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![Eric W. Biederman](/assets/img/avatar_default.png)
Linus recently observed that if we did not worry about the padding member in struct siginfo it is only about 48 bytes, and 48 bytes is much nicer than 128 bytes for allocating on the stack and copying around in the kernel. The obvious thing of only adding the padding when userspace is including siginfo.h won't work as there are sigframe definitions in the kernel that embed struct siginfo. So split siginfo in two; kernel_siginfo and siginfo. Keeping the traditional name for the userspace definition. While the version that is used internally to the kernel and ultimately will not be padded to 128 bytes is called kernel_siginfo. The definition of struct kernel_siginfo I have put in include/signal_types.h A set of buildtime checks has been added to verify the two structures have the same field offsets. To make it easy to verify the change kernel_siginfo retains the same size as siginfo. The reduction in size comes in a following change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
130 lines
3.7 KiB
C
130 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _linux_POSIX_TIMERS_H
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#define _linux_POSIX_TIMERS_H
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#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/sched.h>
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#include <linux/timex.h>
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#include <linux/alarmtimer.h>
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struct siginfo;
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struct cpu_timer_list {
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struct list_head entry;
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u64 expires, incr;
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struct task_struct *task;
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int firing;
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};
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/*
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* Bit fields within a clockid:
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*
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* The most significant 29 bits hold either a pid or a file descriptor.
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*
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* Bit 2 indicates whether a cpu clock refers to a thread or a process.
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*
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* Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
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*
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* A clockid is invalid if bits 2, 1, and 0 are all set.
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*/
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#define CPUCLOCK_PID(clock) ((pid_t) ~((clock) >> 3))
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#define CPUCLOCK_PERTHREAD(clock) \
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(((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
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#define CPUCLOCK_PERTHREAD_MASK 4
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#define CPUCLOCK_WHICH(clock) ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
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#define CPUCLOCK_CLOCK_MASK 3
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#define CPUCLOCK_PROF 0
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#define CPUCLOCK_VIRT 1
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#define CPUCLOCK_SCHED 2
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#define CPUCLOCK_MAX 3
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#define CLOCKFD CPUCLOCK_MAX
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#define CLOCKFD_MASK (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)
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static inline clockid_t make_process_cpuclock(const unsigned int pid,
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const clockid_t clock)
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{
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return ((~pid) << 3) | clock;
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}
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static inline clockid_t make_thread_cpuclock(const unsigned int tid,
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const clockid_t clock)
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{
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return make_process_cpuclock(tid, clock | CPUCLOCK_PERTHREAD_MASK);
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}
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static inline clockid_t fd_to_clockid(const int fd)
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{
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return make_process_cpuclock((unsigned int) fd, CLOCKFD);
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}
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static inline int clockid_to_fd(const clockid_t clk)
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{
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return ~(clk >> 3);
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}
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#define REQUEUE_PENDING 1
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/**
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* struct k_itimer - POSIX.1b interval timer structure.
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* @list: List head for binding the timer to signals->posix_timers
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* @t_hash: Entry in the posix timer hash table
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* @it_lock: Lock protecting the timer
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* @kclock: Pointer to the k_clock struct handling this timer
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* @it_clock: The posix timer clock id
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* @it_id: The posix timer id for identifying the timer
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* @it_active: Marker that timer is active
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* @it_overrun: The overrun counter for pending signals
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* @it_overrun_last: The overrun at the time of the last delivered signal
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* @it_requeue_pending: Indicator that timer waits for being requeued on
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* signal delivery
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* @it_sigev_notify: The notify word of sigevent struct for signal delivery
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* @it_interval: The interval for periodic timers
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* @it_signal: Pointer to the creators signal struct
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* @it_pid: The pid of the process/task targeted by the signal
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* @it_process: The task to wakeup on clock_nanosleep (CPU timers)
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* @sigq: Pointer to preallocated sigqueue
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* @it: Union representing the various posix timer type
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* internals. Also used for rcu freeing the timer.
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*/
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struct k_itimer {
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struct list_head list;
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struct hlist_node t_hash;
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spinlock_t it_lock;
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const struct k_clock *kclock;
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clockid_t it_clock;
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timer_t it_id;
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int it_active;
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s64 it_overrun;
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s64 it_overrun_last;
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int it_requeue_pending;
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int it_sigev_notify;
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ktime_t it_interval;
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struct signal_struct *it_signal;
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union {
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struct pid *it_pid;
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struct task_struct *it_process;
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};
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struct sigqueue *sigq;
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union {
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struct {
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struct hrtimer timer;
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} real;
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struct cpu_timer_list cpu;
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struct {
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struct alarm alarmtimer;
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} alarm;
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struct rcu_head rcu;
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} it;
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};
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void run_posix_cpu_timers(struct task_struct *task);
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void posix_cpu_timers_exit(struct task_struct *task);
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void posix_cpu_timers_exit_group(struct task_struct *task);
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void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
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u64 *newval, u64 *oldval);
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void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
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void posixtimer_rearm(struct kernel_siginfo *info);
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#endif
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