Add new fields to the mm_context structure to support shared context.
Instead of a simple context ID, add a pointer to a structure with a
reference count. This is needed as multiple tasks will share the
context ID.
Pages using the shared context ID will reside in a separate TSB. So
changes are made to increase the number of TSBs as well. Note that
only support for context sharing of huge pages is provided. Therefore,
no base page size shared context TSB.
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
arch/sparc/include/asm/mmu_64.h | 36 +++++++++++++++++++++++++++++----
arch/sparc/include/asm/mmu_context_64.h | 8 ++++----
2 files changed, 36 insertions(+), 8 deletions(-)
diff --git a/arch/sparc/include/asm/mmu_64.h b/arch/sparc/include/asm/mmu_64.h
index f7de0db..edf8663 100644
--- a/arch/sparc/include/asm/mmu_64.h
+++ b/arch/sparc/include/asm/mmu_64.h
@@ -57,6 +57,13 @@
(!(((__ctx.sparc64_ctx_val) ^ tlb_context_cache) & CTX_VERSION_MASK))
#define CTX_HWBITS(__ctx) ((__ctx.sparc64_ctx_val) & CTX_HW_MASK)
#define CTX_NRBITS(__ctx) ((__ctx.sparc64_ctx_val) & CTX_NR_MASK)
+#define SHARED_CTX_VALID(__ctx) (__ctx.shared_ctx && \
+ (!(((__ctx.shared_ctx->shared_ctx_val) ^ tlb_context_cache) & \
+ CTX_VERSION_MASK)))
+#define SHARED_CTX_HWBITS(__ctx) \
+ ((__ctx.shared_ctx->shared_ctx_val) & CTX_HW_MASK)
+#define SHARED_CTX_NRBITS(__ctx) \
+ ((__ctx.shared_ctx->shared_ctx_val) & CTX_NR_MASK)
#ifndef __ASSEMBLY__
@@ -80,24 +87,45 @@ struct tsb_config {
unsigned long tsb_map_pte;
};
-#define MM_TSB_BASE 0
+#if defined(CONFIG_SHARED_MMU_CTX)
+struct shared_mmu_ctx {
+ atomic_t refcount;
+ unsigned long shared_ctx_val;
+};
+
+#define MM_TSB_HUGE_SHARED 0
+#define MM_TSB_BASE 1
+#define MM_TSB_HUGE 2
+#define MM_NUM_TSBS 3
+#else
+#define MM_TSB_BASE 0
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
-#define MM_TSB_HUGE 1
-#define MM_NUM_TSBS 2
+#define MM_TSB_HUGE 1
+#define MM_TSB_HUGE_SHARED 1 /* Simplifies conditions in code */
+#define MM_NUM_TSBS 2
#else
-#define MM_NUM_TSBS 1
+#define MM_NUM_TSBS 1
+#endif
#endif
typedef struct {
spinlock_t lock;
unsigned long sparc64_ctx_val;
+#if defined(CONFIG_SHARED_MMU_CTX)
+ struct shared_mmu_ctx *shared_ctx;
+ unsigned long shared_hugetlb_pte_count;
+#endif
unsigned long hugetlb_pte_count;
unsigned long thp_pte_count;
struct tsb_config tsb_block[MM_NUM_TSBS];
struct hv_tsb_descr tsb_descr[MM_NUM_TSBS];
} mm_context_t;
+#define mm_shared_ctx_val(mm) \
+ ((mm)->context.shared_ctx ? \
+ (mm)->context.shared_ctx->shared_ctx_val : 0UL)
+
#endif /* !__ASSEMBLY__ */
#define TSB_CONFIG_TSB 0x00
diff --git a/arch/sparc/include/asm/mmu_context_64.h b/arch/sparc/include/asm/mmu_context_64.h
index b84be67..d031799 100644
--- a/arch/sparc/include/asm/mmu_context_64.h
+++ b/arch/sparc/include/asm/mmu_context_64.h
@@ -35,15 +35,15 @@ void __tsb_context_switch(unsigned long pgd_pa,
static inline void tsb_context_switch(struct mm_struct *mm)
{
__tsb_context_switch(__pa(mm->pgd),
- &mm->context.tsb_block[0],
+ &mm->context.tsb_block[MM_TSB_BASE],
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
- (mm->context.tsb_block[1].tsb ?
- &mm->context.tsb_block[1] :
+ (mm->context.tsb_block[MM_TSB_HUGE].tsb ?
+ &mm->context.tsb_block[MM_TSB_HUGE] :
NULL)
#else
NULL
#endif
- , __pa(&mm->context.tsb_descr[0]));
+ , __pa(&mm->context.tsb_descr[MM_TSB_BASE]));
}
void tsb_grow(struct mm_struct *mm,
--
2.7.4
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