diff options
Diffstat (limited to 'kernel/rseq.c')
| -rw-r--r-- | kernel/rseq.c | 561 |
1 files changed, 486 insertions, 75 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c index 395d8b002350..e75e3a5e312c 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -71,12 +71,16 @@ #define RSEQ_BUILD_SLOW_PATH #include <linux/debugfs.h> +#include <linux/hrtimer.h> +#include <linux/percpu.h> +#include <linux/prctl.h> #include <linux/ratelimit.h> #include <linux/rseq_entry.h> #include <linux/sched.h> #include <linux/syscalls.h> #include <linux/uaccess.h> #include <linux/types.h> +#include <linux/rseq.h> #include <asm/ptrace.h> #define CREATE_TRACE_POINTS @@ -120,7 +124,6 @@ void __rseq_trace_ip_fixup(unsigned long ip, unsigned long start_ip, } #endif /* CONFIG_TRACEPOINTS */ -#ifdef CONFIG_DEBUG_FS #ifdef CONFIG_RSEQ_STATS DEFINE_PER_CPU(struct rseq_stats, rseq_stats); @@ -138,6 +141,13 @@ static int rseq_stats_show(struct seq_file *m, void *p) stats.cs += data_race(per_cpu(rseq_stats.cs, cpu)); stats.clear += data_race(per_cpu(rseq_stats.clear, cpu)); stats.fixup += data_race(per_cpu(rseq_stats.fixup, cpu)); + if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSION)) { + stats.s_granted += data_race(per_cpu(rseq_stats.s_granted, cpu)); + stats.s_expired += data_race(per_cpu(rseq_stats.s_expired, cpu)); + stats.s_revoked += data_race(per_cpu(rseq_stats.s_revoked, cpu)); + stats.s_yielded += data_race(per_cpu(rseq_stats.s_yielded, cpu)); + stats.s_aborted += data_race(per_cpu(rseq_stats.s_aborted, cpu)); + } } seq_printf(m, "exit: %16lu\n", stats.exit); @@ -148,6 +158,13 @@ static int rseq_stats_show(struct seq_file *m, void *p) seq_printf(m, "cs: %16lu\n", stats.cs); seq_printf(m, "clear: %16lu\n", stats.clear); seq_printf(m, "fixup: %16lu\n", stats.fixup); + if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSION)) { + seq_printf(m, "sgrant: %16lu\n", stats.s_granted); + seq_printf(m, "sexpir: %16lu\n", stats.s_expired); + seq_printf(m, "srevok: %16lu\n", stats.s_revoked); + seq_printf(m, "syield: %16lu\n", stats.s_yielded); + seq_printf(m, "sabort: %16lu\n", stats.s_aborted); + } return 0; } @@ -205,21 +222,19 @@ static const struct file_operations debug_ops = { .release = single_release, }; +static void rseq_slice_ext_init(struct dentry *root_dir); + static int __init rseq_debugfs_init(void) { struct dentry *root_dir = debugfs_create_dir("rseq", NULL); debugfs_create_file("debug", 0644, root_dir, NULL, &debug_ops); rseq_stats_init(root_dir); + if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSION)) + rseq_slice_ext_init(root_dir); return 0; } __initcall(rseq_debugfs_init); -#endif /* CONFIG_DEBUG_FS */ - -static bool rseq_set_ids(struct task_struct *t, struct rseq_ids *ids, u32 node_id) -{ - return rseq_set_ids_get_csaddr(t, ids, node_id, NULL); -} static bool rseq_handle_cs(struct task_struct *t, struct pt_regs *regs) { @@ -238,14 +253,16 @@ efault: static void rseq_slowpath_update_usr(struct pt_regs *regs) { /* - * Preserve rseq state and user_irq state. The generic entry code - * clears user_irq on the way out, the non-generic entry - * architectures are not having user_irq. + * Preserve has_rseq and user_irq state. The generic entry code clears + * user_irq on the way out, the non-generic entry architectures are not + * setting user_irq. */ - const struct rseq_event evt_mask = { .has_rseq = true, .user_irq = true, }; + const struct rseq_event evt_mask = { + .has_rseq = RSEQ_HAS_RSEQ_VERSION_MASK, + .user_irq = true, + }; struct task_struct *t = current; struct rseq_ids ids; - u32 node_id; bool event; if (unlikely(t->flags & PF_EXITING)) @@ -281,9 +298,9 @@ static void rseq_slowpath_update_usr(struct pt_regs *regs) if (!event) return; - node_id = cpu_to_node(ids.cpu_id); + ids.node_id = cpu_to_node(ids.cpu_id); - if (unlikely(!rseq_update_usr(t, regs, &ids, node_id))) { + if (unlikely(!rseq_update_usr(t, regs, &ids))) { /* * Clear the errors just in case this might survive magically, but * leave the rest intact. @@ -315,8 +332,9 @@ void __rseq_handle_slowpath(struct pt_regs *regs) void __rseq_signal_deliver(int sig, struct pt_regs *regs) { rseq_stat_inc(rseq_stats.signal); + /* - * Don't update IDs, they are handled on exit to user if + * Don't update IDs yet, they are handled on exit to user if * necessary. The important thing is to abort a critical section of * the interrupted context as after this point the instruction * pointer in @regs points to the signal handler. @@ -329,6 +347,13 @@ void __rseq_signal_deliver(int sig, struct pt_regs *regs) current->rseq.event.error = 0; force_sigsegv(sig); } + + /* + * In legacy mode, force the update of IDs before returning to user + * space to stay compatible. + */ + if (!rseq_v2(current)) + rseq_force_update(); } /* @@ -364,19 +389,22 @@ void rseq_syscall(struct pt_regs *regs) static bool rseq_reset_ids(void) { - struct rseq_ids ids = { - .cpu_id = RSEQ_CPU_ID_UNINITIALIZED, - .mm_cid = 0, - }; + struct rseq __user *rseq = current->rseq.usrptr; /* * If this fails, terminate it because this leaves the kernel in * stupid state as exit to user space will try to fixup the ids * again. */ - if (rseq_set_ids(current, &ids, 0)) - return true; + scoped_user_rw_access(rseq, efault) { + unsafe_put_user(0, &rseq->cpu_id_start, efault); + unsafe_put_user(RSEQ_CPU_ID_UNINITIALIZED, &rseq->cpu_id, efault); + unsafe_put_user(0, &rseq->node_id, efault); + unsafe_put_user(0, &rseq->mm_cid, efault); + } + return true; +efault: force_sig(SIGSEGV); return false; } @@ -384,61 +412,30 @@ static bool rseq_reset_ids(void) /* The original rseq structure size (including padding) is 32 bytes. */ #define ORIG_RSEQ_SIZE 32 -/* - * sys_rseq - setup restartable sequences for caller thread. - */ -SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig) +static long rseq_register(struct rseq __user * rseq, u32 rseq_len, int flags, u32 sig) { - if (flags & RSEQ_FLAG_UNREGISTER) { - if (flags & ~RSEQ_FLAG_UNREGISTER) - return -EINVAL; - /* Unregister rseq for current thread. */ - if (current->rseq.usrptr != rseq || !current->rseq.usrptr) - return -EINVAL; - if (rseq_len != current->rseq.len) - return -EINVAL; - if (current->rseq.sig != sig) - return -EPERM; - if (!rseq_reset_ids()) - return -EFAULT; - rseq_reset(current); - return 0; - } - - if (unlikely(flags)) - return -EINVAL; + u32 rseqfl = 0; + u8 version = 1; - if (current->rseq.usrptr) { - /* - * If rseq is already registered, check whether - * the provided address differs from the prior - * one. - */ - if (current->rseq.usrptr != rseq || rseq_len != current->rseq.len) - return -EINVAL; - if (current->rseq.sig != sig) - return -EPERM; - /* Already registered. */ - return -EBUSY; - } + if (!access_ok(rseq, rseq_len)) + return -EFAULT; /* - * If there was no rseq previously registered, ensure the provided rseq - * is properly aligned, as communcated to user-space through the ELF - * auxiliary vector AT_RSEQ_ALIGN. If rseq_len is the original rseq - * size, the required alignment is the original struct rseq alignment. - * - * In order to be valid, rseq_len is either the original rseq size, or - * large enough to contain all supported fields, as communicated to - * user-space through the ELF auxiliary vector AT_RSEQ_FEATURE_SIZE. + * Architectures, which use the generic IRQ entry code (at least) enable + * registrations with a size greater than the original v1 fixed sized + * @rseq_len, which has been validated already to utilize the optimized + * v2 ABI mode which also enables extended RSEQ features beyond MMCID. */ - if (rseq_len < ORIG_RSEQ_SIZE || - (rseq_len == ORIG_RSEQ_SIZE && !IS_ALIGNED((unsigned long)rseq, ORIG_RSEQ_SIZE)) || - (rseq_len != ORIG_RSEQ_SIZE && (!IS_ALIGNED((unsigned long)rseq, __alignof__(*rseq)) || - rseq_len < offsetof(struct rseq, end)))) - return -EINVAL; - if (!access_ok(rseq, rseq_len)) - return -EFAULT; + if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY) && rseq_len > ORIG_RSEQ_SIZE) + version = 2; + + if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSION) && version > 1) { + if (rseq_slice_extension_enabled()) { + rseqfl |= RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE; + if (flags & RSEQ_FLAG_SLICE_EXT_DEFAULT_ON) + rseqfl |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED; + } + } scoped_user_write_access(rseq, efault) { /* @@ -449,11 +446,21 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32 * clearing the fields. Don't bother reading it, just reset it. */ unsafe_put_user(0UL, &rseq->rseq_cs, efault); + unsafe_put_user(rseqfl, &rseq->flags, efault); /* Initialize IDs in user space */ unsafe_put_user(RSEQ_CPU_ID_UNINITIALIZED, &rseq->cpu_id_start, efault); unsafe_put_user(RSEQ_CPU_ID_UNINITIALIZED, &rseq->cpu_id, efault); unsafe_put_user(0U, &rseq->node_id, efault); unsafe_put_user(0U, &rseq->mm_cid, efault); + + /* + * All fields past mm_cid are only valid for non-legacy v2 + * registrations. + */ + if (version > 1) { + if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSION)) + unsafe_put_user(0U, &rseq->slice_ctrl.all, efault); + } } /* @@ -464,15 +471,419 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32 current->rseq.len = rseq_len; current->rseq.sig = sig; +#ifdef CONFIG_RSEQ_SLICE_EXTENSION + current->rseq.slice.state.enabled = !!(rseqfl & RSEQ_CS_FLAG_SLICE_EXT_ENABLED); +#endif + /* - * If rseq was previously inactive, and has just been - * registered, ensure the cpu_id_start and cpu_id fields - * are updated before returning to user-space. + * Ensure the cpu_id_start and cpu_id fields are updated before + * returning to user-space. */ - current->rseq.event.has_rseq = true; + current->rseq.event.has_rseq = version; rseq_force_update(); return 0; efault: return -EFAULT; } + +static long rseq_unregister(struct rseq __user * rseq, u32 rseq_len, int flags, u32 sig) +{ + if (flags & ~RSEQ_FLAG_UNREGISTER) + return -EINVAL; + if (current->rseq.usrptr != rseq || !current->rseq.usrptr) + return -EINVAL; + if (rseq_len != current->rseq.len) + return -EINVAL; + if (current->rseq.sig != sig) + return -EPERM; + if (!rseq_reset_ids()) + return -EFAULT; + rseq_reset(current); + return 0; +} + +static long rseq_reregister(struct rseq __user * rseq, u32 rseq_len, u32 sig) +{ + /* + * If rseq is already registered, check whether the provided address + * differs from the prior one. + */ + if (current->rseq.usrptr != rseq || rseq_len != current->rseq.len) + return -EINVAL; + if (current->rseq.sig != sig) + return -EPERM; + /* Already registered. */ + return -EBUSY; +} + +static bool rseq_length_valid(struct rseq __user *rseq, unsigned int rseq_len) +{ + /* + * Ensure the provided rseq is properly aligned, as communicated to + * user-space through the ELF auxiliary vector AT_RSEQ_ALIGN. If + * rseq_len is the original rseq size, the required alignment is the + * original struct rseq alignment. + * + * In order to be valid, rseq_len is either the original rseq size, or + * large enough to contain all supported fields, as communicated to + * user-space through the ELF auxiliary vector AT_RSEQ_FEATURE_SIZE. + */ + if (rseq_len < ORIG_RSEQ_SIZE) + return false; + + if (rseq_len == ORIG_RSEQ_SIZE) + return IS_ALIGNED((unsigned long)rseq, ORIG_RSEQ_SIZE); + + return IS_ALIGNED((unsigned long)rseq, rseq_alloc_align()) && + rseq_len >= offsetof(struct rseq, end); +} + +#define RSEQ_FLAGS_SUPPORTED (RSEQ_FLAG_SLICE_EXT_DEFAULT_ON) + +/* + * sys_rseq - Register or unregister restartable sequences for the caller thread. + */ +SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig) +{ + if (flags & RSEQ_FLAG_UNREGISTER) + return rseq_unregister(rseq, rseq_len, flags, sig); + + if (unlikely(flags & ~RSEQ_FLAGS_SUPPORTED)) + return -EINVAL; + + if (current->rseq.usrptr) + return rseq_reregister(rseq, rseq_len, sig); + + if (!rseq_length_valid(rseq, rseq_len)) + return -EINVAL; + + return rseq_register(rseq, rseq_len, flags, sig); +} + +#ifdef CONFIG_RSEQ_SLICE_EXTENSION +struct slice_timer { + struct hrtimer timer; + void *cookie; +}; + +static const unsigned int rseq_slice_ext_nsecs_min = 5 * NSEC_PER_USEC; +static const unsigned int rseq_slice_ext_nsecs_max = 50 * NSEC_PER_USEC; +unsigned int rseq_slice_ext_nsecs __read_mostly = rseq_slice_ext_nsecs_min; +static DEFINE_PER_CPU(struct slice_timer, slice_timer); +DEFINE_STATIC_KEY_TRUE(rseq_slice_extension_key); + +/* + * When the timer expires and the task is still in user space, the return + * from interrupt will revoke the grant and schedule. If the task already + * entered the kernel via a syscall and the timer fires before the syscall + * work was able to cancel it, then depending on the preemption model this + * will either reschedule on return from interrupt or in the syscall work + * below. + */ +static enum hrtimer_restart rseq_slice_expired(struct hrtimer *tmr) +{ + struct slice_timer *st = container_of(tmr, struct slice_timer, timer); + + /* + * Validate that the task which armed the timer is still on the + * CPU. It could have been scheduled out without canceling the + * timer. + */ + if (st->cookie == current && current->rseq.slice.state.granted) { + rseq_stat_inc(rseq_stats.s_expired); + set_need_resched_current(); + } + return HRTIMER_NORESTART; +} + +bool __rseq_arm_slice_extension_timer(void) +{ + struct slice_timer *st = this_cpu_ptr(&slice_timer); + struct task_struct *curr = current; + + lockdep_assert_irqs_disabled(); + + /* + * This check prevents a task, which got a time slice extension + * granted, from exceeding the maximum scheduling latency when the + * grant expired before going out to user space. Don't bother to + * clear the grant here, it will be cleaned up automatically before + * going out to user space after being scheduled back in. + */ + if ((unlikely(curr->rseq.slice.expires < ktime_get_mono_fast_ns()))) { + set_need_resched_current(); + return true; + } + + /* + * Store the task pointer as a cookie for comparison in the timer + * function. This is safe as the timer is CPU local and cannot be + * in the expiry function at this point. + */ + st->cookie = curr; + hrtimer_start(&st->timer, curr->rseq.slice.expires, HRTIMER_MODE_ABS_PINNED_HARD); + /* Arm the syscall entry work */ + set_task_syscall_work(curr, SYSCALL_RSEQ_SLICE); + return false; +} + +static void rseq_cancel_slice_extension_timer(void) +{ + struct slice_timer *st = this_cpu_ptr(&slice_timer); + + /* + * st->cookie can be safely read as preemption is disabled and the + * timer is CPU local. + * + * As this is most probably the first expiring timer, the cancel is + * expensive as it has to reprogram the hardware, but that's less + * expensive than going through a full hrtimer_interrupt() cycle + * for nothing. + * + * hrtimer_try_to_cancel() is sufficient here as the timer is CPU + * local and once the hrtimer code disabled interrupts the timer + * callback cannot be running. + */ + if (st->cookie == current) + hrtimer_try_to_cancel(&st->timer); +} + +static inline void rseq_slice_set_need_resched(struct task_struct *curr) +{ + /* + * The interrupt guard is required to prevent inconsistent state in + * this case: + * + * set_tsk_need_resched() + * --> Interrupt + * wakeup() + * set_tsk_need_resched() + * set_preempt_need_resched() + * schedule_on_return() + * clear_tsk_need_resched() + * clear_preempt_need_resched() + * set_preempt_need_resched() <- Inconsistent state + * + * This is safe vs. a remote set of TIF_NEED_RESCHED because that + * only sets the already set bit and does not create inconsistent + * state. + */ + scoped_guard(irq) + set_need_resched_current(); +} + +static void rseq_slice_validate_ctrl(u32 expected) +{ + u32 __user *sctrl = ¤t->rseq.usrptr->slice_ctrl.all; + u32 uval; + + if (get_user(uval, sctrl) || uval != expected) + force_sig(SIGSEGV); +} + +/* + * Invoked from syscall entry if a time slice extension was granted and the + * kernel did not clear it before user space left the critical section. + * + * While the recommended way to relinquish the CPU side effect free is + * rseq_slice_yield(2), any syscall within a granted slice terminates the + * grant and immediately reschedules if required. This supports onion layer + * applications, where the code requesting the grant cannot control the + * code within the critical section. + */ +void rseq_syscall_enter_work(long syscall) +{ + struct task_struct *curr = current; + struct rseq_slice_ctrl ctrl = { .granted = curr->rseq.slice.state.granted }; + + clear_task_syscall_work(curr, SYSCALL_RSEQ_SLICE); + + if (static_branch_unlikely(&rseq_debug_enabled)) + rseq_slice_validate_ctrl(ctrl.all); + + /* + * The kernel might have raced, revoked the grant and updated + * userspace, but kept the SLICE work set. + */ + if (!ctrl.granted) + return; + + /* + * Required to stabilize the per CPU timer pointer and to make + * set_tsk_need_resched() correct on PREEMPT[RT] kernels. + * + * Leaving the scope will reschedule on preemption models FULL, + * LAZY and RT if necessary. + */ + scoped_guard(preempt) { + rseq_cancel_slice_extension_timer(); + /* + * Now that preemption is disabled, quickly check whether + * the task was already rescheduled before arriving here. + */ + if (!curr->rseq.event.sched_switch) { + rseq_slice_set_need_resched(curr); + + if (syscall == __NR_rseq_slice_yield) { + rseq_stat_inc(rseq_stats.s_yielded); + /* Update the yielded state for syscall return */ + curr->rseq.slice.yielded = 1; + } else { + rseq_stat_inc(rseq_stats.s_aborted); + } + } + } + /* Reschedule on NONE/VOLUNTARY preemption models */ + cond_resched(); + + /* Clear the grant in kernel state and user space */ + curr->rseq.slice.state.granted = false; + if (put_user(0U, &curr->rseq.usrptr->slice_ctrl.all)) + force_sig(SIGSEGV); +} + +int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3) +{ + switch (arg2) { + case PR_RSEQ_SLICE_EXTENSION_GET: + if (arg3) + return -EINVAL; + return current->rseq.slice.state.enabled ? PR_RSEQ_SLICE_EXT_ENABLE : 0; + + case PR_RSEQ_SLICE_EXTENSION_SET: { + u32 rflags, valid = RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE; + bool enable = !!(arg3 & PR_RSEQ_SLICE_EXT_ENABLE); + + if (arg3 & ~PR_RSEQ_SLICE_EXT_ENABLE) + return -EINVAL; + if (!rseq_slice_extension_enabled()) + return -ENOTSUPP; + if (!current->rseq.usrptr) + return -ENXIO; + if (!rseq_v2(current)) + return -ENOTSUPP; + + /* No change? */ + if (enable == !!current->rseq.slice.state.enabled) + return 0; + + if (get_user(rflags, ¤t->rseq.usrptr->flags)) + goto die; + + if (current->rseq.slice.state.enabled) + valid |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED; + + if ((rflags & valid) != valid) + goto die; + + rflags &= ~RSEQ_CS_FLAG_SLICE_EXT_ENABLED; + rflags |= RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE; + if (enable) + rflags |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED; + + if (put_user(rflags, ¤t->rseq.usrptr->flags)) + goto die; + + current->rseq.slice.state.enabled = enable; + return 0; + } + default: + return -EINVAL; + } +die: + force_sig(SIGSEGV); + return -EFAULT; +} + +/** + * sys_rseq_slice_yield - yield the current processor side effect free if a + * task granted with a time slice extension is done with + * the critical work before being forced out. + * + * Return: 1 if the task successfully yielded the CPU within the granted slice. + * 0 if the slice extension was either never granted or was revoked by + * going over the granted extension, using a syscall other than this one + * or being scheduled out earlier due to a subsequent interrupt. + * + * The syscall does not schedule because the syscall entry work immediately + * relinquishes the CPU and schedules if required. + */ +SYSCALL_DEFINE0(rseq_slice_yield) +{ + int yielded = !!current->rseq.slice.yielded; + + current->rseq.slice.yielded = 0; + return yielded; +} + +static int rseq_slice_ext_show(struct seq_file *m, void *p) +{ + seq_printf(m, "%d\n", rseq_slice_ext_nsecs); + return 0; +} + +static ssize_t rseq_slice_ext_write(struct file *file, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + unsigned int nsecs; + + if (kstrtouint_from_user(ubuf, count, 10, &nsecs)) + return -EINVAL; + + if (nsecs < rseq_slice_ext_nsecs_min) + return -ERANGE; + + if (nsecs > rseq_slice_ext_nsecs_max) + return -ERANGE; + + rseq_slice_ext_nsecs = nsecs; + + return count; +} + +static int rseq_slice_ext_open(struct inode *inode, struct file *file) +{ + return single_open(file, rseq_slice_ext_show, inode->i_private); +} + +static const struct file_operations slice_ext_ops = { + .open = rseq_slice_ext_open, + .read = seq_read, + .write = rseq_slice_ext_write, + .llseek = seq_lseek, + .release = single_release, +}; + +static void rseq_slice_ext_init(struct dentry *root_dir) +{ + debugfs_create_file("slice_ext_nsec", 0644, root_dir, NULL, &slice_ext_ops); +} + +static int __init rseq_slice_cmdline(char *str) +{ + bool on; + + if (kstrtobool(str, &on)) + return 0; + + if (!on) + static_branch_disable(&rseq_slice_extension_key); + return 1; +} +__setup("rseq_slice_ext=", rseq_slice_cmdline); + +static int __init rseq_slice_init(void) +{ + unsigned int cpu; + + for_each_possible_cpu(cpu) { + hrtimer_setup(per_cpu_ptr(&slice_timer.timer, cpu), rseq_slice_expired, + CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED_HARD); + } + return 0; +} +device_initcall(rseq_slice_init); +#else +static void rseq_slice_ext_init(struct dentry *root_dir) { } +#endif /* CONFIG_RSEQ_SLICE_EXTENSION */ |