sched_ext: Maintain an online cid mask in the scheduler arenagrafted

Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.

Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.

The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.

v2: Reworded the getter kerneldoc (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

1 files changed, 474 insertions, 0 deletions

diff --git a/sound/soc/sof/debug.c b/sound/soc/sof/debug.c
new file mode 100644
index 000000000..6b9e1f1ee
--- /dev/null
+++ b/sound/soc/sof/debug.c
@@ -0,0 +1,474 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018 Intel Corporation
+//
+// Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
+//
+// Generic debug routines used to export DSP MMIO and memories to userspace
+// for firmware debugging.
+//
+
+#include <linux/debugfs.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+#include <sound/sof/ext_manifest.h>
+#include <sound/sof/debug.h>
+#include "sof-priv.h"
+#include "ops.h"
+
+static ssize_t sof_dfsentry_read(struct file *file, char __user *buffer,
+				 size_t count, loff_t *ppos)
+{
+	struct snd_sof_dfsentry *dfse = file->private_data;
+	struct snd_sof_dev *sdev = dfse->sdev;
+	loff_t pos = *ppos;
+	size_t size_ret;
+	int skip = 0;
+	int size;
+	u8 *buf;
+
+	size = dfse->size;
+
+	/* validate position & count */
+	if (pos < 0)
+		return -EINVAL;
+	if (pos >= size || !count)
+		return 0;
+	/* find the minimum. min() is not used since it adds sparse warnings */
+	if (count > size - pos)
+		count = size - pos;
+
+	/* align io read start to u32 multiple */
+	pos = ALIGN_DOWN(pos, 4);
+
+	/* intermediate buffer size must be u32 multiple */
+	size = ALIGN(count, 4);
+
+	/* if start position is unaligned, read extra u32 */
+	if (unlikely(pos != *ppos)) {
+		skip = *ppos - pos;
+		if (pos + size + 4 < dfse->size)
+			size += 4;
+	}
+
+	buf = kzalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	if (dfse->type == SOF_DFSENTRY_TYPE_IOMEM) {
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_ENABLE_DEBUGFS_CACHE)
+		/*
+		 * If the DSP is active: copy from IO.
+		 * If the DSP is suspended:
+		 *	- Copy from IO if the memory is always accessible.
+		 *	- Otherwise, copy from cached buffer.
+		 */
+		if (pm_runtime_active(sdev->dev) ||
+		    dfse->access_type == SOF_DEBUGFS_ACCESS_ALWAYS) {
+			memcpy_fromio(buf, dfse->io_mem + pos, size);
+		} else {
+			dev_info(sdev->dev,
+				 "Copying cached debugfs data\n");
+			memcpy(buf, dfse->cache_buf + pos, size);
+		}
+#else
+		/* if the DSP is in D3 */
+		if (!pm_runtime_active(sdev->dev) &&
+		    dfse->access_type == SOF_DEBUGFS_ACCESS_D0_ONLY) {
+			dev_err(sdev->dev,
+				"error: debugfs entry cannot be read in DSP D3\n");
+			kfree(buf);
+			return -EINVAL;
+		}
+
+		memcpy_fromio(buf, dfse->io_mem + pos, size);
+#endif
+	} else {
+		memcpy(buf, ((u8 *)(dfse->buf) + pos), size);
+	}
+
+	/* copy to userspace */
+	size_ret = copy_to_user(buffer, buf + skip, count);
+
+	kfree(buf);
+
+	/* update count & position if copy succeeded */
+	if (size_ret)
+		return -EFAULT;
+
+	*ppos = pos + count;
+
+	return count;
+}
+
+static const struct file_operations sof_dfs_fops = {
+	.open = simple_open,
+	.read = sof_dfsentry_read,
+	.llseek = default_llseek,
+};
+
+/* create FS entry for debug files that can expose DSP memories, registers */
+static int snd_sof_debugfs_io_item(struct snd_sof_dev *sdev,
+				   void __iomem *base, size_t size,
+				   const char *name,
+				   enum sof_debugfs_access_type access_type)
+{
+	struct snd_sof_dfsentry *dfse;
+
+	if (!sdev)
+		return -EINVAL;
+
+	dfse = devm_kzalloc(sdev->dev, sizeof(*dfse), GFP_KERNEL);
+	if (!dfse)
+		return -ENOMEM;
+
+	dfse->type = SOF_DFSENTRY_TYPE_IOMEM;
+	dfse->io_mem = base;
+	dfse->size = size;
+	dfse->sdev = sdev;
+	dfse->access_type = access_type;
+
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_ENABLE_DEBUGFS_CACHE)
+	/*
+	 * allocate cache buffer that will be used to save the mem window
+	 * contents prior to suspend
+	 */
+	if (access_type == SOF_DEBUGFS_ACCESS_D0_ONLY) {
+		dfse->cache_buf = devm_kzalloc(sdev->dev, size, GFP_KERNEL);
+		if (!dfse->cache_buf)
+			return -ENOMEM;
+	}
+#endif
+
+	debugfs_create_file(name, 0444, sdev->debugfs_root, dfse,
+			    &sof_dfs_fops);
+
+	/* add to dfsentry list */
+	list_add(&dfse->list, &sdev->dfsentry_list);
+
+	return 0;
+}
+
+int snd_sof_debugfs_add_region_item_iomem(struct snd_sof_dev *sdev,
+					  enum snd_sof_fw_blk_type blk_type, u32 offset,
+					  size_t size, const char *name,
+					  enum sof_debugfs_access_type access_type)
+{
+	int bar = snd_sof_dsp_get_bar_index(sdev, blk_type);
+
+	if (bar < 0)
+		return bar;
+
+	return snd_sof_debugfs_io_item(sdev, sdev->bar[bar] + offset, size, name,
+				       access_type);
+}
+EXPORT_SYMBOL_GPL(snd_sof_debugfs_add_region_item_iomem);
+
+/* create FS entry for debug files to expose kernel memory */
+int snd_sof_debugfs_buf_item(struct snd_sof_dev *sdev,
+			     void *base, size_t size,
+			     const char *name, mode_t mode)
+{
+	struct snd_sof_dfsentry *dfse;
+
+	if (!sdev)
+		return -EINVAL;
+
+	dfse = devm_kzalloc(sdev->dev, sizeof(*dfse), GFP_KERNEL);
+	if (!dfse)
+		return -ENOMEM;
+
+	dfse->type = SOF_DFSENTRY_TYPE_BUF;
+	dfse->buf = base;
+	dfse->size = size;
+	dfse->sdev = sdev;
+
+	debugfs_create_file(name, mode, sdev->debugfs_root, dfse,
+			    &sof_dfs_fops);
+	/* add to dfsentry list */
+	list_add(&dfse->list, &sdev->dfsentry_list);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_sof_debugfs_buf_item);
+
+static int memory_info_update(struct snd_sof_dev *sdev, char *buf, size_t buff_size)
+{
+	struct sof_ipc_cmd_hdr msg = {
+		.size = sizeof(struct sof_ipc_cmd_hdr),
+		.cmd = SOF_IPC_GLB_DEBUG | SOF_IPC_DEBUG_MEM_USAGE,
+	};
+	struct sof_ipc_dbg_mem_usage *reply;
+	int len;
+	int ret;
+	int i;
+
+	reply = kmalloc(SOF_IPC_MSG_MAX_SIZE, GFP_KERNEL);
+	if (!reply)
+		return -ENOMEM;
+
+	ret = pm_runtime_resume_and_get(sdev->dev);
+	if (ret < 0 && ret != -EACCES) {
+		dev_err(sdev->dev, "error: enabling device failed: %d\n", ret);
+		goto error;
+	}
+
+	/* Make sure the DSP/firmware is booted up */
+	ret = snd_sof_boot_dsp_firmware(sdev);
+	if (!ret)
+		ret = sof_ipc_tx_message(sdev->ipc, &msg, msg.size, reply,
+					 SOF_IPC_MSG_MAX_SIZE);
+
+	pm_runtime_put_autosuspend(sdev->dev);
+	if (ret < 0 || reply->rhdr.error < 0) {
+		ret = min(ret, reply->rhdr.error);
+		dev_err(sdev->dev, "error: reading memory info failed, %d\n", ret);
+		goto error;
+	}
+
+	if (struct_size(reply, elems, reply->num_elems) != reply->rhdr.hdr.size) {
+		dev_err(sdev->dev, "error: invalid memory info ipc struct size, %d\n",
+			reply->rhdr.hdr.size);
+		ret = -EINVAL;
+		goto error;
+	}
+
+	for (i = 0, len = 0; i < reply->num_elems; i++) {
+		ret = scnprintf(buf + len, buff_size - len, "zone %d.%d used %#8x free %#8x\n",
+				reply->elems[i].zone, reply->elems[i].id,
+				reply->elems[i].used, reply->elems[i].free);
+		if (ret < 0)
+			goto error;
+		len += ret;
+	}
+
+	ret = len;
+error:
+	kfree(reply);
+	return ret;
+}
+
+static ssize_t memory_info_read(struct file *file, char __user *to, size_t count, loff_t *ppos)
+{
+	struct snd_sof_dfsentry *dfse = file->private_data;
+	struct snd_sof_dev *sdev = dfse->sdev;
+	int data_length;
+
+	/* read memory info from FW only once for each file read */
+	if (!*ppos) {
+		dfse->buf_data_size = 0;
+		data_length = memory_info_update(sdev, dfse->buf, dfse->size);
+		if (data_length < 0)
+			return data_length;
+		dfse->buf_data_size = data_length;
+	}
+
+	return simple_read_from_buffer(to, count, ppos, dfse->buf, dfse->buf_data_size);
+}
+
+static int memory_info_open(struct inode *inode, struct file *file)
+{
+	struct snd_sof_dfsentry *dfse = inode->i_private;
+	struct snd_sof_dev *sdev = dfse->sdev;
+
+	file->private_data = dfse;
+
+	/* allocate buffer memory only in first open run, to save memory when unused */
+	if (!dfse->buf) {
+		dfse->buf = devm_kmalloc(sdev->dev, PAGE_SIZE, GFP_KERNEL);
+		if (!dfse->buf)
+			return -ENOMEM;
+		dfse->size = PAGE_SIZE;
+	}
+
+	return 0;
+}
+
+static const struct file_operations memory_info_fops = {
+	.open = memory_info_open,
+	.read = memory_info_read,
+	.llseek = default_llseek,
+};
+
+int snd_sof_dbg_memory_info_init(struct snd_sof_dev *sdev)
+{
+	struct snd_sof_dfsentry *dfse;
+
+	dfse = devm_kzalloc(sdev->dev, sizeof(*dfse), GFP_KERNEL);
+	if (!dfse)
+		return -ENOMEM;
+
+	/* don't allocate buffer before first usage, to save memory when unused */
+	dfse->type = SOF_DFSENTRY_TYPE_BUF;
+	dfse->sdev = sdev;
+
+	debugfs_create_file("memory_info", 0444, sdev->debugfs_root, dfse, &memory_info_fops);
+
+	/* add to dfsentry list */
+	list_add(&dfse->list, &sdev->dfsentry_list);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_sof_dbg_memory_info_init);
+
+int snd_sof_dbg_init(struct snd_sof_dev *sdev)
+{
+	const struct snd_sof_dsp_ops *ops = sof_ops(sdev);
+	struct snd_sof_pdata *plat_data = sdev->pdata;
+	const struct snd_sof_debugfs_map *map;
+	struct dentry *fw_profile;
+	int i;
+	int err;
+
+	/* use "sof" as top level debugFS dir */
+	sdev->debugfs_root = debugfs_create_dir("sof", NULL);
+
+	/* expose firmware/topology prefix/names for test purposes */
+	fw_profile = debugfs_create_dir("fw_profile", sdev->debugfs_root);
+
+	debugfs_create_str("fw_path", 0444, fw_profile,
+			   (char **)&plat_data->fw_filename_prefix);
+	/* library path is not valid for IPC3 */
+	if (plat_data->ipc_type != SOF_IPC_TYPE_3) {
+		/*
+		 * fw_lib_prefix can be NULL if the vendor/platform does not
+		 * support loadable libraries
+		 */
+		if (plat_data->fw_lib_prefix) {
+			debugfs_create_str("fw_lib_path", 0444, fw_profile,
+					   (char **)&plat_data->fw_lib_prefix);
+		} else {
+			static char *fw_lib_path;
+
+			fw_lib_path = devm_kasprintf(sdev->dev, GFP_KERNEL,
+						     "Not supported");
+			if (!fw_lib_path)
+				return -ENOMEM;
+
+			debugfs_create_str("fw_lib_path", 0444, fw_profile,
+					   (char **)&fw_lib_path);
+		}
+	}
+	debugfs_create_str("tplg_path", 0444, fw_profile,
+			   (char **)&plat_data->tplg_filename_prefix);
+	debugfs_create_str("fw_name", 0444, fw_profile,
+			   (char **)&plat_data->fw_filename);
+	debugfs_create_str("tplg_name", 0444, fw_profile,
+			   (char **)&plat_data->tplg_filename);
+	debugfs_create_u32("ipc_type", 0444, fw_profile,
+			   (u32 *)&plat_data->ipc_type);
+
+	/* init dfsentry list */
+	INIT_LIST_HEAD(&sdev->dfsentry_list);
+
+	/* create debugFS files for platform specific MMIO/DSP memories */
+	for (i = 0; i < ops->debug_map_count; i++) {
+		map = &ops->debug_map[i];
+
+		err = snd_sof_debugfs_io_item(sdev, sdev->bar[map->bar] +
+					      map->offset, map->size,
+					      map->name, map->access_type);
+		/* errors are only due to memory allocation, not debugfs */
+		if (err < 0)
+			return err;
+	}
+
+	return snd_sof_debugfs_buf_item(sdev, &sdev->fw_state,
+					sizeof(sdev->fw_state),
+					"fw_state", 0444);
+}
+EXPORT_SYMBOL_GPL(snd_sof_dbg_init);
+
+void snd_sof_free_debug(struct snd_sof_dev *sdev)
+{
+	debugfs_remove_recursive(sdev->debugfs_root);
+}
+EXPORT_SYMBOL_GPL(snd_sof_free_debug);
+
+static const struct soc_fw_state_info {
+	enum sof_fw_state state;
+	const char *name;
+} fw_state_dbg[] = {
+	{SOF_FW_BOOT_NOT_STARTED, "SOF_FW_BOOT_NOT_STARTED"},
+	{SOF_DSPLESS_MODE, "SOF_DSPLESS_MODE"},
+	{SOF_FW_BOOT_PREPARE, "SOF_FW_BOOT_PREPARE"},
+	{SOF_FW_BOOT_IN_PROGRESS, "SOF_FW_BOOT_IN_PROGRESS"},
+	{SOF_FW_BOOT_FAILED, "SOF_FW_BOOT_FAILED"},
+	{SOF_FW_BOOT_READY_FAILED, "SOF_FW_BOOT_READY_FAILED"},
+	{SOF_FW_BOOT_READY_OK, "SOF_FW_BOOT_READY_OK"},
+	{SOF_FW_BOOT_COMPLETE, "SOF_FW_BOOT_COMPLETE"},
+	{SOF_FW_CRASHED, "SOF_FW_CRASHED"},
+};
+
+static void snd_sof_dbg_print_fw_state(struct snd_sof_dev *sdev, const char *level)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(fw_state_dbg); i++) {
+		if (sdev->fw_state == fw_state_dbg[i].state) {
+			dev_printk(level, sdev->dev, "fw_state: %s (%d)\n",
+				   fw_state_dbg[i].name, i);
+			return;
+		}
+	}
+
+	dev_printk(level, sdev->dev, "fw_state: UNKNOWN (%d)\n", sdev->fw_state);
+}
+
+void snd_sof_dsp_dbg_dump(struct snd_sof_dev *sdev, const char *msg, u32 flags)
+{
+	char *level = (flags & SOF_DBG_DUMP_OPTIONAL) ? KERN_DEBUG : KERN_ERR;
+	bool print_all = sof_debug_check_flag(SOF_DBG_PRINT_ALL_DUMPS);
+
+	if (flags & SOF_DBG_DUMP_OPTIONAL && !print_all)
+		return;
+
+	if (sof_ops(sdev)->dbg_dump && !sdev->dbg_dump_printed) {
+		dev_printk(level, sdev->dev,
+			   "------------[ DSP dump start ]------------\n");
+		if (msg)
+			dev_printk(level, sdev->dev, "%s\n", msg);
+		snd_sof_dbg_print_fw_state(sdev, level);
+		sof_ops(sdev)->dbg_dump(sdev, flags);
+		dev_printk(level, sdev->dev,
+			   "------------[ DSP dump end ]------------\n");
+		if (!print_all)
+			sdev->dbg_dump_printed = true;
+	} else if (msg) {
+		dev_printk(level, sdev->dev, "%s\n", msg);
+	}
+}
+EXPORT_SYMBOL(snd_sof_dsp_dbg_dump);
+
+static void snd_sof_ipc_dump(struct snd_sof_dev *sdev)
+{
+	if (sof_ops(sdev)->ipc_dump  && !sdev->ipc_dump_printed) {
+		dev_err(sdev->dev, "------------[ IPC dump start ]------------\n");
+		sof_ops(sdev)->ipc_dump(sdev);
+		dev_err(sdev->dev, "------------[ IPC dump end ]------------\n");
+		if (!sof_debug_check_flag(SOF_DBG_PRINT_ALL_DUMPS))
+			sdev->ipc_dump_printed = true;
+	}
+}
+
+void snd_sof_handle_fw_exception(struct snd_sof_dev *sdev, const char *msg)
+{
+	if ((IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_RETAIN_DSP_CONTEXT) ||
+	    sof_debug_check_flag(SOF_DBG_RETAIN_CTX)) && !sdev->d3_prevented) {
+		/* should we prevent DSP entering D3 ? */
+		if (!sdev->ipc_dump_printed)
+			dev_info(sdev->dev,
+				 "Attempting to prevent DSP from entering D3 state to preserve context\n");
+
+		if (pm_runtime_get_if_in_use(sdev->dev) == 1)
+			sdev->d3_prevented = true;
+	}
+
+	/* dump vital information to the logs */
+	snd_sof_ipc_dump(sdev);
+	snd_sof_dsp_dbg_dump(sdev, msg, SOF_DBG_DUMP_REGS | SOF_DBG_DUMP_MBOX);
+	sof_fw_trace_fw_crashed(sdev);
+}
+EXPORT_SYMBOL(snd_sof_handle_fw_exception);