s390/irq: store interrupt information in pt_regs

Copy the interrupt parameters from the lowcore to the pt_regs structure
in entry[64].S and reduce the arguments of the low level interrupt handler
to the pt_regs pointer only. In addition move the test-pending-interrupt
loop from do_IRQ to entry[64].S to make sure that interrupt information
is always delivered via pt_regs.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/ptrace.h

@@ -24,6 +24,7 @@ struct pt_regs
 	unsigned long gprs[NUM_GPRS];
 	unsigned long orig_gpr2;
 	unsigned int int_code;
+	unsigned int int_parm;
 	unsigned long int_parm_long;
 };
 

arch/s390/kernel/asm-offsets.c

@@ -47,6 +47,7 @@ int main(void)
 	DEFINE(__PT_GPRS, offsetof(struct pt_regs, gprs));
 	DEFINE(__PT_ORIG_GPR2, offsetof(struct pt_regs, orig_gpr2));
 	DEFINE(__PT_INT_CODE, offsetof(struct pt_regs, int_code));
+	DEFINE(__PT_INT_PARM, offsetof(struct pt_regs, int_parm));
 	DEFINE(__PT_INT_PARM_LONG, offsetof(struct pt_regs, int_parm_long));
 	DEFINE(__PT_SIZE, sizeof(struct pt_regs));
 	BLANK();

arch/s390/kernel/entry.S

@@ -429,11 +429,19 @@ io_skip:
 	stm	%r0,%r7,__PT_R0(%r11)
 	mvc	__PT_R8(32,%r11),__LC_SAVE_AREA_ASYNC
 	stm	%r8,%r9,__PT_PSW(%r11)
+	mvc	__PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
 	TRACE_IRQS_OFF
 	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
+io_loop:
 	l	%r1,BASED(.Ldo_IRQ)
 	lr	%r2,%r11		# pass pointer to pt_regs
 	basr	%r14,%r1		# call do_IRQ
+	tm	__LC_MACHINE_FLAGS+2,0x10	# MACHINE_FLAG_LPAR
+	jz	io_return
+	tpi	0
+	jz	io_return
+	mvc	__PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
+	j	io_loop
 io_return:
 	LOCKDEP_SYS_EXIT
 	TRACE_IRQS_ON
@@ -573,10 +581,10 @@ ext_skip:
 	stm	%r0,%r7,__PT_R0(%r11)
 	mvc	__PT_R8(32,%r11),__LC_SAVE_AREA_ASYNC
 	stm	%r8,%r9,__PT_PSW(%r11)
+	mvc	__PT_INT_CODE(4,%r11),__LC_EXT_CPU_ADDR
+	mvc	__PT_INT_PARM(4,%r11),__LC_EXT_PARAMS
 	TRACE_IRQS_OFF
 	lr	%r2,%r11		# pass pointer to pt_regs
-	l	%r3,__LC_EXT_CPU_ADDR	# get cpu address + interruption code
-	l	%r4,__LC_EXT_PARAMS	# get external parameters
 	l	%r1,BASED(.Ldo_extint)
 	basr	%r14,%r1		# call do_extint
 	j	io_return

arch/s390/kernel/entry.h

@@ -54,7 +54,7 @@ void handle_signal32(unsigned long sig, struct k_sigaction *ka,
 void do_notify_resume(struct pt_regs *regs);
 
 struct ext_code;
-void do_extint(struct pt_regs *regs, struct ext_code, unsigned int, unsigned long);
+void do_extint(struct pt_regs *regs);
 void do_restart(void);
 void __init startup_init(void);
 void die(struct pt_regs *regs, const char *str);

arch/s390/kernel/entry64.S

@@ -460,10 +460,18 @@ io_skip:
 	stmg	%r0,%r7,__PT_R0(%r11)
 	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
 	stmg	%r8,%r9,__PT_PSW(%r11)
+	mvc	__PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
 	TRACE_IRQS_OFF
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+io_loop:
 	lgr	%r2,%r11		# pass pointer to pt_regs
 	brasl	%r14,do_IRQ
+	tm	__LC_MACHINE_FLAGS+6,0x10	# MACHINE_FLAG_LPAR
+	jz	io_return
+	tpi	0
+	jz	io_return
+	mvc	__PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
+	j	io_loop
 io_return:
 	LOCKDEP_SYS_EXIT
 	TRACE_IRQS_ON
@@ -605,13 +613,13 @@ ext_skip:
 	stmg	%r0,%r7,__PT_R0(%r11)
 	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
 	stmg	%r8,%r9,__PT_PSW(%r11)
+	lghi	%r1,__LC_EXT_PARAMS2
+	mvc	__PT_INT_CODE(4,%r11),__LC_EXT_CPU_ADDR
+	mvc	__PT_INT_PARM(4,%r11),__LC_EXT_PARAMS
+	mvc	__PT_INT_PARM_LONG(8,%r11),0(%r1)
 	TRACE_IRQS_OFF
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
-	lghi	%r1,4096
 	lgr	%r2,%r11		# pass pointer to pt_regs
-	llgf	%r3,__LC_EXT_CPU_ADDR	# get cpu address + interruption code
-	llgf	%r4,__LC_EXT_PARAMS	# get external parameter
-	lg	%r5,__LC_EXT_PARAMS2-4096(%r1)	# get 64 bit external parameter
 	brasl	%r14,do_extint
 	j	io_return
 

arch/s390/kernel/irq.c

@@ -234,9 +234,9 @@ int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
 }
 EXPORT_SYMBOL(unregister_external_interrupt);
 
-void __irq_entry do_extint(struct pt_regs *regs, struct ext_code ext_code,
-			   unsigned int param32, unsigned long param64)
+void __irq_entry do_extint(struct pt_regs *regs)
 {
+	struct ext_code ext_code;
 	struct pt_regs *old_regs;
 	struct ext_int_info *p;
 	int index;
@@ -248,6 +248,7 @@ void __irq_entry do_extint(struct pt_regs *regs, struct ext_code ext_code,
 		clock_comparator_work();
 	}
 	kstat_incr_irqs_this_cpu(EXTERNAL_INTERRUPT, NULL);
+	ext_code = *(struct ext_code *) &regs->int_code;
 	if (ext_code.code != 0x1004)
 		__get_cpu_var(s390_idle).nohz_delay = 1;
 
@@ -255,7 +256,8 @@ void __irq_entry do_extint(struct pt_regs *regs, struct ext_code ext_code,
 	rcu_read_lock();
 	list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
 		if (likely(p->code == ext_code.code))
-			p->handler(ext_code, param32, param64);
+			p->handler(ext_code, regs->int_parm,
+				   regs->int_parm_long);
 	rcu_read_unlock();
 	irq_exit();
 	set_irq_regs(old_regs);

drivers/s390/cio/cio.c

@@ -568,7 +568,7 @@ out:
  */
 void __irq_entry do_IRQ(struct pt_regs *regs)
 {
-	struct tpi_info *tpi_info;
+	struct tpi_info *tpi_info = (struct tpi_info *) &regs->int_code;
 	struct subchannel *sch;
 	struct irb *irb;
 	struct pt_regs *old_regs;
@@ -579,46 +579,34 @@ void __irq_entry do_IRQ(struct pt_regs *regs)
 	if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 		/* Serve timer interrupts first. */
 		clock_comparator_work();
-	/*
-	 * Get interrupt information from lowcore
-	 */
-	tpi_info = (struct tpi_info *)&S390_lowcore.subchannel_id;
-	irb = (struct irb *)&S390_lowcore.irb;
-	do {
-		kstat_incr_irqs_this_cpu(IO_INTERRUPT, NULL);
-		if (tpi_info->adapter_IO) {
-			do_adapter_IO(tpi_info->isc);
-			continue;
-		}
-		sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
-		if (!sch) {
-			/* Clear pending interrupt condition. */
-			inc_irq_stat(IRQIO_CIO);
-			tsch(tpi_info->schid, irb);
-			continue;
-		}
-		spin_lock(sch->lock);
-		/* Store interrupt response block to lowcore. */
-		if (tsch(tpi_info->schid, irb) == 0) {
-			/* Keep subchannel information word up to date. */
-			memcpy (&sch->schib.scsw, &irb->scsw,
-				sizeof (irb->scsw));
-			/* Call interrupt handler if there is one. */
-			if (sch->driver && sch->driver->irq)
-				sch->driver->irq(sch);
-			else
-				inc_irq_stat(IRQIO_CIO);
-		} else
+
+	kstat_incr_irqs_this_cpu(IO_INTERRUPT, NULL);
+	irb = (struct irb *) &S390_lowcore.irb;
+	if (tpi_info->adapter_IO) {
+		do_adapter_IO(tpi_info->isc);
+		goto out;
+	}
+	sch = (struct subchannel *)(unsigned long) tpi_info->intparm;
+	if (!sch) {
+		/* Clear pending interrupt condition. */
+		inc_irq_stat(IRQIO_CIO);
+		tsch(tpi_info->schid, irb);
+		goto out;
+	}
+	spin_lock(sch->lock);
+	/* Store interrupt response block to lowcore. */
+	if (tsch(tpi_info->schid, irb) == 0) {
+		/* Keep subchannel information word up to date. */
+		memcpy (&sch->schib.scsw, &irb->scsw, sizeof (irb->scsw));
+		/* Call interrupt handler if there is one. */
+		if (sch->driver && sch->driver->irq)
+			sch->driver->irq(sch);
+		else
 			inc_irq_stat(IRQIO_CIO);
-		spin_unlock(sch->lock);
-		/*
-		 * Are more interrupts pending?
-		 * If so, the tpi instruction will update the lowcore
-		 * to hold the info for the next interrupt.
-		 * We don't do this for VM because a tpi drops the cpu
-		 * out of the sie which costs more cycles than it saves.
-		 */
-	} while (MACHINE_IS_LPAR && tpi(NULL) != 0);
+	} else
+		inc_irq_stat(IRQIO_CIO);
+	spin_unlock(sch->lock);
+out:
 	irq_exit();
 	set_irq_regs(old_regs);
 }