diff options
Diffstat (limited to 'man2/modify_ldt.2')
| -rw-r--r-- | man2/modify_ldt.2 | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/man2/modify_ldt.2 b/man2/modify_ldt.2 index 0364289..7ef2722 100644 --- a/man2/modify_ldt.2 +++ b/man2/modify_ldt.2 @@ -3,7 +3,7 @@ .\" .\" SPDX-License-Identifier: GPL-2.0-or-later .\" -.TH modify_ldt 2 2023-03-30 "Linux man-pages 6.05.01" +.TH modify_ldt 2 2023-10-31 "Linux man-pages 6.7" .SH NAME modify_ldt \- get or set a per-process LDT entry .SH LIBRARY @@ -14,11 +14,11 @@ Standard C library .BR "#include <asm/ldt.h>" " /* Definition of " "struct user_desc" " */" .BR "#include <sys/syscall.h>" " /* Definition of " SYS_* " constants */" .B #include <unistd.h> -.PP +.P .BI "int syscall(SYS_modify_ldt, int " func ", void " ptr [. bytecount ], .BI " unsigned long " bytecount ); .fi -.PP +.P .IR Note : glibc provides no wrapper for .BR modify_ldt (), @@ -32,7 +32,7 @@ is an array of segment descriptors that can be referenced by user code. Linux allows processes to configure a per-process (actually per-mm) LDT. For more information about the LDT, see the Intel Software Developer's Manual or the AMD Architecture Programming Manual. -.PP +.P When .I func is 0, @@ -46,7 +46,7 @@ the LDT is padded with additional trailing zero bytes. On success, .BR modify_ldt () will return the number of bytes read. -.PP +.P When .I func is 1 or 0x11, @@ -60,11 +60,11 @@ structure and .I bytecount must equal the size of this structure. -.PP +.P The .I user_desc structure is defined in \fI<asm/ldt.h>\fP as: -.PP +.P .in +4n .EX struct user_desc { @@ -80,10 +80,10 @@ struct user_desc { }; .EE .in -.PP +.P In Linux 2.4 and earlier, this structure was named .IR modify_ldt_ldt_s . -.PP +.P The .I contents field is the segment type (data, expand-down data, non-conforming code, or @@ -91,7 +91,7 @@ conforming code). The other fields match their descriptions in the CPU manual, although .BR modify_ldt () cannot set the hardware-defined "accessed" bit described in the CPU manual. -.PP +.P A .I user_desc is considered "empty" if @@ -108,7 +108,7 @@ is 1, by setting both and .I limit to 0. -.PP +.P A conforming code segment (i.e., one with .IR contents==3 ) will be rejected if @@ -117,7 +117,7 @@ func is 1 or if .I seg_not_present is 0. -.PP +.P When .I func is 2, @@ -168,12 +168,12 @@ or .BR arch_prctl (2) instead, except on extremely old kernels that do not support those system calls. -.PP +.P The normal use for .BR modify_ldt () is to run legacy 16-bit or segmented 32-bit code. Not all kernels allow 16-bit segments to be installed, however. -.PP +.P Even on 64-bit kernels, .BR modify_ldt () cannot be used to create a long mode (i.e., 64-bit) code segment. |