> > Should re-order to reverse xmas tree order.
> >
>
> We have no such requirement in the EFI subsystem.
>
My apologies, I didn't realize that this subsystem didn't use that.
> > > +
> > > + if (size < offsetof(efi_load_option_t, variable_data))
> > > + return false;
> > > + pos = src->variable_data;
> > > + size -= offsetof(efi_load_option_t, variable_data);
> > > +
> > > + if ((src->attributes & ~EFI_LOAD_OPTION_MASK) != 0)
> > > + return false;
> > > +
> > > + /* Scan description. */
> > > + description = pos;
> > > + do {
> > > + if (size < sizeof(c))
> > > + return false;
> > > + c = *(const u16 *)pos;
> > > + pos += sizeof(c);
> > > + size -= sizeof(c);
> > > + } while (c != L'\0');
> > > +
> > > + /* Scan file_path_list. */
> > > + file_path_list = pos;
> > > + do {
> > > + if (size < sizeof(header))
> > > + return false;
> > > + header = *(const efi_device_path_protocol_t *)pos;
> > > + if (header.length < sizeof(header))
> > > + return false;
> > > + if (size < header.length)
> > > + return false;
> > > + pos += header.length;
> > > + size -= header.length;
> > > + } while ((header.type != EFI_DEV_END_PATH && header.type !=
> > > EFI_DEV_END_PATH2) ||
> > > + (header.sub_type != EFI_DEV_END_ENTIRE));
> > > + if (pos != (const void *)file_path_list + src-
> >file_path_list_length)
> > > + return false;
> > > +
> > > + dest->attributes = src->attributes;
> > > + dest->file_path_list_length = src->file_path_list_length;
> > > + dest->description = description;
> > > + dest->file_path_list = file_path_list;
> > > + dest->optional_data_size = size;
> > > + dest->optional_data = size ? pos : NULL;
> > > +
> > > + return true;
> > > +}
> > > +
> > > +/*
> > > + * At least some versions of Dell firmware pass the entire contents of
> the
> > > + * Boot#### variable, i.e. the EFI_LOAD_OPTION descriptor, rather than
> just
> > > the
> > > + * OptionalData field.
> > > + *
> > > + * Detect this case and extract OptionalData.
> > > + */
> > > +void efi_apply_loadoptions_quirk(const void **load_options, int
> > > *load_options_size)
> > > +{
> > > + const efi_load_option_t *load_option = *load_options;
> > > + efi_load_option_unpacked_t load_option_unpacked;
> > > +
> > > + if (!IS_ENABLED(CONFIG_X86))
> > > + return;
> > > + if (!load_option)
> > > + return;
> > > + if (*load_options_size < sizeof(*load_option))
> > > + return;
> > > + if ((load_option->attributes & ~EFI_LOAD_OPTION_BOOT_MASK) != 0)
> > > + return;
> > > +
> > > + if (!efi_load_option_unpack(&load_option_unpacked, load_option,
> > > *load_options_size))
> > > + return;
> > > +
> >
> > In case this was ever to be attributed to a cause for someone to fail to
> > boot, it may be useful to drop a pr_debug here that could be easily turned
> > on.
> >
>
> Agree that adding a efi_info() here makes sense, not only for
> potential failures, but also simply to have some confirmation that the
> quirk is taking effect.
Should a change be developed in the firmware side to resolve it, it's a nice way to
confirm that it landed properly too, and to come up with a timeline to eventually
sunset this type of quirk.
This is some precedence of putting stuff like this which Linux kernel has worked around
what is generally viewed as a firmware bug as pr_notice_once (*):
https://github.com/torvalds/linux/blob/89d57dddd7d319ded00415790a0bb3c954b7e386/drivers/acpi/osi.c#L77
Stuff of the like can flow into test tools like the firmware test suite (FWTS) which can
help identify them earlier and to resolve during development before codebases generally lock down.
>
> Note that I am not 100% convinced yet that we need this change to
> begin with. How large is the intersection of the set of affected
> systems and the set of systems that are likely to run future kernels
> that carry this quirk?
Right now there is no confirmation that "current" systems have been fixed in the
current firmware codebase. I don't have access to that codebase, so I have some inquiries
to those that do.
So it's anywhere in between "all Dell X86 client systems manufactured in 2017 and older" to
"all Dell systems up until 2020-2021 when/if this behavior is changed".
A lot of distributions uses other bootloaders, and won't be affected by this.
Even if it does get fixed in firmware (which I'll lobby for internally if it's still a problem)
I would personally rather see the quirk land as I think it's harder to see distributions have
the potential to migrate away from GRUB to other solutions with large numbers of known machines
in the field that can't boot the other solution.
>
>
> > > + *load_options = load_option_unpacked.optional_data;
> > > + *load_options_size = load_option_unpacked.optional_data_size;
> > > +}
> > > +
> > > /*
> > > * Convert the unicode UEFI command line to ASCII to pass to kernel.
> > > * Size of memory allocated return in *cmd_line_len.
> > > @@ -247,12 +341,15 @@ char *efi_convert_cmdline(efi_loaded_image_t *image,
> int
> > > *cmd_line_len)
> > > {
> > > const u16 *s2;
> > > unsigned long cmdline_addr = 0;
> > > - int options_chars = efi_table_attr(image, load_options_size) / 2;
> > > + int options_chars = efi_table_attr(image, load_options_size);
> > > const u16 *options = efi_table_attr(image, load_options);
> > > int options_bytes = 0, safe_options_bytes = 0; /* UTF-8 bytes */
> > > bool in_quote = false;
> > > efi_status_t status;
> > >
> > > + efi_apply_loadoptions_quirk((const void **)&options,
> &options_chars);
> > > + options_chars /= sizeof(*options);
> > > +
> > > if (options) {
> > > s2 = options;
> > > while (options_bytes < COMMAND_LINE_SIZE && options_chars--)
> {
> > > diff --git a/drivers/firmware/efi/libstub/efistub.h
> > > b/drivers/firmware/efi/libstub/efistub.h
> > > index 85050f5a1b28..589d07acb22d 100644
> > > --- a/drivers/firmware/efi/libstub/efistub.h
> > > +++ b/drivers/firmware/efi/libstub/efistub.h
> > > @@ -688,6 +688,35 @@ union efi_load_file_protocol {
> > > } mixed_mode;
> > > };
> > >
> > > +typedef struct {
> > > + u32 attributes;
> > > + u16 file_path_list_length;
> > > + u8 variable_data[];
> > > + // efi_char16_t description[];
> > > + // efi_device_path_protocol_t file_path_list[];
> > > + // u8 optional_data[];
> > > +} __packed efi_load_option_t;
> > > +
> > > +#define EFI_LOAD_OPTION_ACTIVE 0x0001U
> > > +#define EFI_LOAD_OPTION_FORCE_RECONNECT 0x0002U
> > > +#define EFI_LOAD_OPTION_HIDDEN 0x0008U
> > > +#define EFI_LOAD_OPTION_CATEGORY 0x1f00U
> > > +#define EFI_LOAD_OPTION_CATEGORY_BOOT 0x0000U
> > > +#define EFI_LOAD_OPTION_CATEGORY_APP 0x0100U
> > > +
> > > +#define EFI_LOAD_OPTION_BOOT_MASK \
> > > +
> (EFI_LOAD_OPTION_ACTIVE|EFI_LOAD_OPTION_HIDDEN|EFI_LOAD_OPTION_CATEGORY)
> > > +#define EFI_LOAD_OPTION_MASK
> > > (EFI_LOAD_OPTION_FORCE_RECONNECT|EFI_LOAD_OPTION_BOOT_MASK)
> > > +
> > > +typedef struct {
> > > + u32 attributes;
> > > + u16 file_path_list_length;
> > > + const efi_char16_t *description;
> > > + const efi_device_path_protocol_t *file_path_list;
> > > + size_t optional_data_size;
> > > + const void *optional_data;
> > > +} efi_load_option_unpacked_t;
> > > +
> > > void efi_pci_disable_bridge_busmaster(void);
> > >
> > > typedef efi_status_t (*efi_exit_boot_map_processing)(
> > > @@ -730,6 +759,8 @@ __printf(1, 2) int efi_printk(char const *fmt, ...);
> > >
> > > void efi_free(unsigned long size, unsigned long addr);
> > >
> > > +void efi_apply_loadoptions_quirk(const void **load_options, int
> > > *load_options_size);
> > > +
> > > char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len);
> > >
> > > efi_status_t efi_get_memory_map(struct efi_boot_memmap *map);
> > > diff --git a/drivers/firmware/efi/libstub/file.c
> > > b/drivers/firmware/efi/libstub/file.c
> > > index 630caa6b1f4c..4e81c6077188 100644
> > > --- a/drivers/firmware/efi/libstub/file.c
> > > +++ b/drivers/firmware/efi/libstub/file.c
> > > @@ -136,7 +136,7 @@ efi_status_t handle_cmdline_files(efi_loaded_image_t
> > > *image,
> > > unsigned long *load_size)
> > > {
> > > const efi_char16_t *cmdline = image->load_options;
> > > - int cmdline_len = image->load_options_size / 2;
> > > + int cmdline_len = image->load_options_size;
> > > unsigned long efi_chunk_size = ULONG_MAX;
> > > efi_file_protocol_t *volume = NULL;
> > > efi_file_protocol_t *file;
> > > @@ -148,6 +148,9 @@ efi_status_t handle_cmdline_files(efi_loaded_image_t
> > > *image,
> > > if (!load_addr || !load_size)
> > > return EFI_INVALID_PARAMETER;
> > >
> > > + efi_apply_loadoptions_quirk((const void **)&cmdline, &cmdline_len);
> > > + cmdline_len /= sizeof(*cmdline);
> > > +
> > > if (IS_ENABLED(CONFIG_X86) && !efi_nochunk)
> > > efi_chunk_size = EFI_READ_CHUNK_SIZE;
> > >
> > > --
> > > 2.26.2
> >
