From fb39e9092be5a18eaab05b5a2492741fe6e395fe Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 27 Feb 2025 20:26:31 -0400 Subject: fwctl: FWCTL_INFO to return basic information about the device Userspace will need to know some details about the fwctl interface being used to locate the correct userspace code to communicate with the kernel. Provide a simple device_type enum indicating what the kernel driver is. Allow the device to provide a device specific info struct that contains any additional information that the driver may need to provide to userspace. Link: https://patch.msgid.link/r/3-v5-642aa0c94070+4447f-fwctl_jgg@nvidia.com Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Reviewed-by: Shannon Nelson Tested-by: Dave Jiang Tested-by: Shannon Nelson Signed-off-by: Jason Gunthorpe --- drivers/fwctl/main.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'drivers/fwctl') diff --git a/drivers/fwctl/main.c b/drivers/fwctl/main.c index 4bba6109712e..bd84c4e5b3b9 100644 --- a/drivers/fwctl/main.c +++ b/drivers/fwctl/main.c @@ -27,8 +27,62 @@ struct fwctl_ucmd { u32 user_size; }; +static int ucmd_respond(struct fwctl_ucmd *ucmd, size_t cmd_len) +{ + if (copy_to_user(ucmd->ubuffer, ucmd->cmd, + min_t(size_t, ucmd->user_size, cmd_len))) + return -EFAULT; + return 0; +} + +static int copy_to_user_zero_pad(void __user *to, const void *from, + size_t from_len, size_t user_len) +{ + size_t copy_len; + + copy_len = min(from_len, user_len); + if (copy_to_user(to, from, copy_len)) + return -EFAULT; + if (copy_len < user_len) { + if (clear_user(to + copy_len, user_len - copy_len)) + return -EFAULT; + } + return 0; +} + +static int fwctl_cmd_info(struct fwctl_ucmd *ucmd) +{ + struct fwctl_device *fwctl = ucmd->uctx->fwctl; + struct fwctl_info *cmd = ucmd->cmd; + size_t driver_info_len = 0; + + if (cmd->flags) + return -EOPNOTSUPP; + + if (!fwctl->ops->info && cmd->device_data_len) { + if (clear_user(u64_to_user_ptr(cmd->out_device_data), + cmd->device_data_len)) + return -EFAULT; + } else if (cmd->device_data_len) { + void *driver_info __free(kfree) = + fwctl->ops->info(ucmd->uctx, &driver_info_len); + if (IS_ERR(driver_info)) + return PTR_ERR(driver_info); + + if (copy_to_user_zero_pad(u64_to_user_ptr(cmd->out_device_data), + driver_info, driver_info_len, + cmd->device_data_len)) + return -EFAULT; + } + + cmd->out_device_type = fwctl->ops->device_type; + cmd->device_data_len = driver_info_len; + return ucmd_respond(ucmd, sizeof(*cmd)); +} + /* On stack memory for the ioctl structs */ union fwctl_ucmd_buffer { + struct fwctl_info info; }; struct fwctl_ioctl_op { @@ -48,6 +102,7 @@ struct fwctl_ioctl_op { .execute = _fn, \ } static const struct fwctl_ioctl_op fwctl_ioctl_ops[] = { + IOCTL_OP(FWCTL_INFO, fwctl_cmd_info, struct fwctl_info, out_device_data), }; static long fwctl_fops_ioctl(struct file *filp, unsigned int cmd, -- cgit v1.2.3