Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> --- man2/prctl.2 | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) diff --git a/man2/prctl.2 b/man2/prctl.2 index f25f05fdb593..2e82c73c10c2 100644 --- a/man2/prctl.2 +++ b/man2/prctl.2 @@ -1533,6 +1533,70 @@ For more information, see the kernel source file (or .I Documentation/arm64/sve.txt before Linux 5.3). +.TP +.\"commit 1446e1df9eb183fdf81c3f0715402f1d7595d4cb +.BR PR_SET_SYSCALL_USER_DISPATCH " (Since Linux 5.11, x86 only)" +.IP +Configure the Syscall User Dispatch mechanism for the calling thread, to +selective intercept system calls and dispatch them back to userspace +through +.IR SIGSYS . +.IP +The current Syscall User Dispatch mode is selected via +.IR "arg2", +which can either be set to +.B PR_SYS_DISPATCH_ON +to enable the feature, or to +.B PR_SYS_DISPATCH_OFF +to turn it off. +.IP +With +.IR "arg2" +set to +.BR PR_SYS_DISPATCH_ON , +.IR "arg3" +and +.I "arg4" +respectively identify the +.I offset +and +.I length +of a memory region in the process map from where system calls are always +allowed to be executed, regardless of the switch variable. +.I "arg5" +points to a char-sized variable that is a fast switch to enable/disable +the mechanism without invoking the kernel. +.I "arg5" +can be set to either +.BR PR_SYS_DISPATCH_ON +to enable the mechanism or to +.BR PR_SYS_DISPATCH_OFF +to temporarily disable it. Any other value will fail the application +with a +.IR SIGSYS . +.IP +When a system call is intercepted, a +.I SIGSYS +is raised with +.I si_code +set to +.B SYS_USER_DISPATCH. +.IP +When +.I "arg2" +is set to +.BR PR_SYS_DISPATCH_OFF , +the remaining arguments must be set to +.BR 0 . +.IP +The setting is not preserved across +.BR fork (2), +.BR clone (2) +or +.BR execve (2) . +.IP +For more information, see the kernel source file +.IR Documentation/admin-guide/syscall-user-dispatch.rst .\" prctl PR_SET_TAGGED_ADDR_CTRL .\" commit 63f0c60379650d82250f22e4cf4137ef3dc4f43d .TP @@ -2000,6 +2064,14 @@ and .I arg3 is an invalid address. .TP +.B EFAULT +.I option +is +.BR PR_SET_SYSCALL_USER_DISPATCH +and +.I arg5 +has an invalid address. +.TP .B EINVAL The value of .I option @@ -2229,6 +2301,27 @@ is and SVE is not available on this platform. .TP .B EINVAL +.I option is +.B PR_SET_SYSCALL_USER_DISPATCH +and one of the following is true: +.RS +.IP * 3 +.I arg2 +is +.B PR_SYS_DISPATCH_OFF +and remaining arguments are not +.BR 0. +.IP * 3 +.I arg2 +is +.B PR_SYS_DISPATCH_ON +and the memory region provided is invalid. +.IP * 3 +.I arg2 +is invalid. +.RE +.TP +.B EINVAL .I option is .BR PR_SET_TAGGED_ADDR_CTRL -- 2.29.2
