On Thu, 19 May 2022 at 08:17, Heinrich Schuchardt <heinrich.schuchardt@xxxxxxxxxxxxx> wrote: > > > > On 5/18/22 23:03, Ard Biesheuvel wrote: > > On Wed, 18 May 2022 at 11:57, Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> wrote: > >> > >> This patch adds the support for getting the boot hart ID in > >> Linux EFI stub using RISCV_EFI_BOOT_PROTOCOL. This protocol > >> is preferred method over existing DT based solution since it > >> works irrespective of DT or ACPI. > >> > >> The specification of the protocol is hosted at: > >> https://github.com/riscv-non-isa/riscv-uefi > >> > >> Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> > >> Acked-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx> > >> Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@xxxxxxxxxxxxx> > >> --- > >> drivers/firmware/efi/libstub/efistub.h | 7 ++++++ > >> drivers/firmware/efi/libstub/riscv-stub.c | 29 +++++++++++++++++++---- > >> include/linux/efi.h | 1 + > >> 3 files changed, 32 insertions(+), 5 deletions(-) > >> > >> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h > >> index edb77b0621ea..aced62a0907e 100644 > >> --- a/drivers/firmware/efi/libstub/efistub.h > >> +++ b/drivers/firmware/efi/libstub/efistub.h > >> @@ -720,6 +720,13 @@ union efi_tcg2_protocol { > >> } mixed_mode; > >> }; > >> > >> +struct riscv_efi_boot_protocol { > >> + u64 revision; > >> + > >> + efi_status_t (__efiapi * get_boot_hartid)(struct riscv_efi_boot_protocol *this, > >> + size_t *boot_hartid); > > > > size_t is not a EFI type, and your spec uses UINTN here, which is > > equivalent to 'unsigned long'. However, jump_kernel_func() takes a > > unsigned int for the hartid. Please clean this up. > > unsigned long and size_t have the same number of bits. This seems to be > a question of taste where we should follow the maintainer. > We use unsigned long wherever the UEFI spec uses UINTN. This is not a matter of taste, really. > jump_kernel_func() assuming boot hart ID to be an unsigned int is not in > line with the RISC-V ISA which allows to use all xlen bits. > > > > > > >> +}; > >> + > >> typedef union efi_load_file_protocol efi_load_file_protocol_t; > >> typedef union efi_load_file_protocol efi_load_file2_protocol_t; > >> > >> diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c > >> index 9c460843442f..012504f6f9a4 100644 > >> --- a/drivers/firmware/efi/libstub/riscv-stub.c > >> +++ b/drivers/firmware/efi/libstub/riscv-stub.c > >> @@ -23,7 +23,7 @@ > >> > >> typedef void __noreturn (*jump_kernel_func)(unsigned int, unsigned long); > >> > >> -static u32 hartid; > >> +static size_t hartid; > >> > > > > and here > > > >> static int get_boot_hartid_from_fdt(void) > >> { > >> @@ -47,14 +47,33 @@ static int get_boot_hartid_from_fdt(void) > >> return 0; > >> } > >> > >> +static efi_status_t get_boot_hartid_from_efi(void) > >> +{ > >> + efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID; > >> + efi_status_t status; > >> + struct riscv_efi_boot_protocol *boot_protocol; > >> + > >> + status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL, > >> + (void **)&boot_protocol); > >> + if (status == EFI_SUCCESS) { > >> + status = efi_call_proto(boot_protocol, > >> + get_boot_hartid, &hartid); > > A lot of the kernel code seems to be unfit to handle hart IDs exceeding > INT_MAX (e.g. sbi_cpu_is_stopped()). Until this is fixed we have to > treat hartid > INT_MAX as an error. > This is an issue in the core kernel code, not in the EFI stub. As you pointed out, the ISA implies UINTN / unsigned long here, and if the startup code cannot deal with that, it can be fixed separately.
