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... --Sean
