[S390] Wire up sys_fallocate.

This patch implements support of fallocate system call on s390(x) platform. A wrapper is added to address the issue which s390 ABI has with the arguments of this system call. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] Wire up sys_fallocate.
This patch implements support of fallocate system call on s390(x) platform. A wrapper is added to address the issue which s390 ABI has with the arguments of this system call. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Martin Schwidefsky
1 parent cb1863a461
Showing 4 changed files with 32 additions and 2 deletions Side-by-side Diff
arch/s390/kernel/compat_wrapper.S
arch/s390/kernel/sys_s390.c
arch/s390/kernel/syscalls.S
include/asm-s390/unistd.h
@@ -1710,4 +1710,14 @@
 sys_eventfd_wrapper:
 	llgfr	%r2,%r2			# unsigned int
 	jg	sys_eventfd
+
+	.globl	sys_fallocate_wrapper
+sys_fallocate_wrapper:
+	lgfr	%r2,%r2			# int
+	lgfr	%r3,%r3			# int
+	sllg	%r4,%r4,32		# get high word of 64bit loff_t
+	lr	%r4,%r5			# get low word of 64bit loff_t
+	sllg	%r5,%r6,32		# get high word of 64bit loff_t
+	l	%r5,164(%r15)		# get low word of 64bit loff_t
+	jg	sys_fallocate
@@ -265,4 +265,24 @@
 		return -EFAULT;
 	return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
 }
+
+#ifndef CONFIG_64BIT
+/*
+ * This is a wrapper to call sys_fallocate(). For 31 bit s390 the last
+ * 64 bit argument "len" is split into the upper and lower 32 bits. The
+ * system call wrapper in the user space loads the value to %r6/%r7.
+ * The code in entry.S keeps the values in %r2 - %r6 where they are and
+ * stores %r7 to 96(%r15). But the standard C linkage requires that
+ * the whole 64 bit value for len is stored on the stack and doesn't
+ * use %r6 at all. So s390_fallocate has to convert the arguments from
+ *   %r2: fd, %r3: mode, %r4/%r5: offset, %r6/96(%r15)-99(%r15): len
+ * to
+ *   %r2: fd, %r3: mode, %r4/%r5: offset, 96(%r15)-103(%r15): len
+ */
+asmlinkage long s390_fallocate(int fd, int mode, loff_t offset,
+			       u32 len_high, u32 len_low)
+{
+	return sys_fallocate(fd, mode, offset, ((u64)len_high << 32) | len_low);
+}
+#endif
@@ -322,7 +322,7 @@
 SYSCALL(sys_getcpu,sys_getcpu,sys_getcpu_wrapper)
 SYSCALL(sys_epoll_pwait,sys_epoll_pwait,compat_sys_epoll_pwait_wrapper)
 SYSCALL(sys_utimes,sys_utimes,compat_sys_utimes_wrapper)
-NI_SYSCALL							/* 314 sys_fallocate */
+SYSCALL(s390_fallocate,sys_fallocate,sys_fallocate_wrapper)
 SYSCALL(sys_utimensat,sys_utimensat,compat_sys_utimensat_wrapper)	/* 315 */
 SYSCALL(sys_signalfd,sys_signalfd,compat_sys_signalfd_wrapper)
 SYSCALL(sys_timerfd,sys_timerfd,compat_sys_timerfd_wrapper)
@@ -251,7 +251,7 @@
 #define __NR_getcpu		311
 #define __NR_epoll_pwait	312
 #define __NR_utimes		313
-/* Number 314 is reserved for new sys_fallocate */
+#define __NR_fallocate		314
 #define __NR_utimensat		315
 #define __NR_signalfd		316
 #define __NR_timerfd		317
...	...	@@ -1710,4 +1710,14 @@
1710	1710	sys_eventfd_wrapper:
1711	1711	llgfr %r2,%r2 # unsigned int
1712	1712	jg sys_eventfd
	1713	+
	1714	+ .globl sys_fallocate_wrapper
	1715	+sys_fallocate_wrapper:
	1716	+ lgfr %r2,%r2 # int
	1717	+ lgfr %r3,%r3 # int
	1718	+ sllg %r4,%r4,32 # get high word of 64bit loff_t
	1719	+ lr %r4,%r5 # get low word of 64bit loff_t
	1720	+ sllg %r5,%r6,32 # get high word of 64bit loff_t
	1721	+ l %r5,164(%r15) # get low word of 64bit loff_t
	1722	+ jg sys_fallocate
...	...	@@ -265,4 +265,24 @@
265	265	return -EFAULT;
266	266	return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
267	267	}
	268	+
	269	+#ifndef CONFIG_64BIT
	270	+/*
	271	+ * This is a wrapper to call sys_fallocate(). For 31 bit s390 the last
	272	+ * 64 bit argument "len" is split into the upper and lower 32 bits. The
	273	+ * system call wrapper in the user space loads the value to %r6/%r7.
	274	+ * The code in entry.S keeps the values in %r2 - %r6 where they are and
	275	+ * stores %r7 to 96(%r15). But the standard C linkage requires that
	276	+ * the whole 64 bit value for len is stored on the stack and doesn't
	277	+ * use %r6 at all. So s390_fallocate has to convert the arguments from
	278	+ * %r2: fd, %r3: mode, %r4/%r5: offset, %r6/96(%r15)-99(%r15): len
	279	+ * to
	280	+ * %r2: fd, %r3: mode, %r4/%r5: offset, 96(%r15)-103(%r15): len
	281	+ */
	282	+asmlinkage long s390_fallocate(int fd, int mode, loff_t offset,
	283	+ u32 len_high, u32 len_low)
	284	+{
	285	+ return sys_fallocate(fd, mode, offset, ((u64)len_high << 32) \| len_low);
	286	+}
	287	+#endif
...	...	@@ -322,7 +322,7 @@
322	322	SYSCALL(sys_getcpu,sys_getcpu,sys_getcpu_wrapper)
323	323	SYSCALL(sys_epoll_pwait,sys_epoll_pwait,compat_sys_epoll_pwait_wrapper)
324	324	SYSCALL(sys_utimes,sys_utimes,compat_sys_utimes_wrapper)
325		-NI_SYSCALL /* 314 sys_fallocate */
	325	+SYSCALL(s390_fallocate,sys_fallocate,sys_fallocate_wrapper)
326	326	SYSCALL(sys_utimensat,sys_utimensat,compat_sys_utimensat_wrapper) /* 315 */
327	327	SYSCALL(sys_signalfd,sys_signalfd,compat_sys_signalfd_wrapper)
328	328	SYSCALL(sys_timerfd,sys_timerfd,compat_sys_timerfd_wrapper)
...	...	@@ -251,7 +251,7 @@
251	251	#define __NR_getcpu 311
252	252	#define __NR_epoll_pwait 312
253	253	#define __NR_utimes 313
254		-/* Number 314 is reserved for new sys_fallocate */
	254	+#define __NR_fallocate 314
255	255	#define __NR_utimensat 315
256	256	#define __NR_signalfd 316
257	257	#define __NR_timerfd 317