powerpc: Split ICSWX ACOP and PID processing

Some processors, like embedded, that already have a PID register that
is managed by the system.  This patch separates the ACOP and PID
processing into separate files so that the ACOP code can be shared.

Signed-off-by: Jimi Xenidis <jimix@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

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);