| Message ID | 20201023120825.30466-1-ard.biesheuvel@arm.com |
|---|---|
| Headers | show |
| Series | linux: implement LoadFile2 initrd loading | expand |
initrd typo in subject minor style comments below On Fri, Oct 23, 2020 at 14:08:24 +0200, Ard Biesheuvel wrote: > Recent Linux kernels will invoke the LoadFile2 protocol installed on > a well-known vendor media path to load the initrd if it is exposed by > the firmware. Using this method is preferred for two reasons: > - the Linux kernel is in charge of allocating the memory, and so it can > implement any placement policy it wants (given that these tend to > change between kernel versions), > - it is no longer necessary to modify the device tree provided by the > firmware. > > So let's install this protocol when handling the 'initrd' command if > such a recent kernel was detected (based on the PE/COFF image version), > and defer loading the initrd contents until the point where the kernel > invokes the LoadFile2 protocol. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com> > --- > grub-core/loader/arm64/linux.c | 117 +++++++++++++++++++- > 1 file changed, 116 insertions(+), 1 deletion(-) > > diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c > index ef3e9f9444ca..285422c7bd43 100644 > --- a/grub-core/loader/arm64/linux.c > +++ b/grub-core/loader/arm64/linux.c > @@ -48,9 +48,16 @@ static grub_uint32_t cmdline_size; > static grub_addr_t initrd_start; > static grub_addr_t initrd_end; > > +static struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 }; > +static grub_efi_handle_t initrd_lf2_handle; > +static int initrd_use_loadfile2; > + > grub_err_t > grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh) > { > + struct grub_pe32_coff_header *coff_header; > + struct grub_pe32_optional_header *optional_header; > + > if (lh->magic != GRUB_LINUX_ARMXX_MAGIC_SIGNATURE) > return grub_error(GRUB_ERR_BAD_OS, "invalid magic number"); > > @@ -61,6 +68,21 @@ grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh) > grub_dprintf ("linux", "UEFI stub kernel:\n"); > grub_dprintf ("linux", "PE/COFF header @ %08x\n", lh->hdr_offset); > > + coff_header = (struct grub_pe32_coff_header *)((unsigned long)lh + lh->hdr_offset); > + optional_header = (struct grub_pe32_optional_header *)(coff_header + 1); > + > + /* > + * Linux kernels built for any architecture are guaranteed to support the > + * LoadFile2 based initrd loading protocol if the image version is >= 1. > + */ > + if (optional_header->major_image_version >= 1) > + initrd_use_loadfile2 = 1; > + else funky indentation > + initrd_use_loadfile2 = 0; > + > + grub_dprintf ("linux", "LoadFile2 initrd loading %sabled\n", > + initrd_use_loadfile2 ? "en" : "dis"); > + > return GRUB_ERR_NONE; > } > > @@ -230,13 +252,88 @@ allocate_initrd_mem (int initrd_pages) > GRUB_EFI_LOADER_DATA); > } > > +struct initrd_media_device_path { > + grub_efi_vendor_media_device_path_t vendor; > + grub_efi_device_path_t end; > +} GRUB_PACKED; > + > +#define LINUX_EFI_INITRD_MEDIA_GUID \ > + { 0x5568e427, 0x68fc, 0x4f3d, \ > + { 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68 } \ > + } > + > +static struct initrd_media_device_path initrd_lf2_device_path = { > + { > + { > + GRUB_EFI_MEDIA_DEVICE_PATH_TYPE, > + GRUB_EFI_VENDOR_MEDIA_DEVICE_PATH_SUBTYPE, > + sizeof(grub_efi_vendor_media_device_path_t), > + }, > + LINUX_EFI_INITRD_MEDIA_GUID > + }, { > + GRUB_EFI_END_DEVICE_PATH_TYPE, > + GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE, > + sizeof(grub_efi_device_path_t) > + } > +}; > + > +static grub_efi_status_t > +grub_efi_initrd_load_file2(grub_efi_load_file2_t *this, Static functions don't need global prefixes (i.e., initrd_load_file2 would be sufficient). > + grub_efi_device_path_t *device_path, > + grub_efi_boolean_t boot_policy, > + grub_efi_uintn_t *buffer_size, > + void *buffer); > + > +static grub_efi_load_file2_t initrd_lf2 = { > + grub_efi_initrd_load_file2 > +}; > + > +static grub_efi_status_t > +grub_efi_initrd_load_file2(grub_efi_load_file2_t *this, > + grub_efi_device_path_t *device_path, > + grub_efi_boolean_t boot_policy, > + grub_efi_uintn_t *buffer_size, > + void *buffer) > +{ > + grub_efi_status_t status = GRUB_EFI_SUCCESS; > + grub_efi_uintn_t initrd_size; > + > + if (!this || this != &initrd_lf2 || !buffer_size) > + return GRUB_EFI_INVALID_PARAMETER; > + > + if (device_path->type != GRUB_EFI_END_DEVICE_PATH_TYPE || > + device_path->subtype != GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE) > + return GRUB_EFI_NOT_FOUND; > + > + if (boot_policy) > + return GRUB_EFI_UNSUPPORTED; > + > + initrd_size = grub_get_initrd_size (&initrd_ctx); > + if (!buffer || *buffer_size < initrd_size) > + { > + *buffer_size = initrd_size; > + return GRUB_EFI_BUFFER_TOO_SMALL; > + } > + > + grub_dprintf ("linux", "Loading initrd via LOAD_FILE2_PROTOCOL\n"); > + > + if (grub_initrd_load (&initrd_ctx, NULL, buffer)) > + status = GRUB_EFI_LOAD_ERROR; > + > + grub_initrd_close (&initrd_ctx); > + return status; > +} > + > static grub_err_t > grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)), > int argc, char *argv[]) > { > - struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 }; > int initrd_size, initrd_pages; > void *initrd_mem = NULL; > + grub_efi_guid_t load_file2_guid = GRUB_EFI_LOAD_FILE2_PROTOCOL_GUID; > + grub_efi_guid_t device_path_guid = GRUB_EFI_DEVICE_PATH_GUID; > + grub_efi_boot_services_t *b; > + grub_efi_status_t status; > > if (argc == 0) > { > @@ -254,6 +351,24 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)), > if (grub_initrd_init (argc, argv, &initrd_ctx)) > goto fail; > > + if (initrd_use_loadfile2 && !initrd_lf2_handle) > + { > + b = grub_efi_system_table->boot_services; > + status = b->install_multiple_protocol_interfaces (&initrd_lf2_handle, > + &load_file2_guid, > + &initrd_lf2, > + &device_path_guid, > + &initrd_lf2_device_path, > + NULL); > + if (status == GRUB_EFI_OUT_OF_RESOURCES) > + { indented by spaces > + grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory")); > + return grub_errno; > + } indented with tab / Leif > + grub_dprintf ("linux", "LoadFile2 initrd loading protocol installed\n"); > + return GRUB_ERR_NONE; > + } > + > initrd_size = grub_get_initrd_size (&initrd_ctx); > grub_dprintf ("linux", "Loading initrd\n"); > > -- > 2.17.1 >
On Fri, Oct 23, 2020 at 14:08:21 +0200, Ard Biesheuvel wrote: > This implements the LoadFile2 initrd loading protocol, which is > essentially a callback face into the bootloader to load the initrd > data into a caller provided buffer. This means the bootloader no > longer has to contain any policy regarding where to load the initrd > (which differs between architectures and kernel versions) and no > longer has to manipulate arch specific data structures such as DT > or struct bootparams to inform the OS where the initrd resides in > memory. > > Sample output from booting a recent Linux/arm64 kernel: > > grub> insmod part_msdos > grub> linux (hd0,msdos1)/Image > grub> initrd (hd0,msdos1)/initrd.img > grub> boot > EFI stub: Booting Linux Kernel... > EFI stub: EFI_RNG_PROTOCOL unavailable, KASLR will be disabled > EFI stub: Generating empty DTB > EFI stub: Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path > EFI stub: Exiting boot services and installing virtual address map... > [ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x411fd070] I don't review enough grub code to be certain I've caught all aspects of style adherence, so with that in mind, for 1-2/4: Reviewed-by: Leif Lindholm <leif@nuviainc.com> For 3-4/4, I did have some minor comments, but this is a really great feature and I would like to see it merged. / Leif > Cc: grub-devel@gnu.org > Cc: daniel.kiper@oracle.com > Cc: leif@nuviainc.com > > Ard Biesheuvel (4): > loader/linux: permit NULL argument for argv[] in grub_initrd_load() > efi: add definition of LoadFile2 protocol > efi: implemented LoadFile2 initr loading protocol for Linux > linux: ignore FDT unless we need to modify it > > grub-core/commands/efi/lsefi.c | 1 + > grub-core/loader/arm64/linux.c | 139 ++++++++++++++++++-- > grub-core/loader/efi/fdt.c | 7 +- > grub-core/loader/linux.c | 2 +- > include/grub/efi/api.h | 15 +++ > 5 files changed, 149 insertions(+), 15 deletions(-) > > -- > 2.17.1 >
On Fri, 23 Oct 2020 at 14:32, Leif Lindholm <leif@nuviainc.com> wrote: > > initrd typo in subject > > minor style comments below > > On Fri, Oct 23, 2020 at 14:08:24 +0200, Ard Biesheuvel wrote: > > Recent Linux kernels will invoke the LoadFile2 protocol installed on > > a well-known vendor media path to load the initrd if it is exposed by > > the firmware. Using this method is preferred for two reasons: > > - the Linux kernel is in charge of allocating the memory, and so it can > > implement any placement policy it wants (given that these tend to > > change between kernel versions), > > - it is no longer necessary to modify the device tree provided by the > > firmware. > > > > So let's install this protocol when handling the 'initrd' command if > > such a recent kernel was detected (based on the PE/COFF image version), > > and defer loading the initrd contents until the point where the kernel > > invokes the LoadFile2 protocol. > > > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com> > > --- > > grub-core/loader/arm64/linux.c | 117 +++++++++++++++++++- > > 1 file changed, 116 insertions(+), 1 deletion(-) > > > > diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c > > index ef3e9f9444ca..285422c7bd43 100644 > > --- a/grub-core/loader/arm64/linux.c > > +++ b/grub-core/loader/arm64/linux.c > > @@ -48,9 +48,16 @@ static grub_uint32_t cmdline_size; > > static grub_addr_t initrd_start; > > static grub_addr_t initrd_end; > > > > +static struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 }; > > +static grub_efi_handle_t initrd_lf2_handle; > > +static int initrd_use_loadfile2; > > + > > grub_err_t > > grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh) > > { > > + struct grub_pe32_coff_header *coff_header; > > + struct grub_pe32_optional_header *optional_header; > > + > > if (lh->magic != GRUB_LINUX_ARMXX_MAGIC_SIGNATURE) > > return grub_error(GRUB_ERR_BAD_OS, "invalid magic number"); > > > > @@ -61,6 +68,21 @@ grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh) > > grub_dprintf ("linux", "UEFI stub kernel:\n"); > > grub_dprintf ("linux", "PE/COFF header @ %08x\n", lh->hdr_offset); > > > > + coff_header = (struct grub_pe32_coff_header *)((unsigned long)lh + lh->hdr_offset); > > + optional_header = (struct grub_pe32_optional_header *)(coff_header + 1); > > + > > + /* > > + * Linux kernels built for any architecture are guaranteed to support the > > + * LoadFile2 based initrd loading protocol if the image version is >= 1. > > + */ > > + if (optional_header->major_image_version >= 1) > > + initrd_use_loadfile2 = 1; > > + else > > funky indentation > > > + initrd_use_loadfile2 = 0; > > + > > + grub_dprintf ("linux", "LoadFile2 initrd loading %sabled\n", > > + initrd_use_loadfile2 ? "en" : "dis"); > > + > > return GRUB_ERR_NONE; > > } > > > > @@ -230,13 +252,88 @@ allocate_initrd_mem (int initrd_pages) > > GRUB_EFI_LOADER_DATA); > > } > > > > +struct initrd_media_device_path { > > + grub_efi_vendor_media_device_path_t vendor; > > + grub_efi_device_path_t end; > > +} GRUB_PACKED; > > + > > +#define LINUX_EFI_INITRD_MEDIA_GUID \ > > + { 0x5568e427, 0x68fc, 0x4f3d, \ > > + { 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68 } \ > > + } > > + > > +static struct initrd_media_device_path initrd_lf2_device_path = { > > + { > > + { > > + GRUB_EFI_MEDIA_DEVICE_PATH_TYPE, > > + GRUB_EFI_VENDOR_MEDIA_DEVICE_PATH_SUBTYPE, > > + sizeof(grub_efi_vendor_media_device_path_t), > > + }, > > + LINUX_EFI_INITRD_MEDIA_GUID > > + }, { > > + GRUB_EFI_END_DEVICE_PATH_TYPE, > > + GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE, > > + sizeof(grub_efi_device_path_t) > > + } > > +}; > > + > > +static grub_efi_status_t > > +grub_efi_initrd_load_file2(grub_efi_load_file2_t *this, > > Static functions don't need global prefixes (i.e., initrd_load_file2 > would be sufficient). > > > + grub_efi_device_path_t *device_path, > > + grub_efi_boolean_t boot_policy, > > + grub_efi_uintn_t *buffer_size, > > + void *buffer); > > + > > +static grub_efi_load_file2_t initrd_lf2 = { > > + grub_efi_initrd_load_file2 > > +}; > > + > > +static grub_efi_status_t > > +grub_efi_initrd_load_file2(grub_efi_load_file2_t *this, > > + grub_efi_device_path_t *device_path, > > + grub_efi_boolean_t boot_policy, > > + grub_efi_uintn_t *buffer_size, > > + void *buffer) > > +{ > > + grub_efi_status_t status = GRUB_EFI_SUCCESS; > > + grub_efi_uintn_t initrd_size; > > + > > + if (!this || this != &initrd_lf2 || !buffer_size) > > + return GRUB_EFI_INVALID_PARAMETER; > > + > > + if (device_path->type != GRUB_EFI_END_DEVICE_PATH_TYPE || > > + device_path->subtype != GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE) > > + return GRUB_EFI_NOT_FOUND; > > + > > + if (boot_policy) > > + return GRUB_EFI_UNSUPPORTED; > > + > > + initrd_size = grub_get_initrd_size (&initrd_ctx); > > + if (!buffer || *buffer_size < initrd_size) > > + { > > + *buffer_size = initrd_size; > > + return GRUB_EFI_BUFFER_TOO_SMALL; > > + } > > + > > + grub_dprintf ("linux", "Loading initrd via LOAD_FILE2_PROTOCOL\n"); > > + > > + if (grub_initrd_load (&initrd_ctx, NULL, buffer)) > > + status = GRUB_EFI_LOAD_ERROR; > > + > > + grub_initrd_close (&initrd_ctx); > > + return status; > > +} > > + > > static grub_err_t > > grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)), > > int argc, char *argv[]) > > { > > - struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 }; > > int initrd_size, initrd_pages; > > void *initrd_mem = NULL; > > + grub_efi_guid_t load_file2_guid = GRUB_EFI_LOAD_FILE2_PROTOCOL_GUID; > > + grub_efi_guid_t device_path_guid = GRUB_EFI_DEVICE_PATH_GUID; > > + grub_efi_boot_services_t *b; > > + grub_efi_status_t status; > > > > if (argc == 0) > > { > > @@ -254,6 +351,24 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)), > > if (grub_initrd_init (argc, argv, &initrd_ctx)) > > goto fail; > > > > + if (initrd_use_loadfile2 && !initrd_lf2_handle) > > + { > > + b = grub_efi_system_table->boot_services; > > + status = b->install_multiple_protocol_interfaces (&initrd_lf2_handle, > > + &load_file2_guid, > > + &initrd_lf2, > > + &device_path_guid, > > + &initrd_lf2_device_path, > > + NULL); > > + if (status == GRUB_EFI_OUT_OF_RESOURCES) > > + { > > indented by spaces > > > + grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory")); > > + return grub_errno; > > + } > > indented with tab > Thanks. I'll fix that up for the next revision. There's actually a bug in this patch which I need to fix too: the code that checks the PE/COFF header for the image version doesn't actually load the entire header :-(