From owner-dev-commits-src-all@freebsd.org Thu Aug 12 08:45:52 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 9F587666E6A; Thu, 12 Aug 2021 08:45:52 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4GlgJJ3xBXz4RwZ; Thu, 12 Aug 2021 08:45:52 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 64E8A1FEAA; Thu, 12 Aug 2021 08:45:52 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 17C8jqFa050426; Thu, 12 Aug 2021 08:45:52 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 17C8jqal050425; Thu, 12 Aug 2021 08:45:52 GMT (envelope-from git) Date: Thu, 12 Aug 2021 08:45:52 GMT Message-Id: <202108120845.17C8jqal050425@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Dmitry Chagin Subject: git: de8374df28cc - main - fork: Allow ABI to specify fork return values for child. MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: dchagin X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: de8374df28cc23ce0d893fd96d1ad0a861414154 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Aug 2021 08:45:52 -0000 The branch main has been updated by dchagin: URL: https://cgit.FreeBSD.org/src/commit/?id=de8374df28cc23ce0d893fd96d1ad0a861414154 commit de8374df28cc23ce0d893fd96d1ad0a861414154 Author: Dmitry Chagin AuthorDate: 2021-08-12 08:45:25 +0000 Commit: Dmitry Chagin CommitDate: 2021-08-12 08:45:25 +0000 fork: Allow ABI to specify fork return values for child. At least Linux x86 ABI's does not use carry bit and expects that the dx register is preserved. For this add a new sv_set_fork_retval hook and call it from cpu_fork(). Add a short comment about touching dx in x86_set_fork_retval(), for more details see phab comments from kib@ and imp@. Reviewed by: kib Differential revision: https://reviews.freebsd.org/D31472 MFC after: 2 weeks --- sys/amd64/amd64/elf_machdep.c | 2 ++ sys/amd64/amd64/vm_machdep.c | 15 ++++++++++++--- sys/amd64/cloudabi32/cloudabi32_sysvec.c | 2 ++ sys/amd64/cloudabi64/cloudabi64_sysvec.c | 2 ++ sys/amd64/linux/linux_sysvec.c | 10 ++++++++++ sys/amd64/linux32/linux32_sysvec.c | 10 ++++++++++ sys/compat/ia32/ia32_sysvec.c | 1 + sys/i386/cloudabi32/cloudabi32_sysvec.c | 2 ++ sys/i386/i386/elf_machdep.c | 1 + sys/i386/i386/vm_machdep.c | 15 ++++++++++++--- sys/i386/linux/linux_sysvec.c | 11 +++++++++++ sys/kern/imgact_aout.c | 2 ++ sys/kern/init_main.c | 7 +++++++ sys/sys/sysent.h | 2 ++ sys/x86/include/x86_var.h | 1 + 15 files changed, 77 insertions(+), 6 deletions(-) diff --git a/sys/amd64/amd64/elf_machdep.c b/sys/amd64/amd64/elf_machdep.c index 80f7d1d8cefa..6535d4bd2446 100644 --- a/sys/amd64/amd64/elf_machdep.c +++ b/sys/amd64/amd64/elf_machdep.c @@ -87,6 +87,7 @@ struct sysentvec elf64_freebsd_sysvec_la48 = { .sv_stackgap = elf64_stackgap, .sv_onexec_old = exec_onexec_old, .sv_onexit = exit_onexit, + .sv_set_fork_retval = x86_set_fork_retval, }; struct sysentvec elf64_freebsd_sysvec_la57 = { @@ -127,6 +128,7 @@ struct sysentvec elf64_freebsd_sysvec_la57 = { .sv_stackgap = elf64_stackgap, .sv_onexec_old = exec_onexec_old, .sv_onexit = exit_onexit, + .sv_set_fork_retval= x86_set_fork_retval, }; static void diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c index 7d65269410e0..4567e6e0eb5d 100644 --- a/sys/amd64/amd64/vm_machdep.c +++ b/sys/amd64/amd64/vm_machdep.c @@ -245,9 +245,8 @@ cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) td2->td_frame = (struct trapframe *)td2->td_md.md_stack_base - 1; bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); - td2->td_frame->tf_rax = 0; /* Child returns zero */ - td2->td_frame->tf_rflags &= ~PSL_C; /* success */ - td2->td_frame->tf_rdx = 1; + /* Set child return values. */ + p2->p_sysent->sv_set_fork_retval(td2); /* * If the parent process has the trap bit set (i.e. a debugger @@ -300,6 +299,16 @@ cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) */ } +void +x86_set_fork_retval(struct thread *td) +{ + struct trapframe *frame = td->td_frame; + + frame->tf_rax = 0; /* Child returns zero */ + frame->tf_rflags &= ~PSL_C; /* success */ + frame->tf_rdx = 1; /* System V emulation */ +} + /* * Intercept the return address from a freshly forked process that has NOT * been scheduled yet. diff --git a/sys/amd64/cloudabi32/cloudabi32_sysvec.c b/sys/amd64/cloudabi32/cloudabi32_sysvec.c index 26924ed5a980..5bb4803ac715 100644 --- a/sys/amd64/cloudabi32/cloudabi32_sysvec.c +++ b/sys/amd64/cloudabi32/cloudabi32_sysvec.c @@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$"); #include #include +#include #include #include @@ -225,6 +226,7 @@ static struct sysentvec cloudabi32_elf_sysvec = { .sv_fetch_syscall_args = cloudabi32_fetch_syscall_args, .sv_syscallnames = cloudabi32_syscallnames, .sv_schedtail = cloudabi32_schedtail, + .sv_set_fork_retval = x86_set_fork_retval, }; INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec); diff --git a/sys/amd64/cloudabi64/cloudabi64_sysvec.c b/sys/amd64/cloudabi64/cloudabi64_sysvec.c index c08d912e84d4..82c971212087 100644 --- a/sys/amd64/cloudabi64/cloudabi64_sysvec.c +++ b/sys/amd64/cloudabi64/cloudabi64_sysvec.c @@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$"); #include #include +#include #include #include @@ -212,6 +213,7 @@ static struct sysentvec cloudabi64_elf_sysvec = { .sv_fetch_syscall_args = cloudabi64_fetch_syscall_args, .sv_syscallnames = cloudabi64_syscallnames, .sv_schedtail = cloudabi64_schedtail, + .sv_set_fork_retval = x86_set_fork_retval, }; INIT_SYSENTVEC(elf_sysvec, &cloudabi64_elf_sysvec); diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c index 75fb21c7d037..558dfb4e0ac0 100644 --- a/sys/amd64/linux/linux_sysvec.c +++ b/sys/amd64/linux/linux_sysvec.c @@ -125,6 +125,7 @@ static void linux_exec_setregs(struct thread *td, struct image_params *imgp, static void linux_exec_sysvec_init(void *param); static int linux_on_exec_vmspace(struct proc *p, struct image_params *imgp); +static void linux_set_fork_retval(struct thread *td); static int linux_vsyscall(struct thread *td); #define LINUX_T_UNKNOWN 255 @@ -269,6 +270,14 @@ linux_set_syscall_retval(struct thread *td, int error) set_pcb_flags(td->td_pcb, PCB_FULL_IRET); } +static void +linux_set_fork_retval(struct thread *td) +{ + struct trapframe *frame = td->td_frame; + + frame->tf_rax = 0; +} + static int linux_copyout_auxargs(struct image_params *imgp, uintptr_t base) { @@ -790,6 +799,7 @@ struct sysentvec elf_linux_sysvec = { .sv_onexit = linux_on_exit, .sv_ontdexit = linux_thread_dtor, .sv_setid_allowed = &linux_setid_allowed_query, + .sv_set_fork_retval = linux_set_fork_retval, }; static int diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c index 901c79fcdda8..2ec420b3024a 100644 --- a/sys/amd64/linux32/linux32_sysvec.c +++ b/sys/amd64/linux32/linux32_sysvec.c @@ -128,6 +128,7 @@ static bool linux32_trans_osrel(const Elf_Note *note, int32_t *osrel); static void linux_vdso_install(const void *param); static void linux_vdso_deinstall(const void *param); static void linux_vdso_reloc(char *mapping, Elf_Addr offset); +static void linux32_set_fork_retval(struct thread *td); static void linux32_set_syscall_retval(struct thread *td, int error); #define LINUX_T_UNKNOWN 255 @@ -703,6 +704,14 @@ linux32_set_syscall_retval(struct thread *td, int error) } } +static void +linux32_set_fork_retval(struct thread *td) +{ + struct trapframe *frame = td->td_frame; + + frame->tf_rax = 0; +} + /* * Clear registers on exec * XXX copied from ia32_signal.c. @@ -956,6 +965,7 @@ struct sysentvec elf_linux_sysvec = { .sv_onexit = linux_on_exit, .sv_ontdexit = linux_thread_dtor, .sv_setid_allowed = &linux_setid_allowed_query, + .sv_set_fork_retval = linux32_set_fork_retval, }; static int diff --git a/sys/compat/ia32/ia32_sysvec.c b/sys/compat/ia32/ia32_sysvec.c index df8a36a34810..969f5645a0f4 100644 --- a/sys/compat/ia32/ia32_sysvec.c +++ b/sys/compat/ia32/ia32_sysvec.c @@ -133,6 +133,7 @@ struct sysentvec ia32_freebsd_sysvec = { .sv_stackgap = elf32_stackgap, .sv_onexec_old = exec_onexec_old, .sv_onexit = exit_onexit, + .sv_set_fork_retval = x86_set_fork_retval, }; INIT_SYSENTVEC(elf_ia32_sysvec, &ia32_freebsd_sysvec); diff --git a/sys/i386/cloudabi32/cloudabi32_sysvec.c b/sys/i386/cloudabi32/cloudabi32_sysvec.c index e0a50f6697a9..773b5803c873 100644 --- a/sys/i386/cloudabi32/cloudabi32_sysvec.c +++ b/sys/i386/cloudabi32/cloudabi32_sysvec.c @@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$"); #include #include +#include #include #include @@ -195,6 +196,7 @@ static struct sysentvec cloudabi32_elf_sysvec = { .sv_fetch_syscall_args = cloudabi32_fetch_syscall_args, .sv_syscallnames = cloudabi32_syscallnames, .sv_schedtail = cloudabi32_schedtail, + .sv_set_fork_retval = x86_set_fork_retval, }; INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec); diff --git a/sys/i386/i386/elf_machdep.c b/sys/i386/i386/elf_machdep.c index 5858c8382e33..3754b36d9e33 100644 --- a/sys/i386/i386/elf_machdep.c +++ b/sys/i386/i386/elf_machdep.c @@ -88,6 +88,7 @@ struct sysentvec elf32_freebsd_sysvec = { .sv_trap = NULL, .sv_onexec_old = exec_onexec_old, .sv_onexit = exit_onexit, + .sv_set_fork_retval = x86_set_fork_retval, }; INIT_SYSENTVEC(elf32_sysvec, &elf32_freebsd_sysvec); diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c index 57377575b9bf..5cdcdee96347 100644 --- a/sys/i386/i386/vm_machdep.c +++ b/sys/i386/i386/vm_machdep.c @@ -258,9 +258,8 @@ cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) VM86_STACK_SPACE) - 1; bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); - td2->td_frame->tf_eax = 0; /* Child returns zero */ - td2->td_frame->tf_eflags &= ~PSL_C; /* success */ - td2->td_frame->tf_edx = 1; + /* Set child return values. */ + p2->p_sysent->sv_set_fork_retval(td2); /* * If the parent process has the trap bit set (i.e. a debugger @@ -302,6 +301,16 @@ cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) */ } +void +x86_set_fork_retval(struct thread *td) +{ + struct trapframe * frame = td->td_frame; + + frame->tf_eax = 0; /* Child returns zero */ + frame->tf_eflags &= ~PSL_C; /* success */ + frame->tf_edx = 1; /* System V emulation */ +} + /* * Intercept the return address from a freshly forked process that has NOT * been scheduled yet. diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c index 9261364e7a24..02d69de4d8f8 100644 --- a/sys/i386/linux/linux_sysvec.c +++ b/sys/i386/linux/linux_sysvec.c @@ -108,6 +108,7 @@ static int linux_on_exec_vmspace(struct proc *p, struct image_params *imgp); static int linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base); +static void linux_set_fork_retval(struct thread *td); static bool linux_trans_osrel(const Elf_Note *note, int32_t *osrel); static void linux_vdso_install(const void *param); static void linux_vdso_deinstall(const void *param); @@ -803,6 +804,14 @@ linux_set_syscall_retval(struct thread *td, int error) } } +static void +linux_set_fork_retval(struct thread *td) +{ + struct trapframe *frame = td->td_frame; + + frame->tf_eax = 0; +} + /* * exec_setregs may initialize some registers differently than Linux * does, thus potentially confusing Linux binaries. If necessary, we @@ -856,6 +865,7 @@ struct sysentvec linux_sysvec = { .sv_onexit = linux_on_exit, .sv_ontdexit = linux_thread_dtor, .sv_setid_allowed = &linux_setid_allowed_query, + .sv_set_fork_retval = linux_set_fork_retval, }; INIT_SYSENTVEC(aout_sysvec, &linux_sysvec); @@ -898,6 +908,7 @@ struct sysentvec elf_linux_sysvec = { .sv_onexit = linux_on_exit, .sv_ontdexit = linux_thread_dtor, .sv_setid_allowed = &linux_setid_allowed_query, + .sv_set_fork_retval = linux_set_fork_retval, }; static int diff --git a/sys/kern/imgact_aout.c b/sys/kern/imgact_aout.c index 9e7455e14e1d..7d7ba51efd84 100644 --- a/sys/kern/imgact_aout.c +++ b/sys/kern/imgact_aout.c @@ -103,6 +103,7 @@ struct sysentvec aout_sysvec = { .sv_trap = NULL, .sv_onexec_old = exec_onexec_old, .sv_onexit = exit_onexit, + .sv_set_fork_retval = x86_set_fork_retval, }; #elif defined(__amd64__) @@ -141,6 +142,7 @@ struct sysentvec aout_sysvec = { .sv_syscallnames = freebsd32_syscallnames, .sv_onexec_old = exec_onexec_old, .sv_onexit = exit_onexit, + .sv_set_fork_retval = x86_set_fork_retval, }; #else #error "Port me" diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c index 86cc2494272f..fde07dcbf46d 100644 --- a/sys/kern/init_main.c +++ b/sys/kern/init_main.c @@ -402,6 +402,12 @@ null_set_syscall_retval(struct thread *td __unused, int error __unused) panic("null_set_syscall_retval"); } +static void +null_set_fork_retval(struct thread *td __unused) +{ + +} + struct sysentvec null_sysvec = { .sv_size = 0, .sv_table = NULL, @@ -430,6 +436,7 @@ struct sysentvec null_sysvec = { .sv_schedtail = NULL, .sv_thread_detach = NULL, .sv_trap = NULL, + .sv_set_fork_retval = null_set_fork_retval, }; /* diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h index 1b43e9692153..e51a66f93f29 100644 --- a/sys/sys/sysent.h +++ b/sys/sys/sysent.h @@ -156,6 +156,8 @@ struct sysentvec { void (*sv_ontdexit)(struct thread *td); int (*sv_setid_allowed)(struct thread *td, struct image_params *imgp); + void (*sv_set_fork_retval)(struct thread *); + /* Only used on x86 */ }; #define SV_ILP32 0x000100 /* 32-bit executable. */ diff --git a/sys/x86/include/x86_var.h b/sys/x86/include/x86_var.h index 0fdff68638cf..ec268503634b 100644 --- a/sys/x86/include/x86_var.h +++ b/sys/x86/include/x86_var.h @@ -153,6 +153,7 @@ int pti_get_default(void); int user_dbreg_trap(register_t dr6); int minidumpsys(struct dumperinfo *); struct pcb *get_pcb_td(struct thread *td); +void x86_set_fork_retval(struct thread *td); /* * MSR ops for x86_msr_op()