On 28.09.20 19:15, Sean Anderson wrote: > On 9/28/20 12:27 PM, Heinrich Schuchardt wrote: >> On 28.09.20 18:08, Sean Anderson wrote: >>> >From section 2.3.7 of the UEFI specification: >>> >>>> RISC-V UEFI will only be executed in machine mode. The machine mode has >>>> the highest privilege and this mode is the only mandatory privilege level >>>> for RISC-V platforms; all other privilege levels are optional depending >>>> on the platform requirements. Machine mode is the first mode entered at >>>> the power-on reset. This level is used in UEFI for low-level access to a >>>> hardware platform. >>> >>> Signed-off-by: Sean Anderson <[email protected]> >>> --- >>> >>> lib/efi_loader/Kconfig | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig >>> index bad1a29ba8..2197c84bf3 100644 >>> --- a/lib/efi_loader/Kconfig >>> +++ b/lib/efi_loader/Kconfig >>> @@ -10,6 +10,8 @@ config EFI_LOADER >>> depends on !EFI_STUB || !X86_64 || EFI_STUB_64BIT >>> # We need EFI_STUB_32BIT to be set on x86_32 with EFI_STUB >>> depends on !EFI_STUB || !X86 || X86_64 || EFI_STUB_32BIT >>> + # RISC-V UEFI must run in machine mode >>> + depends on !RISCV || RISCV_M_MODE >>> default y if !ARM || SYS_CPU = armv7 || SYS_CPU = armv8 >>> select LIB_UUID >>> select HAVE_BLOCK_DEVICE >>> >> >> Hello Sean, >> >> the specification is wrong. A change request has been made to correct >> the specification. We should not change U-Boot here. >> >> See the discussion in this thread: >> https://lists.linaro.org/pipermail/boot-architecture/2020-September/001481.html >> >> Best regards >> >> Heinrich >> > > Thanks for linking that. I'm glad some of these issues are being addressed. > However, I am concerned about your suggestion > >> * Don't trust the values of tp and gp when entered >> from the payloads world. > > Because tp *must* be trusted in S-Mode... > > Of course, all this could be averted by adding an sbi_get_mhartid function...
I thought only the secondary hart uses tp in U-Boot. Best regards Heinrich
