diff options
| -rw-r--r-- | arch/powerpc/include/asm/rtas.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/kernel/rtas.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/Makefile | 2 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/papr-indices.c | 301 |
4 files changed, 304 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h index 04406162fc5a..7dc527a5aaac 100644 --- a/arch/powerpc/include/asm/rtas.h +++ b/arch/powerpc/include/asm/rtas.h @@ -515,6 +515,7 @@ extern char rtas_data_buf[RTAS_DATA_BUF_SIZE]; extern unsigned long rtas_rmo_buf; extern struct mutex rtas_ibm_get_vpd_lock; +extern struct mutex rtas_ibm_get_indices_lock; #define GLOBAL_INTERRUPT_QUEUE 9005 diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index d7a738f1858d..039ac5099aed 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -93,11 +93,11 @@ struct rtas_function { */ static DEFINE_MUTEX(rtas_ibm_activate_firmware_lock); static DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock); -static DEFINE_MUTEX(rtas_ibm_get_indices_lock); static DEFINE_MUTEX(rtas_ibm_lpar_perftools_lock); static DEFINE_MUTEX(rtas_ibm_physical_attestation_lock); static DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock); DEFINE_MUTEX(rtas_ibm_get_vpd_lock); +DEFINE_MUTEX(rtas_ibm_get_indices_lock); static struct rtas_function rtas_function_table[] __ro_after_init = { [RTAS_FNIDX__CHECK_EXCEPTION] = { diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile index 665dcec9ffcf..7ea293c7c5b6 100644 --- a/arch/powerpc/platforms/pseries/Makefile +++ b/arch/powerpc/platforms/pseries/Makefile @@ -3,7 +3,7 @@ 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-rtas-common.o papr-vpd.o \ + papr-rtas-common.o papr-vpd.o papr-indices.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 \ diff --git a/arch/powerpc/platforms/pseries/papr-indices.c b/arch/powerpc/platforms/pseries/papr-indices.c new file mode 100644 index 000000000000..a0b3c9a61c5c --- /dev/null +++ b/arch/powerpc/platforms/pseries/papr-indices.c @@ -0,0 +1,301 @@ +// 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" + +/** + * 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 = ¶ms; + fd = papr_rtas_setup_file_interface(&seq, + &papr_indices_handle_ops, "[papr-indices]"); + + return fd; +} + +/* + * 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; + 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; + + return misc_register(&papr_indices_dev); +} +machine_device_initcall(pseries, papr_indices_init); |