Commit da654b74 authored by Srinivasa Ds's avatar Srinivasa Ds Committed by Ingo Molnar
Browse files

signals: demultiplexing SIGTRAP signal 



Currently a SIGTRAP can denote any one of below reasons.
	- Breakpoint hit
	- H/W debug register hit
	- Single step
	- Signal sent through kill() or rasie()

Architectures like powerpc/parisc provides infrastructure to demultiplex
SIGTRAP signal by passing down the information for receiving SIGTRAP through
si_code of siginfot_t structure. Here is an attempt is generalise this
infrastructure by extending it to x86 and x86_64 archs.

Signed-off-by: default avatarSrinivasa DS <srinivasa@in.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: akpm@linux-foundation.org
Cc: paulus@samba.org
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 101d5b71

arch/ia64/include/asm/siginfo.h

+0 −5
Original line number Diff line number Diff line
@@ -113,11 +113,6 @@ typedef struct siginfo { 
#undef NSIGSEGV

#define NSIGSEGV	3



/*

 * SIGTRAP si_codes

 */

#define TRAP_BRANCH	(__SI_FAULT|3)	/* process taken branch trap */

#define TRAP_HWBKPT	(__SI_FAULT|4)	/* hardware breakpoint or watchpoint */

#undef NSIGTRAP

#define NSIGTRAP	4

arch/powerpc/include/asm/siginfo.h

+0 −5
Original line number Diff line number Diff line
@@ -15,11 +15,6 @@ 


#include <asm-generic/siginfo.h>



/*

 * SIGTRAP si_codes

 */

#define TRAP_BRANCH	(__SI_FAULT|3)	/* process taken branch trap */

#define TRAP_HWBKPT	(__SI_FAULT|4)	/* hardware breakpoint or watchpoint */

#undef NSIGTRAP

#define NSIGTRAP	4

arch/x86/kernel/ptrace.c

+4 −3
Original line number Diff line number Diff line
@@ -1358,7 +1358,8 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task) 
#endif

}



void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)

void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,

					 int error_code, int si_code)

{

	struct siginfo info;
@@ -1367,7 +1368,7 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code) 


	memset(&info, 0, sizeof(info));

	info.si_signo = SIGTRAP;

	info.si_code = TRAP_BRKPT;

	info.si_code = si_code;



	/* User-mode ip? */

	info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;
@@ -1454,5 +1455,5 @@ asmregparm void syscall_trace_leave(struct pt_regs *regs) 
	 */

	if (test_thread_flag(TIF_SINGLESTEP) &&

	    tracehook_consider_fatal_signal(current, SIGTRAP, SIG_DFL))

		send_sigtrap(current, regs, 0);

		send_sigtrap(current, regs, 0, TRAP_BRKPT);

}

arch/x86/kernel/traps_32.c

+3 −1
Original line number Diff line number Diff line
@@ -891,6 +891,7 @@ void __kprobes do_debug(struct pt_regs *regs, long error_code) 
{

	struct task_struct *tsk = current;

	unsigned int condition;

	int si_code;



	trace_hardirqs_fixup();
@@ -935,8 +936,9 @@ void __kprobes do_debug(struct pt_regs *regs, long error_code) 
			goto clear_TF_reenable;

	}



	si_code = get_si_code((unsigned long)condition);

	/* Ok, finally something we can handle */

	send_sigtrap(tsk, regs, error_code);

	send_sigtrap(tsk, regs, error_code, si_code);



	/*

	 * Disable additional traps. They'll be re-enabled when

arch/x86/kernel/traps_64.c

+1 −1
Original line number Diff line number Diff line
@@ -941,7 +941,7 @@ asmlinkage void __kprobes do_debug(struct pt_regs *regs, 
	tsk->thread.error_code = error_code;

	info.si_signo = SIGTRAP;

	info.si_errno = 0;

	info.si_code = TRAP_BRKPT;

	info.si_code = get_si_code(condition);

	info.si_addr = user_mode(regs) ? (void __user *)regs->ip : NULL;

	force_sig_info(SIGTRAP, &info, tsk);

CRA Git | Maintained and supported by SUSTech CRA and CCSE