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authorbibo,mao <bibo.mao@intel.com>2007-01-31 04:50:31 -0500
committerTony Luck <tony.luck@intel.com>2007-02-05 16:49:29 -0500
commit90f9d70a582c02f50b4dd847166cd5b037219891 (patch)
treeffe6b5246f9e2334b474ca0913776668803d1ea0 /arch
parentc237508afa5d47282d3047784864013eebdc68ab (diff)
[IA64] enable singlestep on system call
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/ia64/kernel/ptrace.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index aa705e46b974..f1ec129ae3a1 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -1405,6 +1405,7 @@ ptrace_disable (struct task_struct *child)
1405 struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child)); 1405 struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
1406 1406
1407 /* make sure the single step/taken-branch trap bits are not set: */ 1407 /* make sure the single step/taken-branch trap bits are not set: */
1408 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
1408 child_psr->ss = 0; 1409 child_psr->ss = 0;
1409 child_psr->tb = 0; 1410 child_psr->tb = 0;
1410} 1411}
@@ -1525,6 +1526,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
1525 * Make sure the single step/taken-branch trap bits 1526 * Make sure the single step/taken-branch trap bits
1526 * are not set: 1527 * are not set:
1527 */ 1528 */
1529 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
1528 ia64_psr(pt)->ss = 0; 1530 ia64_psr(pt)->ss = 0;
1529 ia64_psr(pt)->tb = 0; 1531 ia64_psr(pt)->tb = 0;
1530 1532
@@ -1556,6 +1558,7 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
1556 goto out_tsk; 1558 goto out_tsk;
1557 1559
1558 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 1560 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1561 set_tsk_thread_flag(child, TIF_SINGLESTEP);
1559 if (request == PTRACE_SINGLESTEP) { 1562 if (request == PTRACE_SINGLESTEP) {
1560 ia64_psr(pt)->ss = 1; 1563 ia64_psr(pt)->ss = 1;
1561 } else { 1564 } else {
@@ -1595,13 +1598,9 @@ sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
1595} 1598}
1596 1599
1597 1600
1598void 1601static void
1599syscall_trace (void) 1602syscall_trace (void)
1600{ 1603{
1601 if (!test_thread_flag(TIF_SYSCALL_TRACE))
1602 return;
1603 if (!(current->ptrace & PT_PTRACED))
1604 return;
1605 /* 1604 /*
1606 * The 0x80 provides a way for the tracing parent to 1605 * The 0x80 provides a way for the tracing parent to
1607 * distinguish between a syscall stop and SIGTRAP delivery. 1606 * distinguish between a syscall stop and SIGTRAP delivery.
@@ -1664,7 +1663,8 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
1664 audit_syscall_exit(success, result); 1663 audit_syscall_exit(success, result);
1665 } 1664 }
1666 1665
1667 if (test_thread_flag(TIF_SYSCALL_TRACE) 1666 if ((test_thread_flag(TIF_SYSCALL_TRACE)
1667 || test_thread_flag(TIF_SINGLESTEP))
1668 && (current->ptrace & PT_PTRACED)) 1668 && (current->ptrace & PT_PTRACED))
1669 syscall_trace(); 1669 syscall_trace();
1670} 1670}