* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
-/*
- * System Overrides syscall implementation
- */
-
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/kauth.h>
#include <sys/unistd.h>
#include <sys/priv.h>
-#include <security/audit/audit.h>
#include <mach/mach_types.h>
#include <mach/vm_param.h>
#include <kern/task.h>
-#include <kern/lock.h>
+#include <kern/locks.h>
#include <kern/assert.h>
#include <kern/sched_prim.h>
#include <sys/kdebug.h>
#include <sys/sysproto.h>
#include <sys/msgbuf.h>
+#include <sys/kern_memorystatus.h>
/* Mutex for global system override state */
static lck_mtx_t sys_override_lock;
static lck_attr_t *sys_override_mtx_attr;
static lck_grp_attr_t *sys_override_mtx_grp_attr;
-/* Assertion counts for system properties */
+/*
+ * Assertion counts for system properties (add new ones for each new mechanism)
+ *
+ * The assertion count management for system overrides is as follows:
+ *
+ * - All assertion counts are protected by the sys_override_lock.
+ *
+ * - Each caller of system_override() increments the assertion count for the
+ * mechanism it specified in the flags. The caller then blocks for the
+ * timeout specified in the system call.
+ *
+ * - At the end of the timeout, the caller thread wakes up and decrements the
+ * assertion count for the mechanism it originally took an assertion on.
+ *
+ * - If another caller calls the system_override() to disable the override
+ * for a mechanism, it simply disables the mechanism without changing any
+ * assertion counts. That way, the assertion counts are properly balanced.
+ *
+ * One thing to note is that a SYS_OVERRIDE_DISABLE disables the overrides
+ * for a mechanism irrespective of how many clients requested that override.
+ * That makes the implementation simpler and avoids keeping a lot of process
+ * specific state in the kernel.
+ *
+ */
static int64_t io_throttle_assert_cnt;
static int64_t cpu_throttle_assert_cnt;
+static int64_t fast_jetsam_assert_cnt;
/* Wait Channel for system override */
static uint64_t sys_override_wait;
-/* Forward Declarations */
-static void enable_system_override(uint64_t flags);
-static void disable_system_override(uint64_t flags);
-static __attribute__((noinline)) void PROCESS_OVERRIDING_SYSTEM_DEFAULTS(uint64_t timeout);
+/* Global variable to indicate if system_override is enabled */
+int sys_override_enabled;
-/***************************** system_override ********************/
-/*
- * int system_override(uint64_t timeout, uint64_t flags);
- */
+/* Helper routines */
+static void system_override_begin(uint64_t flags);
+static void system_override_end(uint64_t flags);
+static void system_override_abort(uint64_t flags);
+static void system_override_callouts(uint64_t flags, boolean_t enable_override);
+static __attribute__((noinline)) void PROCESS_OVERRIDING_SYSTEM_DEFAULTS(uint64_t timeout);
void
init_system_override()
sys_override_mtx_grp = lck_grp_alloc_init("system_override", sys_override_mtx_grp_attr);
sys_override_mtx_attr = lck_attr_alloc_init();
lck_mtx_init(&sys_override_lock, sys_override_mtx_grp, sys_override_mtx_attr);
- io_throttle_assert_cnt = cpu_throttle_assert_cnt = 0;
+ io_throttle_assert_cnt = cpu_throttle_assert_cnt = fast_jetsam_assert_cnt = 0;
+ sys_override_enabled = 1;
}
/* system call implementation */
goto out;
}
- /* Check to see if some flags are specified. Zero flags are invalid. */
- if ((flags == 0) || ((flags & ~SYS_OVERRIDE_FLAGS_MASK) != 0)) {
+ /* Check to see if sane flags are specified. */
+ if ((flags & ~SYS_OVERRIDE_FLAGS_MASK) != 0) {
error = EINVAL;
goto out;
}
- lck_mtx_lock(&sys_override_lock);
-
- enable_system_override(flags);
+ /* Make sure that the system override syscall has been initialized */
+ if (!sys_override_enabled) {
+ error = EINVAL;
+ goto out;
+ }
- PROCESS_OVERRIDING_SYSTEM_DEFAULTS(timeout);
+ lck_mtx_lock(&sys_override_lock);
- disable_system_override(flags);
+ if (flags & SYS_OVERRIDE_DISABLE) {
+ flags &= ~SYS_OVERRIDE_DISABLE;
+ system_override_abort(flags);
+ } else {
+ system_override_begin(flags);
+ PROCESS_OVERRIDING_SYSTEM_DEFAULTS(timeout);
+ system_override_end(flags);
+ }
lck_mtx_unlock(&sys_override_lock);
}
/*
- * Call for enabling global system override.
- * This should be called only with the sys_override_lock held.
+ * Helper routines for enabling/disabling system overrides for various mechanisms.
+ * These routines should be called with the sys_override_lock held. Each subsystem
+ * which is hooked into the override service provides two routines:
+ *
+ * - void sys_override_foo_init(void);
+ * Routine to initialize the subsystem or the data needed for the override to work.
+ * This routine is optional and if a subsystem needs it, it should be invoked from
+ * init_system_override().
+ *
+ * - void sys_override_foo(boolean_t enable_override);
+ * Routine to enable/disable the override mechanism for that subsystem. A value of
+ * true indicates that the mechanism should be overridden and the special behavior
+ * should begin. A false value indicates that the subsystem should return to default
+ * behavior. This routine is mandatory and should be invoked as part of the helper
+ * routines if the flags passed in the syscall match the subsystem. Also, this
+ * routine should preferably be idempotent.
+ */
+
+static void
+system_override_callouts(uint64_t flags, boolean_t enable_override)
+{
+ switch (flags) {
+ case SYS_OVERRIDE_IO_THROTTLE:
+ if (enable_override) {
+ KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_THROTTLE, IO_THROTTLE_DISABLE) | DBG_FUNC_START,
+ current_proc()->p_pid, 0, 0, 0, 0);
+ } else {
+ KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_THROTTLE, IO_THROTTLE_DISABLE) | DBG_FUNC_END,
+ current_proc()->p_pid, 0, 0, 0, 0);
+ }
+ sys_override_io_throttle(enable_override);
+ break;
+
+ case SYS_OVERRIDE_CPU_THROTTLE:
+ if (enable_override) {
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_CPU_THROTTLE_DISABLE) | DBG_FUNC_START,
+ current_proc()->p_pid, 0, 0, 0, 0);
+ } else {
+ KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_CPU_THROTTLE_DISABLE) | DBG_FUNC_END,
+ current_proc()->p_pid, 0, 0, 0, 0);
+ }
+ sys_override_cpu_throttle(enable_override);
+ break;
+
+ case SYS_OVERRIDE_FAST_JETSAM:
+ if (enable_override) {
+ KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_FAST_JETSAM) | DBG_FUNC_START,
+ current_proc()->p_pid, 0, 0, 0, 0);
+ } else {
+ KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_MEMSTAT, BSD_MEMSTAT_FAST_JETSAM) | DBG_FUNC_END,
+ current_proc()->p_pid, 0, 0, 0, 0);
+ }
+#if CONFIG_JETSAM
+ memorystatus_fast_jetsam_override(enable_override);
+#endif /* CONFIG_JETSAM */
+ break;
+
+ default:
+ panic("Unknown option to system_override_callouts(): %llu\n", flags);
+ }
+}
+
+/*
+ * system_override_begin(uint64_t flags)
+ *
+ * Routine to start a system override if the assertion count
+ * transitions from 0->1 for a specified mechanism.
*/
static void
-enable_system_override(uint64_t flags)
+system_override_begin(uint64_t flags)
{
+ lck_mtx_assert(&sys_override_lock, LCK_MTX_ASSERT_OWNED);
if (flags & SYS_OVERRIDE_IO_THROTTLE) {
if (io_throttle_assert_cnt == 0) {
- /* Disable I/O Throttling */
- printf("Process %s [%d] disabling system-wide I/O Throttling\n", current_proc()->p_comm, current_proc()->p_pid);
- KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_THROTTLE, IO_THROTTLE_DISABLE) | DBG_FUNC_START, current_proc()->p_pid, 0, 0, 0, 0);
- sys_override_io_throttle(THROTTLE_IO_DISABLE);
+ system_override_callouts(SYS_OVERRIDE_IO_THROTTLE, true);
}
io_throttle_assert_cnt++;
}
if (flags & SYS_OVERRIDE_CPU_THROTTLE) {
if (cpu_throttle_assert_cnt == 0) {
- /* Disable CPU Throttling */
- printf("Process %s [%d] disabling system-wide CPU Throttling\n", current_proc()->p_comm, current_proc()->p_pid);
- KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_CPU_THROTTLE_DISABLE) | DBG_FUNC_START, current_proc()->p_pid, 0, 0, 0, 0);
- sys_override_cpu_throttle(CPU_THROTTLE_DISABLE);
+ system_override_callouts(SYS_OVERRIDE_CPU_THROTTLE, true);
}
cpu_throttle_assert_cnt++;
}
+
+ if (flags & SYS_OVERRIDE_FAST_JETSAM) {
+ if (fast_jetsam_assert_cnt == 0) {
+ system_override_callouts(SYS_OVERRIDE_FAST_JETSAM, true);
+ }
+ fast_jetsam_assert_cnt++;
+ }
}
/*
- * Call for disabling global system override.
- * This should be called only with the sys_override_lock held.
+ * system_override_end(uint64_t flags)
+ *
+ * Routine to end a system override if the assertion count
+ * transitions from 1->0 for a specified mechanism.
*/
static void
-disable_system_override(uint64_t flags)
+system_override_end(uint64_t flags)
{
+ lck_mtx_assert(&sys_override_lock, LCK_MTX_ASSERT_OWNED);
+
if (flags & SYS_OVERRIDE_IO_THROTTLE) {
assert(io_throttle_assert_cnt > 0);
io_throttle_assert_cnt--;
if (io_throttle_assert_cnt == 0) {
- /* Enable I/O Throttling */
- KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_THROTTLE, IO_THROTTLE_DISABLE) | DBG_FUNC_END, current_proc()->p_pid, 0, 0, 0, 0);
- sys_override_io_throttle(THROTTLE_IO_ENABLE);
+ system_override_callouts(SYS_OVERRIDE_IO_THROTTLE, false);
}
}
if (flags & SYS_OVERRIDE_CPU_THROTTLE) {
assert(cpu_throttle_assert_cnt > 0);
cpu_throttle_assert_cnt--;
- if (cpu_throttle_assert_cnt == 0) {
- /* Enable CPU Throttling */
- KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_CPU_THROTTLE_DISABLE) | DBG_FUNC_END, current_proc()->p_pid, 0, 0, 0, 0);
- sys_override_cpu_throttle(CPU_THROTTLE_ENABLE);
+ if (cpu_throttle_assert_cnt == 0) {
+ system_override_callouts(SYS_OVERRIDE_CPU_THROTTLE, false);
+ }
+ }
+
+ if (flags & SYS_OVERRIDE_FAST_JETSAM) {
+ assert(fast_jetsam_assert_cnt > 0);
+ fast_jetsam_assert_cnt--;
+ if (fast_jetsam_assert_cnt == 0) {
+ system_override_callouts(SYS_OVERRIDE_FAST_JETSAM, false);
}
}
+
+}
+
+/*
+ * system_override_abort(uint64_t flags)
+ *
+ * Routine to abort a system override (if one was active)
+ * irrespective of the assertion counts and number of blocked
+ * requestors.
+ */
+static void
+system_override_abort(uint64_t flags)
+{
+
+ lck_mtx_assert(&sys_override_lock, LCK_MTX_ASSERT_OWNED);
+
+ if ((flags & SYS_OVERRIDE_IO_THROTTLE) && (io_throttle_assert_cnt > 0)) {
+ system_override_callouts(SYS_OVERRIDE_IO_THROTTLE, false);
+ }
+
+ if ((flags & SYS_OVERRIDE_CPU_THROTTLE) && (cpu_throttle_assert_cnt > 0)) {
+ system_override_callouts(SYS_OVERRIDE_CPU_THROTTLE, false);
+ }
+
+ if ((flags & SYS_OVERRIDE_FAST_JETSAM) && (fast_jetsam_assert_cnt > 0)) {
+ system_override_callouts(SYS_OVERRIDE_FAST_JETSAM, false);
+ }
}
static __attribute__((noinline)) void
projects / apple / xnu.git / blobdiff