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Commit 52d82ef1 authored by Jesper Nilsson's avatar Jesper Nilsson
Browse files

CRIS v32: Avoid work when switching between tasks with shared memory descriptors in mm/tlb.c 

There is no need to do all this work if they share memory descriptors.
Also, fix some minor whitespace and long lines.
parent 3d44305a

arch/cris/arch-v32/mm/tlb.c

+28 −28
Original line number Original line Diff line number Diff line
@@ -30,8 +30,8 @@ do { \ 
 * The TLB can host up to 256 different mm contexts at the same time. The running

 * The TLB can host up to 256 different mm contexts at the same time. The running

 * context is found in the PID register. Each TLB entry contains a page_id that

 * context is found in the PID register. Each TLB entry contains a page_id that

 * has to match the PID register to give a hit. page_id_map keeps track of which

 * has to match the PID register to give a hit. page_id_map keeps track of which

 * mm is assigned to which page_id, making sure it's known when to invalidate TLB

 * mm's is assigned to which page_id's, making sure it's known when to

 * entries.

 * invalidate TLB entries.

 *

 *

 * The last page_id is never running, it is used as an invalid page_id so that

 * The last page_id is never running, it is used as an invalid page_id so that

 * it's possible to make TLB entries that will nerver match.

 * it's possible to make TLB entries that will nerver match.
@@ -179,6 +179,7 @@ void 
switch_mm(struct mm_struct *prev, struct mm_struct *next,

switch_mm(struct mm_struct *prev, struct mm_struct *next,

	  struct task_struct *tsk)

	  struct task_struct *tsk)

{

{

	if (prev != next) {

		int cpu = smp_processor_id();

		int cpu = smp_processor_id();





		/* Make sure there is a MMU context. */

		/* Make sure there is a MMU context. */
@@ -188,20 +189,19 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, 
		spin_unlock(&mmu_context_lock);

		spin_unlock(&mmu_context_lock);





		/*

		/*

	 * Remember the pgd for the fault handlers. Keep a separate copy of it

		 * Remember the pgd for the fault handlers. Keep a seperate

	 * because current and active_mm might be invalid at points where

		 * copy of it because current and active_mm might be invalid

	 * there's still a need to derefer the pgd.

		 * at points where * there's still a need to derefer the pgd.

		 */

		 */

		per_cpu(current_pgd, cpu) = next->pgd;

		per_cpu(current_pgd, cpu) = next->pgd;





		/* Switch context in the MMU. */

		/* Switch context in the MMU. */

        if (tsk && task_thread_info(tsk))

		if (tsk && task_thread_info(tsk)) {

        {

			SPEC_REG_WR(SPEC_REG_PID, next->context.page_id |

          SPEC_REG_WR(SPEC_REG_PID, next->context.page_id | task_thread_info(tsk)->tls);

				task_thread_info(tsk)->tls);

        }

		} else {

        else

        {

			SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);

			SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);

		}

		}

	}

	}

}