IRQ: Maintain regs pointer globally rather than passing to IRQ handlers

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

37 files changed, 165 insertions, 215 deletions

diff --git a/drivers/serial/21285.c b/drivers/serial/21285.c
index 76d83ade985..6a1a568ca64 100644
--- a/drivers/serial/21285.c
+++ b/drivers/serial/21285.c
@@ -85,7 +85,7 @@ static void serial21285_enable_ms(struct uart_port *port)
 {
 }
 
-static irqreturn_t serial21285_rx_chars(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t serial21285_rx_chars(int irq, void *dev_id)
 {
 	struct uart_port *port = dev_id;
 	struct tty_struct *tty = port->info->tty;
@@ -123,7 +123,7 @@ static irqreturn_t serial21285_rx_chars(int irq, void *dev_id, struct pt_regs *r
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t serial21285_tx_chars(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t serial21285_tx_chars(int irq, void *dev_id)
 {
 	struct uart_port *port = dev_id;
 	struct circ_buf *xmit = &port->info->xmit;
diff --git a/drivers/serial/68328serial.c b/drivers/serial/68328serial.c
index bac853c5abb..9b8b585513e 100644
--- a/drivers/serial/68328serial.c
+++ b/drivers/serial/68328serial.c
@@ -275,8 +275,7 @@ static void status_handle(struct m68k_serial *info, unsigned short status)
 	return;
 }
 
-static void receive_chars(struct m68k_serial *info, struct pt_regs *regs,
-			  unsigned short rx)
+static void receive_chars(struct m68k_serial *info, unsigned short rx)
 {
 	struct tty_struct *tty = info->tty;
 	m68328_uart *uart = &uart_addr[info->line];
@@ -377,7 +376,7 @@ clear_and_return:
 /*
  * This is the serial driver's generic interrupt routine
  */
-irqreturn_t rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+irqreturn_t rs_interrupt(int irq, void *dev_id)
 {
 	struct m68k_serial * info;
 	m68328_uart *uart;
@@ -394,10 +393,10 @@ irqreturn_t rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 #ifdef USE_INTS
 	tx = uart->utx.w;
 
-	if (rx & URX_DATA_READY) receive_chars(info, regs, rx);
+	if (rx & URX_DATA_READY) receive_chars(info, rx);
 	if (tx & UTX_TX_AVAIL)   transmit_chars(info);
 #else
-	receive_chars(info, regs, rx);		
+	receive_chars(info, rx);		
 #endif
 	return IRQ_HANDLED;
 }
diff --git a/drivers/serial/68360serial.c b/drivers/serial/68360serial.c
index 1b299e8c57c..4e56ec80386 100644
--- a/drivers/serial/68360serial.c
+++ b/drivers/serial/68360serial.c
@@ -612,7 +612,7 @@ static _INLINE_ void check_modem_status(struct async_struct *info)
  * This is the serial driver's interrupt routine for a single port
  */
 /* static void rs_360_interrupt(void *dev_id) */ /* until and if we start servicing irqs here */
-static void rs_360_interrupt(int vec, void *dev_id, struct pt_regs *fp)
+static void rs_360_interrupt(int vec, void *dev_id)
 {
 	u_char	events;
 	int	idx;
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index cc2a205d423..e34bd03cfce 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1175,7 +1175,7 @@ static void serial8250_enable_ms(struct uart_port *port)
 }
 
 static void
-receive_chars(struct uart_8250_port *up, int *status, struct pt_regs *regs)
+receive_chars(struct uart_8250_port *up, int *status)
 {
 	struct tty_struct *tty = up->port.info->tty;
 	unsigned char ch, lsr = *status;
@@ -1233,7 +1233,7 @@ receive_chars(struct uart_8250_port *up, int *status, struct pt_regs *regs)
 			else if (lsr & UART_LSR_FE)
 				flag = TTY_FRAME;
 		}
-		if (uart_handle_sysrq_char(&up->port, ch, regs))
+		if (uart_handle_sysrq_char(&up->port, ch))
 			goto ignore_char;
 
 		uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
@@ -1309,7 +1309,7 @@ static unsigned int check_modem_status(struct uart_8250_port *up)
  * This handles the interrupt from one port.
  */
 static inline void
-serial8250_handle_port(struct uart_8250_port *up, struct pt_regs *regs)
+serial8250_handle_port(struct uart_8250_port *up)
 {
 	unsigned int status;
 
@@ -1320,7 +1320,7 @@ serial8250_handle_port(struct uart_8250_port *up, struct pt_regs *regs)
 	DEBUG_INTR("status = %x...", status);
 
 	if (status & UART_LSR_DR)
-		receive_chars(up, &status, regs);
+		receive_chars(up, &status);
 	check_modem_status(up);
 	if (status & UART_LSR_THRE)
 		transmit_chars(up);
@@ -1342,7 +1342,7 @@ serial8250_handle_port(struct uart_8250_port *up, struct pt_regs *regs)
  * This means we need to loop through all ports. checking that they
  * don't have an interrupt pending.
  */
-static irqreturn_t serial8250_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
 {
 	struct irq_info *i = dev_id;
 	struct list_head *l, *end = NULL;
@@ -1361,7 +1361,7 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id, struct pt_regs *r
 
 		iir = serial_in(up, UART_IIR);
 		if (!(iir & UART_IIR_NO_INT)) {
-			serial8250_handle_port(up, regs);
+			serial8250_handle_port(up);
 
 			handled = 1;
 
@@ -1461,7 +1461,7 @@ static void serial8250_timeout(unsigned long data)
 
 	iir = serial_in(up, UART_IIR);
 	if (!(iir & UART_IIR_NO_INT))
-		serial8250_handle_port(up, NULL);
+		serial8250_handle_port(up);
 
 	timeout = up->port.timeout;
 	timeout = timeout > 6 ? (timeout / 2 - 2) : 1;
diff --git a/drivers/serial/amba-pl010.c b/drivers/serial/amba-pl010.c
index 7311d8487c9..4213fabc62b 100644
--- a/drivers/serial/amba-pl010.c
+++ b/drivers/serial/amba-pl010.c
@@ -111,12 +111,7 @@ static void pl010_enable_ms(struct uart_port *port)
 	writel(cr, port->membase + UART010_CR);
 }
 
-static void
-#ifdef SUPPORT_SYSRQ
-pl010_rx_chars(struct uart_port *port, struct pt_regs *regs)
-#else
-pl010_rx_chars(struct uart_port *port)
-#endif
+static void pl010_rx_chars(struct uart_port *port)
 {
 	struct tty_struct *tty = port->info->tty;
 	unsigned int status, ch, flag, rsr, max_count = 256;
@@ -156,7 +151,7 @@ pl010_rx_chars(struct uart_port *port)
 				flag = TTY_FRAME;
 		}
 
-		if (uart_handle_sysrq_char(port, ch, regs))
+		if (uart_handle_sysrq_char(port, ch))
 			goto ignore_char;
 
 		uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag);
@@ -227,7 +222,7 @@ static void pl010_modem_status(struct uart_port *port)
 	wake_up_interruptible(&uap->port.info->delta_msr_wait);
 }
 
-static irqreturn_t pl010_int(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t pl010_int(int irq, void *dev_id)
 {
 	struct uart_port *port = dev_id;
 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
@@ -239,11 +234,7 @@ static irqreturn_t pl010_int(int irq, void *dev_id, struct pt_regs *regs)
 	if (status) {
 		do {
 			if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
-#ifdef SUPPORT_SYSRQ
-				pl010_rx_chars(port, regs);
-#else
 				pl010_rx_chars(port);
-#endif
 			if (status & UART010_IIR_MIS)
 				pl010_modem_status(port);
 			if (status & UART010_IIR_TIS)
diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
index a8d7124e84a..d503625730d 100644
--- a/drivers/serial/amba-pl011.c
+++ b/drivers/serial/amba-pl011.c
@@ -107,12 +107,7 @@ static void pl011_enable_ms(struct uart_port *port)
 	writew(uap->im, uap->port.membase + UART011_IMSC);
 }
 
-static void
-#ifdef SUPPORT_SYSRQ
-pl011_rx_chars(struct uart_amba_port *uap, struct pt_regs *regs)
-#else
-pl011_rx_chars(struct uart_amba_port *uap)
-#endif
+static void pl011_rx_chars(struct uart_amba_port *uap)
 {
 	struct tty_struct *tty = uap->port.info->tty;
 	unsigned int status, ch, flag, max_count = 256;
@@ -150,7 +145,7 @@ pl011_rx_chars(struct uart_amba_port *uap)
 				flag = TTY_FRAME;
 		}
 
-		if (uart_handle_sysrq_char(&uap->port, ch & 255, regs))
+		if (uart_handle_sysrq_char(&uap->port, ch & 255))
 			goto ignore_char;
 
 		uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
@@ -218,7 +213,7 @@ static void pl011_modem_status(struct uart_amba_port *uap)
 	wake_up_interruptible(&uap->port.info->delta_msr_wait);
 }
 
-static irqreturn_t pl011_int(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t pl011_int(int irq, void *dev_id)
 {
 	struct uart_amba_port *uap = dev_id;
 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
@@ -234,11 +229,7 @@ static irqreturn_t pl011_int(int irq, void *dev_id, struct pt_regs *regs)
 			       uap->port.membase + UART011_ICR);
 
 			if (status & (UART011_RTIS|UART011_RXIS))
-#ifdef SUPPORT_SYSRQ
-				pl011_rx_chars(uap, regs);
-#else
 				pl011_rx_chars(uap);
-#endif
 			if (status & (UART011_DSRMIS|UART011_DCDMIS|
 				      UART011_CTSMIS|UART011_RIMIS))
 				pl011_modem_status(uap);
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 955c46da580..391a1f4167a 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -249,7 +249,7 @@ static void atmel_break_ctl(struct uart_port *port, int break_state)
 /*
  * Characters received (called from interrupt handler)
  */
-static void atmel_rx_chars(struct uart_port *port, struct pt_regs *regs)
+static void atmel_rx_chars(struct uart_port *port)
 {
 	struct tty_struct *tty = port->info->tty;
 	unsigned int status, ch, flg;
@@ -291,7 +291,7 @@ static void atmel_rx_chars(struct uart_port *port, struct pt_regs *regs)
 				flg = TTY_FRAME;
 		}
 
-		if (uart_handle_sysrq_char(port, ch, regs))
+		if (uart_handle_sysrq_char(port, ch))
 			goto ignore_char;
 
 		uart_insert_char(port, status, ATMEL_US_OVRE, ch, flg);
@@ -339,7 +339,7 @@ static void atmel_tx_chars(struct uart_port *port)
 /*
  * Interrupt handler
  */
-static irqreturn_t atmel_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t atmel_interrupt(int irq, void *dev_id)
 {
 	struct uart_port *port = dev_id;
 	struct atmel_uart_port *atmel_port = (struct atmel_uart_port *) port;
@@ -350,7 +350,7 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	while (pending) {
 		/* Interrupt receive */
 		if (pending & ATMEL_US_RXRDY)
-			atmel_rx_chars(port, regs);
+			atmel_rx_chars(port);
 
 		// TODO: All reads to CSR will clear these interrupts!
 		if (pending & ATMEL_US_RIIC) port->icount.rng++;
diff --git a/drivers/serial/clps711x.c b/drivers/serial/clps711x.c
index f27d852ce50..59801271488 100644
--- a/drivers/serial/clps711x.c
+++ b/drivers/serial/clps711x.c
@@ -93,7 +93,7 @@ static void clps711xuart_enable_ms(struct uart_port *port)
 {
 }
 
-static irqreturn_t clps711xuart_int_rx(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t clps711xuart_int_rx(int irq, void *dev_id)
 {
 	struct uart_port *port = dev_id;
 	struct tty_struct *tty = port->info->tty;
@@ -131,7 +131,7 @@ static irqreturn_t clps711xuart_int_rx(int irq, void *dev_id, struct pt_regs *re
 #endif
 		}
 
-		if (uart_handle_sysrq_char(port, ch, regs))
+		if (uart_handle_sysrq_char(port, ch))
 			goto ignore_char;
 
 		/*
@@ -147,7 +147,7 @@ static irqreturn_t clps711xuart_int_rx(int irq, void *dev_id, struct pt_regs *re
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
 {
 	struct uart_port *port = dev_id;
 	struct circ_buf *xmit = &port->info->xmit;
diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
index a0d6136deb9..0abb544ae63 100644
--- a/drivers/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/serial/cpm_uart/cpm_uart_core.c
@@ -248,7 +248,7 @@ static void cpm_uart_break_ctl(struct uart_port *port, int break_state)
 /*
  * Transmit characters, refill buffer descriptor, if possible
  */
-static void cpm_uart_int_tx(struct uart_port *port, struct pt_regs *regs)
+static void cpm_uart_int_tx(struct uart_port *port)
 {
 	pr_debug("CPM uart[%d]:TX INT\n", port->line);
 
@@ -258,7 +258,7 @@ static void cpm_uart_int_tx(struct uart_port *port, struct pt_regs *regs)
 /*
  * Receive characters
  */
-static void cpm_uart_int_rx(struct uart_port *port, struct pt_regs *regs)
+static void cpm_uart_int_rx(struct uart_port *port)
 {
 	int i;
 	unsigned char ch, *cp;
@@ -304,7 +304,7 @@ static void cpm_uart_int_rx(struct uart_port *port, struct pt_regs *regs)
 			if (status &
 			    (BD_SC_BR | BD_SC_FR | BD_SC_PR | BD_SC_OV))
 				goto handle_error;
-			if (uart_handle_sysrq_char(port, ch, regs))
+			if (uart_handle_sysrq_char(port, ch))
 				continue;
 
 		      error_return:
@@ -373,7 +373,7 @@ static void cpm_uart_int_rx(struct uart_port *port, struct pt_regs *regs)
 /*
  * Asynchron mode interrupt handler
  */
-static irqreturn_t cpm_uart_int(int irq, void *data, struct pt_regs *regs)
+static irqreturn_t cpm_uart_int(int irq, void *data)
 {
 	u8 events;
 	struct uart_port *port = (struct uart_port *)data;
@@ -389,18 +389,18 @@ static irqreturn_t cpm_uart_int(int irq, void *data, struct pt_regs *regs)
 		if (events & SMCM_BRKE)
 			uart_handle_break(port);
 		if (events & SMCM_RX)
-			cpm_uart_int_rx(port, regs);
+			cpm_uart_int_rx(port);
 		if (events & SMCM_TX)
-			cpm_uart_int_tx(port, regs);
+			cpm_uart_int_tx(port);
 	} else {
 		events = sccp->scc_scce;
 		sccp->scc_scce = events;
 		if (events & UART_SCCM_BRKE)
 			uart_handle_break(port);
 		if (events & UART_SCCM_RX)
-			cpm_uart_int_rx(port, regs);
+			cpm_uart_int_rx(port);
 		if (events & UART_SCCM_TX)
-			cpm_uart_int_tx(port, regs);
+			cpm_uart_int_tx(port);
 	}
 	return (events) ? IRQ_HANDLED : IRQ_NONE;
 }
diff --git a/drivers/serial/crisv10.c b/drivers/serial/crisv10.c
index 9851d9eff02..7a24e53546c 100644
--- a/drivers/serial/crisv10.c
+++ b/drivers/serial/crisv10.c
@@ -2346,7 +2346,7 @@ start_receive(struct e100_serial *info)
 */
 
 static irqreturn_t
-tr_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+tr_interrupt(int irq, void *dev_id)
 {
 	struct e100_serial *info;
 	unsigned long ireg;
@@ -2395,7 +2395,7 @@ tr_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 /* dma input channel interrupt handler */
 
 static irqreturn_t
-rec_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+rec_interrupt(int irq, void *dev_id)
 {
 	struct e100_serial *info;
 	unsigned long ireg;
@@ -3054,7 +3054,7 @@ static void handle_ser_tx_interrupt(struct e100_serial *info)
  * ser_int duration: just sending: 8-15 us normally, up to 73 us
  */
 static irqreturn_t
-ser_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+ser_interrupt(int irq, void *dev_id)
 {
 	static volatile int tx_started = 0;
 	struct e100_serial *info;
diff --git a/drivers/serial/dz.c b/drivers/serial/dz.c
index 8a98aae80e2..53662b33b84 100644
--- a/drivers/serial/dz.c
+++ b/drivers/serial/dz.c
@@ -339,7 +339,7 @@ static inline void check_modem_status(struct dz_port *dport)
  * It deals with the multiple ports.
  * ------------------------------------------------------------
  */
-static irqreturn_t dz_interrupt(int irq, void *dev, struct pt_regs *regs)
+static irqreturn_t dz_interrupt(int irq, void *dev)
 {
 	struct dz_port *dport;
 	unsigned short status;
diff --git a/drivers/serial/icom.c b/drivers/serial/icom.c
index a3c00a25214..8aa0f641866 100644
--- a/drivers/serial/icom.c
+++ b/drivers/serial/icom.c
@@ -844,8 +844,7 @@ static void process_interrupt(u16 port_int_reg,
 	spin_unlock(&icom_port->uart_port.lock);
 }
 
-static irqreturn_t icom_interrupt(int irq, void *dev_id,
-				  struct pt_regs *regs)
+static irqreturn_t icom_interrupt(int irq, void *dev_id)
 {
 	void __iomem * int_reg;
 	u32 adapter_interrupts;
diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c
index 4a142d6b8f3..ee5c782597d 100644
--- a/drivers/serial/imx.c
+++ b/drivers/serial/imx.c
@@ -182,7 +182,7 @@ static void imx_start_tx(struct uart_port *port)
 		imx_transmit_buffer(sport);
 }
 
-static irqreturn_t imx_rtsint(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t imx_rtsint(int irq, void *dev_id)
 {
 	struct imx_port *sport = (struct imx_port *)dev_id;
 	unsigned int val = USR1((u32)sport->port.membase)&USR1_RTSS;
@@ -198,7 +198,7 @@ static irqreturn_t imx_rtsint(int irq, void *dev_id, struct pt_regs *regs)
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t imx_txint(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t imx_txint(int irq, void *dev_id)
 {
 	struct imx_port *sport = (struct imx_port *)dev_id;
 	struct circ_buf *xmit = &sport->port.info->xmit;
@@ -227,7 +227,7 @@ out:
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t imx_rxint(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t imx_rxint(int irq, void *dev_id)
 {
 	struct imx_port *sport = dev_id;
 	unsigned int rx,flg,ignored = 0;
@@ -248,7 +248,7 @@ static irqreturn_t imx_rxint(int irq, void *dev_id, struct pt_regs *regs)
 		}
 
 		if (uart_handle_sysrq_char
-		            (&sport->port, (unsigned char)rx, regs))
+		            (&sport->port, (unsigned char)rx))
 			goto ignore_char;
 
 		if( rx & (URXD_PRERR | URXD_OVRRUN | URXD_FRMERR) )
diff --git a/drivers/serial/ioc3_serial.c b/drivers/serial/ioc3_serial.c
index 8097cd91f16..2308d26c862 100644
--- a/drivers/serial/ioc3_serial.c
+++ b/drivers/serial/ioc3_serial.c
@@ -1428,13 +1428,12 @@ static int receive_chars(struct uart_port *the_port)
  * @is : submodule
  * @idd: driver data
  * @pending: interrupts to handle
- * @regs: pt_regs
  */
 
 static int inline
 ioc3uart_intr_one(struct ioc3_submodule *is,
 			struct ioc3_driver_data *idd,
-			unsigned int pending, struct pt_regs *regs)
+			unsigned int pending)
 {
 	int port_num = GET_PORT_FROM_SIO_IR(pending);
 	struct port_hooks *hooks;
@@ -1628,13 +1627,12 @@ ioc3uart_intr_one(struct ioc3_submodule *is,
  * @is : submodule
  * @idd: driver data
  * @pending: interrupts to handle
- * @regs: pt_regs
  *
  */
 
 static int ioc3uart_intr(struct ioc3_submodule *is,
 			struct ioc3_driver_data *idd,
-			unsigned int pending, struct pt_regs *regs)
+			unsigned int pending)
 {
 	int ret = 0;
 
@@ -1644,9 +1642,9 @@ static int ioc3uart_intr(struct ioc3_submodule *is,
 	 */
 
 	if (pending & SIO_IR_SA)
-		ret |= ioc3uart_intr_one(is, idd, pending & SIO_IR_SA, regs);
+		ret |= ioc3uart_intr_one(is, idd, pending & SIO_IR_SA);
 	if (pending & SIO_IR_SB)
-		ret |= ioc3uart_intr_one(is, idd, pending & SIO_IR_SB, regs);
+		ret |= ioc3uart_intr_one(is, idd, pending & SIO_IR_SB);
 
 	return ret;
 }
diff --git a/drivers/serial/ioc4_serial.c b/drivers/serial/ioc4_serial.c
index 5ec4716c99b..98ce88d8020 100644
--- a/drivers/serial/ioc4_serial.c
+++ b/drivers/serial/ioc4_serial.c
@@ -987,10 +987,9 @@ intr_connect(struct ioc4_soft *soft, int type,
  * ioc4_intr - Top level IOC4 interrupt handler.
  * @irq: irq value
  * @arg: handler arg
- * @regs: registers
  */
 
-static irqreturn_t ioc4_intr(int irq, void *arg, struct pt_regs *regs)
+static irqreturn_t ioc4_intr(int irq, void *arg)
 {
 	struct ioc4_soft *soft;
 	uint32_t this_ir, this_mir;
diff --git a/drivers/serial/ip22zilog.c b/drivers/serial/ip22zilog.c
index dbf13c03a1b..dca6c1bde8f 100644
--- a/drivers/serial/ip22zilog.c
+++ b/drivers/serial/ip22zilog.c
@@ -252,8 +252,7 @@ static void ip22zilog_maybe_update_regs(struct uart_ip22zilog_port *up,
 }
 
 static void ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
-				   struct zilog_channel *channel,
-				   struct pt_regs *regs)
+				   struct zilog_channel *channel)
 {
 	struct tty_struct *tty = up->port.info->tty;	/* XXX info==NULL? */
 
@@ -319,7 +318,7 @@ static void ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
 			else if (r1 & CRC_ERR)
 				flag = TTY_FRAME;
 		}
-		if (uart_handle_sysrq_char(&up->port, ch, regs))
+		if (uart_handle_sysrq_char(&up->port, ch))
 			goto next_char;
 
 		if (up->port.ignore_status_mask == 0xff ||
@@ -339,8 +338,7 @@ static void ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
 }
 
 static void ip22zilog_status_handle(struct uart_ip22zilog_port *up,
-				   struct zilog_channel *channel,
-				   struct pt_regs *regs)
+				   struct zilog_channel *channel)
 {
 	unsigned char status;
 
@@ -443,7 +441,7 @@ ack_tx_int:
 	ZS_WSYNC(channel);
 }
 
-static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id)
 {
 	struct uart_ip22zilog_port *up = dev_id;
 
@@ -462,9 +460,9 @@ static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id, struct pt_regs *re
 			ZS_WSYNC(channel);
 
 			if (r3 & CHARxIP)
-				ip22zilog_receive_chars(up, channel, regs);
+				ip22zilog_receive_chars(up, channel);
 			if (r3 & CHAEXT)
-				ip22zilog_status_handle(up, channel, regs);
+				ip22zilog_status_handle(up, channel);
 			if (r3 & CHATxIP)
 				ip22zilog_transmit_chars(up, channel);
 		}
@@ -481,9 +479,9 @@ static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id, struct pt_regs *re
 			ZS_WSYNC(channel);
 
 			if (r3 & CHBRxIP)
-				ip22zilog_receive_chars(up, channel, regs);
+				ip22zilog_receive_chars(up, channel);
 			if (r3 & CHBEXT)
-				ip22zilog_status_handle(up, channel, regs);
+				ip22zilog_status_handle(up, channel);
 			if (r3 & CHBTxIP)
 				ip22zilog_transmit_chars(up, channel);
 		}
diff --git a/drivers/serial/jsm/jsm.h b/drivers/serial/jsm/jsm.h
index 043f50b1d10..12c934a1f27 100644
--- a/drivers/serial/jsm/jsm.h
+++ b/drivers/serial/jsm/jsm.h
@@ -99,7 +99,7 @@ struct jsm_channel;
  * Per board operations structure					*
  ************************************************************************/
 struct board_ops {
-	irqreturn_t (*intr) (int irq, void *voidbrd, struct pt_regs *regs);
+	irq_handler_t intr;
 	void (*uart_init) (struct jsm_channel *ch);
 	void (*uart_off) (struct jsm_channel *ch);
 	void (*param) (struct jsm_channel *ch);
diff --git a/drivers/serial/jsm/jsm_neo.c b/drivers/serial/jsm/jsm_neo.c
index a5fc589d6ef..8fa31e68989 100644
--- a/drivers/serial/jsm/jsm_neo.c
+++ b/drivers/serial/jsm/jsm_neo.c
@@ -1114,7 +1114,7 @@ static void neo_param(struct jsm_channel *ch)
  *
  * Neo specific interrupt handler.
  */
-static irqreturn_t neo_intr(int irq, void *voidbrd, struct pt_regs *regs)
+static irqreturn_t neo_intr(int irq, void *voidbrd)
 {
 	struct jsm_board *brd = (struct jsm_board *) voidbrd;
 	struct jsm_channel *ch;
diff --git a/drivers/serial/m32r_sio.c b/drivers/serial/m32r_sio.c
index 28c9ce6f0bd..c85ac1a7760 100644
--- a/drivers/serial/m32r_sio.c
+++ b/drivers/serial/m32r_sio.c
@@ -323,8 +323,7 @@ static void m32r_sio_enable_ms(struct uart_port *port)
 	serial_out(up, UART_IER, up->ier);
 }
 
-static void receive_chars(struct uart_sio_port *up, int *status,
-			  struct pt_regs *regs)
+static void receive_chars(struct uart_sio_port *up, int *status)
 {
 	struct tty_struct *tty = up->port.info->tty;
 	unsigned char ch;
@@ -378,7 +377,7 @@ static void receive_chars(struct uart_sio_port *up, int *status,
 			else if (*status & UART_LSR_FE)
 				flag = TTY_FRAME;
 		}
-		if (uart_handle_sysrq_char(&up->port, ch, regs))
+		if (uart_handle_sysrq_char(&up->port, ch))
 			goto ignore_char;
 		if ((*status & up->port.ignore_status_mask) == 0)
 			tty_insert_flip_char(tty, ch, flag);
@@ -439,12 +438,12 @@ static void transmit_chars(struct uart_sio_port *up)
  * This handles the interrupt from one port.
  */
 static inline void m32r_sio_handle_port(struct uart_sio_port *up,
-	unsigned int status, struct pt_regs *regs)
+	unsigned int status)
 {
 	DEBUG_INTR("status = %x...",