X86: uv: implement a gru_read_gpa kernel function

The BIOS has decided to store a pointer to the partition reserved page in
a scratch MMR.  The GRU is only able to read an MMR using a vload
instruction.  The gru_read_gpa() function will implemented.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/sgi-gru/gru_instructions.h

@@ -340,6 +340,19 @@ static inline void gru_start_instruction(struct gru_instruction *ins, int op32)
  *     	- nelem and stride are in elements
  *     	- tri0/tri1 is in bytes for the beginning of the data segment.
  */
+static inline void gru_vload_phys(void *cb, unsigned long gpa,
+		unsigned int tri0, int iaa, unsigned long hints)
+{
+	struct gru_instruction *ins = (struct gru_instruction *)cb;
+
+	ins->baddr0 = (long)gpa | ((unsigned long)iaa << 62);
+	ins->nelem = 1;
+	ins->tri0 = tri0;
+	ins->op1_stride = 1;
+	gru_start_instruction(ins, __opword(OP_VLOAD, 0, XTYPE_DW, iaa, 0,
+					CB_IMA(hints)));
+}
+
 static inline void gru_vload(void *cb, unsigned long mem_addr,
 		unsigned int tri0, unsigned char xtype, unsigned long nelem,
 		unsigned long stride, unsigned long hints)

drivers/misc/sgi-gru/grukservices.c

@@ -857,6 +857,29 @@ EXPORT_SYMBOL_GPL(gru_get_next_message);
 
 /* ---------------------- GRU DATA COPY FUNCTIONS ---------------------------*/
 
+/*
+ * Load a DW from a global GPA. The GPA can be a memory or MMR address.
+ */
+int gru_read_gpa(unsigned long *value, unsigned long gpa)
+{
+	void *cb;
+	void *dsr;
+	int ret, iaa;
+
+	STAT(read_gpa);
+	if (gru_get_cpu_resources(GRU_NUM_KERNEL_DSR_BYTES, &cb, &dsr))
+		return MQE_BUG_NO_RESOURCES;
+	iaa = gpa >> 62;
+	gru_vload_phys(cb, gpa, gru_get_tri(dsr), iaa, IMA);
+	ret = gru_wait(cb);
+	if (ret == CBS_IDLE)
+		*value = *(unsigned long *)dsr;
+	gru_free_cpu_resources(cb, dsr);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gru_read_gpa);
+
+
 /*
  * Copy a block of data using the GRU resources
  */

drivers/misc/sgi-gru/grukservices.h

@@ -130,6 +130,20 @@ extern void gru_free_message(struct gru_message_queue_desc *mqd,
 extern void *gru_get_next_message(struct gru_message_queue_desc *mqd);
 
 
+/*
+ * Read a GRU global GPA. Source can be located in a remote partition.
+ *
+ *    Input:
+ *    	value		memory address where MMR value is returned
+ *    	gpa		source numalink physical address of GPA
+ *
+ *    Output:
+ *	0		OK
+ *	>0		error
+ */
+int gru_read_gpa(unsigned long *value, unsigned long gpa);
+
+
 /*
  * Copy data using the GRU. Source or destination can be located in a remote
  * partition.

drivers/misc/sgi-gru/gruprocfs.c

@@ -98,6 +98,7 @@ static int statistics_show(struct seq_file *s, void *p)
 	printstat(s, flush_tlb_gru_tgh);
 	printstat(s, flush_tlb_gru_zero_asid);
 	printstat(s, copy_gpa);
+	printstat(s, read_gpa);
 	printstat(s, mesq_receive);
 	printstat(s, mesq_receive_none);
 	printstat(s, mesq_send);

drivers/misc/sgi-gru/grutables.h

@@ -224,6 +224,7 @@ struct gru_stats_s {
 	atomic_long_t flush_tlb_gru_zero_asid;
 
 	atomic_long_t copy_gpa;
+	atomic_long_t read_gpa;
 
 	atomic_long_t mesq_receive;
 	atomic_long_t mesq_receive_none;