execve.2, exec.3: Consistently use the term 'pathname' (not 'path')

[thirdparty/man-pages.git] / man2 / s390_sthyi.2

diff --git a/man2/s390_sthyi.2 b/man2/s390_sthyi.2
index ef336e3584795fbac879092a8385436facce1a17..3b4226f7c8e082a40eeaca4614bbb6ec5cb9a535 100644 (file)
--- a/man2/s390_sthyi.2
+++ b/man2/s390_sthyi.2
@@ -22,14 +22,14 @@
 .\" <http://www.gnu.org/licenses/>.
 .\" %%%LICENSE_END
 .\"
-.TH S390_STHYI 2 2017-09-21 "Linux Programmer's Manual"
+.TH S390_STHYI 2 2019-03-06 "Linux Programmer's Manual"
 .SH NAME
 s390_sthyi \- emulate STHYI instruction
 .SH SYNOPSIS
 .nf
 .B #include <asm/unistd.h>
 .PP
-.BI "int s390_sthyi(unsigned long " function_code ", void *" buffer ",
+.BI "int s390_sthyi(unsigned long " function_code ", void *" resp_buffer ",
 .BI "               uint64_t *" return_code ", unsigned long " flags ");
 .fi
 .SH DESCRIPTION
@@ -51,8 +51,11 @@ Return CP (Central Processor) and IFL (Integrated Facility for Linux)
 capacity information.
 .PP
 The
-.I buffer 
+.I resp_buffer
 argument specifies the address of a response buffer.
+When the
+.I function_code
+is 0, the buffer must be one page (4K) in size.
 If the system call returns 0,
 the response buffer will be filled with CPU capacity information.
 Otherwise, the response buffer's content is unchanged.
@@ -72,59 +75,68 @@ For further details about
 .IR return_code ,
 .IR function_code ,
 and
-.IR buffer ,
-please see section
-CONFORMING TO
-below.
+.IR resp_buffer ,
+see the reference given in NOTES.
 .PP
 The
 .I flags
 argument is provided to allow for future extensions and currently
 must be set to 0.
 .SH RETURN VALUE
-On success, the return value of
+On success (that is: emulation succeeded), the return value of
 .BR s390_sthyi ()
 matches the condition code of the STHYI instructions, which is a value
-between 0-3 (that is: emulation succeeded).
-Return value of 0 indicates that CPU capacity information is stored to
-.IR buffer .
-Return value of 3 indicates "unsupported function code" and buffer's
-content is unchanged.
-Return value of 1 and 2 are reserved.
+in the range [0..3].
+A return value of 0 indicates that CPU capacity information is stored in
+.IR *resp_buffer .
+A return value of 3 indicates "unsupported function code" and the content of
+.IR *resp_buffer
+is unchanged.
+The return values 1 and 2 are reserved.
 .PP
 On error, \-1 is returned, and
 .IR errno
 is set appropriately.
 .SH ERRORS
 .TP
-.B EINVAL
-The value specified in
-.I flags
-is non-zero.
-.TP
-.B EOPNOTSUPP
-The value specified in
-.I function_code 
-is not a valid value.
-.TP
 .B EFAULT
 The value specified in
-.I buffer 
+.I resp_buffer
 or
 .I return_code
 is not a valid address.
 .TP
+.B EINVAL
+The value specified in
+.I flags
+is nonzero.
+.TP
 .B ENOMEM
 Allocating memory for handling the CPU capacity information failed.
+.TP
+.B EOPNOTSUPP
+The value specified in
+.I function_code
+is not valid.
 .SH VERSIONS
 This system call is available since Linux 4.15.
 .SH CONFORMING TO
 This Linux-specific system call is available only on the s390 architecture.
-For details about the STHYI instruction, see
-https://www.ibm.com\:/support\:/knowledgecenter\:/SSB27U_6.3.0\:/com.ibm.zvm.v630.hcpb4\:/hcpb4sth.htm
 .SH NOTES
 Glibc does not provide a wrapper for this system call, use
 .BR syscall (2)
 to call it.
+.PP
+For details of the STHYI instruction, see
+.UR https://www.ibm.com\:/support\:/knowledgecenter\:/SSB27U_6.3.0\:/com.ibm.zvm.v630.hcpb4\:/hcpb4sth.htm
+the documentation page
+.UE .
+.PP
+When the system call interface is used, the response buffer doesn't
+have to fulfill alignment requirements described in the STHYI
+instruction definition.
+.PP
+The kernel caches the response (for up to one second, as of Linux 4.16).
+Subsequent system call invocations may return the cached response.
 .SH SEE ALSO
 .BR syscall (2)