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Index: sys/cddl/dev/systrace/systrace.c
===================================================================
--- sys/cddl/dev/systrace/systrace.c
+++ sys/cddl/dev/systrace/systrace.c
@@ -318,7 +318,7 @@
SYSENT[sysnum].sy_return = id;
systrace_enabled_count++;
if (systrace_enabled_count == 1)
- systrace_enabled = true;
+ syscall_slow_down(SYSCALL_SLOW_SYSTRACE);
}
static void
@@ -331,7 +331,7 @@
SYSENT[sysnum].sy_return = DTRACE_IDNONE;
systrace_enabled_count--;
if (systrace_enabled_count == 0)
- systrace_enabled = false;
+ syscall_speed_up(SYSCALL_SLOW_SYSTRACE);
}
static void
Index: sys/kern/kern_dtrace.c
===================================================================
--- sys/kern/kern_dtrace.c
+++ sys/kern/kern_dtrace.c
@@ -56,7 +56,6 @@
dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr;
dtrace_return_probe_ptr_t dtrace_return_probe_ptr;
-bool __read_frequently systrace_enabled;
systrace_probe_func_t systrace_probe_func;
/* Return the DTrace process data size compiled in the kernel hooks. */
Index: sys/kern/kern_sig.c
===================================================================
--- sys/kern/kern_sig.c
+++ sys/kern/kern_sig.c
@@ -116,6 +116,7 @@
static int filt_signal(struct knote *kn, long hint);
static struct thread *sigtd(struct proc *p, int sig, bool fast_sigblock);
static void sigqueue_start(void);
+static int sysctl_sigfastblock_check_always(SYSCTL_HANDLER_ARGS);
static uma_zone_t ksiginfo_zone = NULL;
struct filterops sig_filtops = {
@@ -157,9 +158,10 @@
SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0,
"Log invalid syscalls");
-__read_frequently bool sigfastblock_fetch_always = false;
-SYSCTL_BOOL(_kern, OID_AUTO, sigfastblock_fetch_always, CTLFLAG_RWTUN,
- &sigfastblock_fetch_always, 0,
+bool sigfastblock_fetch_always = false;
+SYSCTL_PROC(_kern, OID_AUTO, sigfastblock_fetch_always,
+ CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0,
+ sysctl_sigfastblock_check_always, "U",
"Fetch sigfastblock word on each syscall entry for proper "
"blocking semantic");
@@ -4247,4 +4249,21 @@
reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK);
PROC_UNLOCK(p);
}
+}
+
+static int
+sysctl_sigfastblock_check_always(SYSCTL_HANDLER_ARGS)
+{
+ int error;
+
+ error = sysctl_handle_int(oidp, &sigfastblock_fetch_always, 0, req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+
+ if (sigfastblock_fetch_always)
+ syscall_slow_down(SYSCALL_SLOW_SIGFASTBLOCK);
+ else
+ syscall_speed_up(SYSCALL_SLOW_SIGFASTBLOCK);
+
+ return (0);
}
Index: sys/kern/kern_syscalls.c
===================================================================
--- sys/kern/kern_syscalls.c
+++ sys/kern/kern_syscalls.c
@@ -43,6 +43,8 @@
#include <sys/systm.h>
#include <machine/atomic.h>
+int __read_frequently syscall_slow_path_required = 0;
+
/*
* Acts like "nosys" but can be identified in sysent for dynamic call
* number assignment for a limited number of calls.
@@ -262,4 +264,18 @@
sd1->registered = 0;
}
return (0);
+}
+
+void
+syscall_slow_down(int id)
+{
+
+ atomic_set_int(&syscall_slow_path_required, id);
+}
+
+void
+syscall_speed_up(int id)
+{
+
+ atomic_clear_int(&syscall_slow_path_required, id);
}
Index: sys/kern/subr_syscall.c
===================================================================
--- sys/kern/subr_syscall.c
+++ sys/kern/subr_syscall.c
@@ -129,22 +129,20 @@
}
#endif
- /*
- * Fetch fast sigblock value at the time of syscall entry to
- * handle sleepqueue primitives which might call cursig().
- */
- if (__predict_false(sigfastblock_fetch_always))
- (void)sigfastblock_fetch(td);
-
/* Let system calls set td_errno directly. */
KASSERT((td->td_pflags & TDP_NERRNO) == 0,
("%s: TDP_NERRNO set", __func__));
sy_thr_static = (se->sy_thrcnt & SY_THR_STATIC) != 0;
- if (__predict_false(SYSTRACE_ENABLED() ||
- AUDIT_SYSCALL_ENTER(sa->code, td) ||
- !sy_thr_static)) {
+ if (__predict_false(syscall_slow_path_required || !sy_thr_static)) {
+ /*
+ * Fetch fast sigblock value at the time of syscall entry to
+ * handle sleepqueue primitives which might call cursig().
+ */
+ if (__predict_false(sigfastblock_fetch_always))
+ (void)sigfastblock_fetch(td);
+
if (!sy_thr_static) {
error = syscall_thread_enter(td, se);
if (error != 0) {
Index: sys/security/audit/audit.c
===================================================================
--- sys/security/audit/audit.c
+++ sys/security/audit/audit.c
@@ -227,6 +227,10 @@
#ifdef KDTRACE_HOOKS
}
#endif
+ if (audit_syscalls_enabled)
+ syscall_slow_down(SYSCALL_SLOW_AUDIT);
+ else
+ syscall_speed_up(SYSCALL_SLOW_AUDIT);
mtx_unlock(&audit_mtx);
}
Index: sys/sys/sysent.h
===================================================================
--- sys/sys/sysent.h
+++ sys/sys/sysent.h
@@ -55,13 +55,6 @@
#ifdef _KERNEL
extern systrace_probe_func_t systrace_probe_func;
-extern bool systrace_enabled;
-
-#ifdef KDTRACE_HOOKS
-#define SYSTRACE_ENABLED() (systrace_enabled)
-#else
-#define SYSTRACE_ENABLED() (0)
-#endif
#endif /* _KERNEL */
struct sysent { /* system call table */
@@ -310,6 +303,15 @@
#define INIT_SYSENTVEC(name, sv) \
SYSINIT(name, SI_SUB_EXEC, SI_ORDER_ANY, \
(sysinit_cfunc_t)exec_sysvec_init, sv);
+
+extern int syscall_slow_path_required;
+
+#define SYSCALL_SLOW_AUDIT 0x01
+#define SYSCALL_SLOW_SYSTRACE 0x02
+#define SYSCALL_SLOW_SIGFASTBLOCK 0x04
+
+void syscall_slow_down(int id);
+void syscall_speed_up(int id);
#endif /* _KERNEL */

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