The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=74a2bf1b7a7ff0c872499cb94df24713f61c872c
commit 74a2bf1b7a7ff0c872499cb94df24713f61c872c Author: Konstantin Belousov <[email protected]> AuthorDate: 2026-01-25 17:33:05 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2026-01-26 19:30:05 +0000 libsys: add pdrfork_thread() on x86 Reviewed by: asomers Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D54879 --- lib/libsys/amd64/Makefile.sys | 3 +- lib/libsys/amd64/Symbol.sys.map | 4 ++ lib/libsys/amd64/pdrfork_thread.S | 83 +++++++++++++++++++++++++++++++ lib/libsys/i386/Makefile.sys | 2 +- lib/libsys/i386/Symbol.sys.map | 4 ++ lib/libsys/i386/pdrfork_thread.S | 101 ++++++++++++++++++++++++++++++++++++++ sys/sys/procdesc.h | 1 + 7 files changed, 196 insertions(+), 2 deletions(-) diff --git a/lib/libsys/amd64/Makefile.sys b/lib/libsys/amd64/Makefile.sys index 8134bdc422a6..fc8ebe796081 100644 --- a/lib/libsys/amd64/Makefile.sys +++ b/lib/libsys/amd64/Makefile.sys @@ -4,6 +4,7 @@ SRCS+= \ amd64_set_fsbase.c \ amd64_set_gsbase.c \ amd64_set_tlsbase.c \ - rfork_thread.S + rfork_thread.S \ + pdrfork_thread.S MDASM= vfork.S cerror.S getcontext.S diff --git a/lib/libsys/amd64/Symbol.sys.map b/lib/libsys/amd64/Symbol.sys.map index 11e0507b6613..b037e12d45f5 100644 --- a/lib/libsys/amd64/Symbol.sys.map +++ b/lib/libsys/amd64/Symbol.sys.map @@ -17,6 +17,10 @@ FBSD_1.8 { amd64_set_tlsbase; }; +FBSD_1.9 { + pdrfork_thread; +}; + FBSDprivate_1.0 { _vfork; }; diff --git a/lib/libsys/amd64/pdrfork_thread.S b/lib/libsys/amd64/pdrfork_thread.S new file mode 100644 index 000000000000..cd187ae456ae --- /dev/null +++ b/lib/libsys/amd64/pdrfork_thread.S @@ -0,0 +1,83 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright 2000 Peter Wemm <[email protected]> + * Copyright 2003 Alan L. Cox <[email protected]> + * Copyright 2026 The FreeBSD Foundation + * All rights reserved. + * + * Portions of this software were developed by + * Konstantin Belousov <[email protected]> under sponsorship from + * the FreeBSD Foundation. + */ + +#include <machine/asm.h> +/* + * With thanks to John Dyson for the original version of this. + */ + +#include <SYS.h> + +/* + * %rdi %esi %rdx %rcx %r8 %r9 + * pdrfork_thread(fdp, pdflags, rfflags, stack_addr, start_fnc, start_arg); + * + * fdp Pointer for the resulting fd location + * pdflags Flags as to pdfork. + * rfflags: Flags as to rfork. + * stack_addr: Top of stack for thread. + * start_fnc: Address of thread function to call in child. + * start_arg: Argument to pass to the thread function in child. + */ + +ENTRY(pdrfork_thread) + pushq %rbx + pushq %r12 + pushq %r13 + movq %r8, %rbx + movq %r9, %r12 + movq %rcx, %r13 + + /* + * Prepare and execute the thread creation syscall + */ + _SYSCALL(pdrfork) + jb 2f + + /* + * Check to see if we are in the parent or child + */ + cmpl $0, %edx + jnz 1f + popq %r13 + popq %r12 + popq %rbx + ret + + /* + * If we are in the child (new thread), then + * set-up the call to the internal subroutine. If it + * returns, then call __exit. + */ +1: + movq %r13, %rsp + movq %r12, %rdi + call *%rbx + movl %eax, %edi + + /* + * Exit system call + */ + _SYSCALL(exit) + + /* + * Branch here if the thread creation fails: + */ +2: + popq %r13 + popq %r12 + popq %rbx + jmp HIDENAME(cerror) +END(pdrfork_thread) + + .section .note.GNU-stack,"",%progbits diff --git a/lib/libsys/i386/Makefile.sys b/lib/libsys/i386/Makefile.sys index 2957dc548cf8..69507d930f25 100644 --- a/lib/libsys/i386/Makefile.sys +++ b/lib/libsys/i386/Makefile.sys @@ -1,7 +1,7 @@ SRCS+= i386_get_fsbase.c i386_get_gsbase.c i386_get_ioperm.c i386_get_ldt.c \ i386_set_fsbase.c i386_set_gsbase.c i386_set_ioperm.c i386_set_ldt.c \ i386_clr_watch.c i386_set_watch.c i386_vm86.c \ - rfork_thread.S + rfork_thread.S pdrfork_thread.S MDASM= vfork.S cerror.S getcontext.S syscall.S diff --git a/lib/libsys/i386/Symbol.sys.map b/lib/libsys/i386/Symbol.sys.map index 6b3169336a3f..a35349e4953b 100644 --- a/lib/libsys/i386/Symbol.sys.map +++ b/lib/libsys/i386/Symbol.sys.map @@ -20,6 +20,10 @@ FBSD_1.6 { x86_pkru_unprotect_range; }; +FBSD_1.9 { + pdrfork_thread; +}; + FBSDprivate_1.0 { _vfork; }; diff --git a/lib/libsys/i386/pdrfork_thread.S b/lib/libsys/i386/pdrfork_thread.S new file mode 100644 index 000000000000..92a45fc4783f --- /dev/null +++ b/lib/libsys/i386/pdrfork_thread.S @@ -0,0 +1,101 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright 2000 Peter Wemm <[email protected]> + * Copyright 2026 The FreeBSD Foundation + * All rights reserved. + * + * Portions of this software were developed by + * Konstantin Belousov <[email protected]> under sponsorship from + * the FreeBSD Foundation. + */ + +#include <machine/asm.h> +/* + * With thanks to John Dyson for the original version of this. + */ + +#include <SYS.h> + +/* + * 8 12 16 20 24 28 + * rfork_thread(fdp, pdflags rfflags, stack_addr, start_fnc, start_arg); + * + * fdp Pointer for the resulting fd location + * pdflags Flags as to pdfork. + * rfflags: Flags as to rfork. + * stack_addr: Top of stack for thread. + * start_fnc: Address of thread function to call in child. + * start_arg: Argument to pass to the thread function in child. + */ + +ENTRY(pdrfork_thread) + pushl %ebp + movl %esp, %ebp + pushl %esi + + /* + * Push thread info onto the new thread's stack + */ + movl 20(%ebp), %esi # get stack addr + + subl $4, %esi + movl 28(%ebp), %eax # get start argument + movl %eax, (%esi) + + subl $4, %esi + movl 24(%ebp), %eax # get start thread address + movl %eax, (%esi) + + /* + * Prepare and execute the thread creation syscall + */ + pushl 16(%ebp) + pushl 12(%ebp) + pushl 8(%ebp) + pushl $0 + _SYSCALL(pdrfork) + jb 2f + + /* + * Check to see if we are in the parent or child + */ + cmpl $0, %edx + jnz 1f + addl $16, %esp + popl %esi + movl %ebp, %esp + popl %ebp + ret + .p2align 2 + + /* + * If we are in the child (new thread), then + * set-up the call to the internal subroutine. If it + * returns, then call __exit. + */ +1: + movl %esi,%esp + popl %eax + call *%eax + addl $4, %esp + + /* + * Exit system call + */ + pushl %eax + pushl $0 + _SYSCALL(exit) + + /* + * Branch here if the thread creation fails: + */ +2: + addl $16, %esp + popl %esi + movl %ebp, %esp + popl %ebp + jmp HIDENAME(cerror) +END(pdrfork_thread) + + .section .note.GNU-stack,"",%progbits diff --git a/sys/sys/procdesc.h b/sys/sys/procdesc.h index 6a9168b04a68..b477903f8053 100644 --- a/sys/sys/procdesc.h +++ b/sys/sys/procdesc.h @@ -130,6 +130,7 @@ pid_t pdrfork(int *, int, int); int pdkill(int, int); int pdgetpid(int, pid_t *); int pdwait(int, int *, int, struct __wrusage *, struct __siginfo *); +pid_t pdrfork_thread(int *, int, int, void *, int (*)(void *), void *); __END_DECLS #endif /* _KERNEL */
