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author | Tony Luck <tony.luck@intel.com> | 2006-03-21 08:21:26 -0800 |
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committer | Tony Luck <tony.luck@intel.com> | 2006-03-21 08:21:26 -0800 |
commit | 409761bb6a06bd61e2d8e27a1af534371d9537ed (patch) | |
tree | 2c07068558092a01d70f737de9b9a34212a44d4b /arch/ia64/sn/kernel/sn2 | |
parent | a4e817ba24d2a52f0332c2ddcdbf77ddd6a92bbe (diff) | |
parent | e08e6c521355cd33e647b2f739885bc3050eead6 (diff) | |
download | op-kernel-dev-409761bb6a06bd61e2d8e27a1af534371d9537ed.zip op-kernel-dev-409761bb6a06bd61e2d8e27a1af534371d9537ed.tar.gz |
Pull sn2-mmio-writes into release branch
Hand-fixed conflicts:
include/asm-ia64/machvec_sn2.h
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/sn/kernel/sn2')
-rw-r--r-- | arch/ia64/sn/kernel/sn2/sn2_smp.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/ia64/sn/kernel/sn2/sn2_smp.c b/arch/ia64/sn/kernel/sn2/sn2_smp.c index b2e1e74..d9d306c 100644 --- a/arch/ia64/sn/kernel/sn2/sn2_smp.c +++ b/arch/ia64/sn/kernel/sn2/sn2_smp.c @@ -93,6 +93,27 @@ static inline unsigned long wait_piowc(void) return (ws & SH_PIO_WRITE_STATUS_WRITE_DEADLOCK_MASK) != 0; } +/** + * sn_migrate - SN-specific task migration actions + * @task: Task being migrated to new CPU + * + * SN2 PIO writes from separate CPUs are not guaranteed to arrive in order. + * Context switching user threads which have memory-mapped MMIO may cause + * PIOs to issue from seperate CPUs, thus the PIO writes must be drained + * from the previous CPU's Shub before execution resumes on the new CPU. + */ +void sn_migrate(struct task_struct *task) +{ + pda_t *last_pda = pdacpu(task_thread_info(task)->last_cpu); + volatile unsigned long *adr = last_pda->pio_write_status_addr; + unsigned long val = last_pda->pio_write_status_val; + + /* Drain PIO writes from old CPU's Shub */ + while (unlikely((*adr & SH_PIO_WRITE_STATUS_PENDING_WRITE_COUNT_MASK) + != val)) + cpu_relax(); +} + void sn_tlb_migrate_finish(struct mm_struct *mm) { /* flush_tlb_mm is inefficient if more than 1 users of mm */ |