On 5/25/22 17:48, Ard Biesheuvel wrote:
On Wed, 25 May 2022 at 17:11, Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> wrote:The boot-hartid can be a 64bit value on RV64 platforms. Currently, the "boot-hartid" in DT is assumed to be 32bit only. This patch detects the size of the "boot-hartid" and uses 32bit or 64bit FDT reads appropriately. Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> --- drivers/firmware/efi/libstub/riscv-stub.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c index 9e85e58d1f27..d748533f1329 100644 --- a/drivers/firmware/efi/libstub/riscv-stub.c +++ b/drivers/firmware/efi/libstub/riscv-stub.c @@ -29,7 +29,7 @@ static int get_boot_hartid_from_fdt(void) { const void *fdt; int chosen_node, len; - const fdt32_t *prop; + const void *prop; fdt = get_efi_config_table(DEVICE_TREE_GUID); if (!fdt) @@ -40,10 +40,16 @@ static int get_boot_hartid_from_fdt(void) return -EINVAL; prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len); - if (!prop || len != sizeof(u32)) + if (!prop) + return -EINVAL; + + if (len == sizeof(u32)) + hartid = (unsigned long) fdt32_to_cpu(*(fdt32_t *)prop); + else if (len == sizeof(u64)) + hartid = (unsigned long) fdt64_to_cpu(*(fdt64_t *)prop);Does RISC-V care about alignment? A 64-bit quantity is not guaranteed to appear 64-bit aligned in the DT, and the cast violates C alignment rules, so this should probably used get_unaligned_be64() or something like that.
When running in S-mode the SBI handles unaligned access but this has a performance penalty.
We could use fdt64_to_cpu(__get_unaligned_t(fdt64_t, prop)) here. Best regards Heinrich
+ else return -EINVAL; - hartid = fdt32_to_cpu(*prop); return 0; } -- 2.25.1
