This support allows the DRTM launch to be initiated after an EFI stub launch of the Linux kernel is done. This is accomplished by providing a handler to jump to when a Secure Launch is in progress. This has to be called after the EFI stub does Exit Boot Services. Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxxx> Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- drivers/firmware/efi/libstub/efistub.h | 8 ++ drivers/firmware/efi/libstub/x86-stub.c | 99 +++++++++++++++++++++++++ 2 files changed, 107 insertions(+) diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index d33ccbc4a2c6..baf42d6d0796 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -135,6 +135,14 @@ void efi_set_u64_split(u64 data, u32 *lo, u32 *hi) *hi = upper_32_bits(data); } +static inline +void efi_set_u64_form(u32 lo, u32 hi, u64 *data) +{ + u64 upper = hi; + + *data = lo | upper << 32; +} + /* * Allocation types for calls to boottime->allocate_pages. */ diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index f8e465da344d..2e063bce1080 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -9,6 +9,8 @@ #include <linux/efi.h> #include <linux/pci.h> #include <linux/stddef.h> +#include <linux/slr_table.h> +#include <linux/slaunch.h> #include <asm/efi.h> #include <asm/e820/types.h> @@ -923,6 +925,98 @@ static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry) return efi_adjust_memory_range_protection(addr, kernel_text_size); } +#if (IS_ENABLED(CONFIG_SECURE_LAUNCH)) +static bool efi_secure_launch_update_boot_params(struct slr_table *slrt, + struct boot_params *boot_params) +{ + struct slr_entry_intel_info *txt_info; + struct slr_entry_policy *policy; + struct txt_os_mle_data *os_mle; + bool updated = false; + int i; + + txt_info = slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_INTEL_INFO); + if (!txt_info) + return false; + + os_mle = txt_os_mle_data_start((void *)txt_info->txt_heap); + if (!os_mle) + return false; + + os_mle->boot_params_addr = (u64)boot_params; + + policy = slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_ENTRY_POLICY); + if (!policy) + return false; + + for (i = 0; i < policy->nr_entries; i++) { + if (policy->policy_entries[i].entity_type == SLR_ET_BOOT_PARAMS) { + policy->policy_entries[i].entity = (u64)boot_params; + updated = true; + break; + } + } + + /* + * If this is a PE entry into EFI stub the mocked up boot params will + * be missing some of the setup header data needed for the second stage + * of the Secure Launch boot. + */ + if (image) { + struct setup_header *hdr = (struct setup_header *)((u8 *)image->image_base + + offsetof(struct boot_params, hdr)); + u64 cmdline_ptr; + + boot_params->hdr.setup_sects = hdr->setup_sects; + boot_params->hdr.syssize = hdr->syssize; + boot_params->hdr.version = hdr->version; + boot_params->hdr.loadflags = hdr->loadflags; + boot_params->hdr.kernel_alignment = hdr->kernel_alignment; + boot_params->hdr.min_alignment = hdr->min_alignment; + boot_params->hdr.xloadflags = hdr->xloadflags; + boot_params->hdr.init_size = hdr->init_size; + boot_params->hdr.kernel_info_offset = hdr->kernel_info_offset; + efi_set_u64_form(boot_params->hdr.cmd_line_ptr, boot_params->ext_cmd_line_ptr, + &cmdline_ptr); + boot_params->hdr.cmdline_size = strlen((const char *)cmdline_ptr); + } + + return updated; +} + +static void efi_secure_launch(struct boot_params *boot_params) +{ + struct slr_entry_dl_info *dlinfo; + efi_guid_t guid = SLR_TABLE_GUID; + dl_handler_func handler_callback; + struct slr_table *slrt; + + /* + * The presence of this table indicated a Secure Launch + * is being requested. + */ + slrt = (struct slr_table *)get_efi_config_table(guid); + if (!slrt || slrt->magic != SLR_TABLE_MAGIC) + return; + + /* + * Since the EFI stub library creates its own boot_params on entry, the + * SLRT and TXT heap have to be updated with this version. + */ + if (!efi_secure_launch_update_boot_params(slrt, boot_params)) + return; + + /* Jump through DL stub to initiate Secure Launch */ + dlinfo = slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); + + handler_callback = (dl_handler_func)dlinfo->dl_handler; + + handler_callback(&dlinfo->bl_context); + + unreachable(); +} +#endif + static void __noreturn enter_kernel(unsigned long kernel_addr, struct boot_params *boot_params) { @@ -1050,6 +1144,11 @@ void __noreturn efi_stub_entry(efi_handle_t handle, goto fail; } +#if (IS_ENABLED(CONFIG_SECURE_LAUNCH)) + /* If a Secure Launch is in progress, this never returns */ + efi_secure_launch(boot_params); +#endif + /* * Call the SEV init code while still running with the firmware's * GDT/IDT, so #VC exceptions will be handled by EFI. -- 2.39.3