On Thu, May 19, 2022 at 11:07:28AM -0700, Atish Patra wrote: > On Thu, May 19, 2022 at 1:14 AM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > > > 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. > > It was kept as unsigned int because hartid > INT_MAX is very unlikely to happen. > But I agree that we should just follow the spec(allowing XLEN bits for > hartid) and > change "unsigned int" to "unsigned long" wherever hartid is concerned. > > As the hartid is changed to unsigned long, get_boot_hartid_from_fdt > should be fixed as well. > Currently, it is using fdt32_to_cpu. I am working on a separate patch series to modify these instances. Will send soon for your feedback. Thanks Sunil > > > > -- > Regards, > Atish
