@@ -349,6 +349,8 @@ Code Seq# Include File Comments
<mailto:vgo@ratio.de>
0xB1 00-1F PPPoX
<mailto:mostrows@styx.uwaterloo.ca>
+0xB2 00 arch/powerpc/include/uapi/asm/papr-vpd.h powerpc/pseries VPD API
+ <mailto:linuxppc-dev>
0xB3 00 linux/mmc/ioctl.h
0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
new file mode 100644
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_PAPR_MISCDEV_H_
+#define _UAPI_PAPR_MISCDEV_H_
+
+enum {
+ PAPR_MISCDEV_IOC_ID = 0xb2,
+};
+
+#endif /* _UAPI_PAPR_MISCDEV_H_ */
new file mode 100644
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_PAPR_VPD_H_
+#define _UAPI_PAPR_VPD_H_
+
+#include <asm/ioctl.h>
+#include <asm/papr-miscdev.h>
+
+struct papr_location_code {
+ /*
+ * PAPR+ v2.13 12.3.2.4 Converged Location Code Rules - Length
+ * Restrictions. 79 characters plus nul.
+ */
+ char str[80];
+};
+
+/*
+ * ioctl for /dev/papr-vpd. Returns a VPD handle fd corresponding to
+ * the location code.
+ */
+#define PAPR_VPD_IOC_CREATE_HANDLE _IOW(PAPR_MISCDEV_IOC_ID, 0, struct papr_location_code)
+
+#endif /* _UAPI_PAPR_VPD_H_ */
@@ -4,6 +4,7 @@ ccflags-$(CONFIG_PPC_PSERIES_DEBUG) += -DDEBUG
obj-y := lpar.o hvCall.o nvram.o reconfig.o \
of_helpers.o rtas-work-area.o papr-sysparm.o \
+ papr-vpd.o \
setup.o iommu.o event_sources.o ras.o \
firmware.o power.o dlpar.o mobility.o rng.o \
pci.o pci_dlpar.o eeh_pseries.o msi.o \
new file mode 100644
@@ -0,0 +1,541 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#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 <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/papr-vpd.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. */
+
+/**
+ * struct rtas_ibm_get_vpd_params - Parameters (in and out) for ibm,get-vpd.
+ * @loc_code: In: Caller-provided location code buffer. Must be RTAS-addressable.
+ * @work_area: In: Caller-provided work area buffer for results.
+ * @sequence: In: Sequence number. Out: Next sequence number.
+ * @written: Out: Bytes written by ibm,get-vpd to @work_area.
+ * @status: Out: RTAS call status.
+ */
+struct rtas_ibm_get_vpd_params {
+ const struct papr_location_code *loc_code;
+ struct rtas_work_area *work_area;
+ u32 sequence;
+ u32 written;
+ s32 status;
+};
+
+/**
+ * rtas_ibm_get_vpd() - Call ibm,get-vpd to fill a work area buffer.
+ * @params: See &struct rtas_ibm_get_vpd_params.
+ *
+ * Calls ibm,get-vpd 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_vpd() multiple times
+ * to retrieve all the VPD for the provided location code. Only one
+ * sequence should be in progress at any time; starting a new sequence
+ * will disrupt any sequence already in progress. Serialization of VPD
+ * 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_vpd(struct rtas_ibm_get_vpd_params *params)
+{
+ const struct papr_location_code *loc_code = params->loc_code;
+ struct rtas_work_area *work_area = params->work_area;
+ u32 rets[2];
+ s32 fwrc;
+ int ret;
+
+ lockdep_assert_held(&rtas_ibm_get_vpd_lock);
+
+ do {
+ fwrc = rtas_call(rtas_function_token(RTAS_FN_IBM_GET_VPD), 4, 3,
+ rets,
+ __pa(loc_code),
+ rtas_work_area_phys(work_area),
+ rtas_work_area_size(work_area),
+ params->sequence);
+ } while (rtas_busy_delay(fwrc));
+
+ switch (fwrc) {
+ case RTAS_HARDWARE_ERROR:
+ ret = -EIO;
+ break;
+ case RTAS_INVALID_PARAMETER:
+ ret = -EINVAL;
+ break;
+ case RTAS_IBM_GET_VPD_START_OVER:
+ ret = -EAGAIN;
+ break;
+ case RTAS_IBM_GET_VPD_MORE_DATA:
+ params->sequence = rets[0];
+ fallthrough;
+ case RTAS_IBM_GET_VPD_COMPLETE:
+ params->written = rets[1];
+ /*
+ * Kernel or firmware bug, do not continue.
+ */
+ if (WARN(params->written > rtas_work_area_size(work_area),
+ "possible write beyond end of work area"))
+ ret = -EFAULT;
+ else
+ ret = 0;
+ break;
+ default:
+ ret = -EIO;
+ pr_err_ratelimited("unexpected ibm,get-vpd status %d\n", fwrc);
+ break;
+ }
+
+ params->status = fwrc;
+ 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 = old_ptr ?
+ kvrealloc(old_ptr, old_len, new_len, GFP_KERNEL_ACCOUNT) :
+ kvmalloc(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
+ * error is encountered or all VPD for the location code has been
+ * 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.
+ *
+ * Context: May sleep.
+ */
+static void vpd_sequence_begin(struct vpd_sequence *seq,
+ const struct papr_location_code *loc_code)
+{
+ /*
+ * Use a static data structure for the location code passed to
+ * RTAS to ensure it's in the RMA and avoid a separate work
+ * area allocation. Guarded by the function lock.
+ */
+ static struct papr_location_code static_loc_code;
+
+ /*
+ * 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_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,
+ },
+ };
+}
+
+/**
+ * vpd_sequence_end() - Finalize a VPD retrieval sequence.
+ * @seq: Sequence state.
+ *
+ * Releases resources obtained by vpd_sequence_begin().
+ */
+static void vpd_sequence_end(struct vpd_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;
+
+ 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;
+}
+
+/*
+ * Generator function to be passed to vpd_blob_generate().
+ */
+static const char *vpd_sequence_fill_work_area(void *arg, size_t *len)
+{
+ struct vpd_sequence *seq = arg;
+ struct rtas_ibm_get_vpd_params *p = &seq->params;
+
+ if (vpd_sequence_should_stop(seq))
+ return NULL;
+ if (vpd_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,
+};
+
+/**
+ * papr_vpd_create_handle() - Create a fd-based handle for reading VPD.
+ * @ulc: Location code in user memory; defines the scope of the VPD to
+ * retrieve.
+ *
+ * Handler for PAPR_VPD_IOC_CREATE_HANDLE ioctl command. Validates
+ * @ulc and instantiates an immutable VPD "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 VPD 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-vpd call sequences.
+ *
+ * Return: The installed fd number if successful, -ve errno otherwise.
+ */
+static long papr_vpd_create_handle(struct papr_location_code __user *ulc)
+{
+ 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)))
+ return -EFAULT;
+
+ 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);
+
+ fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ err = fd;
+ goto free_blob;
+ }
+
+ file = anon_inode_getfile("[papr-vpd]", &papr_vpd_handle_ops,
+ (void *)blob, O_RDONLY);
+ if (IS_ERR(file)) {
+ err = PTR_ERR(file);
+ goto put_fd;
+ }
+
+ file->f_mode |= FMODE_LSEEK | FMODE_PREAD;
+ fd_install(fd, file);
+ return fd;
+put_fd:
+ put_unused_fd(fd);
+free_blob:
+ vpd_blob_free(blob);
+ return err;
+}
+
+/*
+ * Top-level ioctl handler for /dev/papr-vpd.
+ */
+static long papr_vpd_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
+{
+ void __user *argp = (__force void __user *)arg;
+ long ret;
+
+ switch (ioctl) {
+ case PAPR_VPD_IOC_CREATE_HANDLE:
+ ret = papr_vpd_create_handle(argp);
+ break;
+ default:
+ ret = -ENOIOCTLCMD;
+ break;
+ }
+ return ret;
+}
+
+static const struct file_operations papr_vpd_ops = {
+ .unlocked_ioctl = papr_vpd_dev_ioctl,
+};
+
+static struct miscdevice papr_vpd_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "papr-vpd",
+ .fops = &papr_vpd_ops,
+};
+
+static __init int papr_vpd_init(void)
+{
+ if (!rtas_function_implemented(RTAS_FN_IBM_GET_VPD))
+ return -ENODEV;
+
+ return misc_register(&papr_vpd_dev);
+}
+machine_device_initcall(pseries, papr_vpd_init);