--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) "papr-common: " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/anon_inodes.h>
+#include <linux/sched/signal.h>
+#include "papr-rtas-common.h"
+
+/*
+ * Sequence based RTAS HCALL has to issue multiple times to retrieve
+ * complete data from the hypervisor. For some of these RTAS calls,
+ * the OS should not interleave calls with different input until the
+ * sequence is completed. So data is collected for these calls during
+ * ioctl handle and export to user space with read() handle.
+ * This file provides common functions needed for such sequence based
+ * RTAS calls Ex: ibm,get-vpd and ibm,get-indices.
+ */
+
+bool papr_rtas_blob_has_data(const struct papr_rtas_blob *blob)
+{
+ return blob->data && blob->len;
+}
+
+void papr_rtas_blob_free(const struct papr_rtas_blob *blob)
+{
+ if (blob) {
+ kvfree(blob->data);
+ kfree(blob);
+ }
+}
+
+/**
+ * papr_rtas_blob_extend() - Append data to a &struct papr_rtas_blob.
+ * @blob: The blob to extend.
+ * @data: The new data to append to @blob.
+ * @len: The length of @data.
+ *
+ * Context: May sleep.
+ * Return: -ENOMEM on allocation failure, 0 otherwise.
+ */
+static int papr_rtas_blob_extend(struct papr_rtas_blob *blob,
+ const char *data, size_t len)
+{
+ const size_t new_len = blob->len + len;
+ const size_t old_len = blob->len;
+ const char *old_ptr = blob->data;
+ char *new_ptr;
+
+ new_ptr = kvrealloc(old_ptr, new_len, GFP_KERNEL_ACCOUNT);
+ if (!new_ptr)
+ return -ENOMEM;
+
+ memcpy(&new_ptr[old_len], data, len);
+ blob->data = new_ptr;
+ blob->len = new_len;
+ return 0;
+}
+
+/**
+ * papr_rtas_blob_generate() - Construct a new &struct papr_rtas_blob.
+ * @seq: work function of the caller that is called to obtain
+ * data with the caller RTAS call.
+ *
+ * The @work callback is invoked until it returns NULL. @seq is
+ * passed to @work in its first argument on each call. When
+ * @work returns data, it should store the data length in its
+ * second argument.
+ *
+ * Context: May sleep.
+ * Return: A completely populated &struct papr_rtas_blob, or NULL on error.
+ */
+static const struct papr_rtas_blob *
+papr_rtas_blob_generate(struct papr_rtas_sequence *seq)
+{
+ struct papr_rtas_blob *blob;
+ const char *buf;
+ size_t len;
+ int err = 0;
+
+ blob = kzalloc(sizeof(*blob), GFP_KERNEL_ACCOUNT);
+ if (!blob)
+ return NULL;
+
+ if (!seq->work)
+ return ERR_PTR(-EINVAL);
+
+
+ while (err == 0 && (buf = seq->work(seq, &len)))
+ err = papr_rtas_blob_extend(blob, buf, len);
+
+ if (err != 0 || !papr_rtas_blob_has_data(blob))
+ goto free_blob;
+
+ return blob;
+free_blob:
+ papr_rtas_blob_free(blob);
+ return NULL;
+}
+
+int papr_rtas_sequence_set_err(struct papr_rtas_sequence *seq, int err)
+{
+ /* Preserve the first error recorded. */
+ if (seq->error == 0)
+ seq->error = err;
+
+ return seq->error;
+}
+
+/*
+ * Higher-level retrieval code below. These functions use the
+ * papr_rtas_blob_* and sequence_* APIs defined above to create fd-based
+ * handles for consumption by user space.
+ */
+
+/**
+ * papr_rtas_run_sequence() - Run a single retrieval sequence.
+ * @seq: Functions of the caller to complete the sequence
+ *
+ * Context: May sleep. Holds a mutex and an RTAS work area for its
+ * duration. Typically performs multiple sleepable slab
+ * allocations.
+ *
+ * Return: A populated &struct papr_rtas_blob on success. Encoded error
+ * pointer otherwise.
+ */
+static const struct papr_rtas_blob *papr_rtas_run_sequence(struct papr_rtas_sequence *seq)
+{
+ const struct papr_rtas_blob *blob;
+
+ if (seq->begin)
+ seq->begin(seq);
+
+ blob = papr_rtas_blob_generate(seq);
+ if (!blob)
+ papr_rtas_sequence_set_err(seq, -ENOMEM);
+
+ if (seq->end)
+ seq->end(seq);
+
+
+ if (seq->error) {
+ papr_rtas_blob_free(blob);
+ return ERR_PTR(seq->error);
+ }
+
+ return blob;
+}
+
+/**
+ * papr_rtas_retrieve() - Return the data blob that is exposed to
+ * user space.
+ * @seq: RTAS call specific functions to be invoked until the
+ * sequence is completed.
+ *
+ * Run sequences against @param until a blob is successfully
+ * instantiated, or a hard error is encountered, or a fatal signal is
+ * pending.
+ *
+ * Context: May sleep.
+ * Return: A fully populated data blob when successful. Encoded error
+ * pointer otherwise.
+ */
+const struct papr_rtas_blob *papr_rtas_retrieve(struct papr_rtas_sequence *seq)
+{
+ const struct papr_rtas_blob *blob;
+
+ /*
+ * EAGAIN means the sequence returns error with a -4 (data
+ * changed and need to start the sequence) status from RTAS calls
+ * and we should attempt a new sequence. PAPR+ (v2.13 R1–7.3.20–5
+ * - ibm,get-vpd, R1–7.3.17–6 - ibm,get-indices) indicates that
+ * this should be a transient condition, not something that
+ * happens continuously. But we'll stop trying on a fatal signal.
+ */
+ do {
+ blob = papr_rtas_run_sequence(seq);
+ if (!IS_ERR(blob)) /* Success. */
+ break;
+ if (PTR_ERR(blob) != -EAGAIN) /* Hard error. */
+ break;
+ cond_resched();
+ } while (!fatal_signal_pending(current));
+
+ return blob;
+}
+
+/**
+ * papr_rtas_setup_file_interface - Complete the sequence and obtain
+ * the data and export to user space with fd-based handles. Then the
+ * user spave gets the data with read() handle.
+ * @seq: RTAS call specific functions to get the data.
+ * @fops: RTAS call specific file operations such as read().
+ * @name: RTAS call specific char device node.
+ *
+ * Return: FD handle for consumption by user space
+ */
+long papr_rtas_setup_file_interface(struct papr_rtas_sequence *seq,
+ const struct file_operations *fops,
+ char *name)
+{
+ const struct papr_rtas_blob *blob;
+ struct file *file;
+ long ret;
+ int fd;
+
+ blob = papr_rtas_retrieve(seq);
+ if (IS_ERR(blob))
+ return PTR_ERR(blob);
+
+ fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ ret = fd;
+ goto free_blob;
+ }
+
+ file = anon_inode_getfile_fmode(name, fops, (void *)blob,
+ O_RDONLY, FMODE_LSEEK | FMODE_PREAD);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto put_fd;
+ }
+
+ fd_install(fd, file);
+ return fd;
+
+put_fd:
+ put_unused_fd(fd);
+free_blob:
+ papr_rtas_blob_free(blob);
+ return ret;
+}
+
+/*
+ * papr_rtas_sequence_should_stop() - Determine whether RTAS retrieval
+ * sequence should continue.
+ *
+ * Examines the sequence error state and outputs of the last call to
+ * the specific RTAS to determine whether the sequence in progress
+ * should continue or stop.
+ *
+ * Return: True if the sequence has encountered an error or if all data
+ * for this sequence has been retrieved. False otherwise.
+ */
+bool papr_rtas_sequence_should_stop(const struct papr_rtas_sequence *seq,
+ s32 status, bool init_state)
+{
+ bool done;
+
+ if (seq->error)
+ return true;
+
+ switch (status) {
+ case RTAS_SEQ_COMPLETE:
+ if (init_state)
+ done = false; /* Initial state. */
+ else
+ done = true; /* All data consumed. */
+ break;
+ case RTAS_SEQ_MORE_DATA:
+ done = false; /* More data available. */
+ break;
+ default:
+ done = true; /* Error encountered. */
+ break;
+ }
+
+ return done;
+}
+
+/*
+ * User space read to retrieve data for the corresponding RTAS call.
+ * papr_rtas_blob is filled with the data using the corresponding RTAS
+ * call sequence API.
+ */
+ssize_t papr_rtas_common_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;
+ }
+
+ return simple_read_from_buffer(buf, size, off, blob->data, blob->len);
+}
+
+int papr_rtas_common_handle_release(struct inode *inode,
+ struct file *file)
+{
+ const struct papr_rtas_blob *blob = file->private_data;
+
+ papr_rtas_blob_free(blob);
+
+ return 0;
+}
+
+loff_t papr_rtas_common_handle_seek(struct file *file, loff_t off,
+ int whence)
+{
+ const struct papr_rtas_blob *blob = file->private_data;
+
+ return fixed_size_llseek(file, off, whence, blob->len);
+}
#define pr_fmt(fmt) "papr-vpd: " fmt
-#include <linux/anon_inodes.h>
#include <linux/build_bug.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <asm/rtas-work-area.h>
#include <asm/rtas.h>
#include <uapi/asm/papr-vpd.h>
-
-/*
- * Function-specific return values for ibm,get-vpd, derived from PAPR+
- * v2.13 7.3.20 "ibm,get-vpd RTAS Call".
- */
-#define RTAS_IBM_GET_VPD_COMPLETE 0 /* All VPD has been retrieved. */
-#define RTAS_IBM_GET_VPD_MORE_DATA 1 /* More VPD is available. */
-#define RTAS_IBM_GET_VPD_START_OVER -4 /* VPD changed, restart call sequence. */
+#include "papr-rtas-common.h"
/**
* struct rtas_ibm_get_vpd_params - Parameters (in and out) for ibm,get-vpd.
case RTAS_INVALID_PARAMETER:
ret = -EINVAL;
break;
- case RTAS_IBM_GET_VPD_START_OVER:
+ case RTAS_SEQ_START_OVER:
ret = -EAGAIN;
+ pr_info_ratelimited("VPD changed during retrieval, retrying\n");
break;
- case RTAS_IBM_GET_VPD_MORE_DATA:
+ case RTAS_SEQ_MORE_DATA:
params->sequence = rets[0];
fallthrough;
- case RTAS_IBM_GET_VPD_COMPLETE:
+ case RTAS_SEQ_COMPLETE:
params->written = rets[1];
/*
* Kernel or firmware bug, do not continue.
return ret;
}
-/*
- * Internal VPD "blob" APIs for accumulating ibm,get-vpd results into
- * an immutable buffer to be attached to a file descriptor.
- */
-struct vpd_blob {
- const char *data;
- size_t len;
-};
-
-static bool vpd_blob_has_data(const struct vpd_blob *blob)
-{
- return blob->data && blob->len;
-}
-
-static void vpd_blob_free(const struct vpd_blob *blob)
-{
- if (blob) {
- kvfree(blob->data);
- kfree(blob);
- }
-}
-
-/**
- * vpd_blob_extend() - Append data to a &struct vpd_blob.
- * @blob: The blob to extend.
- * @data: The new data to append to @blob.
- * @len: The length of @data.
- *
- * Context: May sleep.
- * Return: -ENOMEM on allocation failure, 0 otherwise.
- */
-static int vpd_blob_extend(struct vpd_blob *blob, const char *data, size_t len)
-{
- const size_t new_len = blob->len + len;
- const size_t old_len = blob->len;
- const char *old_ptr = blob->data;
- char *new_ptr;
-
- new_ptr = kvrealloc(old_ptr, new_len, GFP_KERNEL_ACCOUNT);
- if (!new_ptr)
- return -ENOMEM;
-
- memcpy(&new_ptr[old_len], data, len);
- blob->data = new_ptr;
- blob->len = new_len;
- return 0;
-}
-
-/**
- * vpd_blob_generate() - Construct a new &struct vpd_blob.
- * @generator: Function that supplies the blob data.
- * @arg: Context pointer supplied by caller, passed to @generator.
- *
- * The @generator callback is invoked until it returns NULL. @arg is
- * passed to @generator in its first argument on each call. When
- * @generator returns data, it should store the data length in its
- * second argument.
- *
- * Context: May sleep.
- * Return: A completely populated &struct vpd_blob, or NULL on error.
- */
-static const struct vpd_blob *
-vpd_blob_generate(const char * (*generator)(void *, size_t *), void *arg)
-{
- struct vpd_blob *blob;
- const char *buf;
- size_t len;
- int err = 0;
-
- blob = kzalloc(sizeof(*blob), GFP_KERNEL_ACCOUNT);
- if (!blob)
- return NULL;
-
- while (err == 0 && (buf = generator(arg, &len)))
- err = vpd_blob_extend(blob, buf, len);
-
- if (err != 0 || !vpd_blob_has_data(blob))
- goto free_blob;
-
- return blob;
-free_blob:
- vpd_blob_free(blob);
- return NULL;
-}
-
/*
* Internal VPD sequence APIs. A VPD sequence is a series of calls to
* ibm,get-vpd for a given location code. The sequence ends when an
* returned.
*/
-/**
- * struct vpd_sequence - State for managing a VPD sequence.
- * @error: Shall be zero as long as the sequence has not encountered an error,
- * -ve errno otherwise. Use vpd_sequence_set_err() to update this.
- * @params: Parameter block to pass to rtas_ibm_get_vpd().
- */
-struct vpd_sequence {
- int error;
- struct rtas_ibm_get_vpd_params params;
-};
-
/**
* vpd_sequence_begin() - Begin a VPD retrieval sequence.
- * @seq: Uninitialized sequence state.
- * @loc_code: Location code that defines the scope of the VPD to return.
- *
- * Initializes @seq with the resources necessary to carry out a VPD
- * sequence. Callers must pass @seq to vpd_sequence_end() regardless
- * of whether the sequence succeeds.
+ * @seq: vpd call parameters from sequence struct
*
* Context: May sleep.
*/
-static void vpd_sequence_begin(struct vpd_sequence *seq,
- const struct papr_location_code *loc_code)
+static void vpd_sequence_begin(struct papr_rtas_sequence *seq)
{
+ struct rtas_ibm_get_vpd_params *vpd_params;
/*
* Use a static data structure for the location code passed to
* RTAS to ensure it's in the RMA and avoid a separate work
*/
static struct papr_location_code static_loc_code;
+ vpd_params = (struct rtas_ibm_get_vpd_params *)seq->params;
/*
* We could allocate the work area before acquiring the
* function lock, but that would allow concurrent requests to
* allocate the work area under the lock.
*/
mutex_lock(&rtas_ibm_get_vpd_lock);
- static_loc_code = *loc_code;
- *seq = (struct vpd_sequence) {
- .params = {
- .work_area = rtas_work_area_alloc(SZ_4K),
- .loc_code = &static_loc_code,
- .sequence = 1,
- },
- };
+ static_loc_code = *(struct papr_location_code *)vpd_params->loc_code;
+ vpd_params = (struct rtas_ibm_get_vpd_params *)seq->params;
+ vpd_params->work_area = rtas_work_area_alloc(SZ_4K);
+ vpd_params->loc_code = &static_loc_code;
+ vpd_params->sequence = 1;
+ vpd_params->status = 0;
}
/**
*
* Releases resources obtained by vpd_sequence_begin().
*/
-static void vpd_sequence_end(struct vpd_sequence *seq)
+static void vpd_sequence_end(struct papr_rtas_sequence *seq)
{
- rtas_work_area_free(seq->params.work_area);
- mutex_unlock(&rtas_ibm_get_vpd_lock);
-}
-
-/**
- * vpd_sequence_should_stop() - Determine whether a VPD retrieval sequence
- * should continue.
- * @seq: VPD sequence state.
- *
- * Examines the sequence error state and outputs of the last call to
- * ibm,get-vpd to determine whether the sequence in progress should
- * continue or stop.
- *
- * Return: True if the sequence has encountered an error or if all VPD for
- * this sequence has been retrieved. False otherwise.
- */
-static bool vpd_sequence_should_stop(const struct vpd_sequence *seq)
-{
- bool done;
-
- if (seq->error)
- return true;
+ struct rtas_ibm_get_vpd_params *vpd_params;
- switch (seq->params.status) {
- case 0:
- if (seq->params.written == 0)
- done = false; /* Initial state. */
- else
- done = true; /* All data consumed. */
- break;
- case 1:
- done = false; /* More data available. */
- break;
- default:
- done = true; /* Error encountered. */
- break;
- }
-
- return done;
-}
-
-static int vpd_sequence_set_err(struct vpd_sequence *seq, int err)
-{
- /* Preserve the first error recorded. */
- if (seq->error == 0)
- seq->error = err;
-
- return seq->error;
+ vpd_params = (struct rtas_ibm_get_vpd_params *)seq->params;
+ rtas_work_area_free(vpd_params->work_area);
+ mutex_unlock(&rtas_ibm_get_vpd_lock);
}
/*
- * Generator function to be passed to vpd_blob_generate().
+ * Generator function to be passed to papr_rtas_blob_generate().
*/
-static const char *vpd_sequence_fill_work_area(void *arg, size_t *len)
+static const char *vpd_sequence_fill_work_area(struct papr_rtas_sequence *seq,
+ size_t *len)
{
- struct vpd_sequence *seq = arg;
- struct rtas_ibm_get_vpd_params *p = &seq->params;
+ struct rtas_ibm_get_vpd_params *p;
+ bool init_state;
- if (vpd_sequence_should_stop(seq))
+ p = (struct rtas_ibm_get_vpd_params *)seq->params;
+ init_state = (p->written == 0) ? true : false;
+
+ if (papr_rtas_sequence_should_stop(seq, p->status, init_state))
return NULL;
- if (vpd_sequence_set_err(seq, rtas_ibm_get_vpd(p)))
+ if (papr_rtas_sequence_set_err(seq, rtas_ibm_get_vpd(p)))
return NULL;
*len = p->written;
return rtas_work_area_raw_buf(p->work_area);
}
-/*
- * Higher-level VPD retrieval code below. These functions use the
- * vpd_blob_* and vpd_sequence_* APIs defined above to create fd-based
- * VPD handles for consumption by user space.
- */
-
-/**
- * papr_vpd_run_sequence() - Run a single VPD retrieval sequence.
- * @loc_code: Location code that defines the scope of VPD to return.
- *
- * Context: May sleep. Holds a mutex and an RTAS work area for its
- * duration. Typically performs multiple sleepable slab
- * allocations.
- *
- * Return: A populated &struct vpd_blob on success. Encoded error
- * pointer otherwise.
- */
-static const struct vpd_blob *papr_vpd_run_sequence(const struct papr_location_code *loc_code)
-{
- const struct vpd_blob *blob;
- struct vpd_sequence seq;
-
- vpd_sequence_begin(&seq, loc_code);
- blob = vpd_blob_generate(vpd_sequence_fill_work_area, &seq);
- if (!blob)
- vpd_sequence_set_err(&seq, -ENOMEM);
- vpd_sequence_end(&seq);
-
- if (seq.error) {
- vpd_blob_free(blob);
- return ERR_PTR(seq.error);
- }
-
- return blob;
-}
-
-/**
- * papr_vpd_retrieve() - Return the VPD for a location code.
- * @loc_code: Location code that defines the scope of VPD to return.
- *
- * Run VPD sequences against @loc_code until a blob is successfully
- * instantiated, or a hard error is encountered, or a fatal signal is
- * pending.
- *
- * Context: May sleep.
- * Return: A fully populated VPD blob when successful. Encoded error
- * pointer otherwise.
- */
-static const struct vpd_blob *papr_vpd_retrieve(const struct papr_location_code *loc_code)
-{
- const struct vpd_blob *blob;
-
- /*
- * EAGAIN means the sequence errored with a -4 (VPD changed)
- * status from ibm,get-vpd, and we should attempt a new
- * sequence. PAPR+ v2.13 R1–7.3.20–5 indicates that this
- * should be a transient condition, not something that happens
- * continuously. But we'll stop trying on a fatal signal.
- */
- do {
- blob = papr_vpd_run_sequence(loc_code);
- if (!IS_ERR(blob)) /* Success. */
- break;
- if (PTR_ERR(blob) != -EAGAIN) /* Hard error. */
- break;
- pr_info_ratelimited("VPD changed during retrieval, retrying\n");
- cond_resched();
- } while (!fatal_signal_pending(current));
-
- return blob;
-}
-
-static ssize_t papr_vpd_handle_read(struct file *file, char __user *buf, size_t size, loff_t *off)
-{
- const struct vpd_blob *blob = file->private_data;
-
- /* bug: we should not instantiate a handle without any data attached. */
- if (!vpd_blob_has_data(blob)) {
- pr_err_once("handle without data\n");
- return -EIO;
- }
-
- return simple_read_from_buffer(buf, size, off, blob->data, blob->len);
-}
-
-static int papr_vpd_handle_release(struct inode *inode, struct file *file)
-{
- const struct vpd_blob *blob = file->private_data;
-
- vpd_blob_free(blob);
-
- return 0;
-}
-
-static loff_t papr_vpd_handle_seek(struct file *file, loff_t off, int whence)
-{
- const struct vpd_blob *blob = file->private_data;
-
- return fixed_size_llseek(file, off, whence, blob->len);
-}
-
-
static const struct file_operations papr_vpd_handle_ops = {
- .read = papr_vpd_handle_read,
- .llseek = papr_vpd_handle_seek,
- .release = papr_vpd_handle_release,
+ .read = papr_rtas_common_handle_read,
+ .llseek = papr_rtas_common_handle_seek,
+ .release = papr_rtas_common_handle_release,
};
/**
*/
static long papr_vpd_create_handle(struct papr_location_code __user *ulc)
{
+ struct rtas_ibm_get_vpd_params vpd_params = {};
+ struct papr_rtas_sequence seq = {};
struct papr_location_code klc;
- const struct vpd_blob *blob;
- struct file *file;
- long err;
int fd;
if (copy_from_user(&klc, ulc, sizeof(klc)))
if (!string_is_terminated(klc.str, ARRAY_SIZE(klc.str)))
return -EINVAL;
- blob = papr_vpd_retrieve(&klc);
- if (IS_ERR(blob))
- return PTR_ERR(blob);
+ seq = (struct papr_rtas_sequence) {
+ .begin = vpd_sequence_begin,
+ .end = vpd_sequence_end,
+ .work = vpd_sequence_fill_work_area,
+ };
- fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
- if (fd < 0) {
- err = fd;
- goto free_blob;
- }
+ vpd_params.loc_code = &klc;
+ seq.params = (void *)&vpd_params;
+
+ fd = papr_rtas_setup_file_interface(&seq, &papr_vpd_handle_ops,
+ "[papr-vpd]");
- file = anon_inode_getfile_fmode("[papr-vpd]", &papr_vpd_handle_ops,
- (void *)blob, O_RDONLY,
- FMODE_LSEEK | FMODE_PREAD);
- if (IS_ERR(file)) {
- err = PTR_ERR(file);
- goto put_fd;
- }
- fd_install(fd, file);
return fd;
-put_fd:
- put_unused_fd(fd);
-free_blob:
- vpd_blob_free(blob);
- return err;
}
/*
projects / users / willy / linux.git / commitdiff