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Commit 15029285 authored by Jason Uhlenkott's avatar Jason Uhlenkott Committed by Tony Luck
Browse files

[IA64] Handle debug traps in fsys mode 



We need to handle debug traps in fsys mode non-fatally.  They can
happen now that we have fsyscalls which contain probe instructions.

Signed-off-by: default avatarJason Uhlenkott <jasonuhl@sgi.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 6d6e4200

arch/ia64/kernel/traps.c

+19 −7
Original line number Diff line number Diff line
@@ -530,12 +530,15 @@ ia64_fault (unsigned long vector, unsigned long isr, unsigned long ifa, 
		if (fsys_mode(current, &regs)) {

			extern char __kernel_syscall_via_break[];

			/*

			 * Got a trap in fsys-mode: Taken Branch Trap and Single Step trap

			 * need special handling; Debug trap is not supposed to happen.

			 * Got a trap in fsys-mode: Taken Branch Trap

			 * and Single Step trap need special handling;

			 * Debug trap is ignored (we disable it here

			 * and re-enable it in the lower-privilege trap).

			 */

			if (unlikely(vector == 29)) {

				die("Got debug trap in fsys-mode---not supposed to happen!",

				    &regs, 0);

				set_thread_flag(TIF_DB_DISABLED);

				ia64_psr(&regs)->db = 0;

				ia64_psr(&regs)->lp = 1;

				return;

			}

			/* re-do the system call via break 0x100000: */
@@ -589,10 +592,19 @@ ia64_fault (unsigned long vector, unsigned long isr, unsigned long ifa, 
	      case 34:

		if (isr & 0x2) {

			/* Lower-Privilege Transfer Trap */



			/* If we disabled debug traps during an fsyscall,

			 * re-enable them here.

			 */

			if (test_thread_flag(TIF_DB_DISABLED)) {

				clear_thread_flag(TIF_DB_DISABLED);

				ia64_psr(&regs)->db = 1;

			}



			/*

			 * Just clear PSR.lp and then return immediately: all the

			 * interesting work (e.g., signal delivery is done in the kernel

			 * exit path).

			 * Just clear PSR.lp and then return immediately:

			 * all the interesting work (e.g., signal delivery)

			 * is done in the kernel exit path.

			 */

			ia64_psr(&regs)->lp = 0;

			return;

include/asm-ia64/thread_info.h

+3 −1
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ struct thread_info { 
#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 */

#define TIF_DB_DISABLED		19	/* debug trap disabled for fsyscall */



#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)

#define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
@@ -103,6 +104,7 @@ struct thread_info { 
#define _TIF_SIGDELAYED		(1 << TIF_SIGDELAYED)

#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)

#define _TIF_MCA_INIT		(1 << TIF_MCA_INIT)

#define _TIF_DB_DISABLED	(1 << TIF_DB_DISABLED)



/* "work to do on user-return" bits */

#define TIF_ALLWORK_MASK	(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SIGDELAYED)