diff options
Diffstat (limited to 'arch/powerpc/mm/mmu_context_hash64.c')
| -rw-r--r-- | arch/powerpc/mm/mmu_context_hash64.c | 195 |
1 files changed, 1 insertions, 194 deletions
diff --git a/arch/powerpc/mm/mmu_context_hash64.c b/arch/powerpc/mm/mmu_context_hash64.c index ca988a3d5fb2..40677aa0190e 100644 --- a/arch/powerpc/mm/mmu_context_hash64.c +++ b/arch/powerpc/mm/mmu_context_hash64.c @@ -24,200 +24,7 @@ #include <asm/mmu_context.h> -#ifdef CONFIG_PPC_ICSWX -/* - * The processor and its L2 cache cause the icswx instruction to - * generate a COP_REQ transaction on PowerBus. The transaction has - * no address, and the processor does not perform an MMU access - * to authenticate the transaction. The command portion of the - * PowerBus COP_REQ transaction includes the LPAR_ID (LPID) and - * the coprocessor Process ID (PID), which the coprocessor compares - * to the authorized LPID and PID held in the coprocessor, to determine - * if the process is authorized to generate the transaction. - * The data of the COP_REQ transaction is 128-byte or less and is - * placed in cacheable memory on a 128-byte cache line boundary. - * - * The task to use a coprocessor should use use_cop() to allocate - * a coprocessor PID before executing icswx instruction. use_cop() - * also enables the coprocessor context switching. Drop_cop() is - * used to free the coprocessor PID. - * - * Example: - * Host Fabric Interface (HFI) is a PowerPC network coprocessor. - * Each HFI have multiple windows. Each HFI window serves as a - * network device sending to and receiving from HFI network. - * HFI immediate send function uses icswx instruction. The immediate - * send function allows small (single cache-line) packets be sent - * without using the regular HFI send FIFO and doorbell, which are - * much slower than immediate send. - * - * For each task intending to use HFI immediate send, the HFI driver - * calls use_cop() to obtain a coprocessor PID for the task. - * The HFI driver then allocate a free HFI window and save the - * coprocessor PID to the HFI window to allow the task to use the - * HFI window. - * - * The HFI driver repeatedly creates immediate send packets and - * issues icswx instruction to send data through the HFI window. - * The HFI compares the coprocessor PID in the CPU PID register - * to the PID held in the HFI window to determine if the transaction - * is allowed. - * - * When the task to release the HFI window, the HFI driver calls - * drop_cop() to release the coprocessor PID. - */ - -#define COP_PID_NONE 0 -#define COP_PID_MIN (COP_PID_NONE + 1) -#define COP_PID_MAX (0xFFFF) - -static DEFINE_SPINLOCK(mmu_context_acop_lock); -static DEFINE_IDA(cop_ida); - -void switch_cop(struct mm_struct *next) -{ - mtspr(SPRN_PID, next->context.cop_pid); - mtspr(SPRN_ACOP, next->context.acop); -} - -static int new_cop_pid(struct ida *ida, int min_id, int max_id, - spinlock_t *lock) -{ - int index; - int err; - -again: - if (!ida_pre_get(ida, GFP_KERNEL)) - return -ENOMEM; - - spin_lock(lock); - err = ida_get_new_above(ida, min_id, &index); - spin_unlock(lock); - - if (err == -EAGAIN) - goto again; - else if (err) - return err; - - if (index > max_id) { - spin_lock(lock); - ida_remove(ida, index); - spin_unlock(lock); - return -ENOMEM; - } - - return index; -} - -static void sync_cop(void *arg) -{ - struct mm_struct *mm = arg; - - if (mm == current->active_mm) - switch_cop(current->active_mm); -} - -/** - * Start using a coprocessor. - * @acop: mask of coprocessor to be used. - * @mm: The mm the coprocessor to associate with. Most likely current mm. - * - * Return a positive PID if successful. Negative errno otherwise. - * The returned PID will be fed to the coprocessor to determine if an - * icswx transaction is authenticated. - */ -int use_cop(unsigned long acop, struct mm_struct *mm) -{ - int ret; - - if (!cpu_has_feature(CPU_FTR_ICSWX)) - return -ENODEV; - - if (!mm || !acop) - return -EINVAL; - - /* The page_table_lock ensures mm_users won't change under us */ - spin_lock(&mm->page_table_lock); - spin_lock(mm->context.cop_lockp); - - if (mm->context.cop_pid == COP_PID_NONE) { - ret = new_cop_pid(&cop_ida, COP_PID_MIN, COP_PID_MAX, - &mmu_context_acop_lock); - if (ret < 0) - goto out; - - mm->context.cop_pid = ret; - } - mm->context.acop |= acop; - - sync_cop(mm); - - /* - * If this is a threaded process then there might be other threads - * running. We need to send an IPI to force them to pick up any - * change in PID and ACOP. - */ - if (atomic_read(&mm->mm_users) > 1) - smp_call_function(sync_cop, mm, 1); - - ret = mm->context.cop_pid; - -out: - spin_unlock(mm->context.cop_lockp); - spin_unlock(&mm->page_table_lock); - - return ret; -} -EXPORT_SYMBOL_GPL(use_cop); - -/** - * Stop using a coprocessor. - * @acop: mask of coprocessor to be stopped. - * @mm: The mm the coprocessor associated with. - */ -void drop_cop(unsigned long acop, struct mm_struct *mm) -{ - int free_pid = COP_PID_NONE; - - if (!cpu_has_feature(CPU_FTR_ICSWX)) - return; - - if (WARN_ON_ONCE(!mm)) - return; - - /* The page_table_lock ensures mm_users won't change under us */ - spin_lock(&mm->page_table_lock); - spin_lock(mm->context.cop_lockp); - - mm->context.acop &= ~acop; - - if ((!mm->context.acop) && (mm->context.cop_pid != COP_PID_NONE)) { - free_pid = mm->context.cop_pid; - mm->context.cop_pid = COP_PID_NONE; - } - - sync_cop(mm); - - /* - * If this is a threaded process then there might be other threads - * running. We need to send an IPI to force them to pick up any - * change in PID and ACOP. - */ - if (atomic_read(&mm->mm_users) > 1) - smp_call_function(sync_cop, mm, 1); - - if (free_pid != COP_PID_NONE) { - spin_lock(&mmu_context_acop_lock); - ida_remove(&cop_ida, free_pid); - spin_unlock(&mmu_context_acop_lock); - } - - spin_unlock(mm->context.cop_lockp); - spin_unlock(&mm->page_table_lock); -} -EXPORT_SYMBOL_GPL(drop_cop); - -#endif /* CONFIG_PPC_ICSWX */ +#include "icswx.h" static DEFINE_SPINLOCK(mmu_context_lock); static DEFINE_IDA(mmu_context_ida); |