This patch adds debugfs interface to export Hardware Trace Macro (HTM)
function data in a LPAR. New hypervisor call "H_HTM" has been
defined to setup, configure, control and dump the HTM data.
This patch supports only dumping of HTM data in a LPAR.
New debugfs folder called "htmdump" has been added under
/sys/kernel/debug/arch path which contains files need to
pass required parameters for the H_HTM dump function. New Kconfig
option called "CONFIG_HTMDUMP" has been in platform/pseries for the same.
With patch series applied and booted, list of files in debugfs path
# pwd
/sys/kernel/debug/powerpc/htmdump
# ls
coreindexonchip htmtype nodalchipindex nodeindex trace
Signed-off-by: Madhavan Srinivasan <ma...@linux.ibm.com>
---
arch/powerpc/platforms/pseries/Kconfig | 8 ++
arch/powerpc/platforms/pseries/Makefile | 1 +
arch/powerpc/platforms/pseries/htmdump.c | 130 +++++++++++++++++++++++
3 files changed, 139 insertions(+)
create mode 100644 arch/powerpc/platforms/pseries/htmdump.c
diff --git a/arch/powerpc/platforms/pseries/Kconfig
b/arch/powerpc/platforms/pseries/Kconfig
index afc0f6a61337..46c0ea605e33 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -128,6 +128,14 @@ config CMM
will be reused for other LPARs. The interface allows firmware to
balance memory across many LPARs.
+config HTMDUMP
+ tristate "PHYP HTM data dumper"
+ default y
+ help
+ Select this option, if you want to enable the kernel debugfs
+ interface to dump the Hardware Trace Macro (HTM) function data
+ in the LPAR.
+
config HV_PERF_CTRS
bool "Hypervisor supplied PMU events (24x7 & GPCI)"
default y
diff --git a/arch/powerpc/platforms/pseries/Makefile
b/arch/powerpc/platforms/pseries/Makefile
index 7bf506f6b8c8..3f3e3492e436 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_HVC_CONSOLE) += hvconsole.o
obj-$(CONFIG_HVCS) += hvcserver.o
obj-$(CONFIG_HCALL_STATS) += hvCall_inst.o
obj-$(CONFIG_CMM) += cmm.o
+obj-$(CONFIG_HTMDUMP) += htmdump.o
obj-$(CONFIG_IO_EVENT_IRQ) += io_event_irq.o
obj-$(CONFIG_LPARCFG) += lparcfg.o
obj-$(CONFIG_IBMVIO) += vio.o
diff --git a/arch/powerpc/platforms/pseries/htmdump.c
b/arch/powerpc/platforms/pseries/htmdump.c
new file mode 100644
index 000000000000..540cdb7e069c
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/htmdump.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) IBM Corporation, 2024
+ */
+
+#define pr_fmt(fmt) "htmdump: " fmt
+
+#include <linux/bitops.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+#include <linux/memory.h>
+#include <linux/memory_hotplug.h>
+#include <linux/numa.h>
+#include <linux/memblock.h>
+#include <asm/machdep.h>
+#include <asm/plpar_wrappers.h>
+
+/* This enables us to keep track of the memory removed from each node. */
+struct htmdump_entry {
+ void *buf;
+ struct dentry *dir;
+ char name[16];
+};
+
+static u32 nodeindex = 0;
+static u32 nodalchipindex = 0;
+static u32 coreindexonchip = 0;
+static u32 htmtype = 0;
+
+#define BUFFER_SIZE PAGE_SIZE
+
+static ssize_t htmdump_read(struct file *filp, char __user *ubuf,
+ size_t count, loff_t *ppos)
+{
+ struct htmdump_entry *ent = filp->private_data;
+ unsigned long page, read_size, available;
+ loff_t offset;
+ long rc;
+
+ page = ALIGN_DOWN(*ppos, BUFFER_SIZE);
+ offset = (*ppos) % BUFFER_SIZE;
+
+ rc = htm_get_dump_hardware(nodeindex, nodalchipindex, coreindexonchip,
+ htmtype, virt_to_phys(ent->buf),
BUFFER_SIZE, page);
+
+ switch(rc) {
+ case H_SUCCESS:
+ case H_PARTIAL:
+ break;
+ case H_NOT_AVAILABLE:
+ return 0;
+ case H_BUSY:
+ case H_LONG_BUSY_ORDER_1_MSEC:
+ case H_LONG_BUSY_ORDER_10_MSEC:
+ case H_LONG_BUSY_ORDER_100_MSEC:
+ case H_LONG_BUSY_ORDER_1_SEC:
+ case H_LONG_BUSY_ORDER_10_SEC:
+ case H_LONG_BUSY_ORDER_100_SEC:
+ case H_PARAMETER:
+ case H_P2:
+ case H_P3:
+ case H_P4:
+ case H_P5:
+ case H_P6:
+ case H_STATE:
+ case H_AUTHORITY:
+ return -EINVAL;
+ }
+
+ available = BUFFER_SIZE - offset;
+ read_size = min(count, available);
+ *ppos += read_size;
+ return simple_read_from_buffer(ubuf, count, &offset, ent->buf,
available);
+}
+
+static const struct file_operations htmdump_fops = {
+ .llseek = default_llseek,
+ .read = htmdump_read,
+ .open = simple_open,
+};
+
+static struct dentry *htmdump_debugfs_dir;
+
+static int htmdump_init_debugfs(void)
+{
+ struct htmdump_entry *ent;
+
+ ent = kcalloc(1, sizeof(struct htmdump_entry), GFP_KERNEL);
+ if (!ent) {
+ pr_err("Failed to allocate ent\n");
+ return -EINVAL;
+ }
+
+ ent->buf = kmalloc(BUFFER_SIZE, GFP_KERNEL);
+ if (!ent->buf) {
+ pr_err("Failed to allocate htmdump buf\n");
+ return -ENOMEM;
+ }
+
+ pr_debug("%s: ent:%lx buf:%lx\n",
+ __func__, (long unsigned int)ent, (long unsigned
int)ent->buf);
+
+ htmdump_debugfs_dir = debugfs_create_dir("htmdump",
+ arch_debugfs_dir);
+
+ debugfs_create_u32("nodeindex", 0600,
+ htmdump_debugfs_dir, &nodeindex);
+ debugfs_create_u32("nodalchipindex", 0600,
+ htmdump_debugfs_dir, &nodalchipindex);
+ debugfs_create_u32("coreindexonchip", 0600,
+ htmdump_debugfs_dir, &coreindexonchip);
+ debugfs_create_u32("htmtype", 0600,
+ htmdump_debugfs_dir, &htmtype);
+ debugfs_create_file("trace", 0400, htmdump_debugfs_dir, ent,
&htmdump_fops);
+
+ return 0;
+}
+
+static int htmdump_init(void)
+{
+ if (htmdump_init_debugfs())
+ return -EINVAL;
+
+ return 0;
+}
+machine_device_initcall(pseries, htmdump_init);
--
2.45.2
