* [PATCH 1/7] linux: Do set signal handler if it is already SIG_DFL
2022-09-28 20:46 [PATCH 0/7] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
@ 2022-09-28 20:46 ` Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 2/7] linux: Add clone3 CLONE_CLEAR_SIGHAND optimization to posix_spawn Adhemerval Zanella
` (5 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Adhemerval Zanella @ 2022-09-28 20:46 UTC (permalink / raw)
To: libc-alpha, Christian Brauner
There is no need to issue another sigaction is the disposition is
already SIG_DFL.
Checked on x86_64-linux-gnu.
---
sysdeps/unix/sysv/linux/spawni.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
index ee843a2247..65ee03c804 100644
--- a/sysdeps/unix/sysv/linux/spawni.c
+++ b/sysdeps/unix/sysv/linux/spawni.c
@@ -129,7 +129,7 @@ __spawni_child (void *arguments)
else
{
__libc_sigaction (sig, 0, &sa);
- if (sa.sa_handler == SIG_IGN)
+ if (sa.sa_handler == SIG_IGN || sa.sa_handler == SIG_DFL)
continue;
sa.sa_handler = SIG_DFL;
}
--
2.34.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 2/7] linux: Add clone3 CLONE_CLEAR_SIGHAND optimization to posix_spawn
2022-09-28 20:46 [PATCH 0/7] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 1/7] linux: Do set signal handler if it is already SIG_DFL Adhemerval Zanella
@ 2022-09-28 20:46 ` Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 3/7] powerpc64le: Add the clone3 wrapper Adhemerval Zanella
` (4 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Adhemerval Zanella @ 2022-09-28 20:46 UTC (permalink / raw)
To: libc-alpha, Christian Brauner
The clone3 flag resets all signal handlers of the child not set to
SIG_IGN to SIG_DFL. It allows to skip most of the sigaction calls
to setup child signal handling, where previously a posix_spawn
has to issue 2 times NSIG sigaction calls (one to obtain the current
disposition and another to set either SIG_DFL or SIG_IGN).
The expection is POSIX_SPAWN_SETSIGDEF the child still setup the
signal for the case the disposition is SIG_IGN.
It also need to handle the fallback where clone3 is not available,
to set the fallback in child. This is done by splitting of
__clone_internal_fallback from __clone_internal.
Checked on x86_64-linux-gnu.
---
include/clone_internal.h | 5 +
posix/Makefile | 3 +-
posix/tst-spawn7.c | 177 +++++++++++++++++++++++
sysdeps/unix/sysv/linux/clone-internal.c | 38 +++--
sysdeps/unix/sysv/linux/clone3.h | 6 +
sysdeps/unix/sysv/linux/spawni.c | 31 ++--
6 files changed, 235 insertions(+), 25 deletions(-)
create mode 100644 posix/tst-spawn7.c
diff --git a/include/clone_internal.h b/include/clone_internal.h
index 4b23ef33ce..320640e64b 100644
--- a/include/clone_internal.h
+++ b/include/clone_internal.h
@@ -7,6 +7,11 @@ extern __typeof (clone3) __clone3;
-1 with ENOSYS, fall back to clone or clone2. */
extern int __clone_internal (struct clone_args *__cl_args,
int (*__func) (void *__arg), void *__arg);
+/* The fallback code which calls clone/clone2 based on clone3 arguments. */
+extern int __clone_internal_fallback (struct clone_args *__cl_args,
+ int (*__func) (void *__arg),
+ void *__arg)
+ attribute_hidden;
#ifndef _ISOMAC
libc_hidden_proto (__clone3)
diff --git a/posix/Makefile b/posix/Makefile
index d1df7c27cb..7887eb1c8b 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -109,7 +109,7 @@ tests := test-errno tstgetopt testfnm runtests runptests \
tst-glob-tilde test-ssize-max tst-spawn4 bug-regex37 \
bug-regex38 tst-regcomp-truncated tst-spawn-chdir \
tst-wordexp-nocmd tst-execveat tst-spawn5 \
- tst-sched_getaffinity tst-spawn6
+ tst-sched_getaffinity tst-spawn6 tst-spawn7
# Test for the glob symbol version that was replaced in glibc 2.27.
ifeq ($(have-GLIBC_2.26)$(build-shared),yesyes)
@@ -291,6 +291,7 @@ tst-spawn-ARGS = -- $(host-test-program-cmd)
tst-spawn-static-ARGS = $(tst-spawn-ARGS)
tst-spawn5-ARGS = -- $(host-test-program-cmd)
tst-spawn6-ARGS = -- $(host-test-program-cmd)
+tst-spawn7-ARGS = -- $(host-test-program-cmd)
tst-dir-ARGS = `pwd` `cd $(common-objdir)/$(subdir); pwd` `cd $(common-objdir); pwd` $(objpfx)tst-dir
tst-chmod-ARGS = $(objdir)
tst-vfork3-ARGS = --test-dir=$(objpfx)
diff --git a/posix/tst-spawn7.c b/posix/tst-spawn7.c
new file mode 100644
index 0000000000..4b920bf08e
--- /dev/null
+++ b/posix/tst-spawn7.c
@@ -0,0 +1,177 @@
+/* Tests for posix_spawn signal handling.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+#include <getopt.h>
+#include <spawn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/xsignal.h>
+#include <support/xunistd.h>
+#include <unistd.h>
+
+/* Nonzero if the program gets called via `exec'. */
+#define CMDLINE_OPTIONS \
+ { "restart", no_argument, &restart, 1 },
+static int restart;
+
+/* Hold the four initial argument used to respawn the process, plus
+ the extra '--direct' and '--restart', the check type, and a final NULL. */
+static char *spargs[8];
+static int check_type_argc;
+
+/* Called on process re-execution. */
+_Noreturn static void
+handle_restart (int argc, char *argv[])
+{
+ assert (argc == 1);
+
+ if (strcmp (argv[0], "SIG_DFL") == 0)
+ {
+ for (int i = 1; i < NSIG; i++)
+ {
+ struct sigaction sa;
+ int r = sigaction (i, NULL, &sa);
+ /* Skip internal signals (such as SIGCANCEL). */
+ if (r == -1)
+ continue;
+ TEST_VERIFY_EXIT (sa.sa_handler == SIG_DFL);
+ }
+ }
+ else if (strcmp (argv[0], "SIG_IGN") == 0)
+ {
+ for (int i = 1; i < NSIG; i++)
+ {
+ struct sigaction sa;
+ int r = sigaction (i, NULL, &sa);
+ /* Skip internal signals (such as SIGCANCEL). */
+ if (r == -1)
+ continue;
+ if (i == SIGUSR1 || i == SIGUSR2)
+ TEST_VERIFY_EXIT (sa.sa_handler == SIG_IGN);
+ else
+ TEST_VERIFY_EXIT (sa.sa_handler == SIG_DFL);
+ }
+ }
+
+ exit (EXIT_SUCCESS);
+}
+
+static void
+spawn_signal_test (const char *type, const posix_spawnattr_t *attr)
+{
+ spargs[check_type_argc] = (char*) type;
+
+ pid_t pid;
+ int status;
+
+ TEST_COMPARE (posix_spawn (&pid, spargs[0], NULL, attr, spargs, environ), 0);
+ TEST_COMPARE (xwaitpid (pid, &status, 0), pid);
+ TEST_VERIFY (WIFEXITED (status));
+ TEST_VERIFY (!WIFSIGNALED (status));
+ TEST_COMPARE (WEXITSTATUS (status), 0);
+}
+
+static void
+dummy_sa_handler (int)
+{
+}
+
+static void
+do_test_signals (void)
+{
+ {
+ /* Check if all signals handler are set to SIG_DFL on spawned process. */
+ spawn_signal_test ("SIG_DFL", NULL);
+ }
+
+ {
+ /* Same as before, but set SIGUSR1 and SIGUSR2. */
+ struct sigaction sa = { 0 };
+ sa.sa_handler = dummy_sa_handler;
+ xsigaction (SIGUSR1, &sa, NULL);
+ xsigaction (SIGUSR2, &sa, NULL);
+ spawn_signal_test ("SIG_DFL", NULL);
+ }
+
+ {
+ /* Check if SIG_IGN is keep as is. */
+ struct sigaction sa = { 0 };
+ sa.sa_handler = SIG_IGN;
+ xsigaction (SIGUSR1, &sa, NULL);
+ xsigaction (SIGUSR2, &sa, NULL);
+ spawn_signal_test ("SIG_IGN", NULL);
+ }
+
+ {
+ /* Check if SIG_IGN handlers are set to SIG_DFL. */
+ posix_spawnattr_t attr;
+ posix_spawnattr_init (&attr);
+ sigset_t mask;
+ sigemptyset (&mask);
+ sigaddset (&mask, SIGUSR1);
+ sigaddset (&mask, SIGUSR2);
+ posix_spawnattr_setsigdefault (&attr, &mask);
+ posix_spawnattr_setflags (&attr, POSIX_SPAWN_SETSIGDEF);
+ spawn_signal_test ("SIG_DFL", &attr);
+ posix_spawnattr_destroy (&attr);
+ }
+}
+
+static int
+do_test (int argc, char *argv[])
+{
+ /* We must have either:
+
+ - one or four parameters if called initially:
+ + argv[1]: path for ld.so optional
+ + argv[2]: "--library-path" optional
+ + argv[3]: the library path optional
+ + argv[4]: the application name
+
+ - six parameters left if called through re-execution:
+ + argv[1]: the application name
+ + argv[2]: check SIG_IGN
+
+ * When built with --enable-hardcoded-path-in-tests or issued without
+ using the loader directly. */
+
+ if (restart)
+ /* Ignore the application name. */
+ handle_restart (argc - 1, &argv[1]);
+
+ TEST_VERIFY_EXIT (argc == 2 || argc == 5);
+
+ int i;
+
+ for (i = 0; i < argc - 1; i++)
+ spargs[i] = argv[i + 1];
+ spargs[i++] = (char *) "--direct";
+ spargs[i++] = (char *) "--restart";
+ check_type_argc = i++;
+ spargs[i] = NULL;
+
+
+ do_test_signals ();
+
+ return 0;
+}
+
+#define TEST_FUNCTION_ARGV do_test
+#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/clone-internal.c b/sysdeps/unix/sysv/linux/clone-internal.c
index a71effcbd3..d9eb254ffb 100644
--- a/sysdeps/unix/sysv/linux/clone-internal.c
+++ b/sysdeps/unix/sysv/linux/clone-internal.c
@@ -44,27 +44,15 @@ _Static_assert (sizeof (struct clone_args) == CLONE_ARGS_SIZE_VER2,
"sizeof (struct clone_args) != CLONE_ARGS_SIZE_VER2");
int
-__clone_internal (struct clone_args *cl_args,
- int (*func) (void *arg), void *arg)
+__clone_internal_fallback (struct clone_args *cl_args,
+ int (*func) (void *arg), void *arg)
{
- int ret;
-#ifdef HAVE_CLONE3_WRAPPER
- /* Try clone3 first. */
- int saved_errno = errno;
- ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
- if (ret != -1 || errno != ENOSYS)
- return ret;
-
- /* NB: Restore errno since errno may be checked against non-zero
- return value. */
- __set_errno (saved_errno);
-#endif
-
/* Map clone3 arguments to clone arguments. NB: No need to check
invalid clone3 specific bits in flags nor exit_signal since this
is an internal function. */
int flags = cl_args->flags | cl_args->exit_signal;
void *stack = cast_to_pointer (cl_args->stack);
+ int ret;
#ifdef __ia64__
ret = __clone2 (func, stack, cl_args->stack_size,
@@ -88,4 +76,24 @@ __clone_internal (struct clone_args *cl_args,
return ret;
}
+
+int
+__clone_internal (struct clone_args *cl_args,
+ int (*func) (void *arg), void *arg)
+{
+#ifdef HAVE_CLONE3_WRAPPER
+ /* Try clone3 first. */
+ int saved_errno = errno;
+ int ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
+ if (ret != -1 || errno != ENOSYS)
+ return ret;
+
+ /* NB: Restore errno since errno may be checked against non-zero
+ return value. */
+ __set_errno (saved_errno);
+#endif
+
+ return __clone_internal_fallback (cl_args, func, arg);
+}
+
libc_hidden_def (__clone_internal)
diff --git a/sysdeps/unix/sysv/linux/clone3.h b/sysdeps/unix/sysv/linux/clone3.h
index 889014a6a9..a150363f89 100644
--- a/sysdeps/unix/sysv/linux/clone3.h
+++ b/sysdeps/unix/sysv/linux/clone3.h
@@ -25,6 +25,12 @@
__BEGIN_DECLS
+/* Flags for the clone3 syscall. */
+#define CLONE_CLEAR_SIGHAND 0x100000000ULL /* Clear any signal handler and
+ reset to SIG_DFL. */
+#define CLONE_INTO_CGROUP 0x200000000ULL /* Clone into a specific cgroup given
+ the right permissions. */
+
/* The unsigned 64-bit and 8-byte aligned integer type. */
typedef __U64_TYPE __aligned_uint64_t __attribute__ ((__aligned__ (8)));
diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
index 65ee03c804..5251b4c602 100644
--- a/sysdeps/unix/sysv/linux/spawni.c
+++ b/sysdeps/unix/sysv/linux/spawni.c
@@ -66,6 +66,7 @@ struct posix_spawn_args
ptrdiff_t argc;
char *const *envp;
int xflags;
+ bool use_clone3;
int err;
};
@@ -104,12 +105,11 @@ __spawni_child (void *arguments)
const posix_spawnattr_t *restrict attr = args->attr;
const posix_spawn_file_actions_t *file_actions = args->fa;
- /* The child must ensure that no signal handler are enabled because it shared
- memory with parent, so the signal disposition must be either SIG_DFL or
- SIG_IGN. It does by iterating over all signals and although it could
- possibly be more optimized (by tracking which signal potentially have a
- signal handler), it might requires system specific solutions (since the
- sigset_t data type can be very different on different architectures). */
+ /* The child must ensure that no signal handler are enabled because it
+ shared memory with parent, so the signal disposition must be either
+ SIG_DFL or SIG_IGN. If clone3/CLONE_CLEAR_SIGHAND is used, there is
+ only need to set the defined signals to SIG_DFL if POSIX_SPAWN_SETSIGDEF
+ is used; otherwise, the code iterates over all signals. */
struct sigaction sa;
memset (&sa, '\0', sizeof (sa));
@@ -122,7 +122,7 @@ __spawni_child (void *arguments)
{
sa.sa_handler = SIG_DFL;
}
- else if (__sigismember (&hset, sig))
+ else if (!args->use_clone3 && __sigismember (&hset, sig))
{
if (is_internal_signal (sig))
sa.sa_handler = SIG_IGN;
@@ -382,12 +382,25 @@ __spawnix (pid_t * pid, const char *file,
for instance). */
struct clone_args clone_args =
{
- .flags = CLONE_VM | CLONE_VFORK,
+ /* No supported flags like CLONE_CLEAR_SIGHAND will be cleared up by
+ __clone_internal_fallback. */
+ .flags = CLONE_CLEAR_SIGHAND | CLONE_VM | CLONE_VFORK,
.exit_signal = SIGCHLD,
.stack = (uintptr_t) stack,
.stack_size = stack_size,
};
- new_pid = __clone_internal (&clone_args, __spawni_child, &args);
+#ifdef HAVE_CLONE3_WRAPPER
+ args.use_clone3 = true;
+ new_pid = __clone3 (&clone_args, sizeof (clone_args), __spawni_child,
+ &args);
+ /* clone3 was added on 5.3 and CLONE_CLEAR_SIGHAND on 5.5. */
+ if (new_pid == -1 && (errno == ENOSYS || errno == EINVAL))
+#endif
+ {
+ args.use_clone3 = false;
+ new_pid = __clone_internal_fallback (&clone_args, __spawni_child,
+ &args);
+ }
/* It needs to collect the case where the auxiliary process was created
but failed to execute the file (due either any preparation step or
--
2.34.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 3/7] powerpc64le: Add the clone3 wrapper
2022-09-28 20:46 [PATCH 0/7] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 1/7] linux: Do set signal handler if it is already SIG_DFL Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 2/7] linux: Add clone3 CLONE_CLEAR_SIGHAND optimization to posix_spawn Adhemerval Zanella
@ 2022-09-28 20:46 ` Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 4/7] aarch64: " Adhemerval Zanella
` (3 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Adhemerval Zanella @ 2022-09-28 20:46 UTC (permalink / raw)
To: libc-alpha, Christian Brauner
It follows the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
And x86_64 semantics to return EINVAL if either cl_args or func
is NULL. The stack is 16-byte aligned prior executing func.
Checked on powerpc64le-linux-gnu.
---
.../sysv/linux/powerpc/powerpc64/clone3.S | 145 ++++++++++++++++++
sysdeps/unix/sysv/linux/powerpc/sysdep.h | 1 +
2 files changed, 146 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S
new file mode 100644
index 0000000000..a7461a3a42
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone3.S
@@ -0,0 +1,145 @@
+/* The clone3 syscall wrapper. Linux/powerpc64 version.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, size_t size,
+ int (*func)(void *arg), void *arg);
+
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ r3: cl_args
+ r4: size
+ r5: func
+ r6: arg */
+
+ .text
+ENTRY(__clone3)
+ CALL_MCOUNT 4
+
+ /* Sanity checks args. */
+ cmpdi cr0, r3, 0
+ cmpdi cr1, r5, 0
+ cror cr0*4+eq, cr1*4+eq, cr0*4+eq
+ beq cr0,L(badargs)
+
+ /* Save some regs in the "red zone". */
+#ifdef USE_PPC_SCV
+ std r28, -24(r1)
+ cfi_offset (r28, -24)
+#endif
+ std r29, -16(r1)
+ std r30, -8(r1)
+ cfi_offset (r29, -16)
+ cfi_offset (r30, -8)
+
+ /* Save fn and args across syscall. */
+ mr r30, r5 /* Function. */
+ mr r29, r6 /* Arguments. */
+
+ /* End FDE now, because in the child the unwind info will be
+ wrong. */
+ cfi_endproc
+
+ /* Do the system call, the kernel expects:
+ r0: system call numer
+ r3: cl_args
+ r4: size */
+ li r0, SYS_ify(clone3)
+#ifdef USE_PPC_SCV
+ CHECK_SCV_SUPPORT r28 0f
+ /* This is equivalent to DO_CALL_SCV, but we cannot use the macro here
+ because it uses CFI directives and we just called cfi_endproc. */
+ mflr r9
+ std r9, FRAME_LR_SAVE(r1)
+ .machine "push"
+ .machine "power9"
+ scv 0
+ .machine "pop"
+ ld r9, FRAME_LR_SAVE(r1)
+ mtlr r9
+
+ /* When using scv, error is indicated by negative r3. */
+ cmpdi cr1, r3, 0
+ b 1f
+#endif
+0: DO_CALL_SC
+
+ /* With sc, error is indicated by cr0.SO. */
+ cmpdi cr1, r3, 0
+ crandc cr1*4+eq, cr1*4+eq, cr0*4+so
+
+1: bne- cr1,L(parent)
+
+ /* Child, load the function and arguments. */
+
+ /* Align stack. */
+ rldicr r1, r1, 0, 59
+
+ std r2, FRAME_TOC_SAVE(r1)
+ PPC64_LOAD_FUNCPTR r30
+ mr r3, r29
+ bctrl
+ ld r2, FRAME_TOC_SAVE(r1)
+
+ li r0, SYS_ify(exit)
+ DO_CALL_SC
+ /* We won't ever get here but provide a nop so that the linker
+ will insert a toc adjusting stub if necessary. */
+ nop
+
+L(badargs):
+ cfi_startproc
+ li r3, EINVAL
+ TAIL_CALL_SYSCALL_ERROR
+
+L(parent):
+ /* Check if svc is available. */
+ cmpdi cr1, r28, 0
+
+ /* Parent. Restore registers & return. */
+#ifdef USE_PPC_SCV
+ cfi_offset (r28, -24)
+ ld r28, -24(r1)
+ cfi_restore (r28)
+#endif
+ cfi_offset (r29,-16)
+ cfi_offset (r30,-8)
+ ld r29, -16(r1)
+ ld r30, -8(r1)
+ cfi_restore (r29)
+ cfi_restore (r30)
+
+#ifdef USE_PPC_SCV
+ beq cr1, 0f
+ RET_SCV
+ b 1f
+#endif
+0: RET_SC
+1: TAIL_CALL_SYSCALL_ERROR
+
+PSEUDO_END (__clone3)
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
diff --git a/sysdeps/unix/sysv/linux/powerpc/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/sysdep.h
index 4fb135aa8d..b86951207d 100644
--- a/sysdeps/unix/sysv/linux/powerpc/sysdep.h
+++ b/sysdeps/unix/sysv/linux/powerpc/sysdep.h
@@ -246,6 +246,7 @@
#if defined(__PPC64__) || defined(__powerpc64__)
#define HAVE_CLOCK_GETRES64_VSYSCALL "__kernel_clock_getres"
#define HAVE_CLOCK_GETTIME64_VSYSCALL "__kernel_clock_gettime"
+#define HAVE_CLONE3_WRAPPER 1
#else
#define HAVE_CLOCK_GETRES_VSYSCALL "__kernel_clock_getres"
#define HAVE_CLOCK_GETTIME_VSYSCALL "__kernel_clock_gettime"
--
2.34.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 4/7] aarch64: Add the clone3 wrapper
2022-09-28 20:46 [PATCH 0/7] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
` (2 preceding siblings ...)
2022-09-28 20:46 ` [PATCH 3/7] powerpc64le: Add the clone3 wrapper Adhemerval Zanella
@ 2022-09-28 20:46 ` Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 5/7] s390x: " Adhemerval Zanella
` (2 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Adhemerval Zanella @ 2022-09-28 20:46 UTC (permalink / raw)
To: libc-alpha, Christian Brauner
It follow the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
And x86_64 semantics to return EINVAL if either cl_args or func
is NULL. The stack is 16-byte aligned prior executing func.
Checked on aarch64-linux-gnu.
---
sysdeps/unix/sysv/linux/aarch64/clone3.S | 90 ++++++++++++++++++++++++
sysdeps/unix/sysv/linux/aarch64/sysdep.h | 2 +
2 files changed, 92 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/aarch64/clone3.S
diff --git a/sysdeps/unix/sysv/linux/aarch64/clone3.S b/sysdeps/unix/sysv/linux/aarch64/clone3.S
new file mode 100644
index 0000000000..dba93430eb
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/clone3.S
@@ -0,0 +1,90 @@
+/* The clone3 syscall wrapper. Linux/aarch64 version.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, size_t size,
+ int (*func)(void *arg), void *arg);
+
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ x0: cl_args
+ x1: size
+ x2: func
+ x3: arg */
+
+ .text
+ENTRY(__clone3)
+ PTR_ARG (0)
+ PTR_ARG (1)
+ PTR_ARG (3)
+ PTR_ARG (4)
+ /* Save args for the child. */
+ mov x10, x0 /* cl_args */
+ mov x11, x2 /* func */
+ mov x12, x3 /* args */
+
+ /* Sanity check args. */
+ mov x0, #-EINVAL
+ cbz x10, .Lsyscall_error /* No NULL cl_args pointer. */
+ cbz x2, .Lsyscall_error /* No NULL function pointer. */
+
+ /* Do the system call, the kernel expects:
+ x8: system call number
+ x0: cl_args
+ x1: size */
+ mov x0, x10
+ mov x8, #SYS_ify(clone3)
+ svc 0x0
+
+ cmp x0, #0
+ beq thread_start
+ blt .Lsyscall_error
+ RET
+PSEUDO_END (__clone3)
+
+ .align 4
+ .type thread_start, %function
+thread_start:
+ cfi_startproc
+ cfi_undefined (x30)
+ mov x29, 0
+
+ /* Align sp. */
+ mov x0, sp
+ and x0, x0, -16
+ mov sp, x0
+
+ /* Pick the function arg and execute. */
+ mov x0, x12
+ blr x11
+
+ /* We are done, pass the return value through x0. */
+ mov x8, #SYS_ify(exit)
+ svc 0x0
+ cfi_endproc
+ .size thread_start, .-thread_start
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
diff --git a/sysdeps/unix/sysv/linux/aarch64/sysdep.h b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
index f1853e012f..42bb22f5e6 100644
--- a/sysdeps/unix/sysv/linux/aarch64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
@@ -164,6 +164,8 @@
# define HAVE_CLOCK_GETTIME64_VSYSCALL "__kernel_clock_gettime"
# define HAVE_GETTIMEOFDAY_VSYSCALL "__kernel_gettimeofday"
+# define HAVE_CLONE3_WRAPPER 1
+
# undef INTERNAL_SYSCALL_RAW
# define INTERNAL_SYSCALL_RAW(name, nr, args...) \
({ long _sys_result; \
--
2.34.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 5/7] s390x: Add the clone3 wrapper
2022-09-28 20:46 [PATCH 0/7] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
` (3 preceding siblings ...)
2022-09-28 20:46 ` [PATCH 4/7] aarch64: " Adhemerval Zanella
@ 2022-09-28 20:46 ` Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 6/7] riscv: " Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 7/7] Linux: optimize clone3 internal usage Adhemerval Zanella
6 siblings, 0 replies; 8+ messages in thread
From: Adhemerval Zanella @ 2022-09-28 20:46 UTC (permalink / raw)
To: libc-alpha, Christian Brauner
It follows the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
And x86_64 semantics to return EINVAL if either cl_args or func
is NULL. The stack is 16-byte aligned prior executing func.
Checked on s390x-linux-gnu.
---
sysdeps/unix/sysv/linux/s390/s390-64/clone3.S | 84 +++++++++++++++++++
sysdeps/unix/sysv/linux/s390/sysdep.h | 1 +
2 files changed, 85 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/s390/s390-64/clone3.S
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/clone3.S b/sysdeps/unix/sysv/linux/s390/s390-64/clone3.S
new file mode 100644
index 0000000000..d338acfc9c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/clone3.S
@@ -0,0 +1,84 @@
+/* The clone3 syscall wrapper. Linux/s390x version.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, size_t size,
+ int (*func)(void *arg), void *arg);
+
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ r2: cl_args
+ r3: size
+ r4: func
+ r5: arg */
+
+ .text
+ENTRY(__clone3)
+ stg %r6, 48(%r15)
+
+ /* Sanity check args. */
+ ltgr %r2, %r2
+ je error
+ ltgr %r6, %r4
+ je error
+
+ /* Do the system call, the kernel expects:
+ r1: system call number
+ r2: cl_args
+ r3: size */
+ lghi %r1, SYS_ify(clone3)
+ svc 0
+ ltgr %r2,%r2 /* check return code */
+ jz thread_start
+ lg %r6, 48(%r15)
+ jgm SYSCALL_ERROR_LABEL
+ br %r14
+error:
+ lghi %r2,-EINVAL
+ jg SYSCALL_ERROR_LABEL
+PSEUDO_END (__clone3)
+
+ .align 4
+ .type thread_start, %function
+thread_start:
+ cfi_startproc
+ /* Mark r14 as undefined in order to stop unwinding here. */
+ cfi_undefined (r14)
+
+ /* Align stack. */
+ nill %r15, 0xfff0
+
+ /* func is in gpr 6, arg in gpr 5. */
+ lgr %r2, %r5
+ aghi %r15, -160
+ xc 0(8,%r15),0(%r15)
+ basr %r14, %r6
+
+ DO_CALL (exit, 1)
+ cfi_endproc
+ .size thread_start, .-thread_start
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
diff --git a/sysdeps/unix/sysv/linux/s390/sysdep.h b/sysdeps/unix/sysv/linux/s390/sysdep.h
index 930d7efe03..366c797ef1 100644
--- a/sysdeps/unix/sysv/linux/s390/sysdep.h
+++ b/sysdeps/unix/sysv/linux/s390/sysdep.h
@@ -72,6 +72,7 @@
#ifdef __s390x__
#define HAVE_CLOCK_GETRES64_VSYSCALL "__kernel_clock_getres"
#define HAVE_CLOCK_GETTIME64_VSYSCALL "__kernel_clock_gettime"
+#define HAVE_CLONE3_WRAPPER 1
#else
#define HAVE_CLOCK_GETRES_VSYSCALL "__kernel_clock_getres"
#define HAVE_CLOCK_GETTIME_VSYSCALL "__kernel_clock_gettime"
--
2.34.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 6/7] riscv: Add the clone3 wrapper
2022-09-28 20:46 [PATCH 0/7] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
` (4 preceding siblings ...)
2022-09-28 20:46 ` [PATCH 5/7] s390x: " Adhemerval Zanella
@ 2022-09-28 20:46 ` Adhemerval Zanella
2022-09-28 20:46 ` [PATCH 7/7] Linux: optimize clone3 internal usage Adhemerval Zanella
6 siblings, 0 replies; 8+ messages in thread
From: Adhemerval Zanella @ 2022-09-28 20:46 UTC (permalink / raw)
To: libc-alpha, Christian Brauner
It follows the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
And x86_64 semantics to return EINVAL if either cl_args or func
is NULL. The stack is 16-byte aligned prior executing func.
Checked on riscv64-linux-gnu-rv64imafdc-lp64d.
---
sysdeps/unix/sysv/linux/riscv/clone3.S | 83 ++++++++++++++++++++++++++
sysdeps/unix/sysv/linux/riscv/sysdep.h | 1 +
2 files changed, 84 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/riscv/clone3.S
diff --git a/sysdeps/unix/sysv/linux/riscv/clone3.S b/sysdeps/unix/sysv/linux/riscv/clone3.S
new file mode 100644
index 0000000000..1e6e807aa0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/clone3.S
@@ -0,0 +1,83 @@
+/* The clone3 syscall wrapper. Linux/RISC-V version.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <asm/errno.h>
+#include <sys/asm.h>
+#include <sysdep.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, size_t size,
+ int (*func)(void *arg), void *arg);
+
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ a0: cl_args
+ a1: size
+ a2: func
+ a3: arg */
+
+ .text
+ENTRY(__clone3)
+ /* Sanity check args. */
+ beqz a0, L(invalid) /* No NULL cl_args pointer. */
+ beqz a2, L(invalid) /* No NULL function pointer. */
+
+ /* Do the system call, the kernel expects:
+ a7: system call number
+ a0: cl_args
+ a1: size */
+ li a7, __NR_clone3
+ scall
+
+ bltz a0, L(error)
+ beqz a0, L(thread_start)
+
+ ret
+
+L(invalid):
+ li a0, -EINVAL
+L(error):
+ tail __syscall_error
+END (__clone3)
+
+ENTRY(__thread_start_clone3)
+L(thread_start):
+ /* Terminate call stack by noting ra is undefined. Use a dummy
+ .cfi_label to force starting the FDE. */
+ .cfi_label .Ldummy
+ cfi_undefined (ra)
+
+ /* Align stack to a 128-bit boundary as per RISC-V ABI. */
+ andi sp, sp, ALMASK
+
+ /* Restore the arg for user's function and call the user's
+ function. */
+ mv a1, a2 /* Function pointer. */
+ mv a0, a3 /* Argument pointer. */
+ jalr a1
+
+ /* Call exit with the function's return value. */
+ li a7, __NR_exit
+ scall
+END(__thread_start_clone3)
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
index 9b03b10567..57523dc7b7 100644
--- a/sysdeps/unix/sysv/linux/riscv/sysdep.h
+++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
@@ -150,6 +150,7 @@
/* RV32 does not support the gettime VDSO syscalls. */
# endif
+# define HAVE_CLONE3_WRAPPER 1
/* List of system calls which are supported as vsyscalls (for RV32 and
RV64). */
--
2.34.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 7/7] Linux: optimize clone3 internal usage
2022-09-28 20:46 [PATCH 0/7] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella
` (5 preceding siblings ...)
2022-09-28 20:46 ` [PATCH 6/7] riscv: " Adhemerval Zanella
@ 2022-09-28 20:46 ` Adhemerval Zanella
6 siblings, 0 replies; 8+ messages in thread
From: Adhemerval Zanella @ 2022-09-28 20:46 UTC (permalink / raw)
To: libc-alpha, Christian Brauner
Now that clone3 is used on more architectures, add an optimization
to avoid calling when glibc detects that it is no supported by the
kernel. It also adds __ASSUME_CLONE3, which allows skip this
optimization and issue clone3 syscall directly.
It does not handle the the small window between 5.3 and 5.5 for
posix_spawn (CLONE_CLEAR_SIGHAND was added in 5.5).
Checked on x86_64-linux-gnu.
---
include/clone_internal.h | 5 +++++
sysdeps/unix/sysv/linux/clone-internal.c | 25 ++++++++++++++++++++++-
sysdeps/unix/sysv/linux/kernel-features.h | 8 ++++++++
3 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/include/clone_internal.h b/include/clone_internal.h
index 320640e64b..71c52211c7 100644
--- a/include/clone_internal.h
+++ b/include/clone_internal.h
@@ -7,6 +7,11 @@ extern __typeof (clone3) __clone3;
-1 with ENOSYS, fall back to clone or clone2. */
extern int __clone_internal (struct clone_args *__cl_args,
int (*__func) (void *__arg), void *__arg);
+/* clone3 wrapper that avoid issuing the syscall once clone3 fails with
+ ENOSYS. */
+extern int __clone3_internal (struct clone_args *cl_args,
+ int (*func) (void *args), void *arg)
+ attribute_hidden;
/* The fallback code which calls clone/clone2 based on clone3 arguments. */
extern int __clone_internal_fallback (struct clone_args *__cl_args,
int (*__func) (void *__arg),
diff --git a/sysdeps/unix/sysv/linux/clone-internal.c b/sysdeps/unix/sysv/linux/clone-internal.c
index d9eb254ffb..7e20d02025 100644
--- a/sysdeps/unix/sysv/linux/clone-internal.c
+++ b/sysdeps/unix/sysv/linux/clone-internal.c
@@ -76,6 +76,29 @@ __clone_internal_fallback (struct clone_args *cl_args,
return ret;
}
+int
+__clone3_internal (struct clone_args *cl_args, int (*func) (void *args),
+ void *arg)
+{
+#ifdef HAVE_CLONE3_WRAPPER
+# if __ASSUME_CLONE3
+ return __clone3 (cl_args, sizeof (*cl_args), func, arg);
+# else
+ static int clone3_supported = 1;
+ if (atomic_load_relaxed (&clone3_supported) == 1)
+ {
+ int ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
+ if (ret != -1 || errno != ENOSYS)
+ return ret;
+
+ atomic_store_relaxed (&clone3_supported, 0);
+ }
+# endif
+#endif
+ __set_errno (ENOSYS);
+ return -1;
+}
+
int
__clone_internal (struct clone_args *cl_args,
@@ -84,7 +107,7 @@ __clone_internal (struct clone_args *cl_args,
#ifdef HAVE_CLONE3_WRAPPER
/* Try clone3 first. */
int saved_errno = errno;
- int ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
+ int ret = __clone3_internal (cl_args, func, arg);
if (ret != -1 || errno != ENOSYS)
return ret;
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 74adc3956b..496c7f34cb 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -236,4 +236,12 @@
# define __ASSUME_FUTEX_LOCK_PI2 0
#endif
+/* The clone3 system call was introduced across all architectures
+ in Linux 5.3. */
+#if __LINUX_KERNEL_VERSION >= 0x050300
+# define __ASSUME_CLONE3 1
+#else
+# define __ASSUME_CLONE3 0
+#endif
+
#endif /* kernel-features.h */
--
2.34.1
^ permalink raw reply [flat|nested] 8+ messages in thread