Finish off the 'simple' futex2 syscall group by adding
sys_futex_requeue(). Unlike sys_futex_{wait,wake}() its arguments are
too numerous to fit into a regular syscall. As such, use struct
futex_waitv to pass the 'source' and 'destination' futexes to the
syscall.
This syscall implements what was previously known as FUTEX_CMP_REQUEUE
and uses {val, uaddr, flags} for source and {uaddr, flags} for
destination.
This design explicitly allows requeueing between different types of
futex by having a different flags word per uaddr.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230921105248.511860556@noisy.programming.kicks-ass.net
562 common fchmodat2 sys_fchmodat2
563 common futex_wake sys_futex_wake
564 common futex_wait sys_futex_wait
+565 common futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5)
#define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800)
-#define __NR_compat_syscalls 456
+#define __NR_compat_syscalls 457
#endif
#define __ARCH_WANT_SYS_CLONE
__SYSCALL(__NR_futex_wake, sys_futex_wake)
#define __NR_futex_wait 455
__SYSCALL(__NR_futex_wait, sys_futex_wait)
+#define __NR_futex_requeue 456
+__SYSCALL(__NR_futex_requeue, sys_futex_requeue)
/*
* Please add new compat syscalls above this comment and update
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
452 n32 fchmodat2 sys_fchmodat2
454 n32 futex_wake sys_futex_wake
455 n32 futex_wait sys_futex_wait
+456 n32 futex_requeue sys_futex_requeue
452 n64 fchmodat2 sys_fchmodat2
454 n64 futex_wake sys_futex_wake
455 n64 futex_wait sys_futex_wait
+456 n64 futex_requeue sys_futex_requeue
452 o32 fchmodat2 sys_fchmodat2
454 o32 futex_wake sys_futex_wake
455 o32 futex_wait sys_futex_wait
+456 o32 futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
452 i386 fchmodat2 sys_fchmodat2
454 i386 futex_wake sys_futex_wake
455 i386 futex_wait sys_futex_wait
+456 i386 futex_requeue sys_futex_requeue
453 64 map_shadow_stack sys_map_shadow_stack
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
#
# Due to a historical design error, certain syscalls are numbered differently
452 common fchmodat2 sys_fchmodat2
454 common futex_wake sys_futex_wake
455 common futex_wait sys_futex_wait
+456 common futex_requeue sys_futex_requeue
unsigned int flags, struct __kernel_timespec __user *timespec,
clockid_t clockid);
+asmlinkage long sys_futex_requeue(struct futex_waitv __user *waiters,
+ unsigned int flags, int nr_wake, int nr_requeue);
+
asmlinkage long sys_nanosleep(struct __kernel_timespec __user *rqtp,
struct __kernel_timespec __user *rmtp);
asmlinkage long sys_nanosleep_time32(struct old_timespec32 __user *rqtp,
__SYSCALL(__NR_futex_wake, sys_futex_wake)
#define __NR_futex_wait 455
__SYSCALL(__NR_futex_wait, sys_futex_wait)
+#define __NR_futex_requeue 456
+__SYSCALL(__NR_futex_requeue, sys_futex_requeue)
#undef __NR_syscalls
-#define __NR_syscalls 456
+#define __NR_syscalls 457
/*
* 32 bit systems traditionally used different
return ret;
}
+/*
+ * sys_futex_requeue - Requeue a waiter from one futex to another
+ * @waiters: array describing the source and destination futex
+ * @flags: unused
+ * @nr_wake: number of futexes to wake
+ * @nr_requeue: number of futexes to requeue
+ *
+ * Identical to the traditional FUTEX_CMP_REQUEUE op, except it is part of the
+ * futex2 family of calls.
+ */
+
+SYSCALL_DEFINE4(futex_requeue,
+ struct futex_waitv __user *, waiters,
+ unsigned int, flags,
+ int, nr_wake,
+ int, nr_requeue)
+{
+ struct futex_vector futexes[2];
+ u32 cmpval;
+ int ret;
+
+ if (flags)
+ return -EINVAL;
+
+ if (!waiters)
+ return -EINVAL;
+
+ ret = futex_parse_waitv(futexes, waiters, 2);
+ if (ret)
+ return ret;
+
+ cmpval = futexes[0].w.val;
+
+ return futex_requeue(u64_to_user_ptr(futexes[0].w.uaddr), futexes[0].w.flags,
+ u64_to_user_ptr(futexes[1].w.uaddr), futexes[1].w.flags,
+ nr_wake, nr_requeue, &cmpval, 0);
+}
+
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(set_robust_list,
struct compat_robust_list_head __user *, head,
COND_SYSCALL(futex_waitv);
COND_SYSCALL(futex_wake);
COND_SYSCALL(futex_wait);
+COND_SYSCALL(futex_requeue);
COND_SYSCALL(kexec_load);
COND_SYSCALL_COMPAT(kexec_load);
COND_SYSCALL(init_module);