powerpc/oprofile: IBM CELL: add SPU event profiling support

This patch adds the SPU event based profiling funcitonality for the
IBM Cell processor.  Previously, the CELL OProfile kernel code supported
PPU event, PPU cycle profiling and SPU cycle profiling.   The addition of
SPU event profiling allows the users to identify where in their SPU code
various SPU evnets are occuring.  This should help users further identify
issues with their code.  Note, SPU profiling has some limitations due to HW
constraints.  Only one event at a time can be used for profiling and SPU event
profiling must be time sliced across all of the SPUs in a node.

The patch adds a new arch specific file to the OProfile file system. The
file has bit 0 set to indicate that the kernel supports SPU event profiling.
The user tool must check this file/bit to make sure the kernel supports
SPU event profiling before trying to do SPU event profiling.  The user tool
check is part of the user tool patch for SPU event profiling.

Signed-off-by: Carl Love <carll@us.ibm.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/arch/powerpc/oprofile/common.c b/arch/powerpc/oprofile/common.c
index 17807acb05d9..21f16edf6c8d 100644
--- a/arch/powerpc/oprofile/common.c
+++ b/arch/powerpc/oprofile/common.c
@@ -132,6 +132,28 @@ static int op_powerpc_create_files(struct super_block *sb, struct dentry *root)
 	oprofilefs_create_ulong(sb, root, "mmcr0", &sys.mmcr0);
 	oprofilefs_create_ulong(sb, root, "mmcr1", &sys.mmcr1);
 	oprofilefs_create_ulong(sb, root, "mmcra", &sys.mmcra);
+#ifdef CONFIG_OPROFILE_CELL
+	/* create a file the user tool can check to see what level of profiling
+	 * support exits with this kernel. Initialize bit mask to indicate
+	 * what support the kernel has:
+	 * bit 0      -  Supports SPU event profiling in addition to PPU
+	 *               event and cycles; and SPU cycle profiling
+	 * bits 1-31  -  Currently unused.
+	 *
+	 * If the file does not exist, then the kernel only supports SPU
+	 * cycle profiling, PPU event and cycle profiling.
+	 */
+	oprofilefs_create_ulong(sb, root, "cell_support", &sys.cell_support);
+	sys.cell_support = 0x1; /* Note, the user OProfile tool must check
+				 * that this bit is set before attempting to
+				 * user SPU event profiling.  Older kernels
+				 * will not have this file, hence the user
+				 * tool is not allowed to do SPU event
+				 * profiling on older kernels.  Older kernels
+				 * will accept SPU events but collected data
+				 * is garbage.
+				 */
+#endif
 #endif
 
 	for (i = 0; i < model->num_counters; ++i) {