===================
In the proposed approach, the function (export_imc_mode_and_cmd) which creates
the debugfs interface for imc mode and command is implemented in opal-imc.c.
Thus we can use imc_get_mem_addr() to get the homer base address for each chip.
The interface to expose imc mode and command is required only if we have nest
pmu units registered. Employing the existing data structures to track whether
we have any nest units registered will require to extend data from perf side
to opal-imc.c. Instead an integer is introduced to hold that information by
counting successful nest unit registration. Debugfs interface is removed
based on the integer count.
Example for the interface:
root@XXXX:/sys/kernel/debug/imc# ls
imc_cmd_0 imc_cmd_8 imc_mode_0 imc_mode_8
Changes from v1 -> v2
- The latest commit by Rajarshi Das adds the control block offset in the
ima-catalog file. So if there is cb_offset specified in the
ima-catalog, that is used to export the imc mode/command, otherwise
IMC_CNTL_BLK_OFFSET is used.
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/imc-pmu.h | 7 +++
arch/powerpc/platforms/powernv/opal-imc.c | 77 +++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+)
@@ -35,6 +35,13 @@
#define THREAD_IMC_ENABLE 0x8000000000000000ULL
/*
+ * For debugfs interface for imc-mode and imc-command
+ */
+#define IMC_CNTL_BLK_OFFSET 0x3FC00
+#define IMC_CNTL_BLK_CMD_OFFSET 8
+#define IMC_CNTL_BLK_MODE_OFFSET 32
+
+/*
* Structure to hold memory address information for imc units.
*/
struct imc_mem_info {
@@ -21,6 +21,78 @@
#include <asm/io.h>
#include <asm/imc-pmu.h>
#include <asm/cputhreads.h>
+#include <asm/debugfs.h>
+
+static struct dentry *imc_debugfs_parent;
+
+/* Helpers to export imc command and mode via debugfs */
+static int imc_mem_get(void *data, u64 *val)
+{
+ *val = cpu_to_be64(*(u64 *)data);
+ return 0;
+}
+
+static int imc_mem_set(void *data, u64 val)
+{
+ *(u64 *)data = cpu_to_be64(val);
+ return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_imc_x64, imc_mem_get, imc_mem_set, "0x%016llx\n");
+
+static struct dentry *imc_debugfs_create_x64(const char *name, umode_t mode,
+ struct dentry *parent, u64 *value)
+{
+ return debugfs_create_file_unsafe(name, mode, parent,
+ value, &fops_imc_x64);
+}
+
+/*
+ * export_imc_mode_and_cmd: Create a debugfs interface
+ * for imc_cmd and imc_mode
+ * for each node in the system.
+ * imc_mode and imc_cmd can be changed by echo into
+ * this interface.
+ */
+static void export_imc_mode_and_cmd(struct device_node *node,
+ struct imc_pmu *pmu_ptr)
+{
+ static u64 loc, *imc_mode_addr, *imc_cmd_addr;
+ int chip = 0, nid;
+ char mode[16], cmd[16];
+ u32 cb_offset;
+
+ imc_debugfs_parent = debugfs_create_dir("imc", powerpc_debugfs_root);
+
+ /*
+ * Return here, either because 'imc' directory already exists,
+ * Or failed to create a new one.
+ */
+ if (!imc_debugfs_parent)
+ return;
+
+ if (of_property_read_u32(node, "cb_offset", &cb_offset))
+ cb_offset = IMC_CNTL_BLK_OFFSET;
+
+ for_each_node(nid) {
+ loc = (u64)(pmu_ptr->mem_info[chip].vbase) + cb_offset;
+ imc_mode_addr = (u64 *)(loc + IMC_CNTL_BLK_MODE_OFFSET);
+ sprintf(mode, "imc_mode_%d", nid);
+ if (!imc_debugfs_create_x64(mode, 0600, imc_debugfs_parent,
+ imc_mode_addr))
+ goto err;
+
+ imc_cmd_addr = (u64 *)(loc + IMC_CNTL_BLK_CMD_OFFSET);
+ sprintf(cmd, "imc_cmd_%d", nid);
+ if (!imc_debugfs_create_x64(cmd, 0600, imc_debugfs_parent,
+ imc_cmd_addr))
+ goto err;
+ chip++;
+ }
+ return;
+
+err:
+ debugfs_remove_recursive(imc_debugfs_parent);
+}
/*
* imc_get_mem_addr_nest: Function to get nest counter memory region
@@ -65,6 +137,7 @@ static int imc_get_mem_addr_nest(struct device_node *node,
}
pmu_ptr->imc_counter_mmaped = true;
+ export_imc_mode_and_cmd(node, pmu_ptr);
kfree(base_addr_arr);
kfree(chipid_arr);
return 0;
@@ -213,6 +286,10 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
}
}
+ /* If none of the nest units are registered, remove debugfs interface */
+ if (pmu_count == 0)
+ debugfs_remove_recursive(imc_debugfs_parent);
+
return 0;
}