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[IA64] enable singlestep on system call

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As is pointed out in
http://www.gelato.org/community/view_linear.php?id=1_1036&from=authors&value=Ian%20Wienand#1_1039,
if single step on break instruction, the break fault has higher
priority than the single-step trap. When the break fault handler
is entered, it advances the IP by 1 instruction so break instruction
single-stepping is skipped, actually it is next instruction which
is single stepped.

This patch modifies this, it adds TIF_SINGLESTEP bit for thread
flags, and generate a fake sigtrap when single stepping break
instruction. Test case in attachment can verify this. Any comments
is welcome.

Signed-off-by: bibo, mao <bibo.mao@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
bibo,mao 2007-01-31 17:50:31 +08:00 committed by Tony Luck
parent c237508afa
commit 90f9d70a58
2 changed files with 9 additions and 7 deletions
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12
arch/ia64/kernel/ptrace.c
View file

@ -1405,6 +1405,7 @@ ptrace_disable (struct task_struct *child)
struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
/* make sure the single step/taken-branch trap bits are not set: */
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
child_psr->ss = 0;
child_psr->tb = 0;
}
@ -1525,6 +1526,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
* Make sure the single step/taken-branch trap bits
* are not set:
*/
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
ia64_psr(pt)->ss = 0;
ia64_psr(pt)->tb = 0;
@ -1556,6 +1558,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
goto out_tsk;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
set_tsk_thread_flag(child, TIF_SINGLESTEP);
if (request == PTRACE_SINGLESTEP) {
ia64_psr(pt)->ss = 1;
} else {
@ -1595,13 +1598,9 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
}
void
static void
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.
@ -1664,7 +1663,8 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
audit_syscall_exit(success, result);
}
if (test_thread_flag(TIF_SYSCALL_TRACE)
if ((test_thread_flag(TIF_SYSCALL_TRACE)
|| test_thread_flag(TIF_SINGLESTEP))
&& (current->ptrace & PT_PTRACED))
syscall_trace();
}

4
include/asm-ia64/thread_info.h
View file

@ -84,6 +84,7 @@ struct thread_info {
#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
#define TIF_SYSCALL_TRACE 3 /* syscall trace active */
#define TIF_SYSCALL_AUDIT 4 /* syscall auditing active */
#define TIF_SINGLESTEP 5 /* restore singlestep on return to user mode */
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 17
#define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */
@ -92,7 +93,8 @@ struct thread_info {
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEAUDIT (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_SYSCALL_TRACEAUDIT (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)