gru: preload tlb for bcopy instructions

Add anticipatory TLB dropins for GRU TLB misses that occur on BCOPY
instructions that copy large amounts of data.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

9 files changed, 129 insertions, 16 deletions

diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 7d757e9c42f..a1b3a1d66af 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -290,6 +290,61 @@ upm:
 
 
 /*
+ * Flush a CBE from cache. The CBE is clean in the cache. Dirty the
+ * CBE cacheline so that the line will be written back to home agent.
+ * Otherwise the line may be silently dropped. This has no impact
+ * except on performance.
+ */
+static void gru_flush_cache_cbe(struct gru_control_block_extended *cbe)
+{
+        if (unlikely(cbe)) {
+                cbe->cbrexecstatus = 0;         /* make CL dirty */
+                gru_flush_cache(cbe);
+        }
+}
+
+/*
+ * Preload the TLB with entries that may be required. Currently, preloading
+ * is implemented only for BCOPY. Preload  <tlb_preload_count> pages OR to
+ * the end of the bcopy tranfer, whichever is smaller.
+ */
+static void gru_preload_tlb(struct gru_state *gru,
+                        struct gru_thread_state *gts, int atomic,
+                        unsigned long fault_vaddr, int asid, int write,
+                        unsigned char tlb_preload_count,
+                        struct gru_tlb_fault_handle *tfh,
+                        struct gru_control_block_extended *cbe)
+{
+        unsigned long vaddr = 0, gpa;
+        int ret, pageshift;
+
+        if (cbe->opccpy != OP_BCOPY)
+                return;
+
+        if (fault_vaddr == cbe->cbe_baddr0)
+                vaddr = fault_vaddr + GRU_CACHE_LINE_BYTES * cbe->cbe_src_cl - 1;
+        else if (fault_vaddr == cbe->cbe_baddr1)
+                vaddr = fault_vaddr + (1 << cbe->xtypecpy) * cbe->cbe_nelemcur - 1;
+
+        fault_vaddr &= PAGE_MASK;
+        vaddr &= PAGE_MASK;
+        vaddr = min(vaddr, fault_vaddr + tlb_preload_count * PAGE_SIZE);
+
+        while (vaddr > fault_vaddr) {
+                ret = gru_vtop(gts, vaddr, write, atomic, &gpa, &pageshift);
+                if (ret || tfh_write_only(tfh, gpa, GAA_RAM, vaddr, asid, write,
+                                          GRU_PAGESIZE(pageshift)))
+                        return;
+                gru_dbg(grudev,
+                        "%s: gid %d, gts 0x%p, tfh 0x%p, vaddr 0x%lx, asid 0x%x, rw %d, ps %d, gpa 0x%lx\n",
+                        atomic ? "atomic" : "non-atomic", gru->gs_gid, gts, tfh,
+                        vaddr, asid, write, pageshift, gpa);
+                vaddr -= PAGE_SIZE;
+                STAT(tlb_preload_page);
+        }
+}
+
+/*
  * Drop a TLB entry into the GRU. The fault is described by info in an TFH.
  *      Input:
  *              cb    Address of user CBR. Null if not running in user context
@@ -303,6 +358,8 @@ static int gru_try_dropin(struct gru_thread_state *gts,
                           struct gru_tlb_fault_handle *tfh,
                           struct gru_instruction_bits *cbk)
 {
+        struct gru_control_block_extended *cbe = NULL;
+        unsigned char tlb_preload_count = gts->ts_tlb_preload_count;
         int pageshift = 0, asid, write, ret, atomic = !cbk, indexway;
         unsigned long gpa = 0, vaddr = 0;
 
@@ -314,6 +371,14 @@ static int gru_try_dropin(struct gru_thread_state *gts,
          */
 
         /*
+         * Prefetch the CBE if doing TLB preloading
+         */
+        if (unlikely(tlb_preload_count)) {
+                cbe = gru_tfh_to_cbe(tfh);
+                prefetchw(cbe);
+        }
+
+        /*
          * Error if TFH state is IDLE or FMM mode & the user issuing a UPM call.
          * Might be a hardware race OR a stupid user. Ignore FMM because FMM
          * is a transient state.
@@ -359,6 +424,12 @@ static int gru_try_dropin(struct gru_thread_state *gts,
                         goto failupm;
                 }
         }
+
+        if (unlikely(cbe) && pageshift == PAGE_SHIFT) {
+                gru_preload_tlb(gts->ts_gru, gts, atomic, vaddr, asid, write, tlb_preload_count, tfh, cbe);
+                gru_flush_cache_cbe(cbe);
+        }
+
         gru_cb_set_istatus_active(cbk);
         tfh_write_restart(tfh, gpa, GAA_RAM, vaddr, asid, write,
                           GRU_PAGESIZE(pageshift));
@@ -378,11 +449,13 @@ failnoasid:
                 tfh_user_polling_mode(tfh);
         else
                 gru_flush_cache(tfh);
+        gru_flush_cache_cbe(cbe);
         return -EAGAIN;
 
 failupm:
         /* Atomic failure switch CBR to UPM */
         tfh_user_polling_mode(tfh);
+        gru_flush_cache_cbe(cbe);
         STAT(tlb_dropin_fail_upm);
         gru_dbg(grudev, "FAILED upm tfh: 0x%p, vaddr 0x%lx\n", tfh, vaddr);
         return 1;
@@ -390,6 +463,7 @@ failupm:
 failfmm:
         /* FMM state on UPM call */
         gru_flush_cache(tfh);
+        gru_flush_cache_cbe(cbe);
         STAT(tlb_dropin_fail_fmm);
         gru_dbg(grudev, "FAILED fmm tfh: 0x%p, state %d\n", tfh, tfh->state);
         return 0;
@@ -397,6 +471,7 @@ failfmm:
 failnoexception:
         /* TFH status did not show exception pending */
         gru_flush_cache(tfh);
+        gru_flush_cache_cbe(cbe);
         if (cbk)
                 gru_flush_cache(cbk);
         STAT(tlb_dropin_fail_no_exception);
@@ -407,6 +482,7 @@ failnoexception:
 failidle:
         /* TFH state was idle  - no miss pending */
         gru_flush_cache(tfh);
+        gru_flush_cache_cbe(cbe);
         if (cbk)
                 gru_flush_cache(cbk);
         STAT(tlb_dropin_fail_idle);
@@ -416,6 +492,7 @@ failidle:
 failinval:
         /* All errors (atomic & non-atomic) switch CBR to EXCEPTION state */
         tfh_exception(tfh);
+        gru_flush_cache_cbe(cbe);
         STAT(tlb_dropin_fail_invalid);
         gru_dbg(grudev, "FAILED inval tfh: 0x%p, vaddr 0x%lx\n", tfh, vaddr);
         return -EFAULT;
@@ -426,6 +503,7 @@ failactive:
                 tfh_user_polling_mode(tfh);
         else
                 gru_flush_cache(tfh);
+        gru_flush_cache_cbe(cbe);
         STAT(tlb_dropin_fail_range_active);
         gru_dbg(grudev, "FAILED range active: tfh 0x%p, vaddr 0x%lx\n",
                 tfh, vaddr);
@@ -627,7 +705,7 @@ int gru_get_exception_detail(unsigned long arg)
                 excdet.exceptdet1 = cbe->idef3upd;
                 excdet.cbrstate = cbe->cbrstate;
                 excdet.cbrexecstatus = cbe->cbrexecstatus;
-                gru_flush_cache(cbe);
+                gru_flush_cache_cbe(cbe);
                 ret = 0;
         } else {
                 ret = -EAGAIN;
@@ -770,9 +848,12 @@ int gru_set_context_option(unsigned long arg)
                 return -EFAULT;
         gru_dbg(grudev, "op %d, gseg 0x%lx, value1 0x%lx\n", req.op, req.gseg, req.val1);
 
-        gts = gru_alloc_locked_gts(req.gseg);
-        if (IS_ERR(gts))
-                return PTR_ERR(gts);
+        gts = gru_find_lock_gts(req.gseg);
+        if (!gts) {
+                gts = gru_alloc_locked_gts(req.gseg);
+                if (IS_ERR(gts))
+                        return PTR_ERR(gts);
+        }
 
         switch (req.op) {
         case sco_blade_chiplet:
diff --git a/drivers/misc/sgi-gru/grufile.c b/drivers/misc/sgi-gru/grufile.c
index 9d41208a6c9..cb3b4d22847 100644
--- a/drivers/misc/sgi-gru/grufile.c
+++ b/drivers/misc/sgi-gru/grufile.c
@@ -152,6 +152,7 @@ static int gru_create_new_context(unsigned long arg)
                 vdata->vd_dsr_au_count =
                     GRU_DS_BYTES_TO_AU(req.data_segment_bytes);
                 vdata->vd_cbr_au_count = GRU_CB_COUNT_TO_AU(req.control_blocks);
+                vdata->vd_tlb_preload_count = req.tlb_preload_count;
                 ret = 0;
         }
         up_write(&current->mm->mmap_sem);
diff --git a/drivers/misc/sgi-gru/gruhandles.c b/drivers/misc/sgi-gru/gruhandles.c
index 66d67d9bc9b..2f30badc6ff 100644
--- a/drivers/misc/sgi-gru/gruhandles.c
+++ b/drivers/misc/sgi-gru/gruhandles.c
@@ -165,17 +165,20 @@ int tgh_invalidate(struct gru_tlb_global_handle *tgh,
         return wait_instruction_complete(tgh, tghop_invalidate);
 }
 
-void tfh_write_only(struct gru_tlb_fault_handle *tfh,
-                                  unsigned long pfn, unsigned long vaddr,
-                                  int asid, int dirty, int pagesize)
+int tfh_write_only(struct gru_tlb_fault_handle *tfh,
+                                  unsigned long paddr, int gaa,
+                                  unsigned long vaddr, int asid, int dirty,
+                                  int pagesize)
 {
         tfh->fillasid = asid;
         tfh->fillvaddr = vaddr;
-        tfh->pfn = pfn;
+        tfh->pfn = paddr >> GRU_PADDR_SHIFT;
+        tfh->gaa = gaa;
         tfh->dirty = dirty;
         tfh->pagesize = pagesize;
         tfh->opc = TFHOP_WRITE_ONLY;
         start_instruction(tfh);
+        return wait_instruction_complete(tfh, tfhop_write_only);
 }
 
 void tfh_write_restart(struct gru_tlb_fault_handle *tfh,
diff --git a/drivers/misc/sgi-gru/gruhandles.h b/drivers/misc/sgi-gru/gruhandles.h
index 47b762f89e0..ea584ebf65b 100644
--- a/drivers/misc/sgi-gru/gruhandles.h
+++ b/drivers/misc/sgi-gru/gruhandles.h
@@ -164,6 +164,16 @@ static inline void *gru_chiplet_vaddr(void *vaddr, int pnode, int chiplet)
         return vaddr + GRU_SIZE * (2 * pnode  + chiplet);
 }
 
+static inline struct gru_control_block_extended *gru_tfh_to_cbe(
+                                        struct gru_tlb_fault_handle *tfh)
+{
+        unsigned long cbe;
+
+        cbe = (unsigned long)tfh - GRU_TFH_BASE + GRU_CBE_BASE;
+        return (struct gru_control_block_extended*)cbe;
+}
+
+
 
 
 /*
@@ -446,6 +456,12 @@ struct gru_control_block_extended {
         unsigned int cbrexecstatus:8;
 };
 
+/* CBE fields for active BCOPY instructions */
+#define cbe_baddr0      idef1upd
+#define cbe_baddr1      idef3upd
+#define cbe_src_cl      idef6cpy
+#define cbe_nelemcur    idef5upd
+
 enum gru_cbr_state {
         CBRSTATE_INACTIVE,
         CBRSTATE_IDLE,
@@ -493,8 +509,8 @@ int cch_interrupt_sync(struct gru_context_configuration_handle *cch);
 int tgh_invalidate(struct gru_tlb_global_handle *tgh, unsigned long vaddr,
         unsigned long vaddrmask, int asid, int pagesize, int global, int n,
         unsigned short ctxbitmap);
-void tfh_write_only(struct gru_tlb_fault_handle *tfh, unsigned long pfn,
-        unsigned long vaddr, int asid, int dirty, int pagesize);
+int tfh_write_only(struct gru_tlb_fault_handle *tfh, unsigned long paddr,
+        int gaa, unsigned long vaddr, int asid, int dirty, int pagesize);
 void tfh_write_restart(struct gru_tlb_fault_handle *tfh, unsigned long paddr,
         int gaa, unsigned long vaddr, int asid, int dirty, int pagesize);
 void tfh_restart(struct gru_tlb_fault_handle *tfh);
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index 4da6f56833d..d9ff0289a1c 100644
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -161,7 +161,7 @@ static void gru_load_kernel_context(struct gru_blade_state *bs, int blade_id)
         down_write(&bs->bs_kgts_sema);
 
         if (!bs->bs_kgts) {
-                bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0);
+                bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0);
                 bs->bs_kgts->ts_user_blade_id = blade_id;
         }
         kgts = bs->bs_kgts;
diff --git a/drivers/misc/sgi-gru/grulib.h b/drivers/misc/sgi-gru/grulib.h
index e033b36df7e..c6928af7393 100644
--- a/drivers/misc/sgi-gru/grulib.h
+++ b/drivers/misc/sgi-gru/grulib.h
@@ -86,6 +86,7 @@ struct gru_create_context_req {
         unsigned int            control_blocks;
         unsigned int            maximum_thread_count;
         unsigned int            options;
+        unsigned char           tlb_preload_count;
 };
 
 /*
diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c
index ebabbdcbb97..ade0925eab0 100644
--- a/drivers/misc/sgi-gru/grumain.c
+++ b/drivers/misc/sgi-gru/grumain.c
@@ -316,7 +316,8 @@ static struct gru_thread_state *gru_find_current_gts_nolock(struct gru_vma_data
  * Allocate a thread state structure.
  */
 struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
-                int cbr_au_count, int dsr_au_count, int options, int tsid)
+                int cbr_au_count, int dsr_au_count,
+                unsigned char tlb_preload_count, int options, int tsid)
 {
         struct gru_thread_state *gts;
         struct gru_mm_struct *gms;
@@ -334,6 +335,7 @@ struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
         mutex_init(&gts->ts_ctxlock);
         gts->ts_cbr_au_count = cbr_au_count;
         gts->ts_dsr_au_count = dsr_au_count;
+        gts->ts_tlb_preload_count = tlb_preload_count;
         gts->ts_user_options = options;
         gts->ts_user_blade_id = -1;
         gts->ts_user_chiplet_id = -1;
@@ -403,7 +405,9 @@ struct gru_thread_state *gru_alloc_thread_state(struct vm_area_struct *vma,
         struct gru_vma_data *vdata = vma->vm_private_data;
         struct gru_thread_state *gts, *ngts;
 
-        gts = gru_alloc_gts(vma, vdata->vd_cbr_au_count, vdata->vd_dsr_au_count,
+        gts = gru_alloc_gts(vma, vdata->vd_cbr_au_count,
+                            vdata->vd_dsr_au_count,
+                            vdata->vd_tlb_preload_count,
                             vdata->vd_user_options, tsid);
         if (IS_ERR(gts))
                 return gts;
diff --git a/drivers/misc/sgi-gru/gruprocfs.c b/drivers/misc/sgi-gru/gruprocfs.c
index 0a57ab29cd3..54a5a1c35ad 100644
--- a/drivers/misc/sgi-gru/gruprocfs.c
+++ b/drivers/misc/sgi-gru/gruprocfs.c
@@ -76,6 +76,7 @@ static int statistics_show(struct seq_file *s, void *p)
         printstat(s, check_context_retarget_intr);
         printstat(s, check_context_unload);
         printstat(s, tlb_dropin);
+        printstat(s, tlb_preload_page);
         printstat(s, tlb_dropin_fail_no_asid);
         printstat(s, tlb_dropin_fail_upm);
         printstat(s, tlb_dropin_fail_invalid);
@@ -127,7 +128,8 @@ static int mcs_statistics_show(struct seq_file *s, void *p)
         int op;
         unsigned long total, count, max;
         static char *id[] = {"cch_allocate", "cch_start", "cch_interrupt",
-                "cch_interrupt_sync", "cch_deallocate", "tgh_invalidate"};
+                "cch_interrupt_sync", "cch_deallocate", "tfh_write_only",
+                "tfh_write_restart", "tgh_invalidate"};
 
         seq_printf(s, "%-20s%12s%12s%12s\n", "#id", "count", "aver-clks", "max-clks");
         for (op = 0; op < mcsop_last; op++) {
diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h
index 76fe2987fc9..adaf691d59f 100644
--- a/drivers/misc/sgi-gru/grutables.h
+++ b/drivers/misc/sgi-gru/grutables.h
@@ -202,6 +202,7 @@ struct gru_stats_s {
         atomic_long_t check_context_retarget_intr;
         atomic_long_t check_context_unload;
         atomic_long_t tlb_dropin;
+        atomic_long_t tlb_preload_page;
         atomic_long_t tlb_dropin_fail_no_asid;
         atomic_long_t tlb_dropin_fail_upm;
         atomic_long_t tlb_dropin_fail_invalid;
@@ -245,7 +246,8 @@ struct gru_stats_s {
 };
 
 enum mcs_op {cchop_allocate, cchop_start, cchop_interrupt, cchop_interrupt_sync,
-        cchop_deallocate, tghop_invalidate, mcsop_last};
+        cchop_deallocate, tfhop_write_only, tfhop_write_restart,
+        tghop_invalidate, mcsop_last};
 
 struct mcs_op_statistic {
         atomic_long_t   count;
@@ -335,6 +337,7 @@ struct gru_vma_data {
         long                    vd_user_options;/* misc user option flags */
         int                     vd_cbr_au_count;
         int                     vd_dsr_au_count;
+        unsigned char           vd_tlb_preload_count;
 };
 
 /*
@@ -350,6 +353,7 @@ struct gru_thread_state {
         struct gru_state        *ts_gru;        /* GRU where the context is
                                                    loaded */
         struct gru_mm_struct    *ts_gms;        /* asid & ioproc struct */
+        unsigned char           ts_tlb_preload_count; /* TLB preload pages */
         unsigned long           ts_cbr_map;     /* map of allocated CBRs */
         unsigned long           ts_dsr_map;     /* map of allocated DATA
                                                    resources */
@@ -661,7 +665,8 @@ extern int gru_proc_init(void);
 extern void gru_proc_exit(void);
 
 extern struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
-                int cbr_au_count, int dsr_au_count, int options, int tsid);
+                int cbr_au_count, int dsr_au_count,
+                unsigned char tlb_preload_count, int options, int tsid);
 extern unsigned long gru_reserve_cb_resources(struct gru_state *gru,
                 int cbr_au_count, char *cbmap);
 extern unsigned long gru_reserve_ds_resources(struct gru_state *gru,