Commit 7104e162 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'sparc32-SRMMU-fixes-for-SMP' 



Will Deacon says:

====================
sparc32 SRMMU fixes for SMP

Enabling SMP for sparc32 uncovered some issues in the SRMMU page-table
allocation code. One of these was introduced by me, but the other two
seem to have been there a while and are probably just exposed more
easily by my recent changes.

Tested on QEMU. I'm assuming these will go via David's tree.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents ee7c7953 1996d47a

arch/sparc/mm/srmmu.c

+11 −4
Original line number Diff line number Diff line
@@ -364,10 +364,13 @@ pgtable_t pte_alloc_one(struct mm_struct *mm) 
	if ((ptep = pte_alloc_one_kernel(mm)) == 0)

		return NULL;

	page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);

	if (!pgtable_pte_page_ctor(page)) {

		__free_page(page);

		return NULL;

	spin_lock(&mm->page_table_lock);

	if (page_ref_inc_return(page) == 2 && !pgtable_pte_page_ctor(page)) {

		page_ref_dec(page);

		ptep = NULL;

	}

	spin_unlock(&mm->page_table_lock);



	return ptep;

}
@@ -376,7 +379,11 @@ void pte_free(struct mm_struct *mm, pgtable_t ptep) 
	struct page *page;



	page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);

	spin_lock(&mm->page_table_lock);

	if (page_ref_dec_return(page) == 1)

		pgtable_pte_page_dtor(page);

	spin_unlock(&mm->page_table_lock);



	srmmu_free_nocache(ptep, SRMMU_PTE_TABLE_SIZE);

}

mm/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -192,6 +192,9 @@ config MEMORY_HOTREMOVE 
# Default to 4 for wider testing, though 8 might be more appropriate.

# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.

# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.

# SPARC32 allocates multiple pte tables within a single page, and therefore

# a per-page lock leads to problems when multiple tables need to be locked

# at the same time (e.g. copy_page_range()).

# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.

#

config SPLIT_PTLOCK_CPUS
@@ -199,6 +202,7 @@ config SPLIT_PTLOCK_CPUS 
	default "999999" if !MMU

	default "999999" if ARM && !CPU_CACHE_VIPT

	default "999999" if PARISC && !PA20

	default "999999" if SPARC32

	default "4"



config ARCH_ENABLE_SPLIT_PMD_PTLOCK

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