parisc: stop using task->ptrace for {single,block}step flags

task->ptrace flags belong to generic code, so instead thief some
TIF_ bits to use. Somewhat risky conversion of code to test TASK_FLAGS
instead of TASK_PTRACE in assembly, but it looks alright in the end.
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

arch/parisc/include/asm/thread_info.h

@@ -60,6 +60,8 @@ struct thread_info {
 #define TIF_RESTORE_SIGMASK	6	/* restore saved signal mask */
 #define TIF_FREEZE		7	/* is freezing for suspend */
 #define TIF_NOTIFY_RESUME	8	/* callback before returning to user */
+#define TIF_SINGLESTEP		9	/* single stepping? */
+#define TIF_BLOCKSTEP		10	/* branch stepping? */
 
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
@@ -69,6 +71,8 @@ struct thread_info {
 #define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
 #define _TIF_FREEZE		(1 << TIF_FREEZE)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
+#define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
+#define _TIF_BLOCKSTEP		(1 << TIF_BLOCKSTEP)
 
 #define _TIF_USER_WORK_MASK     (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | \
                                  _TIF_NEED_RESCHED | _TIF_RESTORE_SIGMASK)

arch/parisc/kernel/asm-offsets.c

@@ -270,8 +270,8 @@ int main(void)
 	DEFINE(DTLB_OFF_COUNT, offsetof(struct pdc_cache_info, dt_off_count));
 	DEFINE(DTLB_LOOP, offsetof(struct pdc_cache_info, dt_loop));
 	BLANK();
-	DEFINE(PA_BLOCKSTEP_BIT, 31-PT_BLOCKSTEP_BIT);
-	DEFINE(PA_SINGLESTEP_BIT, 31-PT_SINGLESTEP_BIT);
+	DEFINE(TIF_BLOCKSTEP_PA_BIT, 31-TIF_BLOCKSTEP);
+	DEFINE(TIF_SINGLESTEP_PA_BIT, 31-TIF_SINGLESTEP);
 	BLANK();
 	DEFINE(ASM_PMD_SHIFT, PMD_SHIFT);
 	DEFINE(ASM_PGDIR_SHIFT, PGDIR_SHIFT);

arch/parisc/kernel/entry.S

@@ -2047,12 +2047,13 @@ syscall_do_signal:
 	b,n     syscall_check_sig
 
 syscall_restore:
-	/* Are we being ptraced? */
 	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1
 
-	ldw	TASK_PTRACE(%r1), %r19
-	bb,<	%r19,31,syscall_restore_rfi
-	nop
+	/* Are we being ptraced? */
+	ldw	TASK_FLAGS(%r1),%r19
+	ldi	(_TIF_SINGLESTEP|_TIF_BLOCKSTEP),%r2
+	and,COND(=)	%r19,%r2,%r0
+	b,n	syscall_restore_rfi
 
 	ldo	TASK_PT_FR31(%r1),%r19		   /* reload fpregs */
 	rest_fp	%r19
@@ -2113,16 +2114,16 @@ syscall_restore_rfi:
 	ldi	0x0b,%r20			   /* Create new PSW */
 	depi	-1,13,1,%r20			   /* C, Q, D, and I bits */
 
-	/* The values of PA_SINGLESTEP_BIT and PA_BLOCKSTEP_BIT are
-	 * set in include/linux/ptrace.h and converted to PA bitmap
+	/* The values of SINGLESTEP_BIT and BLOCKSTEP_BIT are
+	 * set in thread_info.h and converted to PA bitmap
 	 * numbers in asm-offsets.c */
 
-	/* if ((%r19.PA_SINGLESTEP_BIT)) { %r20.27=1} */
-	extru,=	%r19,PA_SINGLESTEP_BIT,1,%r0
+	/* if ((%r19.SINGLESTEP_BIT)) { %r20.27=1} */
+	extru,=	%r19,TIF_SINGLESTEP_PA_BIT,1,%r0
 	depi	-1,27,1,%r20			   /* R bit */
 
-	/* if ((%r19.PA_BLOCKSTEP_BIT)) { %r20.7=1} */
-	extru,= %r19,PA_BLOCKSTEP_BIT,1,%r0
+	/* if ((%r19.BLOCKSTEP_BIT)) { %r20.7=1} */
+	extru,= %r19,TIF_BLOCKSTEP_PA_BIT,1,%r0
 	depi	-1,7,1,%r20			   /* T bit */
 
 	STREG	%r20,TASK_PT_PSW(%r1)

arch/parisc/kernel/ptrace.c

@@ -36,7 +36,8 @@
  */
 void ptrace_disable(struct task_struct *task)
 {
-	task->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP);
+	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
+	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
 
 	/* make sure the trap bits are not set */
 	pa_psw(task)->r = 0;
@@ -56,8 +57,8 @@ void user_disable_single_step(struct task_struct *task)
 
 void user_enable_single_step(struct task_struct *task)
 {
-	task->ptrace &= ~PT_BLOCKSTEP;
-	task->ptrace |= PT_SINGLESTEP;
+	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
+	set_tsk_thread_flag(task, TIF_SINGLESTEP);
 
 	if (pa_psw(task)->n) {
 		struct siginfo si;
@@ -99,8 +100,8 @@ void user_enable_single_step(struct task_struct *task)
 
 void user_enable_block_step(struct task_struct *task)
 {
-	task->ptrace &= ~PT_SINGLESTEP;
-	task->ptrace |= PT_BLOCKSTEP;
+	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
+	set_tsk_thread_flag(task, TIF_BLOCKSTEP);
 
 	/* Enable taken branch trap. */
 	pa_psw(task)->r = 0;
@@ -275,7 +276,8 @@ long do_syscall_trace_enter(struct pt_regs *regs)
 
 void do_syscall_trace_exit(struct pt_regs *regs)
 {
-	int stepping = !!(current->ptrace & (PT_SINGLESTEP|PT_BLOCKSTEP));
+	int stepping = test_thread_flag(TIF_SINGLESTEP) ||
+		test_thread_flag(TIF_BLOCKSTEP);
 
 	if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
 		tracehook_report_syscall_exit(regs, stepping);