git: 202ac0975edc - main - sysent: add a new NORETURN type flag

The branch main has been updated by brooks:

URL: https://cgit.FreeBSD.org/src/commit/?id=202ac0975edcc4729e7016a9e9cb921de45e3a70

commit 202ac0975edcc4729e7016a9e9cb921de45e3a70
Author:     Brooks Davis <brooks@FreeBSD.org>
AuthorDate: 2025-08-08 09:30:17 +0000
Commit:     Brooks Davis <brooks@FreeBSD.org>
CommitDate: 2025-08-08 09:30:17 +0000

    sysent: add a new NORETURN type flag
    
    System calls of type NORETURN don't return and their stubs are declare
    not to.
    
    Reviewed by:    kevans, kib
    Differential Revision:  https://reviews.freebsd.org/D51673
---
 sys/kern/syscalls.master                | 1 +
 sys/tools/syscalls/core/syscall.lua     | 1 +
 sys/tools/syscalls/scripts/libsys_h.lua | 8 ++++++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 29f9d9dae390..9329a4213828 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -51,6 +51,7 @@
 ;	SYSMUX	syscall multiplexer.  No prototype, argument struct, or
 ;		handler is declared or used.  Handled in MD syscall code.
 ;	CAPENABLED syscall is allowed in capability mode
+;	NORETURN the syscall does not return
 ;
 ; To support programmatic generation of both the default ABI and 32-bit compat
 ; (freebsd32) we impose a number of restrictions on the types of system calls.
diff --git a/sys/tools/syscalls/core/syscall.lua b/sys/tools/syscalls/core/syscall.lua
index e7e3dc3aac33..277613ec27b7 100644
--- a/sys/tools/syscalls/core/syscall.lua
+++ b/sys/tools/syscalls/core/syscall.lua
@@ -28,6 +28,7 @@ syscall.known_flags = util.set {
 	-- flags beyond this point are modifiers
 	"CAPENABLED",
 	"NOLIB",
+	"NORETURN",
 	"NOTSTATIC",
 	"SYSMUX",
 }
diff --git a/sys/tools/syscalls/scripts/libsys_h.lua b/sys/tools/syscalls/scripts/libsys_h.lua
index 91349d5dc870..8c1993ecf683 100755
--- a/sys/tools/syscalls/scripts/libsys_h.lua
+++ b/sys/tools/syscalls/scripts/libsys_h.lua
@@ -76,8 +76,12 @@ function libsys_h.generate(tbl, config, fh)
 
 	for _, v in pairs(s) do
 		if print_decl(v) then
-			gen:write(string.format("%s __sys_%s(%s);\n",
-			    v.ret, v.name, v.argstr_type_var))
+			local ret_attr = "";
+			if v.type.NORETURN then
+				ret_attr = "_Noreturn "
+			end
+			gen:write(string.format("%s%s __sys_%s(%s);\n",
+			    ret_attr, v.ret, v.name, v.argstr_type_var))
 		end
 	end