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Avoid dynamic syscall overhead for statically compiled modules.

Browse Source 
The kernel tracks syscall users so that modules can safely unregister them.

But if the module is not unloadable or was compiled into the kernel, there is
no need to do this.

Achieve this by adding SY_THR_STATIC_KLD macro which expands to SY_THR_STATIC
during kernel build and 0 otherwise.

Reviewed by:	kib (previous version)
MFC after:	2 weeks
This commit is contained in:
Mateusz Guzik 2014-10-26 19:42:44 +00:00
parent f0c8263e55
commit e015b1ab0a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=273707
14 changed files with 59 additions and 38 deletions
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23
sys/compat/freebsd32/freebsd32_misc.c
View File

@ -2628,8 +2628,12 @@ freebsd32_xxx(struct thread *td, struct freebsd32_xxx_args *uap)
int
syscall32_register(int *offset, struct sysent *new_sysent,
struct sysent *old_sysent)
struct sysent *old_sysent, int flags)
{
if ((flags & ~SY_THR_STATIC) != 0)
return (EINVAL);
if (*offset == NO_SYSCALL) {
int i;
@ -2648,16 +2652,19 @@ syscall32_register(int *offset, struct sysent *new_sysent,
*old_sysent = freebsd32_sysent[*offset];
freebsd32_sysent[*offset] = *new_sysent;
return 0;
atomic_store_rel_32(&freebsd32_sysent[*offset].sy_thrcnt, flags);
return (0);
}
int
syscall32_deregister(int *offset, struct sysent *old_sysent)
{
if (*offset)
freebsd32_sysent[*offset] = *old_sysent;
return 0;
if (*offset == 0)
return (0);
freebsd32_sysent[*offset] = *old_sysent;
return (0);
}
int
@ -2670,7 +2677,7 @@ syscall32_module_handler(struct module *mod, int what, void *arg)
switch (what) {
case MOD_LOAD:
error = syscall32_register(data->offset, data->new_sysent,
&data->old_sysent);
&data->old_sysent, SY_THR_STATIC_KLD);
if (error) {
/* Leave a mark so we know to safely unload below. */
data->offset = NULL;
@ -2707,14 +2714,14 @@ syscall32_module_handler(struct module *mod, int what, void *arg)
}
int
syscall32_helper_register(struct syscall_helper_data *sd)
syscall32_helper_register(struct syscall_helper_data *sd, int flags)
{
struct syscall_helper_data *sd1;
int error;
for (sd1 = sd; sd1->syscall_no != NO_SYSCALL; sd1++) {
error = syscall32_register(&sd1->syscall_no, &sd1->new_sysent,
&sd1->old_sysent);
&sd1->old_sysent, flags);
if (error != 0) {
syscall32_helper_unregister(sd);
return (error);

4
sys/compat/freebsd32/freebsd32_util.h
View File

@ -98,10 +98,10 @@ SYSCALL32_MODULE(syscallname, \
}
int syscall32_register(int *offset, struct sysent *new_sysent,
struct sysent *old_sysent);
struct sysent *old_sysent, int flags);
int syscall32_deregister(int *offset, struct sysent *old_sysent);
int syscall32_module_handler(struct module *mod, int what, void *arg);
int syscall32_helper_register(struct syscall_helper_data *sd);
int syscall32_helper_register(struct syscall_helper_data *sd, int flags);
int syscall32_helper_unregister(struct syscall_helper_data *sd);
struct iovec32;

26
sys/kern/kern_syscalls.c
View File

@ -105,10 +105,13 @@ syscall_thread_exit(struct thread *td, struct sysent *se)
int
syscall_register(int *offset, struct sysent *new_sysent,
struct sysent *old_sysent)
struct sysent *old_sysent, int flags)
{
int i;
if ((flags & ~SY_THR_STATIC) != 0)
return (EINVAL);
if (*offset == NO_SYSCALL) {
for (i = 1; i < SYS_MAXSYSCALL; ++i)
if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
@ -127,18 +130,23 @@ syscall_register(int *offset, struct sysent *new_sysent,
*old_sysent = sysent[*offset];
new_sysent->sy_thrcnt = SY_THR_ABSENT;
sysent[*offset] = *new_sysent;
atomic_store_rel_32(&sysent[*offset].sy_thrcnt, 0);
atomic_store_rel_32(&sysent[*offset].sy_thrcnt, flags);
return (0);
}
int
syscall_deregister(int *offset, struct sysent *old_sysent)
{
struct sysent *se;
if (*offset) {
syscall_thread_drain(&sysent[*offset]);
sysent[*offset] = *old_sysent;
}
if (*offset == 0)
return (0); /* XXX? */
se = &sysent[*offset];
if ((se->sy_thrcnt & SY_THR_STATIC) != 0)
return (EINVAL);
syscall_thread_drain(se);
sysent[*offset] = *old_sysent;
return (0);
}
@ -152,7 +160,7 @@ syscall_module_handler(struct module *mod, int what, void *arg)
switch (what) {
case MOD_LOAD:
error = syscall_register(data->offset, data->new_sysent,
&data->old_sysent);
&data->old_sysent, SY_THR_STATIC_KLD);
if (error) {
/* Leave a mark so we know to safely unload below. */
data->offset = NULL;
@ -190,14 +198,14 @@ syscall_module_handler(struct module *mod, int what, void *arg)
}
int
syscall_helper_register(struct syscall_helper_data *sd)
syscall_helper_register(struct syscall_helper_data *sd, int flags)
{
struct syscall_helper_data *sd1;
int error;
for (sd1 = sd; sd1->syscall_no != NO_SYSCALL; sd1++) {
error = syscall_register(&sd1->syscall_no, &sd1->new_sysent,
&sd1->old_sysent);
&sd1->old_sysent, flags);
if (error != 0) {
syscall_helper_unregister(sd);
return (error);

4
sys/kern/sysv_msg.c
View File

@ -252,11 +252,11 @@ msginit()
}
mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
error = syscall_helper_register(msg_syscalls);
error = syscall_helper_register(msg_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(msg32_syscalls);
error = syscall32_helper_register(msg32_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#endif

4
sys/kern/sysv_sem.c
View File

@ -278,11 +278,11 @@ seminit(void)
semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
EVENTHANDLER_PRI_ANY);
error = syscall_helper_register(sem_syscalls);
error = syscall_helper_register(sem_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(sem32_syscalls);
error = syscall32_helper_register(sem32_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#endif

4
sys/kern/sysv_shm.c
View File

@ -910,11 +910,11 @@ shminit()
shmexit_hook = &shmexit_myhook;
shmfork_hook = &shmfork_myhook;
error = syscall_helper_register(shm_syscalls);
error = syscall_helper_register(shm_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(shm32_syscalls);
error = syscall32_helper_register(shm32_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#endif

4
sys/kern/uipc_mqueue.c
View File

@ -2809,11 +2809,11 @@ mqinit(void)
{
int error;
error = syscall_helper_register(mq_syscalls);
error = syscall_helper_register(mq_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(mq32_syscalls);
error = syscall32_helper_register(mq32_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#endif

4
sys/kern/uipc_sem.c
View File

@ -993,11 +993,11 @@ ksem_module_init(void)
p31b_setcfg(CTL_P1003_1B_SEM_NSEMS_MAX, SEM_MAX);
p31b_setcfg(CTL_P1003_1B_SEM_VALUE_MAX, SEM_VALUE_MAX);
error = syscall_helper_register(ksem_syscalls);
error = syscall_helper_register(ksem_syscalls, SY_THR_STATIC_KLD);
if (error)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(ksem32_syscalls);
error = syscall32_helper_register(ksem32_syscalls, SY_THR_STATIC_KLD);
if (error)
return (error);
#endif

4
sys/kern/vfs_aio.c
View File

@ -511,11 +511,11 @@ aio_onceonly(void)
p31b_setcfg(CTL_P1003_1B_AIO_MAX, MAX_AIO_QUEUE);
p31b_setcfg(CTL_P1003_1B_AIO_PRIO_DELTA_MAX, 0);
error = syscall_helper_register(aio_syscalls);
error = syscall_helper_register(aio_syscalls, SY_THR_STATIC_KLD);
if (error)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(aio32_syscalls);
error = syscall32_helper_register(aio32_syscalls, SY_THR_STATIC_KLD);
if (error)
return (error);
#endif

2
sys/kgssapi/gss_impl.c
View File

@ -70,7 +70,7 @@ kgss_init(void *dummy)
LIST_INIT(&kgss_mechs);
error = syscall_register(&gssd_syscall_offset, &gssd_syscall_sysent,
&gssd_syscall_prev_sysent);
&gssd_syscall_prev_sysent, SY_THR_STATIC_KLD);
if (error)
printf("Can't register GSSD syscall\n");
else

4
sys/netinet/sctp_syscalls.c
View File

@ -94,11 +94,11 @@ sctp_syscalls_init(void *unused __unused)
{
int error;
error = syscall_helper_register(sctp_syscalls);
error = syscall_helper_register(sctp_syscalls, SY_THR_STATIC);
KASSERT((error == 0),
("%s: syscall_helper_register failed for sctp syscalls", __func__));
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(sctp_syscalls);
error = syscall32_helper_register(sctp_syscalls, SY_THR_STATIC);
KASSERT((error == 0),
("%s: syscall32_helper_register failed for sctp syscalls",
__func__));

2
sys/nfs/nfs_nfssvc.c
View File

@ -123,7 +123,7 @@ nfssvc_modevent(module_t mod, int type, void *data)
switch (type) {
case MOD_LOAD:
error = syscall_register(&nfssvc_offset, &nfssvc_sysent,
&nfssvc_prev_sysent);
&nfssvc_prev_sysent, SY_THR_STATIC_KLD);
if (error)
break;
registered = 1;

2
sys/nlm/nlm_prot_impl.c
View File

@ -295,7 +295,7 @@ nlm_init(void *dummy)
TAILQ_INIT(&nlm_hosts);
error = syscall_register(&nlm_syscall_offset, &nlm_syscall_sysent,
&nlm_syscall_prev_sysent);
&nlm_syscall_prev_sysent, SY_THR_STATIC_KLD);
if (error)
NLM_ERR("Can't register NLM syscall\n");
else

10
sys/sys/sysent.h
View File

@ -76,6 +76,12 @@ struct sysent { /* system call table */
#define SY_THR_ABSENT 0x4
#define SY_THR_INCR 0x8
#ifdef KLD_MODULE
#define SY_THR_STATIC_KLD 0
#else
#define SY_THR_STATIC_KLD SY_THR_STATIC
#endif
struct image_params;
struct __sigset;
struct syscall_args;
@ -242,10 +248,10 @@ struct syscall_helper_data {
}
int syscall_register(int *offset, struct sysent *new_sysent,
struct sysent *old_sysent);
struct sysent *old_sysent, int flags);
int syscall_deregister(int *offset, struct sysent *old_sysent);
int syscall_module_handler(struct module *mod, int what, void *arg);
int syscall_helper_register(struct syscall_helper_data *sd);
int syscall_helper_register(struct syscall_helper_data *sd, int flags);
int syscall_helper_unregister(struct syscall_helper_data *sd);
struct proc;