sched_setattr.2: Use syscall(SYS_...); for system calls without a wrapper

Document also why each header is required

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/memfd_create.2

@@ -201,6 +201,19 @@ The
 .BR memfd_create ()
 system call first appeared in Linux 3.17;
 glibc support was added in version 2.27.
+.TP
+.B EPERM
+The
+.B MFD_HUGETLB
+flag was specified, but the caller was not privileged (did not have the
+.B CAP_IPC_LOCK
+capability)
+and is not a member of the
+.I sysctl_hugetlb_shm_group
+group; see the description of
+.I /proc/sys/vm/sysctl_hugetlb_shm_group
+in
+.BR proc (5).
 .SH CONFORMING TO
 The
 .BR memfd_create ()

man2/mmap.2

@@ -628,6 +628,18 @@ was mounted no-exec.
 The operation was prevented by a file seal; see
 .BR fcntl (2).
 .TP
+.B EPERM
+The
+.B MAP_HUGETLB
+flag was specified, but the caller was not privileged (did not have the
+.B CAP_IPC_LOCK
+capability)
+and is not a member of the
+.I sysctl_hugetlb_shm_group
+group; see the description of
+.I /proc/sys/vm/sysctl_hugetlb_shm_group
+in
+.TP
 .B ETXTBSY
 .B MAP_DENYWRITE
 was set but the object specified by

man2/rename.2

@@ -39,7 +39,7 @@ rename, renameat, renameat2 \- change the name or location of a file
 .PP
 .BI "int rename(const char *" oldpath ", const char *" newpath );
 .PP
-.BR "#include <fcntl.h>           " "/* Definition of AT_* constants */"
+.BR "#include <fcntl.h>           " "/* Definition of " AT_* " constants */"
 .B #include <stdio.h>
 .PP
 .BI "int renameat(int " olddirfd ", const char *" oldpath ,

man2/s390_guarded_storage.2

@@ -27,13 +27,20 @@
 s390_guarded_storage \- operations with z/Architecture guarded storage facility
 .SH SYNOPSIS
 .nf
-.B #include <asm/guarded_storage.h>
+.BR "#include <asm/guarded_storage.h> " "/* Definition of " GS_* " constants */"
+.BR "#include <sys/syscall.h>         " \
+"/* Definition of " SYS_* " constants */"
+.B #include <unistd.h>
 .PP
-.BI "int s390_guarded_storage(int " command ", struct gs_cb *" gs_cb ");"
+.BI "int syscall(SYS_s390_guarded_storage, int " command ,
+.BI "            struct gs_cb *" gs_cb );
 .fi
 .PP
 .IR Note :
-There is no glibc wrapper for this system call; see NOTES.
+glibc provides no wrapper for
+.BR s390_guarded_storage (2),
+necessitating the use of
+.BR syscall (2).
 .SH DESCRIPTION
 The
 .BR s390_guarded_storage ()
@@ -144,9 +151,6 @@ This Linux-specific system call is available only on the s390 architecture.
 .PP
 The guarded storage facility is available beginning with System z14.
 .SH NOTES
-Glibc does not provide a wrapper for this system call; call it using
-.BR syscall (2).
-.PP
 The description of the guarded storage facility along with related
 instructions and Guarded Storage Control Block and
 Guarded Storage Event Parameter List structure layouts

man2/s390_pci_mmio_write.2

@@ -28,16 +28,19 @@ s390_pci_mmio_write, s390_pci_mmio_read \- transfer data to/from PCI
 MMIO memory page
 .SH SYNOPSIS
 .nf
-.B #include <asm/unistd.h>
+.BR "#include <sys/syscall.h>" "      /* Definition of " SYS_* " constants */"
+.B #include <unistd.h>
 .PP
-.BI "int s390_pci_mmio_write(unsigned long " mmio_addr ,
+.BI "int syscall(SYS_s390_pci_mmio_write, unsigned long " mmio_addr ,
 .BI "                       const void *" user_buffer ", size_t " length );
-.BI "int s390_pci_mmio_read(unsigned long " mmio_addr ,
+.BI "int syscall(SYS_s390_pci_mmio_read, unsigned long " mmio_addr ,
 .BI "                       void *" user_buffer ", size_t " length );
 .fi
 .PP
 .IR Note :
-There are no glibc wrappers for these system calls; see NOTES.
+glibc provides no wrappers for these system calls,
+necessitating the use of
+.BR syscall (2).
 .SH DESCRIPTION
 The
 .BR s390_pci_mmio_write ()
@@ -102,8 +105,5 @@ These system calls are available since Linux 3.19.
 .SH CONFORMING TO
 This Linux-specific system call is available only on the s390 architecture.
 The required PCI support is available beginning with System z EC12.
-.SH NOTES
-Glibc does not provide wrappers for these system calls; call them using
-.BR syscall (2)
 .SH SEE ALSO
 .BR syscall (2)

man2/s390_runtime_instr.2

@@ -27,13 +27,18 @@
 s390_runtime_instr \- enable/disable s390 CPU run-time instrumentation
 .SH SYNOPSIS
 .nf
-.B #include <asm/runtime_instr.h>
+.BR "#include <asm/runtime_instr.h>" " /* Definition of " S390_* " constants */"
+.BR "#include <sys/syscall.h>" "       /* Definition of " SYS_* " constants */"
+.B #include <unistd.h>
 .PP
-.BI "int s390_runtime_instr(int " command ", int " signum ");"
+.BI "int syscall(SYS_s390_runtime_instr, int " command ", int " signum );
 .fi
 .PP
 .IR Note :
-There is no glibc wrapper for this system call; see NOTES.
+glibc provides no wrapper for
+.BR s390_runtime_instr (2),
+necessitating the use of
+.BR syscall (2).
 .SH DESCRIPTION
 The
 .BR s390_runtime_instr ()
@@ -97,9 +102,6 @@ This Linux-specific system call is available only on the s390 architecture.
 The run-time instrumentation facility is available
 beginning with System z EC12.
 .SH NOTES
-Glibc does not provide a wrapper for this system call; call it using
-.BR syscall (2)
-.PP
 The
 .I asm/runtime_instr.h
 header file is available

man2/s390_sthyi.2

@@ -27,14 +27,20 @@
 s390_sthyi \- emulate STHYI instruction
 .SH SYNOPSIS
 .nf
-.B #include <asm/unistd.h>
+.BR "#include <asm/sthyi.h>" "        /* Definition of " STHYI_* " constants */"
+.BR "#include <sys/syscall.h>" "      /* Definition of " SYS_* " constants */"
+.B #include <unistd.h>
 .PP
-.BI "int s390_sthyi(unsigned long " function_code ", void *" resp_buffer ","
-.BI "               uint64_t *" return_code ", unsigned long " flags ");"
+.BI "int syscall(SYS_s390_sthyi, unsigned long " function_code ,
+.BI "            void *" resp_buffer ", uint64_t *" return_code ,
+.BI "            unsigned long " flags );
 .fi
 .PP
 .IR Note :
-There is no glibc wrapper for this system call; see NOTES.
+glibc provides no wrapper for
+.BR s390_sthyi (2),
+necessitating the use of
+.BR syscall (2).
 .SH DESCRIPTION
 The
 .BR s390_sthyi ()
@@ -49,7 +55,7 @@ The
 argument indicates which function to perform.
 The following code(s) are supported:
 .TP
-0
+.B STHYI_FC_CP_IFL_CAP
 Return CP (Central Processor) and IFL (Integrated Facility for Linux)
 capacity information.
 .PP
@@ -58,7 +64,9 @@ The
 argument specifies the address of a response buffer.
 When the
 .I function_code
-is 0, the buffer must be one page (4K) in size.
+is
+.BR STHYI_FC_CP_IFL_CAP ,
+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.
@@ -126,9 +134,6 @@ This system call is available since Linux 4.15.
 .SH CONFORMING TO
 This Linux-specific system call is available only on the s390 architecture.
 .SH NOTES
-Glibc does not provide a wrapper for this system call; call it using
-.BR syscall (2)
-.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

man2/sched_setattr.2

@@ -29,17 +29,21 @@ sched_setattr, sched_getattr \-
 set and get scheduling policy and attributes
 .SH SYNOPSIS
 .nf
-.B #include <sched.h>
+.BR "#include <sched.h>" "            /* Definition of " SCHED_* " constants */"
+.BR "#include <sys/syscall.h>" "      /* Definition of " SYS_* " constants */"
+.B #include <unistd.h>
 .PP
-.BI "int sched_setattr(pid_t " pid ", struct sched_attr *" attr ,
-.BI "                  unsigned int " flags );
-.BI "int sched_getattr(pid_t " pid ", struct sched_attr *" attr ,
-.BI "                  unsigned int " size ", unsigned int " flags );
+.BI "int syscall(SYS_sched_setattr, pid_t " pid ", struct sched_attr *" attr ,
+.BI "            unsigned int " flags );
+.BI "int syscall(SYS_sched_getattr, pid_t " pid ", struct sched_attr *" attr ,
+.BI "            unsigned int " size ", unsigned int " flags );
 .fi
 .\" FIXME . Add feature test macro requirements
 .PP
 .IR Note :
-There are no glibc wrappers for these system calls; see NOTES.
+glibc provides no wrappers for these system calls,
+necessitating the use of
+.BR syscall (2).
 .SH DESCRIPTION
 .SS sched_setattr()
 The

man2/shmget.2

@@ -273,7 +273,13 @@ The
 .B SHM_HUGETLB
 flag was specified, but the caller was not privileged (did not have the
 .B CAP_IPC_LOCK
-capability).
+capability)
+and is not a member of the
+.I sysctl_hugetlb_shm_group
+group; see the description of
+.I /proc/sys/vm/sysctl_hugetlb_shm_group
+in
+.BR proc (5).
 .SH CONFORMING TO
 POSIX.1-2001, POSIX.1-2008, SVr4.
 .\" SVr4 documents an additional error condition EEXIST.

man3/ctime.3

@@ -425,6 +425,7 @@ The glibc version of \fIstruct tm\fP has additional fields
 .PP
 .in +4n
 .EX
+long tm_gmtoff;           /* Seconds east of UTC */
 const char *tm_zone;      /* Timezone abbreviation */
 .EE
 .in

man4/console_codes.4

@@ -298,7 +298,7 @@ T}
 .TE
 .ad
 .PP
-.B ECMA-48 Set Graphics Rendition
+.B ECMA-48 Select Graphic Rendition
 .PP
 The ECMA-48 SGR sequence ESC [ \fIparameters\fP m sets display
 attributes.

man5/proc.5

@@ -5603,6 +5603,19 @@ user should run
 .BR sync (1)
 first.
 .TP
+.IR  /proc/sys/vm/sysctl_hugetlb_shm_group " (since Linux 2.6.7)"
+This writable file contains a group ID that is allowed
+to allocate memory using huge pages.
+If a process has a filesystem group ID or any supplememtary group ID that
+matches this group ID,
+then it can make huge-page allocations without holding the
+.BR CAP_IPC_LOCK
+capability; see
+.BR memfd_create (2),
+.BR mmap (2),
+and
+.BR shmget (2).
+.TP
 .IR /proc/sys/vm/legacy_va_layout " (since Linux 2.6.9)"
 .\" The following is from Documentation/filesystems/proc.txt
 If nonzero, this disables the new 32-bit memory-mapping layout;

man7/capabilities.7

@@ -205,11 +205,21 @@ the filesystem or any of the supplementary GIDs of the calling process.
 .B CAP_IPC_LOCK
 .\" FIXME . As at Linux 3.2, there are some strange uses of this capability
 .\" in other places; they probably should be replaced with something else.
+.PD 0
+.RS
+.IP * 2
 Lock memory
 .RB ( mlock (2),
 .BR mlockall (2),
 .BR mmap (2),
+.BR shmctl (2));
+.IP *
+Allocate memory using huge pages
+.RB ( memfd_create (2)
+.BR mmap (2),
 .BR shmctl (2)).
+.PD 0
+.RE
 .TP
 .B CAP_IPC_OWNER
 Bypass permission checks for operations on System V IPC objects.