xtheadvector is not vector 1.0 compatible, but it can leverage all of the same save/restore routines as vector plus riscv_v_first_use_handler(). vector 1.0 and xtheadvector are mutually exclusive so there is no risk of overlap.
Signed-off-by: Charlie Jenkins charlie@rivosinc.com --- arch/riscv/kernel/cpufeature.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 41a4d2028428..59f628b1341c 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -647,9 +647,13 @@ static void __init riscv_fill_hwcap_from_isa_string(unsigned long *isa2hwcap) * Many vendors with T-Head CPU cores which implement the 0.7.1 * version of the vector specification put "v" into their DTs. * CPU cores with the ratified spec will contain non-zero - * marchid. + * marchid. Only allow "v" to be set if xtheadvector is present. */ - if (acpi_disabled && this_vendorid == THEAD_VENDOR_ID && + if (__riscv_isa_vendor_extension_available(isavendorinfo->isa, + RISCV_ISA_VENDOR_EXT_XTHEADVECTOR)) { + this_hwcap |= isa2hwcap[RISCV_ISA_EXT_v]; + set_bit(RISCV_ISA_EXT_v, isainfo->isa); + } else if (acpi_disabled && this_vendorid == THEAD_VENDOR_ID && this_archid == 0x0) { this_hwcap &= ~isa2hwcap[RISCV_ISA_EXT_v]; clear_bit(RISCV_ISA_EXT_v, isainfo->isa); @@ -776,6 +780,15 @@ static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap)
of_node_put(cpu_node);
+ /* + * Enable kernel vector routines if xtheadvector is present + */ + if (__riscv_isa_vendor_extension_available(isavendorinfo->isa, + RISCV_ISA_VENDOR_EXT_XTHEADVECTOR)) { + this_hwcap |= isa2hwcap[RISCV_ISA_EXT_v]; + set_bit(RISCV_ISA_EXT_v, isainfo->isa); + } + /* * All "okay" harts should have same isa. Set HWCAP based on * common capabilities of every "okay" hart, in case they don't.