diff --git a/drivers/platform/x86/amd/hsmp/acpi.c b/drivers/platform/x86/amd/hsmp/acpi.c index 24f54dc7254f..8257cd1da48e 100644 --- a/drivers/platform/x86/amd/hsmp/acpi.c +++ b/drivers/platform/x86/amd/hsmp/acpi.c @@ -277,13 +277,31 @@ static ssize_t hsmp_metric_tbl_acpi_read(struct file *filp, struct kobject *kobj struct device *dev = container_of(kobj, struct device, kobj); struct hsmp_socket *sock = dev_get_drvdata(dev); + /* + * metrics_bin is a sysfs binary attribute and is capped at PAGE_SIZE. + * It can therefore only carry the protocol version 6 metric table + * (struct hsmp_metric_table). The larger tables defined from protocol + * version 7 onwards do not fit; userspace on those systems must read + * the snapshot through HSMP_IOCTL_GET_TELEMETRY_DATA on /dev/hsmp. + * Surface the unsupported case here as -EOPNOTSUPP rather than + * silently truncating the snapshot. + */ + if (hsmp_pdev->proto_ver != HSMP_PROTO_VER6) + return -EOPNOTSUPP; + return hsmp_metric_tbl_read(sock, buf, count); } static umode_t hsmp_is_sock_attr_visible(struct kobject *kobj, const struct bin_attribute *battr, int id) { - if (hsmp_pdev->proto_ver == HSMP_PROTO_VER6) + /* + * Keep metrics_bin visible on protocol version 7 and later as well, + * so that userspace which expects the file to exist gets a clear + * -EOPNOTSUPP from the read handler instead of -ENOENT, and is + * pointed at HSMP_IOCTL_GET_TELEMETRY_DATA as the supported path. + */ + if (hsmp_pdev->proto_ver >= HSMP_PROTO_VER6) return battr->attr.mode; return 0; @@ -539,7 +557,7 @@ static int init_acpi(struct device *dev) return ret; } - if (hsmp_pdev->proto_ver == HSMP_PROTO_VER6) { + if (hsmp_pdev->proto_ver >= HSMP_PROTO_VER6) { ret = hsmp_get_tbl_dram_base(sock_ind); if (ret) dev_info(dev, "Failed to init metric table\n");