Eric Lee / smarc-fsl-linux-kernel

30 Jul, 2009

1 commit

  • 3fc7b4b22   lib: export generic atomic64_t functions ... Browse Code »

    The generic atomic64_t implementation in lib/ did not export the functions
    it defined, which means that modules that use atomic64_t would not link on
    platforms (such as 32-bit powerpc). For example, trying to build a kernel
    with CONFIG_NET_RDS on such a platform would fail with:

    ERROR: "atomic64_read" [net/rds/rds.ko] undefined!
    ERROR: "atomic64_set" [net/rds/rds.ko] undefined!

    Fix this by exporting the atomic64_t functions to modules. (I export the
    entire API even if it's not all currently used by in-tree modules to avoid
    having to continue fixing this in dribs and drabs)

    Signed-off-by: Roland Dreier
    Acked-by: Paul Mackerras
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Roland Dreier
     

15 Jun, 2009

1 commit

  • 09d4e0edd   lib: Provide generic atomic64_t implementation ... Browse Code »

    Many processor architectures have no 64-bit atomic instructions, but
    we need atomic64_t in order to support the perf_counter subsystem.

    This adds an implementation of 64-bit atomic operations using hashed
    spinlocks to provide atomicity. For each atomic operation, the address
    of the atomic64_t variable is hashed to an index into an array of 16
    spinlocks. That spinlock is taken (with interrupts disabled) around the
    operation, which can then be coded non-atomically within the lock.

    On UP, all the spinlock manipulation goes away and we simply disable
    interrupts around each operation. In fact gcc eliminates the whole
    atomic64_lock variable as well.

    Signed-off-by: Paul Mackerras
    Signed-off-by: Benjamin Herrenschmidt

    Paul Mackerras