GRU driver: minor updates

A few minor updates for the GRU driver.
	- documentation changes found in code reviews
	- changes to #ifdefs to make them recognized by "unifdef"
	  (used in simulator testing)
	- change GRU context load/unload to prefetch data

[akpm@linux-foundation.org: fix typo in comment]
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>

7 files changed, 39 insertions, 29 deletions

diff --git a/drivers/misc/sgi-gru/gru.h b/drivers/misc/sgi-gru/gru.h
index 40df7cb3f0a5..f93f03a9e6e9 100644
--- a/drivers/misc/sgi-gru/gru.h
+++ b/drivers/misc/sgi-gru/gru.h
@@ -30,9 +30,9 @@
 /*
  * Size used to map GRU GSeg
  */
-#if defined CONFIG_IA64
+#if defined(CONFIG_IA64)
 #define GRU_GSEG_PAGESIZE       (256 * 1024UL)
-#elif defined CONFIG_X86_64
+#elif defined(CONFIG_X86_64)
 #define GRU_GSEG_PAGESIZE       (256 * 1024UL)          /* ZZZ 2MB ??? */
 #else
 #error "Unsupported architecture"
diff --git a/drivers/misc/sgi-gru/gru_instructions.h b/drivers/misc/sgi-gru/gru_instructions.h
index 0dc36225c7c6..48762e7b98be 100644
--- a/drivers/misc/sgi-gru/gru_instructions.h
+++ b/drivers/misc/sgi-gru/gru_instructions.h
@@ -26,7 +26,7 @@
  * Architecture dependent functions
  */
 
-#if defined CONFIG_IA64
+#if defined(CONFIG_IA64)
 #include <linux/compiler.h>
 #include <asm/intrinsics.h>
 #define __flush_cache(p)                ia64_fc(p)
@@ -36,7 +36,7 @@
                         barrier();                                      \
                         *((volatile int *)(p)) = v; /* force st.rel */  \
                 } while (0)
-#elif defined CONFIG_X86_64
+#elif defined(CONFIG_X86_64)
 #define __flush_cache(p)                clflush(p)
 #define gru_ordered_store_int(p,v)                                      \
                 do {                                                    \
@@ -299,6 +299,7 @@ static inline void gru_flush_cache(void *p)
 static inline void gru_start_instruction(struct gru_instruction *ins, int op32)
 {
         gru_ordered_store_int(ins, op32);
+        gru_flush_cache(ins);
 }
 
 
@@ -604,8 +605,9 @@ static inline int gru_get_cb_substatus(void *cb)
 static inline int gru_check_status(void *cb)
 {
         struct gru_control_block_status *cbs = (void *)cb;
-        int ret = cbs->istatus;
+        int ret;
 
+        ret = cbs->istatus;
         if (ret == CBS_CALL_OS)
                 ret = gru_check_status_proc(cb);
         return ret;
@@ -617,7 +619,7 @@ static inline int gru_check_status(void *cb)
 static inline int gru_wait(void *cb)
 {
         struct gru_control_block_status *cbs = (void *)cb;
-        int ret = cbs->istatus;;
+        int ret = cbs->istatus;
 
         if (ret != CBS_IDLE)
                 ret = gru_wait_proc(cb);
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 3d33015bbf31..8c389d606c30 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -214,12 +214,14 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma,
 }
 
 /*
- *
  * atomic_pte_lookup
  *
  * Convert a user virtual address to a physical address
  * Only supports Intel large pages (2MB only) on x86_64.
  *      ZZZ - hugepage support is incomplete
+ *
+ * NOTE: mmap_sem is already held on entry to this function. This
+ * guarantees existence of the page tables.
  */
 static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
         int write, unsigned long *paddr, int *pageshift)
@@ -229,9 +231,6 @@ static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
         pud_t *pudp;
         pte_t pte;
 
-        WARN_ON(irqs_disabled());               /* ZZZ debug */
-
-        local_irq_disable();
         pgdp = pgd_offset(vma->vm_mm, vaddr);
         if (unlikely(pgd_none(*pgdp)))
                 goto err;
@@ -250,8 +249,6 @@ static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
 #endif
                 pte = *pte_offset_kernel(pmdp, vaddr);
 
-        local_irq_enable();
-
         if (unlikely(!pte_present(pte) ||
                      (write && (!pte_write(pte) || !pte_dirty(pte)))))
                 return 1;
@@ -324,6 +321,7 @@ static int gru_try_dropin(struct gru_thread_state *gts,
          * Atomic lookup is faster & usually works even if called in non-atomic
          * context.
          */
+        rmb();  /* Must/check ms_range_active before loading PTEs */
         ret = atomic_pte_lookup(vma, vaddr, write, &paddr, &pageshift);
         if (ret) {
                 if (!cb)
@@ -543,6 +541,7 @@ int gru_get_exception_detail(unsigned long arg)
                 ucbnum = get_cb_number((void *)excdet.cb);
                 cbrnum = thread_cbr_number(gts, ucbnum);
                 cbe = get_cbe_by_index(gts->ts_gru, cbrnum);
+                prefetchw(cbe);         /* Harmless on hardware, required for emulator */
                 excdet.opc = cbe->opccpy;
                 excdet.exopc = cbe->exopccpy;
                 excdet.ecause = cbe->ecause;
diff --git a/drivers/misc/sgi-gru/grufile.c b/drivers/misc/sgi-gru/grufile.c
index d61cee796efd..5c027b6b4e5a 100644
--- a/drivers/misc/sgi-gru/grufile.c
+++ b/drivers/misc/sgi-gru/grufile.c
@@ -113,7 +113,7 @@ static int gru_file_mmap(struct file *file, struct vm_area_struct *vma)
                 return -EPERM;
 
         if (vma->vm_start & (GRU_GSEG_PAGESIZE - 1) ||
-                        vma->vm_end & (GRU_GSEG_PAGESIZE - 1))
+                                vma->vm_end & (GRU_GSEG_PAGESIZE - 1))
                 return -EINVAL;
 
         vma->vm_flags |=
@@ -398,6 +398,12 @@ static int __init gru_init(void)
         irq = get_base_irq();
         for (chip = 0; chip < GRU_CHIPLETS_PER_BLADE; chip++) {
                 ret = request_irq(irq + chip, gru_intr, 0, id, NULL);
+                /* TODO: fix irq handling on x86. For now ignore failures because
+                 * interrupts are not required & not yet fully supported */
+                if (ret) {
+                        printk("!!!WARNING: GRU ignoring request failure!!!\n");
+                        ret = 0;
+                }
                 if (ret) {
                         printk(KERN_ERR "%s: request_irq failed\n",
                                GRU_DRIVER_ID_STR);
diff --git a/drivers/misc/sgi-gru/gruhandles.h b/drivers/misc/sgi-gru/gruhandles.h
index d16031d62673..b63018d60fe1 100644
--- a/drivers/misc/sgi-gru/gruhandles.h
+++ b/drivers/misc/sgi-gru/gruhandles.h
@@ -91,12 +91,7 @@
 #define GSEGPOFF(h)             ((h) & (GRU_SIZE - 1))
 
 /* Convert an arbitrary handle address to the beginning of the GRU segment */
-#ifndef __PLUGIN__
 #define GRUBASE(h)              ((void *)((unsigned long)(h) & ~(GRU_SIZE - 1)))
-#else
-extern void *gmu_grubase(void *h);
-#define GRUBASE(h)              gmu_grubase(h)
-#endif
 
 /* General addressing macros. */
 static inline void *get_gseg_base_address(void *base, int ctxnum)
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index 08d29cd756b4..880c55dfb662 100644
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -122,6 +122,7 @@ int gru_get_cb_exception_detail(void *cb,
         struct gru_control_block_extended *cbe;
 
         cbe = get_cbe(GRUBASE(cb), get_cb_number(cb));
+        prefetchw(cbe);         /* Harmless on hardware, required for emulator */
         excdet->opc = cbe->opccpy;
         excdet->exopc = cbe->exopccpy;
         excdet->ecause = cbe->ecause;
diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c
index 0eeb8dddd2f5..e11e1ac50900 100644
--- a/drivers/misc/sgi-gru/grumain.c
+++ b/drivers/misc/sgi-gru/grumain.c
@@ -432,29 +432,35 @@ static inline long gru_copy_handle(void *d, void *s)
         return GRU_HANDLE_BYTES;
 }
 
-/* rewrite in assembly & use lots of prefetch */
-static void gru_load_context_data(void *save, void *grubase, int ctxnum,
-                                  unsigned long cbrmap, unsigned long dsrmap)
+static void gru_prefetch_context(void *gseg, void *cb, void *cbe, unsigned long cbrmap,
+                                unsigned long length)
 {
-        void *gseg, *cb, *cbe;
-        unsigned long length;
         int i, scr;
 
-        gseg = grubase + ctxnum * GRU_GSEG_STRIDE;
-        length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
         prefetch_data(gseg + GRU_DS_BASE, length / GRU_CACHE_LINE_BYTES,
                       GRU_CACHE_LINE_BYTES);
 
-        cb = gseg + GRU_CB_BASE;
-        cbe = grubase + GRU_CBE_BASE;
         for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
                 prefetch_data(cb, 1, GRU_CACHE_LINE_BYTES);
                 prefetch_data(cbe + i * GRU_HANDLE_STRIDE, 1,
                               GRU_CACHE_LINE_BYTES);
                 cb += GRU_HANDLE_STRIDE;
         }
+}
+
+static void gru_load_context_data(void *save, void *grubase, int ctxnum,
+                                  unsigned long cbrmap, unsigned long dsrmap)
+{
+        void *gseg, *cb, *cbe;
+        unsigned long length;
+        int i, scr;
 
+        gseg = grubase + ctxnum * GRU_GSEG_STRIDE;
         cb = gseg + GRU_CB_BASE;
+        cbe = grubase + GRU_CBE_BASE;
+        length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
+        gru_prefetch_context(gseg, cb, cbe, cbrmap, length);
+
         for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
                 save += gru_copy_handle(cb, save);
                 save += gru_copy_handle(cbe + i * GRU_HANDLE_STRIDE, save);
@@ -472,15 +478,16 @@ static void gru_unload_context_data(void *save, void *grubase, int ctxnum,
         int i, scr;
 
         gseg = grubase + ctxnum * GRU_GSEG_STRIDE;
-
         cb = gseg + GRU_CB_BASE;
         cbe = grubase + GRU_CBE_BASE;
+        length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
+        gru_prefetch_context(gseg, cb, cbe, cbrmap, length);
+
         for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
                 save += gru_copy_handle(save, cb);
                 save += gru_copy_handle(save, cbe + i * GRU_HANDLE_STRIDE);
                 cb += GRU_HANDLE_STRIDE;
         }
-        length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
         memcpy(save, gseg + GRU_DS_BASE, length);
 }