIXME. There is a problem at the moment in that r3-r18 are only + saved if the process is ptraced on syscall entry, and even then + those values are overwritten by actual register values on syscall + exit. */ + case PTRACE_POKEUSR: + ret = -EIO; + /* Some register values written here may be ignored in + * entry.S:syscall_restore_rfi; e.g. iaoq is written with + * r31/r31+4, and not with the values in pt_regs. + */ + /* PT_PSW=0, so this is valid for 32 bit processes under 64 + * bit kernels. + */ + if (addr == PT_PSW) { + /* PT_PSW=0, so this is valid for 32 bit processes + * under 64 bit kernels. + * + * Allow writing to Nullify, Divide-step-correction, + * and carry/borrow bits. + * BEWARE, if you set N, and then single step, it won't + * stop on the nullified instruction. + */ + DBG("sys_ptrace(POKEUSR, %d, %lx, %lx)\n", + pid, oaddr, odata); + data &= USER_PSW_BITS; + task_regs(child)->gr[0] &= ~USER_PSW_BITS; + task_regs(child)->gr[0] |= data; + ret = 0; + goto out_tsk; + } +#ifdef __LP64__ + if (is_compat_task(child)) { + if (addr & (sizeof(int)-1)) + goto out_tsk; + if ((addr = translate_usr_offset(addr)) < 0) + goto out_tsk; + DBG("sys_ptrace(POKEUSR, %d, %lx, %lx) addr %lx\n", + pid, oaddr, odata, addr); + if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { + /* Special case, fp regs are 64 bits anyway */ + *(unsigned int *) ((char *) task_regs(child) + addr) = data; + ret = 0; + } + else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) || + addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 || + addr == PT_SAR+4) { + /* Zero the top 32 bits */ + *(unsigned int *) ((char *) task_regs(child) + addr - 4) = 0; + *(unsigned int *) ((char *) task_regs(child) + addr) = data; + ret = 0; + } + goto out_tsk; + } + else +#endif + { + if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs)) + goto out_tsk; + if ((addr >= PT_GR1 && addr <= PT_GR31) || + addr == PT_IAOQ0 || addr == PT_IAOQ1 || + (addr >= PT_FR0 && addr <= PT_FR31 + 4) || + addr == PT_SAR) { + *(unsigned long *) ((char *) task_regs(child) + addr) = data; + ret = 0; + } + goto out_tsk; + } + + case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ + case PTRACE_CONT: + ret = -EIO; + DBG("sys_ptrace(%s)\n", + request == PTRACE_SYSCALL ? "SYSCALL" : "CONT"); + if ((unsigned long) data > _NSIG) + goto out_tsk; + child->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP); + 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; + goto out_wake_notrap; + + case PTRACE_KILL: + /* + * 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. + */ + DBG("sys_ptrace(KILL)\n"); + if (child->exit_state == EXIT_ZOMBIE) /* already dead */ + goto out_tsk; + child->exit_code = SIGKILL; + goto out_wake_notrap; + + case PTRACE_SINGLEBLOCK: + DBG("sys_ptrace(SINGLEBLOCK)\n"); + ret = -EIO; + if ((unsigned long) data > _NSIG) + goto out_tsk; + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + child->ptrace &= ~PT_SINGLESTEP; + child->ptrace |= PT_BLOCKSTEP; + child->exit_code = data; + + /* Enable taken branch trap. */ + pa_psw(child)->r = 0; + pa_psw(child)->t = 1; + pa_psw(child)->h = 0; + pa_psw(child)->l = 0; + goto out_wake; + + case PTRACE_SINGLESTEP: + DBG("sys_ptrace(SINGLESTEP)\n"); + ret = -EIO; + if ((unsigned long) data > _NSIG) + goto out_tsk; + + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + child->ptrace &= ~PT_BLOCKSTEP; + child->ptrace |= PT_SINGLESTEP; + child->exit_code = data; + + if (pa_psw(child)->n) { + struct siginfo si; + + /* Nullified, just crank over the queue. */ + task_regs(child)->iaoq[0] = task_regs(child)->iaoq[1]; + task_regs(child)->iasq[0] = task_regs(child)->iasq[1]; + task_regs(child)->iaoq[1] = task_regs(child)->iaoq[0] + 4; + pa_psw(child)->n = 0; + pa_psw(child)->x = 0; + pa_psw(child)->y = 0; + pa_psw(child)->z = 0; + pa_psw(child)->b = 0; + ptrace_disable(child); + /* Don't wake up the child, but let the + parent know something happened. */ + si.si_code = TRAP_TRACE; + si.si_addr = (void __user *) (task_regs(child)->iaoq[0] & ~3); + si.si_signo = SIGTRAP; + si.si_errno = 0; + force_sig_info(SIGTRAP, &si, child); + //notify_parent(child, SIGCHLD); + //ret = 0; + goto out_wake; + } + + /* Enable recovery counter traps. The recovery counter + * itself will be set to zero on a task switch. If the + * task is suspended on a syscall then the syscall return + * path will overwrite the recovery counter with a suitable + * value such that it traps once back in user space. We + * disable interrupts in the childs PSW here also, to avoid + * interrupts while the recovery counter is decrementing. + */ + pa_psw(child)->r = 1; + pa_psw(child)->t = 0; + pa_psw(child)->h = 0; + pa_psw(child)->l = 0; + /* give it a chance to run. */ + goto out_wake; + + case PTRACE_DETACH: + ret = ptrace_detach(child, data); + goto out_tsk; + + case PTRACE_GETEVENTMSG: + ret = put_user(child->ptrace_message, (unsigned int __user *) data); + goto out_tsk; + + default: + ret = ptrace_request(child, request, addr, data); + goto out_tsk; + } + +out_wake_notrap: + ptrace_disable(child); +out_wake: + wake_up_process(child); + ret = 0; +out_tsk: + put_task_struct(child); +out: + unlock_kernel(); + DBG("sys_ptrace(%ld, %d, %lx, %lx) returning %ld\n", + request, pid, oaddr, odata, ret); + return ret; +} + +void syscall_trace(void) +{ + if (!test_thread_flag(TIF_SYSCALL_TRACE)) + return; + if (!(current->ptrace & PT_PTRACED)) + return; + 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; + } +} |