1 files changed, 488 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/papr-indices.c b/arch/powerpc/platforms/pseries/papr-indices.c
new file mode 100644
index 000000000000..3c7545591c45
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/papr-indices.c
@@ -0,0 +1,488 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) "papr-indices: " fmt
+
+#include <linux/build_bug.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/lockdep.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/string_helpers.h>
+#include <linux/uaccess.h>
+#include <asm/machdep.h>
+#include <asm/rtas-work-area.h>
+#include <asm/rtas.h>
+#include <uapi/asm/papr-indices.h>
+#include "papr-rtas-common.h"
+
+/*
+ * Function-specific return values for ibm,set-dynamic-indicator and
+ * ibm,get-dynamic-sensor-state RTAS calls.
+ * PAPR+ v2.13 7.3.18 and 7.3.19.
+ */
+#define RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR	-3
+
+/**
+ * struct rtas_get_indices_params - Parameters (in and out) for
+ *                                      ibm,get-indices.
+ * @is_sensor:	In: Caller-provided whether sensor or indicator.
+ * @indice_type:In: Caller-provided indice (sensor or indicator) token
+ * @work_area:	In: Caller-provided work area buffer for results.
+ * @next:	In: Sequence number. Out: Next sequence number.
+ * @status:	Out: RTAS call status.
+ */
+struct rtas_get_indices_params {
+	u8 is_sensor;
+	u32 indice_type;
+	struct rtas_work_area *work_area;
+	u32 next;
+	s32 status;
+};
+
+/*
+ * rtas_ibm_get_indices() - Call ibm,get-indices to fill a work area buffer.
+ * @params: See &struct rtas_ibm_get_indices_params.
+ *
+ * Calls ibm,get-indices until it errors or successfully deposits data
+ * into the supplied work area. Handles RTAS retry statuses. Maps RTAS
+ * error statuses to reasonable errno values.
+ *
+ * The caller is expected to invoke rtas_ibm_get_indices() multiple times
+ * to retrieve all indices data for the provided indice type. Only one
+ * sequence should be in progress at any time; starting a new sequence
+ * will disrupt any sequence already in progress. Serialization of
+ * indices retrieval sequences is the responsibility of the caller.
+ *
+ * The caller should inspect @params.status to determine whether more
+ * calls are needed to complete the sequence.
+ *
+ * Context: May sleep.
+ * Return: -ve on error, 0 otherwise.
+ */
+static int rtas_ibm_get_indices(struct rtas_get_indices_params *params)
+{
+	struct rtas_work_area *work_area = params->work_area;
+	const s32 token = rtas_function_token(RTAS_FN_IBM_GET_INDICES);
+	u32 rets;
+	s32 fwrc;
+	int ret;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	lockdep_assert_held(&rtas_ibm_get_indices_lock);
+
+	do {
+		fwrc = rtas_call(token, 5, 2, &rets, params->is_sensor,
+				params->indice_type,
+				rtas_work_area_phys(work_area),
+				rtas_work_area_size(work_area),
+				params->next);
+	} while (rtas_busy_delay(fwrc));
+
+	switch (fwrc) {
+	case RTAS_HARDWARE_ERROR:
+		ret = -EIO;
+		break;
+	case RTAS_INVALID_PARAMETER: /* Indicator type is not supported */
+		ret = -EINVAL;
+		break;
+	case RTAS_SEQ_START_OVER:
+		ret = -EAGAIN;
+		pr_info_ratelimited("Indices changed during retrieval, retrying\n");
+		params->next = 1;
+		break;
+	case RTAS_SEQ_MORE_DATA:
+		params->next = rets;
+		ret = 0;
+		break;
+	case RTAS_SEQ_COMPLETE:
+		params->next = 0;
+		ret = 0;
+		break;
+	default:
+		ret = -EIO;
+		pr_err_ratelimited("unexpected ibm,get-indices status %d\n", fwrc);
+		break;
+	}
+
+	params->status = fwrc;
+	return ret;
+}
+
+/*
+ * Internal indices sequence APIs. A sequence is a series of calls to
+ * ibm,get-indices for a given location code. The sequence ends when
+ * an error is encountered or all indices for the input has been
+ * returned.
+ */
+
+/*
+ * indices_sequence_begin() - Begin a indices retrieval sequence.
+ *
+ * Context: May sleep.
+ */
+static void indices_sequence_begin(struct papr_rtas_sequence *seq)
+{
+	struct rtas_get_indices_params  *param;
+
+	param = (struct rtas_get_indices_params *)seq->params;
+	/*
+	 * We could allocate the work area before acquiring the
+	 * function lock, but that would allow concurrent requests to
+	 * exhaust the limited work area pool for no benefit. So
+	 * allocate the work area under the lock.
+	 */
+	mutex_lock(&rtas_ibm_get_indices_lock);
+	param->work_area = rtas_work_area_alloc(RTAS_GET_INDICES_BUF_SIZE);
+	param->next = 1;
+	param->status = 0;
+}
+
+/*
+ * indices_sequence_end() - Finalize a indices retrieval sequence.
+ *
+ * Releases resources obtained by indices_sequence_begin().
+ */
+static void indices_sequence_end(struct papr_rtas_sequence *seq)
+{
+	struct rtas_get_indices_params *param;
+
+	param =  (struct rtas_get_indices_params *)seq->params;
+	rtas_work_area_free(param->work_area);
+	mutex_unlock(&rtas_ibm_get_indices_lock);
+}
+
+/*
+ * Work function to be passed to papr_rtas_blob_generate().
+ *
+ * ibm,get-indices RTAS call fills the work area with the certain
+ * format but does not return the bytes written in the buffer. So
+ * instead of kernel parsing this work area to determine the buffer
+ * length, copy the complete work area (RTAS_GET_INDICES_BUF_SIZE)
+ * to the blob and let the user space to obtain the data.
+ * Means RTAS_GET_INDICES_BUF_SIZE data will be returned for each
+ * read().
+ */
+
+static const char *indices_sequence_fill_work_area(struct papr_rtas_sequence *seq,
+						size_t *len)
+{
+	struct rtas_get_indices_params *p;
+	bool init_state;
+
+	p = (struct rtas_get_indices_params *)seq->params;
+	init_state = (p->next == 1) ? true : false;
+
+	if (papr_rtas_sequence_should_stop(seq, p->status, init_state))
+		return NULL;
+	if (papr_rtas_sequence_set_err(seq, rtas_ibm_get_indices(p)))
+		return NULL;
+
+	*len = RTAS_GET_INDICES_BUF_SIZE;
+	return rtas_work_area_raw_buf(p->work_area);
+}
+
+/*
+ * papr_indices_handle_read - returns indices blob data to the user space
+ *
+ * ibm,get-indices RTAS call fills the work area with the certian
+ * format but does not return the bytes written in the buffer and
+ * copied RTAS_GET_INDICES_BUF_SIZE data to the blob for each RTAS
+ * call. So send RTAS_GET_INDICES_BUF_SIZE buffer to the user space
+ * for each read().
+ */
+static ssize_t papr_indices_handle_read(struct file *file,
+		char __user *buf, size_t size, loff_t *off)
+{
+	const struct papr_rtas_blob *blob = file->private_data;
+
+	/* we should not instantiate a handle without any data attached. */
+	if (!papr_rtas_blob_has_data(blob)) {
+		pr_err_once("handle without data\n");
+		return -EIO;
+	}
+
+	if (size < RTAS_GET_INDICES_BUF_SIZE) {
+		pr_err_once("Invalid buffer length %ld, expect %d\n",
+				size, RTAS_GET_INDICES_BUF_SIZE);
+		return -EINVAL;
+	} else if (size > RTAS_GET_INDICES_BUF_SIZE)
+		size = RTAS_GET_INDICES_BUF_SIZE;
+
+	return simple_read_from_buffer(buf, size, off, blob->data, blob->len);
+}
+
+static const struct file_operations papr_indices_handle_ops = {
+	.read = papr_indices_handle_read,
+	.llseek = papr_rtas_common_handle_seek,
+	.release = papr_rtas_common_handle_release,
+};
+
+/*
+ * papr_indices_create_handle() - Create a fd-based handle for reading
+ *                                indices data
+ * @ubuf: Input parameters to RTAS call such as whether sensor or indicator
+ *        and indice type in user memory
+ *
+ * Handler for PAPR_INDICES_IOC_GET ioctl command. Validates @ubuf
+ * and instantiates an immutable indices "blob" for it. The blob is
+ * attached to a file descriptor for reading by user space. The memory
+ * backing the blob is freed when the file is released.
+ *
+ * The entire requested indices is retrieved by this call and all
+ * necessary RTAS interactions are performed before returning the fd
+ * to user space. This keeps the read handler simple and ensures that
+ * the kernel can prevent interleaving of ibm,get-indices call sequences.
+ *
+ * Return: The installed fd number if successful, -ve errno otherwise.
+ */
+static long papr_indices_create_handle(struct papr_indices_io_block __user *ubuf)
+{
+	struct papr_rtas_sequence seq = {};
+	struct rtas_get_indices_params params = {};
+	int fd;
+
+	if (get_user(params.is_sensor, &ubuf->indices.is_sensor))
+		return -EFAULT;
+
+	if (get_user(params.indice_type, &ubuf->indices.indice_type))
+		return -EFAULT;
+
+	seq = (struct papr_rtas_sequence) {
+		.begin = indices_sequence_begin,
+		.end = indices_sequence_end,
+		.work = indices_sequence_fill_work_area,
+	};
+
+	seq.params = &params;
+	fd = papr_rtas_setup_file_interface(&seq,
+			&papr_indices_handle_ops, "[papr-indices]");
+
+	return fd;
+}
+
+/*
+ * Create work area with the input parameters. This function is used
+ * for both ibm,set-dynamic-indicator and ibm,get-dynamic-sensor-state
+ * RTAS Calls.
+ */
+static struct rtas_work_area *
+papr_dynamic_indice_buf_from_user(struct papr_indices_io_block __user *ubuf,
+				struct papr_indices_io_block *kbuf)
+{
+	struct rtas_work_area *work_area;
+	u32 length;
+	__be32 len_be;
+
+	if (copy_from_user(kbuf, ubuf, sizeof(*kbuf)))
+		return ERR_PTR(-EFAULT);
+
+
+	if (!string_is_terminated(kbuf->dynamic_param.location_code_str,
+			ARRAY_SIZE(kbuf->dynamic_param.location_code_str)))
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * The input data in the work area should be as follows:
+	 * - 32-bit integer length of the location code string,
+	 *   including NULL.
+	 * - Location code string, NULL terminated, identifying the
+	 *   token (sensor or indicator).
+	 * PAPR 2.13 - R1–7.3.18–5 ibm,set-dynamic-indicator
+	 *           - R1–7.3.19–5 ibm,get-dynamic-sensor-state
+	 */
+	/*
+	 * Length that user space passed should also include NULL
+	 * terminator.
+	 */
+	length = strlen(kbuf->dynamic_param.location_code_str) + 1;
+	if (length > LOC_CODE_SIZE)
+		return ERR_PTR(-EINVAL);
+
+	len_be = cpu_to_be32(length);
+
+	work_area = rtas_work_area_alloc(LOC_CODE_SIZE + sizeof(u32));
+	memcpy(rtas_work_area_raw_buf(work_area), &len_be, sizeof(u32));
+	memcpy((rtas_work_area_raw_buf(work_area) + sizeof(u32)),
+			&kbuf->dynamic_param.location_code_str, length);
+
+	return work_area;
+}
+
+/**
+ * papr_dynamic_indicator_ioc_set - ibm,set-dynamic-indicator RTAS Call
+ * PAPR 2.13 7.3.18
+ *
+ * @ubuf: Input parameters to RTAS call such as indicator token and
+ *        new state.
+ *
+ * Returns success or -errno.
+ */
+static long papr_dynamic_indicator_ioc_set(struct papr_indices_io_block __user *ubuf)
+{
+	struct papr_indices_io_block kbuf;
+	struct rtas_work_area *work_area;
+	s32 fwrc, token, ret;
+
+	token = rtas_function_token(RTAS_FN_IBM_SET_DYNAMIC_INDICATOR);
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	mutex_lock(&rtas_ibm_set_dynamic_indicator_lock);
+	work_area = papr_dynamic_indice_buf_from_user(ubuf, &kbuf);
+	if (IS_ERR(work_area)) {
+		ret = PTR_ERR(work_area);
+		goto out;
+	}
+
+	do {
+		fwrc = rtas_call(token, 3, 1, NULL,
+				kbuf.dynamic_param.token,
+				kbuf.dynamic_param.state,
+				rtas_work_area_phys(work_area));
+	} while (rtas_busy_delay(fwrc));
+
+	rtas_work_area_free(work_area);
+
+	switch (fwrc) {
+	case RTAS_SUCCESS:
+		ret = 0;
+		break;
+	case RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR:	/* No such indicator */
+		ret = -EOPNOTSUPP;
+		break;
+	default:
+		pr_err("unexpected ibm,set-dynamic-indicator result %d\n",
+			fwrc);
+		fallthrough;
+	case RTAS_HARDWARE_ERROR:	/* Hardware/platform error */
+		ret = -EIO;
+		break;
+	}
+
+out:
+	mutex_unlock(&rtas_ibm_set_dynamic_indicator_lock);
+	return ret;
+}
+
+/**
+ * papr_dynamic_sensor_ioc_get - ibm,get-dynamic-sensor-state RTAS Call
+ * PAPR 2.13 7.3.19
+ *
+ * @ubuf: Input parameters to RTAS call such as sensor token
+ *        Copies the state in user space buffer.
+ *
+ *
+ * Returns success or -errno.
+ */
+
+static long papr_dynamic_sensor_ioc_get(struct papr_indices_io_block __user *ubuf)
+{
+	struct papr_indices_io_block kbuf;
+	struct rtas_work_area *work_area;
+	s32 fwrc, token, ret;
+	u32 rets;
+
+	token = rtas_function_token(RTAS_FN_IBM_GET_DYNAMIC_SENSOR_STATE);
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	mutex_lock(&rtas_ibm_get_dynamic_sensor_state_lock);
+	work_area = papr_dynamic_indice_buf_from_user(ubuf, &kbuf);
+	if (IS_ERR(work_area)) {
+		ret = PTR_ERR(work_area);
+		goto out;
+	}
+
+	do {
+		fwrc = rtas_call(token, 2, 2, &rets,
+				kbuf.dynamic_param.token,
+				rtas_work_area_phys(work_area));
+	} while (rtas_busy_delay(fwrc));
+
+	rtas_work_area_free(work_area);
+
+	switch (fwrc) {
+	case RTAS_SUCCESS:
+		if (put_user(rets, &ubuf->dynamic_param.state))
+			ret = -EFAULT;
+		else
+			ret = 0;
+		break;
+	case RTAS_IBM_DYNAMIC_INDICE_NO_INDICATOR:	/* No such indicator */
+		ret = -EOPNOTSUPP;
+		break;
+	default:
+		pr_err("unexpected ibm,get-dynamic-sensor result %d\n",
+				fwrc);
+		fallthrough;
+	case RTAS_HARDWARE_ERROR:	/* Hardware/platform error */
+		ret = -EIO;
+		break;
+	}
+
+out:
+	mutex_unlock(&rtas_ibm_get_dynamic_sensor_state_lock);
+	return ret;
+}
+
+/*
+ * Top-level ioctl handler for /dev/papr-indices.
+ */
+static long papr_indices_dev_ioctl(struct file *filp, unsigned int ioctl,
+				unsigned long arg)
+{
+	void __user *argp = (__force void __user *)arg;
+	long ret;
+
+	switch (ioctl) {
+	case PAPR_INDICES_IOC_GET:
+		ret = papr_indices_create_handle(argp);
+		break;
+	case PAPR_DYNAMIC_SENSOR_IOC_GET:
+		ret = papr_dynamic_sensor_ioc_get(argp);
+		break;
+	case PAPR_DYNAMIC_INDICATOR_IOC_SET:
+		if (filp->f_mode & FMODE_WRITE)
+			ret = papr_dynamic_indicator_ioc_set(argp);
+		else
+			ret = -EBADF;
+		break;
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+
+	return ret;
+}
+
+static const struct file_operations papr_indices_ops = {
+	.unlocked_ioctl = papr_indices_dev_ioctl,
+};
+
+static struct miscdevice papr_indices_dev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "papr-indices",
+	.fops = &papr_indices_ops,
+};
+
+static __init int papr_indices_init(void)
+{
+	if (!rtas_function_implemented(RTAS_FN_IBM_GET_INDICES))
+		return -ENODEV;
+
+	if (!rtas_function_implemented(RTAS_FN_IBM_SET_DYNAMIC_INDICATOR))
+		return -ENODEV;
+
+	if (!rtas_function_implemented(RTAS_FN_IBM_GET_DYNAMIC_SENSOR_STATE))
+		return -ENODEV;
+
+	return misc_register(&papr_indices_dev);
+}
+machine_device_initcall(pseries, papr_indices_init);