On Mon, Jul 01, 2024 at 11:20:24AM -0500, Samuel Holland wrote:
> Hi Charlie,
>
> A couple of suggestions for simplification below.
>
> On 2024-06-19 6:57 PM, Charlie Jenkins wrote:
> > Use alternatives to add support for xtheadvector vector save/restore
> > routines.
> >
> > Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
> > Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> > ---
> > arch/riscv/include/asm/csr.h | 6 +
> > arch/riscv/include/asm/switch_to.h | 2 +-
> > arch/riscv/include/asm/vector.h | 249 ++++++++++++++++++++++++++-------
> > arch/riscv/kernel/cpufeature.c | 2 +-
> > arch/riscv/kernel/kernel_mode_vector.c | 8 +-
> > arch/riscv/kernel/process.c | 4 +-
> > arch/riscv/kernel/signal.c | 6 +-
> > arch/riscv/kernel/vector.c | 13 +-
> > 8 files changed, 222 insertions(+), 68 deletions(-)
> >
> > diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
> > index 9086639a3dde..407d4a5687f5 100644
> > --- a/arch/riscv/include/asm/csr.h
> > +++ b/arch/riscv/include/asm/csr.h
> > @@ -30,6 +30,12 @@
> > #define SR_VS_CLEAN _AC(0x00000400, UL)
> > #define SR_VS_DIRTY _AC(0x00000600, UL)
> >
> > +#define SR_VS_THEAD _AC(0x01800000, UL) /* xtheadvector Status */
> > +#define SR_VS_OFF_THEAD _AC(0x00000000, UL)
> > +#define SR_VS_INITIAL_THEAD _AC(0x00800000, UL)
> > +#define SR_VS_CLEAN_THEAD _AC(0x01000000, UL)
> > +#define SR_VS_DIRTY_THEAD _AC(0x01800000, UL)
> > +
> > #define SR_XS _AC(0x00018000, UL) /* Extension Status */
> > #define SR_XS_OFF _AC(0x00000000, UL)
> > #define SR_XS_INITIAL _AC(0x00008000, UL)
> > diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h
> > index 7594df37cc9f..f9cbebe372b8 100644
> > --- a/arch/riscv/include/asm/switch_to.h
> > +++ b/arch/riscv/include/asm/switch_to.h
> > @@ -99,7 +99,7 @@ do { \
> > __set_prev_cpu(__prev->thread); \
> > if (has_fpu()) \
> > __switch_to_fpu(__prev, __next); \
> > - if (has_vector()) \
> > + if (has_vector() || has_xtheadvector()) \
> > __switch_to_vector(__prev, __next); \
> > if (switch_to_should_flush_icache(__next)) \
> > local_flush_icache_all(); \
> > diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
> > index 731dcd0ed4de..6294dcaabc6a 100644
> > --- a/arch/riscv/include/asm/vector.h
> > +++ b/arch/riscv/include/asm/vector.h
> > @@ -18,6 +18,27 @@
> > #include <asm/cpufeature.h>
> > #include <asm/csr.h>
> > #include <asm/asm.h>
> > +#include <asm/vendorid_list.h>
> > +#include <asm/vendor_extensions.h>
> > +#include <asm/vendor_extensions/thead.h>
> > +
> > +#define __riscv_v_vstate_or(_val, TYPE) ({ \
> > + typeof(_val) _res = _val; \
> > + if (has_xtheadvector()) \
> > + _res = (_res & ~SR_VS_THEAD) | SR_VS_##TYPE##_THEAD; \
> > + else \
> > + _res = (_res & ~SR_VS) | SR_VS_##TYPE; \
> > + _res; \
> > +})
> > +
> > +#define __riscv_v_vstate_check(_val, TYPE) ({ \
> > + bool _res; \
> > + if (has_xtheadvector()) \
> > + _res = ((_val) & SR_VS_THEAD) == SR_VS_##TYPE##_THEAD; \
> > + else \
> > + _res = ((_val) & SR_VS) == SR_VS_##TYPE; \
> > + _res; \
> > +})
> >
> > extern unsigned long riscv_v_vsize;
> > int riscv_v_setup_vsize(void);
> > @@ -40,39 +61,62 @@ static __always_inline bool has_vector(void)
> > return riscv_has_extension_unlikely(RISCV_ISA_EXT_v);
> > }
> >
> > +static __always_inline bool has_xtheadvector_no_alternatives(void)
> > +{
> > + if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR))
> > + return riscv_isa_vendor_extension_available(THEAD_VENDOR_ID, XTHEADVECTOR);
> > + else
> > + return false;
> > +}
> > +
> > +static __always_inline bool has_xtheadvector(void)
> > +{
> > + if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR))
> > + return riscv_has_vendor_extension_unlikely(THEAD_VENDOR_ID,
> > + RISCV_ISA_VENDOR_EXT_XTHEADVECTOR);
> > + else
> > + return false;
> > +}
> > +
> > static inline void __riscv_v_vstate_clean(struct pt_regs *regs)
> > {
> > - regs->status = (regs->status & ~SR_VS) | SR_VS_CLEAN;
> > + regs->status = __riscv_v_vstate_or(regs->status, CLEAN);
> > }
> >
> > static inline void __riscv_v_vstate_dirty(struct pt_regs *regs)
> > {
> > - regs->status = (regs->status & ~SR_VS) | SR_VS_DIRTY;
> > + regs->status = __riscv_v_vstate_or(regs->status, DIRTY);
> > }
> >
> > static inline void riscv_v_vstate_off(struct pt_regs *regs)
> > {
> > - regs->status = (regs->status & ~SR_VS) | SR_VS_OFF;
> > + regs->status = __riscv_v_vstate_or(regs->status, OFF);
> > }
> >
> > static inline void riscv_v_vstate_on(struct pt_regs *regs)
> > {
> > - regs->status = (regs->status & ~SR_VS) | SR_VS_INITIAL;
> > + regs->status = __riscv_v_vstate_or(regs->status, INITIAL);
> > }
> >
> > static inline bool riscv_v_vstate_query(struct pt_regs *regs)
> > {
> > - return (regs->status & SR_VS) != 0;
> > + return !__riscv_v_vstate_check(regs->status, OFF);
> > }
> >
> > static __always_inline void riscv_v_enable(void)
> > {
> > - csr_set(CSR_SSTATUS, SR_VS);
> > + if (has_xtheadvector())
> > + csr_set(CSR_SSTATUS, SR_VS_THEAD);
> > + else
> > + csr_set(CSR_SSTATUS, SR_VS);
> > }
> >
> > static __always_inline void riscv_v_disable(void)
> > {
> > - csr_clear(CSR_SSTATUS, SR_VS);
> > + if (has_xtheadvector())
> > + csr_clear(CSR_SSTATUS, SR_VS_THEAD);
> > + else
> > + csr_clear(CSR_SSTATUS, SR_VS);
> > }
> >
> > static __always_inline void __vstate_csr_save(struct __riscv_v_ext_state *dest)
> > @@ -81,10 +125,49 @@ static __always_inline void __vstate_csr_save(struct __riscv_v_ext_state *dest)
> > "csrr %0, " __stringify(CSR_VSTART) "\n\t"
> > "csrr %1, " __stringify(CSR_VTYPE) "\n\t"
> > "csrr %2, " __stringify(CSR_VL) "\n\t"
> > - "csrr %3, " __stringify(CSR_VCSR) "\n\t"
> > - "csrr %4, " __stringify(CSR_VLENB) "\n\t"
> > : "=r" (dest->vstart), "=r" (dest->vtype), "=r" (dest->vl),
> > - "=r" (dest->vcsr), "=r" (dest->vlenb) : :);
> > + "=r" (dest->vcsr) : :);
> > +
> > + if (has_xtheadvector()) {
> > + u32 tmp_vcsr;
> > + bool restore_fpu = false;
> > + unsigned long status = csr_read(CSR_SSTATUS);
> > +
> > + /*
> > + * CSR_VCSR is defined as
> > + * [2:1] - vxrm[1:0]
> > + * [0] - vxsat
> > + * The earlier vector spec implemented by T-Head uses separate
> > + * registers for the same bit-elements, so just combine those
> > + * into the existing output field.
> > + *
> > + * Additionally T-Head cores need FS to be enabled when accessing
> > + * the VXRM and VXSAT CSRs, otherwise ending in illegal instructions.
> > + * Though the cores do not implement the VXRM and VXSAT fields in the
> > + * FCSR CSR that vector-0.7.1 specifies.
> > + */
> > + if ((status & SR_FS) == SR_FS_OFF) {
> > + csr_set(CSR_SSTATUS, (status & ~SR_FS) | SR_FS_CLEAN);
> > + restore_fpu = true;
> > + }
>
> This simplifies to:
>
> unsigned long status = csr_read_set(CSR_STATUS, SR_FS_DIRTY);
>
> and then below:
>
> if ((status & SR_FS) != SR_FS_DIRTY)
> csr_write(CSR_STATUS, status);
>
Great suggestions, thank you!
> > +
> > + asm volatile (
> > + "csrr %[tmp_vcsr], " __stringify(VCSR_VXRM) "\n\t"
> > + "slliw %[vcsr], %[tmp_vcsr], " __stringify(VCSR_VXRM_SHIFT) "\n\t"
> > + "csrr %[tmp_vcsr], " __stringify(VCSR_VXSAT) "\n\t"
> > + "or %[vcsr], %[vcsr], %[tmp_vcsr]\n\t"
> > + : [vcsr] "=r" (dest->vcsr), [tmp_vcsr] "=&r" (tmp_vcsr));
>
> None of this needs to be inline assembly. I think the only reason that
> __vstate_csr_save() uses inline assembly is to match __vstate_csr_restore(),
> which needs it to execute a vsetvl instruction. This would be easier to parse if
> it used csr_read().
You are totally right! Converting this to C will make the code much easier to follow.
>
> > +
> > + dest->vlenb = riscv_v_vsize / 32;
>
> This value can't change at runtime (for either standard V or Xtheadvector), so
> we don't need to save it every time. So (possibly as a future optimization) this
> could be saved only once when the context is first initialized.
Yes that is something that should be optimized. I can optimize this in a
follow up patch so this series doesn't grow any more.
>
> > +
> > + if (restore_fpu)
> > + csr_set(CSR_SSTATUS, status);
> > + } else {
> > + asm volatile (
> > + "csrr %[vcsr], " __stringify(CSR_VCSR) "\n\t"
> > + "csrr %[vlenb], " __stringify(CSR_VLENB) "\n\t"
> > + : [vcsr] "=r" (dest->vcsr), [vlenb] "=r" (dest->vlenb));
> > + }
> > }
> >
> > static __always_inline void __vstate_csr_restore(struct __riscv_v_ext_state *src)
> > @@ -95,9 +178,37 @@ static __always_inline void __vstate_csr_restore(struct __riscv_v_ext_state *src
> > "vsetvl x0, %2, %1\n\t"
> > ".option pop\n\t"
> > "csrw " __stringify(CSR_VSTART) ", %0\n\t"
> > - "csrw " __stringify(CSR_VCSR) ", %3\n\t"
> > - : : "r" (src->vstart), "r" (src->vtype), "r" (src->vl),
> > - "r" (src->vcsr) :);
> > + : : "r" (src->vstart), "r" (src->vtype), "r" (src->vl));
> > +
> > + if (has_xtheadvector()) {
> > + u32 tmp_vcsr;
> > + bool restore_fpu = false;
> > + unsigned long status = csr_read(CSR_SSTATUS);
> > +
> > + /*
> > + * Similar to __vstate_csr_save above, restore values for the
> > + * separate VXRM and VXSAT CSRs from the vcsr variable.
> > + */
> > + if ((status & SR_FS) == SR_FS_OFF) {
> > + csr_set(CSR_SSTATUS, (status & ~SR_FS) | SR_FS_CLEAN);
> > + restore_fpu = true;
> > + }
> > +
> > + asm volatile (
> > + "srliw %[tmp_vcsr], %[vcsr], " __stringify(VCSR_VXRM_SHIFT) "\n\t"
> > + "andi %[tmp_vcsr], %[tmp_vcsr], " __stringify(VCSR_VXRM_MASK) "\n\t"
> > + "csrw " __stringify(VCSR_VXRM) ", %[tmp_vcsr]\n\t"
> > + "andi %[tmp_vcsr], %[vcsr], " __stringify(VCSR_VXSAT_MASK) "\n\t"
> > + "csrw " __stringify(VCSR_VXSAT) ", %[tmp_vcsr]\n\t"
> > + : [tmp_vcsr] "=&r" (tmp_vcsr) : [vcsr] "r" (src->vcsr));
>
> Similarly, this would be a lot easier to parse with csr_write() instead of
> inline assembly.
Will do, thank you!
- Charlie
>
> Regards,
> Samuel
>
> > +
> > + if (restore_fpu)
> > + csr_set(CSR_SSTATUS, status);
> > + } else {
> > + asm volatile (
> > + "csrw " __stringify(CSR_VCSR) ", %[vcsr]\n\t"
> > + : : [vcsr] "r" (src->vcsr));
> > + }
> > }
> >
> > static inline void __riscv_v_vstate_save(struct __riscv_v_ext_state *save_to,
> > @@ -107,19 +218,33 @@ static inline void __riscv_v_vstate_save(struct __riscv_v_ext_state *save_to,
> >
> > riscv_v_enable();
> > __vstate_csr_save(save_to);
> > - asm volatile (
> > - ".option push\n\t"
> > - ".option arch, +v\n\t"
> > - "vsetvli %0, x0, e8, m8, ta, ma\n\t"
> > - "vse8.v v0, (%1)\n\t"
> > - "add %1, %1, %0\n\t"
> > - "vse8.v v8, (%1)\n\t"
> > - "add %1, %1, %0\n\t"
> > - "vse8.v v16, (%1)\n\t"
> > - "add %1, %1, %0\n\t"
> > - "vse8.v v24, (%1)\n\t"
> > - ".option pop\n\t"
> > - : "=&r" (vl) : "r" (datap) : "memory");
> > + if (has_xtheadvector()) {
> > + asm volatile (
> > + "mv t0, %0\n\t"
> > + THEAD_VSETVLI_T4X0E8M8D1
> > + THEAD_VSB_V_V0T0
> > + "add t0, t0, t4\n\t"
> > + THEAD_VSB_V_V0T0
> > + "add t0, t0, t4\n\t"
> > + THEAD_VSB_V_V0T0
> > + "add t0, t0, t4\n\t"
> > + THEAD_VSB_V_V0T0
> > + : : "r" (datap) : "memory", "t0", "t4");
> > + } else {
> > + asm volatile (
> > + ".option push\n\t"
> > + ".option arch, +v\n\t"
> > + "vsetvli %0, x0, e8, m8, ta, ma\n\t"
> > + "vse8.v v0, (%1)\n\t"
> > + "add %1, %1, %0\n\t"
> > + "vse8.v v8, (%1)\n\t"
> > + "add %1, %1, %0\n\t"
> > + "vse8.v v16, (%1)\n\t"
> > + "add %1, %1, %0\n\t"
> > + "vse8.v v24, (%1)\n\t"
> > + ".option pop\n\t"
> > + : "=&r" (vl) : "r" (datap) : "memory");
> > + }
> > riscv_v_disable();
> > }
> >
> > @@ -129,55 +254,77 @@ static inline void __riscv_v_vstate_restore(struct __riscv_v_ext_state *restore_
> > unsigned long vl;
> >
> > riscv_v_enable();
> > - asm volatile (
> > - ".option push\n\t"
> > - ".option arch, +v\n\t"
> > - "vsetvli %0, x0, e8, m8, ta, ma\n\t"
> > - "vle8.v v0, (%1)\n\t"
> > - "add %1, %1, %0\n\t"
> > - "vle8.v v8, (%1)\n\t"
> > - "add %1, %1, %0\n\t"
> > - "vle8.v v16, (%1)\n\t"
> > - "add %1, %1, %0\n\t"
> > - "vle8.v v24, (%1)\n\t"
> > - ".option pop\n\t"
> > - : "=&r" (vl) : "r" (datap) : "memory");
> > + if (has_xtheadvector()) {
> > + asm volatile (
> > + "mv t0, %0\n\t"
> > + THEAD_VSETVLI_T4X0E8M8D1
> > + THEAD_VLB_V_V0T0
> > + "add t0, t0, t4\n\t"
> > + THEAD_VLB_V_V0T0
> > + "add t0, t0, t4\n\t"
> > + THEAD_VLB_V_V0T0
> > + "add t0, t0, t4\n\t"
> > + THEAD_VLB_V_V0T0
> > + : : "r" (datap) : "memory", "t0", "t4");
> > + } else {
> > + asm volatile (
> > + ".option push\n\t"
> > + ".option arch, +v\n\t"
> > + "vsetvli %0, x0, e8, m8, ta, ma\n\t"
> > + "vle8.v v0, (%1)\n\t"
> > + "add %1, %1, %0\n\t"
> > + "vle8.v v8, (%1)\n\t"
> > + "add %1, %1, %0\n\t"
> > + "vle8.v v16, (%1)\n\t"
> > + "add %1, %1, %0\n\t"
> > + "vle8.v v24, (%1)\n\t"
> > + ".option pop\n\t"
> > + : "=&r" (vl) : "r" (datap) : "memory");
> > + }
> > __vstate_csr_restore(restore_from);
> > riscv_v_disable();
> > }
> >
> > static inline void __riscv_v_vstate_discard(void)
> > {
> > - unsigned long vl, vtype_inval = 1UL << (BITS_PER_LONG - 1);
> > + unsigned long vtype_inval = 1UL << (BITS_PER_LONG - 1);
> >
> > riscv_v_enable();
> > + if (has_xtheadvector())
> > + asm volatile (THEAD_VSETVLI_X0X0E8M8D1);
> > + else
> > + asm volatile (
> > + ".option push\n\t"
> > + ".option arch, +v\n\t"
> > + "vsetvli x0, x0, e8, m8, ta, ma\n\t"
> > + ".option pop\n\t");
> > +
> > asm volatile (
> > ".option push\n\t"
> > ".option arch, +v\n\t"
> > - "vsetvli %0, x0, e8, m8, ta, ma\n\t"
> > "vmv.v.i v0, -1\n\t"
> > "vmv.v.i v8, -1\n\t"
> > "vmv.v.i v16, -1\n\t"
> > "vmv.v.i v24, -1\n\t"
> > - "vsetvl %0, x0, %1\n\t"
> > + "vsetvl x0, x0, %0\n\t"
> > ".option pop\n\t"
> > - : "=&r" (vl) : "r" (vtype_inval) : "memory");
> > + : : "r" (vtype_inval));
> > +
> > riscv_v_disable();
> > }
> >
> > static inline void riscv_v_vstate_discard(struct pt_regs *regs)
> > {
> > - if ((regs->status & SR_VS) == SR_VS_OFF)
> > - return;
> > -
> > - __riscv_v_vstate_discard();
> > - __riscv_v_vstate_dirty(regs);
> > + if (riscv_v_vstate_query(regs)) {
> > + __riscv_v_vstate_discard();
> > + __riscv_v_vstate_dirty(regs);
> > + }
> > }
> >
> > static inline void riscv_v_vstate_save(struct __riscv_v_ext_state *vstate,
> > struct pt_regs *regs)
> > {
> > - if ((regs->status & SR_VS) == SR_VS_DIRTY) {
> > + if (__riscv_v_vstate_check(regs->status, DIRTY)) {
> > __riscv_v_vstate_save(vstate, vstate->datap);
> > __riscv_v_vstate_clean(regs);
> > }
> > @@ -186,7 +333,7 @@ static inline void riscv_v_vstate_save(struct __riscv_v_ext_state *vstate,
> > static inline void riscv_v_vstate_restore(struct __riscv_v_ext_state *vstate,
> > struct pt_regs *regs)
> > {
> > - if ((regs->status & SR_VS) != SR_VS_OFF) {
> > + if (riscv_v_vstate_query(regs)) {
> > __riscv_v_vstate_restore(vstate, vstate->datap);
> > __riscv_v_vstate_clean(regs);
> > }
> > @@ -195,7 +342,7 @@ static inline void riscv_v_vstate_restore(struct __riscv_v_ext_state *vstate,
> > static inline void riscv_v_vstate_set_restore(struct task_struct *task,
> > struct pt_regs *regs)
> > {
> > - if ((regs->status & SR_VS) != SR_VS_OFF) {
> > + if (riscv_v_vstate_query(regs)) {
> > set_tsk_thread_flag(task, TIF_RISCV_V_DEFER_RESTORE);
> > riscv_v_vstate_on(regs);
> > }
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index 077be4ab1f9a..180f7eae9086 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -789,7 +789,7 @@ void __init riscv_fill_hwcap(void)
> > elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
> > }
> >
> > - if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
> > + if (elf_hwcap & COMPAT_HWCAP_ISA_V || has_xtheadvector_no_alternatives()) {
> > riscv_v_setup_vsize();
> > /*
> > * ISA string in device tree might have 'v' flag, but
> > diff --git a/arch/riscv/kernel/kernel_mode_vector.c b/arch/riscv/kernel/kernel_mode_vector.c
> > index 6afe80c7f03a..99972a48e86b 100644
> > --- a/arch/riscv/kernel/kernel_mode_vector.c
> > +++ b/arch/riscv/kernel/kernel_mode_vector.c
> > @@ -143,7 +143,7 @@ static int riscv_v_start_kernel_context(bool *is_nested)
> >
> > /* Transfer the ownership of V from user to kernel, then save */
> > riscv_v_start(RISCV_PREEMPT_V | RISCV_PREEMPT_V_DIRTY);
> > - if ((task_pt_regs(current)->status & SR_VS) == SR_VS_DIRTY) {
> > + if (__riscv_v_vstate_check(task_pt_regs(current)->status, DIRTY)) {
> > uvstate = ¤t->thread.vstate;
> > __riscv_v_vstate_save(uvstate, uvstate->datap);
> > }
> > @@ -160,7 +160,7 @@ asmlinkage void riscv_v_context_nesting_start(struct pt_regs *regs)
> > return;
> >
> > depth = riscv_v_ctx_get_depth();
> > - if (depth == 0 && (regs->status & SR_VS) == SR_VS_DIRTY)
> > + if (depth == 0 && __riscv_v_vstate_check(regs->status, DIRTY))
> > riscv_preempt_v_set_dirty();
> >
> > riscv_v_ctx_depth_inc();
> > @@ -208,7 +208,7 @@ void kernel_vector_begin(void)
> > {
> > bool nested = false;
> >
> > - if (WARN_ON(!has_vector()))
> > + if (WARN_ON(!(has_vector() || has_xtheadvector())))
> > return;
> >
> > BUG_ON(!may_use_simd());
> > @@ -236,7 +236,7 @@ EXPORT_SYMBOL_GPL(kernel_vector_begin);
> > */
> > void kernel_vector_end(void)
> > {
> > - if (WARN_ON(!has_vector()))
> > + if (WARN_ON(!(has_vector() || has_xtheadvector())))
> > return;
> >
> > riscv_v_disable();
> > diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> > index e4bc61c4e58a..191023decd16 100644
> > --- a/arch/riscv/kernel/process.c
> > +++ b/arch/riscv/kernel/process.c
> > @@ -176,7 +176,7 @@ void flush_thread(void)
> > void arch_release_task_struct(struct task_struct *tsk)
> > {
> > /* Free the vector context of datap. */
> > - if (has_vector())
> > + if (has_vector() || has_xtheadvector())
> > riscv_v_thread_free(tsk);
> > }
> >
> > @@ -222,7 +222,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
> > p->thread.s[0] = 0;
> > }
> > p->thread.riscv_v_flags = 0;
> > - if (has_vector())
> > + if (has_vector() || has_xtheadvector())
> > riscv_v_thread_alloc(p);
> > p->thread.ra = (unsigned long)ret_from_fork;
> > p->thread.sp = (unsigned long)childregs; /* kernel sp */
> > diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
> > index 5a2edd7f027e..1d5e4b3ca9e1 100644
> > --- a/arch/riscv/kernel/signal.c
> > +++ b/arch/riscv/kernel/signal.c
> > @@ -189,7 +189,7 @@ static long restore_sigcontext(struct pt_regs *regs,
> >
> > return 0;
> > case RISCV_V_MAGIC:
> > - if (!has_vector() || !riscv_v_vstate_query(regs) ||
> > + if (!(has_vector() || has_xtheadvector()) || !riscv_v_vstate_query(regs) ||
> > size != riscv_v_sc_size)
> > return -EINVAL;
> >
> > @@ -211,7 +211,7 @@ static size_t get_rt_frame_size(bool cal_all)
> >
> > frame_size = sizeof(*frame);
> >
> > - if (has_vector()) {
> > + if (has_vector() || has_xtheadvector()) {
> > if (cal_all || riscv_v_vstate_query(task_pt_regs(current)))
> > total_context_size += riscv_v_sc_size;
> > }
> > @@ -284,7 +284,7 @@ static long setup_sigcontext(struct rt_sigframe __user *frame,
> > if (has_fpu())
> > err |= save_fp_state(regs, &sc->sc_fpregs);
> > /* Save the vector state. */
> > - if (has_vector() && riscv_v_vstate_query(regs))
> > + if ((has_vector() || has_xtheadvector()) && riscv_v_vstate_query(regs))
> > err |= save_v_state(regs, (void __user **)&sc_ext_ptr);
> > /* Write zero to fp-reserved space and check it on restore_sigcontext */
> > err |= __put_user(0, &sc->sc_extdesc.reserved);
> > diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
> > index 3ba2f2432483..83126995f61a 100644
> > --- a/arch/riscv/kernel/vector.c
> > +++ b/arch/riscv/kernel/vector.c
> > @@ -63,7 +63,7 @@ int riscv_v_setup_vsize(void)
> >
> > void __init riscv_v_setup_ctx_cache(void)
> > {
> > - if (!has_vector())
> > + if (!(has_vector() || has_xtheadvector()))
> > return;
> >
> > riscv_v_user_cachep = kmem_cache_create_usercopy("riscv_vector_ctx",
> > @@ -184,7 +184,8 @@ bool riscv_v_first_use_handler(struct pt_regs *regs)
> > u32 insn = (u32)regs->badaddr;
> >
> > /* Do not handle if V is not supported, or disabled */
> > - if (!(ELF_HWCAP & COMPAT_HWCAP_ISA_V))
> > + if (!(ELF_HWCAP & COMPAT_HWCAP_ISA_V) &&
> > + !(has_xtheadvector() && riscv_v_vstate_ctrl_user_allowed()))
> > return false;
> >
> > /* If V has been enabled then it is not the first-use trap */
> > @@ -223,7 +224,7 @@ void riscv_v_vstate_ctrl_init(struct task_struct *tsk)
> > bool inherit;
> > int cur, next;
> >
> > - if (!has_vector())
> > + if (!(has_vector() || has_xtheadvector()))
> > return;
> >
> > next = riscv_v_ctrl_get_next(tsk);
> > @@ -245,7 +246,7 @@ void riscv_v_vstate_ctrl_init(struct task_struct *tsk)
> >
> > long riscv_v_vstate_ctrl_get_current(void)
> > {
> > - if (!has_vector())
> > + if (!(has_vector() || has_xtheadvector()))
> > return -EINVAL;
> >
> > return current->thread.vstate_ctrl & PR_RISCV_V_VSTATE_CTRL_MASK;
> > @@ -256,7 +257,7 @@ long riscv_v_vstate_ctrl_set_current(unsigned long arg)
> > bool inherit;
> > int cur, next;
> >
> > - if (!has_vector())
> > + if (!(has_vector() || has_xtheadvector()))
> > return -EINVAL;
> >
> > if (arg & ~PR_RISCV_V_VSTATE_CTRL_MASK)
> > @@ -306,7 +307,7 @@ static struct ctl_table riscv_v_default_vstate_table[] = {
> >
> > static int __init riscv_v_sysctl_init(void)
> > {
> > - if (has_vector())
> > + if (has_vector() || has_xtheadvector())
> > if (!register_sysctl("abi", riscv_v_default_vstate_table))
> > return -EINVAL;
> > return 0;
> >
>
