powerpc/pseries/htmdump: Add htm configure support to htmdump module

Support configuring of Hardware Trace Macro (HTM) function
via debugfs interface. Under debugfs folder
"/sys/kernel/debug/powerpc/htmdump", add file "htmconfigure".
The interface allows configuring of htm via this file
by writing value "1". Allow deconfiguring of htm via this file
by writing value "0".  Any other value returns -EINVAL.

Signed-off-by: Athira Rajeev <atrajeev@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250420180844.53128-3-atrajeev@linux.ibm.com

diff --git a/arch/powerpc/platforms/pseries/htmdump.c b/arch/powerpc/platforms/pseries/htmdump.c
index 604fde6a05597b670c24debd8dff19478904e4ee..5c1eef1b827af84800860bf23ac23c3e79088645 100644 (file)
--- a/arch/powerpc/platforms/pseries/htmdump.c
+++ b/arch/powerpc/platforms/pseries/htmdump.c
@@ -16,7 +16,10 @@ static u32 nodeindex;
 static u32 nodalchipindex;
 static u32 coreindexonchip;
 static u32 htmtype;
+static u32 htmconfigure;
 static struct dentry *htmdump_debugfs_dir;
+#define        HTM_ENABLE      1
+#define        HTM_DISABLE     0
 
 /*
  * Check the return code for H_HTM hcall.
@@ -108,6 +111,54 @@ static const struct file_operations htmdump_fops = {
        .open   = simple_open,
 };
 
+static int  htmconfigure_set(void *data, u64 val)
+{
+       long rc, ret;
+
+       /*
+        * value as 1 : configure HTM.
+        * value as 0 : deconfigure HTM. Return -EINVAL for
+        * other values.
+        */
+       if (val == HTM_ENABLE) {
+               /*
+                * Invoke H_HTM call with:
+                * - operation as htm configure (H_HTM_OP_CONFIGURE)
+                * - last three values are unused, hence set to zero
+                */
+               rc = htm_hcall_wrapper(nodeindex, nodalchipindex, coreindexonchip,
+                          htmtype, H_HTM_OP_CONFIGURE, 0, 0, 0);
+       } else if (val == HTM_DISABLE) {
+               /*
+                * Invoke H_HTM call with:
+                * - operation as htm deconfigure (H_HTM_OP_DECONFIGURE)
+                * - last three values are unused, hence set to zero
+                */
+               rc = htm_hcall_wrapper(nodeindex, nodalchipindex, coreindexonchip,
+                               htmtype, H_HTM_OP_DECONFIGURE, 0, 0, 0);
+       } else
+               return -EINVAL;
+
+       ret = htm_return_check(rc);
+       if (ret <= 0) {
+               pr_debug("H_HTM hcall failed, returning %ld\n", ret);
+               return ret;
+       }
+
+       /* Set htmconfigure if operation succeeds */
+       htmconfigure = val;
+
+       return 0;
+}
+
+static int htmconfigure_get(void *data, u64 *val)
+{
+       *val = htmconfigure;
+       return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(htmconfigure_fops, htmconfigure_get, htmconfigure_set, "%llu\n");
+
 static int htmdump_init_debugfs(void)
 {
        htm_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
@@ -129,6 +180,11 @@ static int htmdump_init_debugfs(void)
                        htmdump_debugfs_dir, &htmtype);
        debugfs_create_file("trace", 0400, htmdump_debugfs_dir, htm_buf, &htmdump_fops);
 
+       /*
+        * Debugfs interface files to control HTM operations:
+        */
+       debugfs_create_file("htmconfigure", 0600, htmdump_debugfs_dir, NULL, &htmconfigure_fops);
+
        return 0;
 }