extern unsigned long mmu_context_bmap[];
extern void get_new_mmu_context(struct mm_struct *mm);
+#ifdef CONFIG_SMP
+extern void smp_new_mmu_context_version(void);
+#else
+#define smp_new_mmu_context_version() do { } while (0)
+#endif
-/* Initialize a new mmu context. This is invoked when a new
- * address space instance (unique or shared) is instantiated.
- * This just needs to set mm->context to an invalid context.
- */
-#define init_new_context(__tsk, __mm) \
-({ unsigned long __pg = get_zeroed_page(GFP_KERNEL); \
- (__mm)->context.sparc64_ctx_val = 0UL; \
- (__mm)->context.sparc64_tsb = \
- (unsigned long *) __pg; \
- (__pg ? 0 : -ENOMEM); \
-})
-
-
-/* Destroy a dead context. This occurs when mmput drops the
- * mm_users count to zero, the mmaps have been released, and
- * all the page tables have been flushed. Our job is to destroy
- * any remaining processor-specific state, and in the sparc64
- * case this just means freeing up the mmu context ID held by
- * this task if valid.
- */
-#define destroy_context(__mm) \
-do { free_page((unsigned long)(__mm)->context.sparc64_tsb); \
- spin_lock(&ctx_alloc_lock); \
- if (CTX_VALID((__mm)->context)) { \
- unsigned long nr = CTX_NRBITS((__mm)->context); \
- mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63)); \
- } \
- spin_unlock(&ctx_alloc_lock); \
-} while(0)
-
-extern unsigned long tsb_context_switch(unsigned long pgd_pa, unsigned long *tsb);
+extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
+extern void destroy_context(struct mm_struct *mm);
+
+extern void __tsb_context_switch(unsigned long pgd_pa,
+ struct tsb_config *tsb_base,
+ struct tsb_config *tsb_huge,
+ unsigned long tsb_descr_pa);
+
+static inline void tsb_context_switch(struct mm_struct *mm)
+{
+ __tsb_context_switch(__pa(mm->pgd),
+ &mm->context.tsb_block[0],
+#ifdef CONFIG_HUGETLB_PAGE
+ (mm->context.tsb_block[1].tsb ?
+ &mm->context.tsb_block[1] :
+ NULL)
+#else
+ NULL
+#endif
+ , __pa(&mm->context.tsb_descr[0]));
+}
+
+extern void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long mm_rss);
+#ifdef CONFIG_SMP
+extern void smp_tsb_sync(struct mm_struct *mm);
+#else
+#define smp_tsb_sync(__mm) do { } while (0)
+#endif
/* Set MMU context in the actual hardware. */
#define load_secondary_context(__mm) \
- __asm__ __volatile__("stxa %0, [%1] %2\n\t" \
- "flush %%g6" \
- : /* No outputs */ \
- : "r" (CTX_HWBITS((__mm)->context)), \
- "r" (SECONDARY_CONTEXT), "i" (ASI_DMMU))
+ __asm__ __volatile__( \
+ "\n661: stxa %0, [%1] %2\n" \
+ " .section .sun4v_1insn_patch, \"ax\"\n" \
+ " .word 661b\n" \
+ " stxa %0, [%1] %3\n" \
+ " .previous\n" \
+ " flush %%g6\n" \
+ : /* No outputs */ \
+ : "r" (CTX_HWBITS((__mm)->context)), \
+ "r" (SECONDARY_CONTEXT), "i" (ASI_DMMU), "i" (ASI_MMU))
extern void __flush_tlb_mm(unsigned long, unsigned long);
-/* Switch the current MM context. */
+/* Switch the current MM context. Interrupts are disabled. */
static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
{
- unsigned long ctx_valid;
+ unsigned long ctx_valid, flags;
int cpu;
- /* Note: page_table_lock is used here to serialize switch_mm
- * and activate_mm, and their calls to get_new_mmu_context.
- * This use of page_table_lock is unrelated to its other uses.
- */
- spin_lock(&mm->page_table_lock);
+ spin_lock_irqsave(&mm->context.lock, flags);
ctx_valid = CTX_VALID(mm->context);
if (!ctx_valid)
get_new_mmu_context(mm);
- spin_unlock(&mm->page_table_lock);
- if (!ctx_valid || (old_mm != mm)) {
- load_secondary_context(mm);
- tsb_context_switch(__pa(mm->pgd),
- mm->context.sparc64_tsb);
- }
+ /* We have to be extremely careful here or else we will miss
+ * a TSB grow if we switch back and forth between a kernel
+ * thread and an address space which has it's TSB size increased
+ * on another processor.
+ *
+ * It is possible to play some games in order to optimize the
+ * switch, but the safest thing to do is to unconditionally
+ * perform the secondary context load and the TSB context switch.
+ *
+ * For reference the bad case is, for address space "A":
+ *
+ * CPU 0 CPU 1
+ * run address space A
+ * set cpu0's bits in cpu_vm_mask
+ * switch to kernel thread, borrow
+ * address space A via entry_lazy_tlb
+ * run address space A
+ * set cpu1's bit in cpu_vm_mask
+ * flush_tlb_pending()
+ * reset cpu_vm_mask to just cpu1
+ * TSB grow
+ * run address space A
+ * context was valid, so skip
+ * TSB context switch
+ *
+ * At that point cpu0 continues to use a stale TSB, the one from
+ * before the TSB grow performed on cpu1. cpu1 did not cross-call
+ * cpu0 to update it's TSB because at that point the cpu_vm_mask
+ * only had cpu1 set in it.
+ */
+ load_secondary_context(mm);
+ tsb_context_switch(mm);
- /* Even if (mm == old_mm) we _must_ check
- * the cpu_vm_mask. If we do not we could
- * corrupt the TLB state because of how
- * smp_flush_tlb_{page,range,mm} on sparc64
- * and lazy tlb switches work. -DaveM
+ /* Any time a processor runs a context on an address space
+ * for the first time, we must flush that context out of the
+ * local TLB.
*/
cpu = smp_processor_id();
if (!ctx_valid || !cpu_isset(cpu, mm->cpu_vm_mask)) {
__flush_tlb_mm(CTX_HWBITS(mm->context),
SECONDARY_CONTEXT);
}
+ spin_unlock_irqrestore(&mm->context.lock, flags);
}
#define deactivate_mm(tsk,mm) do { } while (0)
/* Activate a new MM instance for the current task. */
static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm)
{
+ unsigned long flags;
int cpu;
- /* Note: page_table_lock is used here to serialize switch_mm
- * and activate_mm, and their calls to get_new_mmu_context.
- * This use of page_table_lock is unrelated to its other uses.
- */
- spin_lock(&mm->page_table_lock);
+ spin_lock_irqsave(&mm->context.lock, flags);
if (!CTX_VALID(mm->context))
get_new_mmu_context(mm);
cpu = smp_processor_id();
if (!cpu_isset(cpu, mm->cpu_vm_mask))
cpu_set(cpu, mm->cpu_vm_mask);
- spin_unlock(&mm->page_table_lock);
load_secondary_context(mm);
__flush_tlb_mm(CTX_HWBITS(mm->context), SECONDARY_CONTEXT);
- tsb_context_switch(__pa(mm->pgd), mm->context.sparc64_tsb);
+ tsb_context_switch(mm);
+ spin_unlock_irqrestore(&mm->context.lock, flags);
}
#endif /* !(__ASSEMBLY__) */
projects / powerpc.git / blobdiff