> On 30 Jun 2024, at 4:59 PM, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > Hello Aditya, Lukas, > >> On Sun, 30 Jun 2024 at 10:04, Lukas Wunner <lukas@xxxxxxxxx> wrote: >> >>> On Sun, Jun 30, 2024 at 04:42:55AM +0000, Aditya Garg wrote: >>> Commit 0c18184de990 brought support for T2 Macs in apple-gmux. But in order to >> >> Please run patches through scripts/checkpatch.pl before submission. >> The subject of the commit is missing here and lines should be wrapped >> at 72 or at least 74 chars. >> >> >>> Based on this patch for GRUB by Andreas Heider <andreas@xxxxxxxxx>: >>> https://lists.gnu.org/archive/html/grub-devel/2013-12/msg00442.html >> >> Please include his Signed-off-by and cc him. >> >> > > No. You cannot simply add a signed-off-by on someone else's behalf, > even if you cc the person. > > Andreas contributed code to GRUB (which is a GPLv3 project), and had > no involvement whatsoever in creating this patch. > > A signed-off-by is a statement on the part of the contributor (which > may or may not be the author) that the contribution in question > complies with the requirements imposed by the project in terms of > copyright and licensing. Linux is GPLv2 not v3, so this code should at > least be dual licensed in order to be reused directly. > > I did not look at the GRUB patch, and IANAL, but this code invokes an > Apple provided protocol (which is proprietary) in a hardcoded way for > interoperability purposes, and so there is not much to > copyright/license anyway. I would be fine with having just your > signoff on this patch, but you could ask Andreas for a GPLv2+3 version > of his GRUB patch if you are not sure. > I believe this should be GPL2 compatible since it's simple reverse engineered Apple stuff and there are many kernel drivers with apple specific stuff. >>> --- a/Documentation/admin-guide/kernel-parameters.txt >>> +++ b/Documentation/admin-guide/kernel-parameters.txt >>> @@ -399,6 +399,8 @@ >>> useful so that a dump capture kernel won't be >>> shot down by NMI >>> >>> + apple_set_os [KNL] Report that macOS is being booted to the firmware >>> + >> >> Why the kernel parameter? Why not do this unconditionally? >> >> > > Agree that this is suboptimal. If we need a command line param for > this, please make add it to the efi= list I'll leave this to you. If you are fine with a parameter, I'll add it. If you have to be enforced by default, I'm fine with that. Or, maybe we add add a parameter that disables this so that in case things break, we can atleast get it done. >>> +struct apple_set_os_protocol { > > This should be a union not a struct > >>> + u64 version; > > This should be unsigned long > >>> + efi_status_t (__efiapi *set_os_version) (const char *); >>> + efi_status_t (__efiapi *set_os_vendor) (const char *); >>> + struct { >>> + u32 version; > > ... to match the mixed_mode overlay which is u32. Alternatively, they > could both be u64 but the current arrangement is definitely incorrect. > >>> + u32 set_os_version; >>> + u32 set_os_vendor; >>> + } mixed_mode; >>> +}; >> >> How about declaring this __packed, just to be on the safe side? >> > > I don't think that is necessary. If the mixed_mode overlay is never > used, it doesn't really matter and you can use unsigned long vs u32, > in which case all struct members are native word size so there is no > padding issue. > >> Why "mixed_mode"? Seems like an odd name given "mixed mode" >> in EFI context usually means 64-bit OS, but 32-bit EFI. >> > > This is how the x86 plumbing works for mixed mode. Every EFI protocol > is a union, with a mixed_mode member describing the 32-bit view. The > accessor macros (efi_bs_call, efi_table_attr) automatically do the > right thing depending on the bitness of the firmware. > > This means, though, that even protocols that are known not to exist on > 32-bit firmware need to be implemented in the same way, or the code > will not build. > So should I keep mixed mode or not? >> >>> +static void apple_set_os(void) >>> +{ >>> + efi_guid_t guid = APPLE_SET_OS_PROTOCOL_GUID; >> >> My recollection is that if you don't declare this static const, >> gcc generates suboptimal code. (It constructs the GUID on the >> stack at runtime instead of storing it in .rodata.) >> Maybe it's become smarter in the meantime, but I doubt it. >> > > I don't remember the details but it looks like we stopped doing this a > while ago. I don't mind keeping it like this.
