[MIPS] MT: Improved multithreading support.

    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 109 insertions, 3 deletions

diff --git a/include/asm-mips/mmu_context.h b/include/asm-mips/mmu_context.h
index 61cf22588137..6e09f4c87211 100644
--- a/include/asm-mips/mmu_context.h
+++ b/include/asm-mips/mmu_context.h
@@ -17,6 +17,10 @@
 #include <linux/slab.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
+#ifdef CONFIG_MIPS_MT_SMTC
+#include <asm/mipsmtregs.h>
+#include <asm/smtc.h>
+#endif /* SMTC */
 
 /*
  * For the fast tlb miss handlers, we keep a per cpu array of pointers
@@ -54,6 +58,14 @@ extern unsigned long pgd_current[];
 #define ASID_INC        0x1
 #define ASID_MASK       0xfff
 
+/* SMTC/34K debug hack - but maybe we'll keep it */
+#elif defined(CONFIG_MIPS_MT_SMTC)
+
+#define ASID_INC        0x1
+extern unsigned long smtc_asid_mask;
+#define ASID_MASK       (smtc_asid_mask)
+#define HW_ASID_MASK    0xff
+/* End SMTC/34K debug hack */
 #else /* FIXME: not correct for R6000 */
 
 #define ASID_INC        0x1
@@ -76,6 +88,8 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 #define ASID_VERSION_MASK  ((unsigned long)~(ASID_MASK|(ASID_MASK-1)))
 #define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1)
 
+#ifndef CONFIG_MIPS_MT_SMTC
+/* Normal, classic MIPS get_new_mmu_context */
 static inline void
 get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
 {
@@ -91,6 +105,12 @@ get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 }
 
+#else /* CONFIG_MIPS_MT_SMTC */
+
+#define get_new_mmu_context(mm,cpu) smtc_get_new_mmu_context((mm),(cpu))
+
+#endif /* CONFIG_MIPS_MT_SMTC */
+
 /*
  * Initialize the context related info for a new mm_struct
  * instance.
@@ -111,14 +131,46 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 {
         unsigned int cpu = smp_processor_id();
         unsigned long flags;
-
+#ifdef CONFIG_MIPS_MT_SMTC
+        unsigned long oldasid;
+        unsigned long mtflags;
+        int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
         local_irq_save(flags);
+        mtflags = dvpe();
+#else /* Not SMTC */
+        local_irq_save(flags);
+#endif /* CONFIG_MIPS_MT_SMTC */
 
         /* Check if our ASID is of an older version and thus invalid */
         if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & ASID_VERSION_MASK)
                 get_new_mmu_context(next, cpu);
-
+#ifdef CONFIG_MIPS_MT_SMTC
+        /*
+         * If the EntryHi ASID being replaced happens to be
+         * the value flagged at ASID recycling time as having
+         * an extended life, clear the bit showing it being
+         * in use by this "CPU", and if that's the last bit,
+         * free up the ASID value for use and flush any old
+         * instances of it from the TLB.
+         */
+        oldasid = (read_c0_entryhi() & ASID_MASK);
+        if(smtc_live_asid[mytlb][oldasid]) {
+                smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
+                if(smtc_live_asid[mytlb][oldasid] == 0)
+                        smtc_flush_tlb_asid(oldasid);
+        }
+        /*
+         * Tread softly on EntryHi, and so long as we support
+         * having ASID_MASK smaller than the hardware maximum,
+         * make sure no "soft" bits become "hard"...
+         */
+        write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
+                        | (cpu_context(cpu, next) & ASID_MASK));
+        ehb(); /* Make sure it propagates to TCStatus */
+        evpe(mtflags);
+#else
         write_c0_entryhi(cpu_context(cpu, next));
+#endif /* CONFIG_MIPS_MT_SMTC */
         TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 
         /*
@@ -151,12 +203,34 @@ activate_mm(struct mm_struct *prev, struct mm_struct *next)
         unsigned long flags;
         unsigned int cpu = smp_processor_id();
 
+#ifdef CONFIG_MIPS_MT_SMTC
+        unsigned long oldasid;
+        unsigned long mtflags;
+        int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
+#endif /* CONFIG_MIPS_MT_SMTC */
+
         local_irq_save(flags);
 
         /* Unconditionally get a new ASID.  */
         get_new_mmu_context(next, cpu);
 
+#ifdef CONFIG_MIPS_MT_SMTC
+        /* See comments for similar code above */
+        mtflags = dvpe();
+        oldasid = read_c0_entryhi() & ASID_MASK;
+        if(smtc_live_asid[mytlb][oldasid]) {
+                smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
+                if(smtc_live_asid[mytlb][oldasid] == 0)
+                         smtc_flush_tlb_asid(oldasid);
+        }
+        /* See comments for similar code above */
+        write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
+                         (cpu_context(cpu, next) & ASID_MASK));
+        ehb(); /* Make sure it propagates to TCStatus */
+        evpe(mtflags);
+#else
         write_c0_entryhi(cpu_context(cpu, next));
+#endif /* CONFIG_MIPS_MT_SMTC */
         TLBMISS_HANDLER_SETUP_PGD(next->pgd);
 
         /* mark mmu ownership change */
@@ -174,17 +248,49 @@ static inline void
 drop_mmu_context(struct mm_struct *mm, unsigned cpu)
 {
         unsigned long flags;
+#ifdef CONFIG_MIPS_MT_SMTC
+        unsigned long oldasid;
+        /* Can't use spinlock because called from TLB flush within DVPE */
+        unsigned int prevvpe;
+        int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
+#endif /* CONFIG_MIPS_MT_SMTC */
 
         local_irq_save(flags);
 
         if (cpu_isset(cpu, mm->cpu_vm_mask))  {
                 get_new_mmu_context(mm, cpu);
+#ifdef CONFIG_MIPS_MT_SMTC
+                /* See comments for similar code above */
+                prevvpe = dvpe();
+                oldasid = (read_c0_entryhi() & ASID_MASK);
+                if(smtc_live_asid[mytlb][oldasid]) {
+                  smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
+                  if(smtc_live_asid[mytlb][oldasid] == 0)
+                        smtc_flush_tlb_asid(oldasid);
+                }
+                /* See comments for similar code above */
+                write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
+                                | cpu_asid(cpu, mm));
+                ehb(); /* Make sure it propagates to TCStatus */
+                evpe(prevvpe);
+#else /* not CONFIG_MIPS_MT_SMTC */
                 write_c0_entryhi(cpu_asid(cpu, mm));
+#endif /* CONFIG_MIPS_MT_SMTC */
         } else {
                 /* will get a new context next time */
+#ifndef CONFIG_MIPS_MT_SMTC
                 cpu_context(cpu, mm) = 0;
+#else /* SMTC */
+                int i;
+
+                /* SMTC shares the TLB (and ASIDs) across VPEs */
+                for (i = 0; i < num_online_cpus(); i++) {
+                    if((smtc_status & SMTC_TLB_SHARED)
+                    || (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))
+                        cpu_context(i, mm) = 0;
+                }
+#endif /* CONFIG_MIPS_MT_SMTC */
         }
-
         local_irq_restore(flags);
 }