xtensa: don't use a7 in simcalls

To support FRAME_POINTER avoid using a7 in __simc (none of the existing
simcalls needs it). Replace calls to __simc with more specific
simc_read, simc_write and simc_lseek calls.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/platforms/iss/console.c

@@ -99,14 +99,13 @@ static int rs_write(struct tty_struct * tty,
 static void rs_poll(unsigned long priv)
 {
 	struct tty_port *port = (struct tty_port *)priv;
-	struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
 	int i = 0;
 	unsigned char c;
 
 	spin_lock(&timer_lock);
 
-	while (__simc(SYS_select_one, 0, XTISS_SELECT_ONE_READ, (int)&tv,0,0)){
-		__simc (SYS_read, 0, (unsigned long)&c, 1, 0, 0);
+	while (simc_poll(0)) {
+		simc_read(0, &c, 1);
 		tty_insert_flip_char(port, c, TTY_NORMAL);
 		i++;
 	}
@@ -244,8 +243,7 @@ static void iss_console_write(struct console *co, const char *s, unsigned count)
 	int len = strlen(s);
 
 	if (s != 0 && *s != 0)
-		__simc (SYS_write, 1, (unsigned long)s,
-			count < len ? count : len,0,0);
+		simc_write(1, s, count < len ? count : len);
 }
 
 static struct tty_driver* iss_console_device(struct console *c, int *index)

arch/xtensa/platforms/iss/include/platform/simcall.h

@@ -59,56 +59,58 @@
 
 static int errno;
 
-static inline int __simc(int a, int b, int c, int d, int e, int f)
+static inline int __simc(int a, int b, int c, int d)
 {
 	int ret;
 	register int a1 asm("a2") = a;
 	register int b1 asm("a3") = b;
 	register int c1 asm("a4") = c;
 	register int d1 asm("a5") = d;
-	register int e1 asm("a6") = e;
-	register int f1 asm("a7") = f;
 	__asm__ __volatile__ (
 			"simcall\n"
 			"mov %0, a2\n"
 			"mov %1, a3\n"
 			: "=a" (ret), "=a" (errno), "+r"(a1), "+r"(b1)
-			: "r"(c1), "r"(d1), "r"(e1), "r"(f1)
+			: "r"(c1), "r"(d1)
 			: "memory");
 	return ret;
 }
 
 static inline int simc_open(const char *file, int flags, int mode)
 {
-	return __simc(SYS_open, (int) file, flags, mode, 0, 0);
+	return __simc(SYS_open, (int) file, flags, mode);
 }
 
 static inline int simc_close(int fd)
 {
-	return __simc(SYS_close, fd, 0, 0, 0, 0);
+	return __simc(SYS_close, fd, 0, 0);
 }
 
 static inline int simc_ioctl(int fd, int request, void *arg)
 {
-	return __simc(SYS_ioctl, fd, request, (int) arg, 0, 0);
+	return __simc(SYS_ioctl, fd, request, (int) arg);
 }
 
 static inline int simc_read(int fd, void *buf, size_t count)
 {
-	return __simc(SYS_read, fd, (int) buf, count, 0, 0);
+	return __simc(SYS_read, fd, (int) buf, count);
 }
 
 static inline int simc_write(int fd, const void *buf, size_t count)
 {
-	return __simc(SYS_write, fd, (int) buf, count, 0, 0);
+	return __simc(SYS_write, fd, (int) buf, count);
 }
 
 static inline int simc_poll(int fd)
 {
 	struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
 
-	return __simc(SYS_select_one, fd, XTISS_SELECT_ONE_READ, (int)&tv,
-			0, 0);
+	return __simc(SYS_select_one, fd, XTISS_SELECT_ONE_READ, (int)&tv);
+}
+
+static inline int simc_lseek(int fd, uint32_t off, int whence)
+{
+	return __simc(SYS_lseek, fd, off, whence);
 }
 
 #endif /* _XTENSA_PLATFORM_ISS_SIMCALL_H */

arch/xtensa/platforms/iss/simdisk.c

@@ -85,7 +85,7 @@ static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
 	while (nbytes > 0) {
 		unsigned long io;
 
-		__simc(SYS_lseek, dev->fd, offset, SEEK_SET, 0, 0);
+		simc_lseek(dev->fd, offset, SEEK_SET);
 		if (write)
 			io = simc_write(dev->fd, buffer, nbytes);
 		else
@@ -177,7 +177,7 @@ static int simdisk_attach(struct simdisk *dev, const char *filename)
 		err = -ENODEV;
 		goto out;
 	}
-	dev->size = __simc(SYS_lseek, dev->fd, 0, SEEK_END, 0, 0);
+	dev->size = simc_lseek(dev->fd, 0, SEEK_END);
 	set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
 	dev->filename = filename;
 	pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);