Signed-off-by: Kyle Huey <khuey@xxxxxxxxxxxx> --- man2/arch_prctl.2 | 73 +++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 60 insertions(+), 13 deletions(-) diff --git a/man2/arch_prctl.2 b/man2/arch_prctl.2 index 989d369..c388797 100644 --- a/man2/arch_prctl.2 +++ b/man2/arch_prctl.2 @@ -22,7 +22,7 @@ .\" the source, must acknowledge the copyright and authors of this work. .\" %%%LICENSE_END .\" -.TH ARCH_PRCTL 2 2015-02-21 "Linux" "Linux Programmer's Manual" +.TH ARCH_PRCTL 2 2016-09-14 "Linux" "Linux Programmer's Manual" .SH NAME arch_prctl \- set architecture-specific thread state .SH SYNOPSIS @@ -31,8 +31,8 @@ arch_prctl \- set architecture-specific thread state .br .B #include <sys/prctl.h> .sp -.BI "int arch_prctl(int " code ", unsigned long " addr ); -.BI "int arch_prctl(int " code ", unsigned long *" addr ); +.BI "int arch_prctl(int " code ", unsigned long " arg2 ); +.BI "int arch_prctl(int " code ", unsigned long *" arg2 ); .fi .SH DESCRIPTION The @@ -41,22 +41,47 @@ function sets architecture-specific process or thread state. .I code selects a subfunction and passes argument -.I addr +.I arg2 to it; -.I addr +.I arg2 is interpreted as either an .I "unsigned long" for the "set" operations, or as an .IR "unsigned long\ *" , for the "get" operations. .LP +Subfunctions for both x86-64 and x86-32 are: +.TP +.B ARCH_GET_CPUID " (since Linux 4.X)" +Return the state of the flag determining whether the +.I cpuid +instruction can be executed by the process, in the +.I unsigned long +pointed to by +.IR arg2 . +.TP +.B ARCH_SET_CPUID " (since Linux 4.X)" +Set the state of the flag determining whether the +.I cpuid +instruction can be executed by the process. Pass +.B ARCH_CPUID_ENABLE +in +.I arg2 +to allow it to be executed, or +.B ARCH_CPUID_SIGSEGV +to generate a +.B SIGSEGV +when the process tries to execute the +.I cpuid +instruction. This flag is propagated across fork and exec. +.LP Subfunctions for x86-64 are: .TP .B ARCH_SET_FS Set the 64-bit base for the .I FS register to -.IR addr . +.IR arg2 . .TP .B ARCH_GET_FS Return the 64-bit base value for the @@ -64,13 +89,13 @@ Return the 64-bit base value for the register of the current thread in the .I unsigned long pointed to by -.IR addr . +.IR arg2 . .TP .B ARCH_SET_GS Set the 64-bit base for the .I GS register to -.IR addr . +.IR arg2 . .TP .B ARCH_GET_GS Return the 64-bit base value for the @@ -78,7 +103,7 @@ Return the 64-bit base value for the register of the current thread in the .I unsigned long pointed to by -.IR addr . +.IR arg2 . .SH RETURN VALUE On success, .BR arch_prctl () @@ -87,26 +112,48 @@ returns 0; on error, \-1 is returned, and is set to indicate the error. .SH ERRORS .TP +.B EACCES +.I code +is +.B ARCH_SET_CPUID +and +.I arg2 +is +.B ARCH_CPUID_ENABLE +and cpuid was previously disabled with +.B ARCH_CPUID_SIGSEGV +and the +.I no_new_privs +bit is set on this thread. +.TP .B EFAULT -.I addr +.I arg2 points to an unmapped address or is outside the process address space. .TP .B EINVAL .I code is not a valid subcommand. .TP +.B EINVAL +.I code +is +.B ARCH_SET_CPUID +and +.I cpuid +faulting is not supported on this machine. +.TP .B EPERM -.I addr +.I arg2 is outside the process address space. .\" .SH AUTHOR .\" Man page written by Andi Kleen. .SH CONFORMING TO .BR arch_prctl () -is a Linux/x86-64 extension and should not be used in programs intended +is a Linux/x86 extension and should not be used in programs intended to be portable. .SH NOTES .BR arch_prctl () -is supported only on Linux/x86-64 for 64-bit programs currently. +is supported only on Linux/x86 currently. The 64-bit base changes when a new 32-bit segment selector is loaded. -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
