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Subject[PATCH 10/17] sparc32/tlb: Fix __p*_free_tlb()
Just like regular pages, page directories need to observe the
following order:

1) unhook
2) TLB invalidate
3) free

to ensure it is safe against concurrent accesses.

Because Sparc32 has non-page based page directories, use a custom
table freeer.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/sparc/Kconfig | 1 +
arch/sparc/include/asm/pgalloc_32.h | 7 +++++--
arch/sparc/mm/srmmu.c | 28 ++++++++++++++++++++++++++++
3 files changed, 34 insertions(+), 2 deletions(-)

--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -57,6 +57,7 @@ config SPARC32
select CLZ_TAB
select HAVE_UID16
select OLD_SIGACTION
+ select MMU_GATHER_TABLE_FREE

config SPARC64
def_bool 64BIT
--- a/arch/sparc/include/asm/pgalloc_32.h
+++ b/arch/sparc/include/asm/pgalloc_32.h
@@ -12,6 +12,9 @@

struct page;

+extern void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int idx);
+extern void __tlb_remove_table(void *table);
+
void *srmmu_get_nocache(int size, int align);
void srmmu_free_nocache(void *addr, int size);

@@ -48,7 +51,7 @@ static inline void free_pmd_fast(pmd_t *
}

#define pmd_free(mm, pmd) free_pmd_fast(pmd)
-#define __pmd_free_tlb(tlb, pmd, addr) pmd_free((tlb)->mm, pmd)
+#define __pmd_free_tlb(tlb, pmd, addr) pgtable_free_tlb((tlb), (pmd), 1)

void pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *ptep);
#define pmd_pgtable(pmd) pmd_page(pmd)
@@ -72,6 +75,6 @@ static inline void free_pte_fast(pte_t *
#define pte_free_kernel(mm, pte) free_pte_fast(pte)

void pte_free(struct mm_struct * mm, pgtable_t pte);
-#define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte)
+#define __pte_free_tlb(tlb, pte, addr) pgtable_free_tlb((tlb), (pte), 0)

#endif /* _SPARC_PGALLOC_H */
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -38,6 +38,7 @@
#include <asm/page.h>
#include <asm/asi.h>
#include <asm/smp.h>
+#include <asm/tlb.h>
#include <asm/io.h>

/* Now the cpu specific definitions. */
@@ -1849,3 +1850,30 @@ void __init load_mmu(void)
sun4m_init_smp();
#endif
}
+
+#define TLB_IDX_MASK 1UL
+
+void __tlb_remove_table(void *table)
+{
+ void *dir = (void *)((unsigned long)table & ~TLB_IDX_MASK);
+ int idx = (unsigned long)table & TLB_IDX_MASK;
+
+ switch (idx) {
+ case 1: /* PMD */
+ pmd_free(NULL, dir);
+ break;
+ case 0: /* PTE */
+ pte_free(NULL, dir);
+ break;
+ }
+}
+
+void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int idx)
+{
+ unsigned long pgf = (unsigned long)table;
+ BUG_ON(idx > TLB_IDX_MASK);
+ BUG_ON(pgf & TLB_IDX_MASK);
+ pgf |= idx;
+ tlb_remove_table(tlb, (void *)pgf);
+}
+

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