Adding a couple AMD guys. I know this is already merged but I have a few questions after some internal discussions. On 2019-05-07 12:27 p.m., Ramalingam C wrote: > On every hdcp revocation check request SRM is read from fw file > /lib/firmware/display_hdcp_srm.bin > According to section 5 of the HDCP 2.3 spec [1] a device compliant with HDCP 2.0 and higher must be capable of storing and updating the SRM in non-volatile memory. Section 5.2 describes how this SRM needs to be updated when a new version is served alongside protected content. Isn't /lib/firmware intended for static firmware making updates to the folder problematic for anyone but the system's package maintainer? I've heard /lib might even be treated as read-only in certain environments. This would mean it'd be impossible to support HDCP 2.x on those systems. Wouldn't it be easier to provide a sysfs entry for SRM that allows userspace (e.g. system startup/shutdown scripts) to (a) retrieve the SRM from the HDCP implementation for non-volatile storage and (b) to pass the SRM to the HDCP implementation for revocation checking? [1] https://www.digital-cp.com/sites/default/files/HDCP%20on%20HDMI%20Specification%20Rev2_3.pdf Thanks, Harry > SRM table is parsed and stored at drm_hdcp.c, with functions exported > for the services for revocation check from drivers (which > implements the HDCP authentication) > > This patch handles the HDCP1.4 and 2.2 versions of SRM table. > > v2: > moved the uAPI to request_firmware_direct() [Daniel] > v3: > kdoc added. [Daniel] > srm_header unified and bit field definitions are removed. [Daniel] > locking improved. [Daniel] > vrl length violation is fixed. [Daniel] > v4: > s/__swab16/be16_to_cpu [Daniel] > be24_to_cpu is done through a global func [Daniel] > Unused variables are removed. [Daniel] > unchecked return values are dropped from static funcs [Daniel] > > Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx> > Acked-by: Satyeshwar Singh <satyeshwar.singh@xxxxxxxxx> > Reviewed-by: Daniel Vetter <daniel@xxxxxxxx> > --- > Documentation/gpu/drm-kms-helpers.rst | 6 + > drivers/gpu/drm/Makefile | 2 +- > drivers/gpu/drm/drm_hdcp.c | 333 ++++++++++++++++++++++++++ > drivers/gpu/drm/drm_internal.h | 4 + > drivers/gpu/drm/drm_sysfs.c | 2 + > include/drm/drm_hdcp.h | 24 ++ > 6 files changed, 370 insertions(+), 1 deletion(-) > create mode 100644 drivers/gpu/drm/drm_hdcp.c > > diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst > index 14102ae035dc..0fe726a6ee67 100644 > --- a/Documentation/gpu/drm-kms-helpers.rst > +++ b/Documentation/gpu/drm-kms-helpers.rst > @@ -181,6 +181,12 @@ Panel Helper Reference > .. kernel-doc:: drivers/gpu/drm/drm_panel_orientation_quirks.c > :export: > > +HDCP Helper Functions Reference > +=============================== > + > +.. kernel-doc:: drivers/gpu/drm/drm_hdcp.c > + :export: > + > Display Port Helper Functions Reference > ======================================= > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > index 72f5036d9bfa..dd02e9dec810 100644 > --- a/drivers/gpu/drm/Makefile > +++ b/drivers/gpu/drm/Makefile > @@ -17,7 +17,7 @@ drm-y := drm_auth.o drm_cache.o \ > drm_plane.o drm_color_mgmt.o drm_print.o \ > drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \ > drm_syncobj.o drm_lease.o drm_writeback.o drm_client.o \ > - drm_atomic_uapi.o > + drm_atomic_uapi.o drm_hdcp.o > > drm-$(CONFIG_DRM_LEGACY) += drm_legacy_misc.o drm_bufs.o drm_context.o drm_dma.o drm_scatter.o drm_lock.o > drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o > diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c > new file mode 100644 > index 000000000000..5e5409505c31 > --- /dev/null > +++ b/drivers/gpu/drm/drm_hdcp.c > @@ -0,0 +1,333 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 Intel Corporation. > + * > + * Authors: > + * Ramalingam C <ramalingam.c@xxxxxxxxx> > + */ > + > +#include <linux/device.h> > +#include <linux/err.h> > +#include <linux/gfp.h> > +#include <linux/export.h> > +#include <linux/slab.h> > +#include <linux/firmware.h> > + > +#include <drm/drm_hdcp.h> > +#include <drm/drm_sysfs.h> > +#include <drm/drm_print.h> > +#include <drm/drm_device.h> > + > +struct hdcp_srm { > + u32 revoked_ksv_cnt; > + u8 *revoked_ksv_list; > + > + /* Mutex to protect above struct member */ > + struct mutex mutex; > +} *srm_data; > + > +static inline void drm_hdcp_print_ksv(const u8 *ksv) > +{ > + DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n", > + ksv[0], ksv[1], ksv[2], ksv[3], ksv[4]); > +} > + > +static u32 drm_hdcp_get_revoked_ksv_count(const u8 *buf, u32 vrls_length) > +{ > + u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz; > + > + while (parsed_bytes < vrls_length) { > + vrl_ksv_cnt = *buf; > + ksv_count += vrl_ksv_cnt; > + > + vrl_sz = (vrl_ksv_cnt * DRM_HDCP_KSV_LEN) + 1; > + buf += vrl_sz; > + parsed_bytes += vrl_sz; > + } > + > + /* > + * When vrls are not valid, ksvs are not considered. > + * Hence SRM will be discarded. > + */ > + if (parsed_bytes != vrls_length) > + ksv_count = 0; > + > + return ksv_count; > +} > + > +static u32 drm_hdcp_get_revoked_ksvs(const u8 *buf, u8 *revoked_ksv_list, > + u32 vrls_length) > +{ > + u32 parsed_bytes = 0, ksv_count = 0; > + u32 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0; > + > + do { > + vrl_ksv_cnt = *buf; > + vrl_ksv_sz = vrl_ksv_cnt * DRM_HDCP_KSV_LEN; > + > + buf++; > + > + DRM_DEBUG("vrl: %d, Revoked KSVs: %d\n", vrl_idx++, > + vrl_ksv_cnt); > + memcpy(revoked_ksv_list, buf, vrl_ksv_sz); > + > + ksv_count += vrl_ksv_cnt; > + revoked_ksv_list += vrl_ksv_sz; > + buf += vrl_ksv_sz; > + > + parsed_bytes += (vrl_ksv_sz + 1); > + } while (parsed_bytes < vrls_length); > + > + return ksv_count; > +} > + > +static inline u32 get_vrl_length(const u8 *buf) > +{ > + return drm_hdcp_be24_to_cpu(buf); > +} > + > +static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count) > +{ > + struct hdcp_srm_header *header; > + u32 vrl_length, ksv_count; > + > + if (count < (sizeof(struct hdcp_srm_header) + > + DRM_HDCP_1_4_VRL_LENGTH_SIZE + DRM_HDCP_1_4_DCP_SIG_SIZE)) { > + DRM_ERROR("Invalid blob length\n"); > + return -EINVAL; > + } > + > + header = (struct hdcp_srm_header *)buf; > + DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n", > + header->srm_id, > + be16_to_cpu(header->srm_version), header->srm_gen_no); > + > + WARN_ON(header->reserved); > + > + buf = buf + sizeof(*header); > + vrl_length = get_vrl_length(buf); > + if (count < (sizeof(struct hdcp_srm_header) + vrl_length) || > + vrl_length < (DRM_HDCP_1_4_VRL_LENGTH_SIZE + > + DRM_HDCP_1_4_DCP_SIG_SIZE)) { > + DRM_ERROR("Invalid blob length or vrl length\n"); > + return -EINVAL; > + } > + > + /* Length of the all vrls combined */ > + vrl_length -= (DRM_HDCP_1_4_VRL_LENGTH_SIZE + > + DRM_HDCP_1_4_DCP_SIG_SIZE); > + > + if (!vrl_length) { > + DRM_ERROR("No vrl found\n"); > + return -EINVAL; > + } > + > + buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE; > + ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length); > + if (!ksv_count) { > + DRM_DEBUG("Revoked KSV count is 0\n"); > + return count; > + } > + > + kfree(srm_data->revoked_ksv_list); > + srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, > + GFP_KERNEL); > + if (!srm_data->revoked_ksv_list) { > + DRM_ERROR("Out of Memory\n"); > + return -ENOMEM; > + } > + > + if (drm_hdcp_get_revoked_ksvs(buf, srm_data->revoked_ksv_list, > + vrl_length) != ksv_count) { > + srm_data->revoked_ksv_cnt = 0; > + kfree(srm_data->revoked_ksv_list); > + return -EINVAL; > + } > + > + srm_data->revoked_ksv_cnt = ksv_count; > + return count; > +} > + > +static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count) > +{ > + struct hdcp_srm_header *header; > + u32 vrl_length, ksv_count, ksv_sz; > + > + if (count < (sizeof(struct hdcp_srm_header) + > + DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) { > + DRM_ERROR("Invalid blob length\n"); > + return -EINVAL; > + } > + > + header = (struct hdcp_srm_header *)buf; > + DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n", > + header->srm_id & DRM_HDCP_SRM_ID_MASK, > + be16_to_cpu(header->srm_version), header->srm_gen_no); > + > + if (header->reserved) > + return -EINVAL; > + > + buf = buf + sizeof(*header); > + vrl_length = get_vrl_length(buf); > + > + if (count < (sizeof(struct hdcp_srm_header) + vrl_length) || > + vrl_length < (DRM_HDCP_2_VRL_LENGTH_SIZE + > + DRM_HDCP_2_DCP_SIG_SIZE)) { > + DRM_ERROR("Invalid blob length or vrl length\n"); > + return -EINVAL; > + } > + > + /* Length of the all vrls combined */ > + vrl_length -= (DRM_HDCP_2_VRL_LENGTH_SIZE + > + DRM_HDCP_2_DCP_SIG_SIZE); > + > + if (!vrl_length) { > + DRM_ERROR("No vrl found\n"); > + return -EINVAL; > + } > + > + buf += DRM_HDCP_2_VRL_LENGTH_SIZE; > + ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1)); > + if (!ksv_count) { > + DRM_DEBUG("Revoked KSV count is 0\n"); > + return count; > + } > + > + kfree(srm_data->revoked_ksv_list); > + srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, > + GFP_KERNEL); > + if (!srm_data->revoked_ksv_list) { > + DRM_ERROR("Out of Memory\n"); > + return -ENOMEM; > + } > + > + ksv_sz = ksv_count * DRM_HDCP_KSV_LEN; > + buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ; > + > + DRM_DEBUG("Revoked KSVs: %d\n", ksv_count); > + memcpy(srm_data->revoked_ksv_list, buf, ksv_sz); > + > + srm_data->revoked_ksv_cnt = ksv_count; > + return count; > +} > + > +static inline bool is_srm_version_hdcp1(const u8 *buf) > +{ > + return *buf == (u8)(DRM_HDCP_1_4_SRM_ID << 4); > +} > + > +static inline bool is_srm_version_hdcp2(const u8 *buf) > +{ > + return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR); > +} > + > +static void drm_hdcp_srm_update(const u8 *buf, size_t count) > +{ > + if (count < sizeof(struct hdcp_srm_header)) > + return; > + > + if (is_srm_version_hdcp1(buf)) > + drm_hdcp_parse_hdcp1_srm(buf, count); > + else if (is_srm_version_hdcp2(buf)) > + drm_hdcp_parse_hdcp2_srm(buf, count); > +} > + > +void drm_hdcp_request_srm(struct drm_device *drm_dev) > +{ > + char fw_name[36] = "display_hdcp_srm.bin"; > + const struct firmware *fw; > + > + int ret; > + > + ret = request_firmware_direct(&fw, (const char *)fw_name, > + drm_dev->dev); > + if (ret < 0) > + goto exit; > + > + if (fw->size && fw->data) > + drm_hdcp_srm_update(fw->data, fw->size); > + > +exit: > + release_firmware(fw); > +} > + > +/** > + * drm_hdcp_check_ksvs_revoked - Check the revoked status of the IDs > + * > + * @drm_dev: drm_device for which HDCP revocation check is requested > + * @ksvs: List of KSVs (HDCP receiver IDs) > + * @ksv_count: KSV count passed in through @ksvs > + * > + * This function reads the HDCP System renewability Message(SRM Table) > + * from userspace as a firmware and parses it for the revoked HDCP > + * KSVs(Receiver IDs) detected by DCP LLC. Once the revoked KSVs are known, > + * revoked state of the KSVs in the list passed in by display drivers are > + * decided and response is sent. > + * > + * SRM should be presented in the name of "display_hdcp_srm.bin". > + * > + * Returns: > + * TRUE on any of the KSV is revoked, else FALSE. > + */ > +bool drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs, > + u32 ksv_count) > +{ > + u32 rev_ksv_cnt, cnt, i, j; > + u8 *rev_ksv_list; > + > + if (!srm_data) > + return false; > + > + mutex_lock(&srm_data->mutex); > + drm_hdcp_request_srm(drm_dev); > + > + rev_ksv_cnt = srm_data->revoked_ksv_cnt; > + rev_ksv_list = srm_data->revoked_ksv_list; > + > + /* If the Revoked ksv list is empty */ > + if (!rev_ksv_cnt || !rev_ksv_list) { > + mutex_unlock(&srm_data->mutex); > + return false; > + } > + > + for (cnt = 0; cnt < ksv_count; cnt++) { > + rev_ksv_list = srm_data->revoked_ksv_list; > + for (i = 0; i < rev_ksv_cnt; i++) { > + for (j = 0; j < DRM_HDCP_KSV_LEN; j++) > + if (ksvs[j] != rev_ksv_list[j]) { > + break; > + } else if (j == (DRM_HDCP_KSV_LEN - 1)) { > + DRM_DEBUG("Revoked KSV is "); > + drm_hdcp_print_ksv(ksvs); > + mutex_unlock(&srm_data->mutex); > + return true; > + } > + /* Move the offset to next KSV in the revoked list */ > + rev_ksv_list += DRM_HDCP_KSV_LEN; > + } > + > + /* Iterate to next ksv_offset */ > + ksvs += DRM_HDCP_KSV_LEN; > + } > + mutex_unlock(&srm_data->mutex); > + return false; > +} > +EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked); > + > +int drm_setup_hdcp_srm(struct class *drm_class) > +{ > + srm_data = kzalloc(sizeof(*srm_data), GFP_KERNEL); > + if (!srm_data) > + return -ENOMEM; > + mutex_init(&srm_data->mutex); > + > + return 0; > +} > + > +void drm_teardown_hdcp_srm(struct class *drm_class) > +{ > + if (srm_data) { > + kfree(srm_data->revoked_ksv_list); > + kfree(srm_data); > + } > +} > diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h > index e19ac7ca602d..476a422414f6 100644 > --- a/drivers/gpu/drm/drm_internal.h > +++ b/drivers/gpu/drm/drm_internal.h > @@ -201,3 +201,7 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data, > void drm_framebuffer_print_info(struct drm_printer *p, unsigned int indent, > const struct drm_framebuffer *fb); > int drm_framebuffer_debugfs_init(struct drm_minor *minor); > + > +/* drm_hdcp.c */ > +int drm_setup_hdcp_srm(struct class *drm_class); > +void drm_teardown_hdcp_srm(struct class *drm_class); > diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c > index ecb7b33002bb..18b1ac442997 100644 > --- a/drivers/gpu/drm/drm_sysfs.c > +++ b/drivers/gpu/drm/drm_sysfs.c > @@ -78,6 +78,7 @@ int drm_sysfs_init(void) > } > > drm_class->devnode = drm_devnode; > + drm_setup_hdcp_srm(drm_class); > return 0; > } > > @@ -90,6 +91,7 @@ void drm_sysfs_destroy(void) > { > if (IS_ERR_OR_NULL(drm_class)) > return; > + drm_teardown_hdcp_srm(drm_class); > class_remove_file(drm_class, &class_attr_version.attr); > class_destroy(drm_class); > drm_class = NULL; > diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h > index 1cc66df05a43..2f0335d0a50f 100644 > --- a/include/drm/drm_hdcp.h > +++ b/include/drm/drm_hdcp.h > @@ -265,4 +265,28 @@ void drm_hdcp_cpu_to_be24(u8 seq_num[HDCP_2_2_SEQ_NUM_LEN], u32 val) > seq_num[2] = val; > } > > +#define DRM_HDCP_SRM_GEN1_MAX_BYTES (5 * 1024) > +#define DRM_HDCP_1_4_SRM_ID 0x8 > +#define DRM_HDCP_SRM_ID_MASK (0xF << 4) > +#define DRM_HDCP_1_4_VRL_LENGTH_SIZE 3 > +#define DRM_HDCP_1_4_DCP_SIG_SIZE 40 > +#define DRM_HDCP_2_SRM_ID 0x9 > +#define DRM_HDCP_2_INDICATOR 0x1 > +#define DRM_HDCP_2_INDICATOR_MASK 0xF > +#define DRM_HDCP_2_VRL_LENGTH_SIZE 3 > +#define DRM_HDCP_2_DCP_SIG_SIZE 384 > +#define DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ 4 > +#define DRM_HDCP_2_KSV_COUNT_2_LSBITS(byte) (((byte) & 0xC) >> 6) > + > +struct hdcp_srm_header { > + u8 srm_id; > + u8 reserved; > + __be16 srm_version; > + u8 srm_gen_no; > +} __packed; > + > +struct drm_device; > + > +bool drm_hdcp_check_ksvs_revoked(struct drm_device *dev, > + u8 *ksvs, u32 ksv_count); > #endif > -- > 2.19.1 > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
