1 files changed, 490 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/htmdump.c b/arch/powerpc/platforms/pseries/htmdump.c
new file mode 100644
index 000000000000..742ec52c9d4d
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/htmdump.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) IBM Corporation, 2024
+ */
+
+#define pr_fmt(fmt) "htmdump: " fmt
+
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <asm/io.h>
+#include <asm/machdep.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/kvm_guest.h>
+
+static void *htm_buf;
+static void *htm_status_buf;
+static void *htm_info_buf;
+static void *htm_caps_buf;
+static u32 nodeindex;
+static u32 nodalchipindex;
+static u32 coreindexonchip;
+static u32 htmtype;
+static u32 htmconfigure;
+static u32 htmstart;
+static u32 htmsetup;
+static u64 htmflags;
+
+static struct dentry *htmdump_debugfs_dir;
+#define	HTM_ENABLE	1
+#define	HTM_DISABLE	0
+#define	HTM_NOWRAP	1
+#define	HTM_WRAP	0
+
+/*
+ * Check the return code for H_HTM hcall.
+ * Return non-zero value (1) if either H_PARTIAL or H_SUCCESS
+ * is returned. For other return codes:
+ * Return zero if H_NOT_AVAILABLE.
+ * Return -EBUSY if hcall return busy.
+ * Return -EINVAL if any parameter or operation is not valid.
+ * Return -EPERM if HTM Virtualization Engine Technology code
+ * is not applied.
+ * Return -EIO if the HTM state is not valid.
+ */
+static ssize_t htm_return_check(long rc)
+{
+	switch (rc) {
+	case H_SUCCESS:
+	/* H_PARTIAL for the case where all available data can't be
+	 * returned due to buffer size constraint.
+	 */
+	case H_PARTIAL:
+		break;
+	/* H_NOT_AVAILABLE indicates reading from an offset outside the range,
+	 * i.e. past end of file.
+	 */
+	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:
+		return -EBUSY;
+	case H_PARAMETER:
+	case H_P2:
+	case H_P3:
+	case H_P4:
+	case H_P5:
+	case H_P6:
+		return -EINVAL;
+	case H_STATE:
+		return -EIO;
+	case H_AUTHORITY:
+		return -EPERM;
+	}
+
+	/*
+	 * Return 1 for H_SUCCESS/H_PARTIAL
+	 */
+	return 1;
+}
+
+static ssize_t htmdump_read(struct file *filp, char __user *ubuf,
+			     size_t count, loff_t *ppos)
+{
+	void *htm_buf = filp->private_data;
+	unsigned long page, read_size, available;
+	loff_t offset;
+	long rc, ret;
+
+	page = ALIGN_DOWN(*ppos, PAGE_SIZE);
+	offset = (*ppos) % PAGE_SIZE;
+
+	/*
+	 * Invoke H_HTM call with:
+	 * - operation as htm dump (H_HTM_OP_DUMP_DATA)
+	 * - last three values are address, size and offset
+	 */
+	rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+				   htmtype, H_HTM_OP_DUMP_DATA, virt_to_phys(htm_buf),
+				   PAGE_SIZE, page);
+
+	ret = htm_return_check(rc);
+	if (ret <= 0) {
+		pr_debug("H_HTM hcall failed for op: H_HTM_OP_DUMP_DATA, returning %ld\n", ret);
+		return ret;
+	}
+
+	available = PAGE_SIZE;
+	read_size = min(count, available);
+	*ppos += read_size;
+	return simple_read_from_buffer(ubuf, count, &offset, htm_buf, available);
+}
+
+static const struct file_operations htmdump_fops = {
+	.llseek = NULL,
+	.read	= htmdump_read,
+	.open	= simple_open,
+};
+
+static int  htmconfigure_set(void *data, u64 val)
+{
+	long rc, ret;
+	unsigned long param1 = -1, param2 = -1;
+
+	/*
+	 * 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)
+		 * - If htmflags is set, param1 and param2 will be -1
+		 *   which is an indicator to use default htm mode reg mask
+		 *   and htm mode reg value.
+		 * - last three values are unused, hence set to zero
+		 */
+		if (!htmflags) {
+			param1 = 0;
+			param2 = 0;
+		}
+
+		rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+			   htmtype, H_HTM_OP_CONFIGURE, param1, param2, 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(htmflags, 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;
+}
+
+static int  htmstart_set(void *data, u64 val)
+{
+	long rc, ret;
+
+	/*
+	 * value as 1: start HTM
+	 * value as 0: stop HTM
+	 * Return -EINVAL for other values.
+	 */
+	if (val == HTM_ENABLE) {
+		/*
+		 * Invoke H_HTM call with:
+		 * - operation as htm start (H_HTM_OP_START)
+		 * - last three values are unused, hence set to zero
+		 */
+		rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+			   htmtype, H_HTM_OP_START, 0, 0, 0);
+
+	} else if (val == HTM_DISABLE) {
+		/*
+		 * Invoke H_HTM call with:
+		 * - operation as htm stop (H_HTM_OP_STOP)
+		 * - last three values are unused, hence set to zero
+		 */
+		rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+				htmtype, H_HTM_OP_STOP, 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 htmstart if H_HTM_OP_START/H_HTM_OP_STOP operation succeeds */
+	htmstart = val;
+
+	return 0;
+}
+
+static int htmstart_get(void *data, u64 *val)
+{
+	*val = htmstart;
+	return 0;
+}
+
+static ssize_t htmstatus_read(struct file *filp, char __user *ubuf,
+			     size_t count, loff_t *ppos)
+{
+	void *htm_status_buf = filp->private_data;
+	long rc, ret;
+	u64 *num_entries;
+	u64 to_copy;
+	int htmstatus_flag;
+
+	/*
+	 * Invoke H_HTM call with:
+	 * - operation as htm status (H_HTM_OP_STATUS)
+	 * - last three values as addr, size and offset
+	 */
+	rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+				   htmtype, H_HTM_OP_STATUS, virt_to_phys(htm_status_buf),
+				   PAGE_SIZE, 0);
+
+	ret = htm_return_check(rc);
+	if (ret <= 0) {
+		pr_debug("H_HTM hcall failed for op: H_HTM_OP_STATUS, returning %ld\n", ret);
+		return ret;
+	}
+
+	/*
+	 * HTM status buffer, start of buffer + 0x10 gives the
+	 * number of HTM entries in the buffer. Each nest htm status
+	 * entry is 0x6 bytes where each core htm status entry is
+	 * 0x8 bytes.
+	 * So total count to copy is:
+	 * 32 bytes (for first 7 fields) + (number of HTM entries * entry size)
+	 */
+	num_entries = htm_status_buf + 0x10;
+	if (htmtype == 0x2)
+		htmstatus_flag = 0x8;
+	else
+		htmstatus_flag = 0x6;
+	to_copy = 32 + (be64_to_cpu(*num_entries) * htmstatus_flag);
+	return simple_read_from_buffer(ubuf, count, ppos, htm_status_buf, to_copy);
+}
+
+static const struct file_operations htmstatus_fops = {
+	.llseek = NULL,
+	.read	= htmstatus_read,
+	.open	= simple_open,
+};
+
+static ssize_t htminfo_read(struct file *filp, char __user *ubuf,
+			     size_t count, loff_t *ppos)
+{
+	void *htm_info_buf = filp->private_data;
+	long rc, ret;
+	u64 *num_entries;
+	u64 to_copy;
+
+	/*
+	 * Invoke H_HTM call with:
+	 * - operation as htm status (H_HTM_OP_STATUS)
+	 * - last three values as addr, size and offset
+	 */
+	rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+				   htmtype, H_HTM_OP_DUMP_SYSPROC_CONF, virt_to_phys(htm_info_buf),
+				   PAGE_SIZE, 0);
+
+	ret = htm_return_check(rc);
+	if (ret <= 0) {
+		pr_debug("H_HTM hcall failed for op: H_HTM_OP_DUMP_SYSPROC_CONF, returning %ld\n", ret);
+		return ret;
+	}
+
+	/*
+	 * HTM status buffer, start of buffer + 0x10 gives the
+	 * number of HTM entries in the buffer. Each entry of processor
+	 * is 16 bytes.
+	 *
+	 * So total count to copy is:
+	 * 32 bytes (for first 5 fields) + (number of HTM entries * entry size)
+	 */
+	num_entries = htm_info_buf + 0x10;
+	to_copy = 32 + (be64_to_cpu(*num_entries) * 16);
+	return simple_read_from_buffer(ubuf, count, ppos, htm_info_buf, to_copy);
+}
+
+static ssize_t htmcaps_read(struct file *filp, char __user *ubuf,
+			     size_t count, loff_t *ppos)
+{
+	void *htm_caps_buf = filp->private_data;
+	long rc, ret;
+
+	/*
+	 * Invoke H_HTM call with:
+	 * - operation as htm capabilities (H_HTM_OP_CAPABILITIES)
+	 * - last three values as addr, size (0x80 for Capabilities Output Buffer
+	 *   and zero
+	 */
+	rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+				   htmtype, H_HTM_OP_CAPABILITIES, virt_to_phys(htm_caps_buf),
+				   0x80, 0);
+
+	ret = htm_return_check(rc);
+	if (ret <= 0) {
+		pr_debug("H_HTM hcall failed for op: H_HTM_OP_CAPABILITIES, returning %ld\n", ret);
+		return ret;
+	}
+
+	return simple_read_from_buffer(ubuf, count, ppos, htm_caps_buf, 0x80);
+}
+
+static const struct file_operations htminfo_fops = {
+	.llseek = NULL,
+	.read   = htminfo_read,
+	.open   = simple_open,
+};
+
+static const struct file_operations htmcaps_fops = {
+	.llseek = NULL,
+	.read   = htmcaps_read,
+	.open   = simple_open,
+};
+
+static int  htmsetup_set(void *data, u64 val)
+{
+	long rc, ret;
+
+	/*
+	 * Input value: HTM buffer size in the power of 2
+	 * example: hex value 0x21 ( decimal: 33 ) is for
+	 * 8GB
+	 * Invoke H_HTM call with:
+	 * - operation as htm start (H_HTM_OP_SETUP)
+	 * - parameter 1 set to input value.
+	 * - last two values are unused, hence set to zero
+	 */
+	rc = htm_hcall_wrapper(htmflags, nodeindex, nodalchipindex, coreindexonchip,
+			htmtype, H_HTM_OP_SETUP, val, 0, 0);
+
+	ret = htm_return_check(rc);
+	if (ret <= 0) {
+		pr_debug("H_HTM hcall failed for op: H_HTM_OP_SETUP, returning %ld\n", ret);
+		return ret;
+	}
+
+	/* Set htmsetup if H_HTM_OP_SETUP operation succeeds */
+	htmsetup = val;
+
+	return 0;
+}
+
+static int htmsetup_get(void *data, u64 *val)
+{
+	*val = htmsetup;
+	return 0;
+}
+
+static int  htmflags_set(void *data, u64 val)
+{
+	/*
+	 * Input value:
+	 * Currently supported flag value is to enable/disable
+	 * HTM buffer wrap. wrap is used along with "configure"
+	 * to prevent HTM buffer from wrapping.
+	 * Writing 1 will set noWrap while configuring HTM
+	 */
+	if (val == HTM_NOWRAP)
+		htmflags = H_HTM_FLAGS_NOWRAP;
+	else if (val == HTM_WRAP)
+		htmflags = 0;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int htmflags_get(void *data, u64 *val)
+{
+	*val = htmflags;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(htmconfigure_fops, htmconfigure_get, htmconfigure_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(htmstart_fops, htmstart_get, htmstart_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(htmsetup_fops, htmsetup_get, htmsetup_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(htmflags_fops, htmflags_get, htmflags_set, "%llu\n");
+
+static int htmdump_init_debugfs(void)
+{
+	htm_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!htm_buf) {
+		pr_err("Failed to allocate htmdump buf\n");
+		return -ENOMEM;
+	}
+
+	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, htm_buf, &htmdump_fops);
+
+	/*
+	 * Debugfs interface files to control HTM operations:
+	 */
+	debugfs_create_file("htmconfigure", 0600, htmdump_debugfs_dir, NULL, &htmconfigure_fops);
+	debugfs_create_file("htmstart", 0600, htmdump_debugfs_dir, NULL, &htmstart_fops);
+	debugfs_create_file("htmsetup", 0600, htmdump_debugfs_dir, NULL, &htmsetup_fops);
+	debugfs_create_file("htmflags", 0600, htmdump_debugfs_dir, NULL, &htmflags_fops);
+
+	/* Debugfs interface file to present status of HTM */
+	htm_status_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!htm_status_buf) {
+		pr_err("Failed to allocate htmstatus buf\n");
+		return -ENOMEM;
+	}
+
+	/* Debugfs interface file to present System Processor Configuration */
+	htm_info_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!htm_info_buf) {
+		pr_err("Failed to allocate htm info buf\n");
+		return -ENOMEM;
+	}
+
+	/* Debugfs interface file to present HTM capabilities */
+	htm_caps_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!htm_caps_buf) {
+		pr_err("Failed to allocate htm caps buf\n");
+		return -ENOMEM;
+	}
+
+	debugfs_create_file("htmstatus", 0400, htmdump_debugfs_dir, htm_status_buf, &htmstatus_fops);
+	debugfs_create_file("htminfo", 0400, htmdump_debugfs_dir, htm_info_buf, &htminfo_fops);
+	debugfs_create_file("htmcaps", 0400, htmdump_debugfs_dir, htm_caps_buf, &htmcaps_fops);
+
+	return 0;
+}
+
+static int __init htmdump_init(void)
+{
+	/* Disable on kvm guest */
+	if (is_kvm_guest()) {
+		pr_info("htmdump not supported inside KVM guest\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (htmdump_init_debugfs())
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void __exit htmdump_exit(void)
+{
+	debugfs_remove_recursive(htmdump_debugfs_dir);
+	kfree(htm_buf);
+}
+
+module_init(htmdump_init);
+module_exit(htmdump_exit);
+MODULE_DESCRIPTION("PHYP Hardware Trace Macro (HTM) data dumper");
+MODULE_LICENSE("GPL");