Make has_vector take one argument. This argument represents the minimum
Vector subextension that the following Vector actions assume.

Also, change riscv_v_first_use_handler(), and boot code that calls
riscv_v_setup_vsize() to accept the minimum Vector sub-extension,
ZVE32X.

Most kernel/user interfaces requires minimum of ZVE32X. Thus, programs
compiled and run with ZVE32X should be supported by the kernel on most
aspects. This includes context-switch, signal, ptrace, prctl, and
hwprobe.

One exception is that ELF_HWCAP returns 'V' only if full V is supported
on the platform. This means that the system without a full V must not
rely on ELF_HWCAP to tell whether it is allowable to execute Vector
without first invoking a prctl() check.

Signed-off-by: Andy Chiu <andy.c...@sifive.com>
Acked-by: Joel Granados <j.grana...@samsung.com>
---
Changelog v4:
- check static_assert for !CONFIG_RISCV_ISA_V case in has_vector.
Changelog v2:
 - update the comment in hwprobe.
---
 arch/riscv/include/asm/switch_to.h     |  2 +-
 arch/riscv/include/asm/vector.h        | 25 ++++++++++++++++---------
 arch/riscv/include/asm/xor.h           |  2 +-
 arch/riscv/kernel/cpufeature.c         |  5 ++++-
 arch/riscv/kernel/kernel_mode_vector.c |  4 ++--
 arch/riscv/kernel/process.c            |  4 ++--
 arch/riscv/kernel/signal.c             |  6 +++---
 arch/riscv/kernel/smpboot.c            |  2 +-
 arch/riscv/kernel/sys_hwprobe.c        |  8 ++++++--
 arch/riscv/kernel/vector.c             | 15 +++++++++------
 arch/riscv/lib/uaccess.S               |  2 +-
 11 files changed, 46 insertions(+), 29 deletions(-)

diff --git a/arch/riscv/include/asm/switch_to.h 
b/arch/riscv/include/asm/switch_to.h
index 7efdb0584d47..df1adf196c4f 100644
--- a/arch/riscv/include/asm/switch_to.h
+++ b/arch/riscv/include/asm/switch_to.h
@@ -78,7 +78,7 @@ do {                                                  \
        struct task_struct *__next = (next);            \
        if (has_fpu())                                  \
                __switch_to_fpu(__prev, __next);        \
-       if (has_vector())                                       \
+       if (has_vector(ZVE32X))                 \
                __switch_to_vector(__prev, __next);     \
        ((last) = __switch_to(__prev, __next));         \
 } while (0)
diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
index 731dcd0ed4de..ed5fb6515d54 100644
--- a/arch/riscv/include/asm/vector.h
+++ b/arch/riscv/include/asm/vector.h
@@ -8,6 +8,19 @@
 
 #include <linux/types.h>
 #include <uapi/asm-generic/errno.h>
+#include <asm/cpufeature.h>
+#include <asm/hwcap.h>
+
+#define has_vector(VEXT)                                                       
                \
+({                                                                             
                \
+       static_assert(RISCV_ISA_EXT_##VEXT == RISCV_ISA_EXT_ZVE32X ||           
                \
+                     RISCV_ISA_EXT_##VEXT == RISCV_ISA_EXT_ZVE32F ||           
                \
+                     RISCV_ISA_EXT_##VEXT == RISCV_ISA_EXT_ZVE64X ||           
                \
+                     RISCV_ISA_EXT_##VEXT == RISCV_ISA_EXT_ZVE64F ||           
                \
+                     RISCV_ISA_EXT_##VEXT == RISCV_ISA_EXT_ZVE64D ||           
                \
+                     RISCV_ISA_EXT_##VEXT == RISCV_ISA_EXT_v);                 
                \
+       IS_ENABLED(CONFIG_RISCV_ISA_V) && 
riscv_has_extension_unlikely(RISCV_ISA_EXT_##VEXT);   \
+})
 
 #ifdef CONFIG_RISCV_ISA_V
 
@@ -15,9 +28,9 @@
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
 #include <asm/ptrace.h>
-#include <asm/cpufeature.h>
 #include <asm/csr.h>
 #include <asm/asm.h>
+#include <asm/bug.h>
 
 extern unsigned long riscv_v_vsize;
 int riscv_v_setup_vsize(void);
@@ -35,11 +48,6 @@ static inline u32 riscv_v_flags(void)
        return READ_ONCE(current->thread.riscv_v_flags);
 }
 
-static __always_inline bool has_vector(void)
-{
-       return riscv_has_extension_unlikely(RISCV_ISA_EXT_v);
-}
-
 static inline void __riscv_v_vstate_clean(struct pt_regs *regs)
 {
        regs->status = (regs->status & ~SR_VS) | SR_VS_CLEAN;
@@ -131,7 +139,7 @@ static inline void __riscv_v_vstate_restore(struct 
__riscv_v_ext_state *restore_
        riscv_v_enable();
        asm volatile (
                ".option push\n\t"
-               ".option arch, +v\n\t"
+               ".option arch, +zve32x\n\t"
                "vsetvli        %0, x0, e8, m8, ta, ma\n\t"
                "vle8.v         v0, (%1)\n\t"
                "add            %1, %1, %0\n\t"
@@ -153,7 +161,7 @@ static inline void __riscv_v_vstate_discard(void)
        riscv_v_enable();
        asm volatile (
                ".option push\n\t"
-               ".option arch, +v\n\t"
+               ".option arch, +zve32x\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"
@@ -267,7 +275,6 @@ bool riscv_v_vstate_ctrl_user_allowed(void);
 struct pt_regs;
 
 static inline int riscv_v_setup_vsize(void) { return -EOPNOTSUPP; }
-static __always_inline bool has_vector(void) { return false; }
 static inline bool riscv_v_first_use_handler(struct pt_regs *regs) { return 
false; }
 static inline bool riscv_v_vstate_query(struct pt_regs *regs) { return false; }
 static inline bool riscv_v_vstate_ctrl_user_allowed(void) { return false; }
diff --git a/arch/riscv/include/asm/xor.h b/arch/riscv/include/asm/xor.h
index 96011861e46b..46042ef5a2f7 100644
--- a/arch/riscv/include/asm/xor.h
+++ b/arch/riscv/include/asm/xor.h
@@ -61,7 +61,7 @@ static struct xor_block_template xor_block_rvv = {
        do {        \
                xor_speed(&xor_block_8regs);    \
                xor_speed(&xor_block_32regs);    \
-               if (has_vector()) { \
+               if (has_vector(ZVE32X)) { \
                        xor_speed(&xor_block_rvv);\
                } \
        } while (0)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 38d09de518b1..8b52060649d2 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -715,12 +715,15 @@ void __init riscv_fill_hwcap(void)
                elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
        }
 
-       if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+       if (__riscv_isa_extension_available(NULL, RISCV_ISA_EXT_ZVE32X)) {
                /*
                 * This callsite can't fail here. It cannot fail when called on
                 * the boot hart.
                 */
                riscv_v_setup_vsize();
+       }
+
+       if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
                /*
                 * ISA string in device tree might have 'v' flag, but
                 * CONFIG_RISCV_ISA_V is disabled in kernel.
diff --git a/arch/riscv/kernel/kernel_mode_vector.c 
b/arch/riscv/kernel/kernel_mode_vector.c
index 6afe80c7f03a..0d4d1a03d1c7 100644
--- a/arch/riscv/kernel/kernel_mode_vector.c
+++ b/arch/riscv/kernel/kernel_mode_vector.c
@@ -208,7 +208,7 @@ void kernel_vector_begin(void)
 {
        bool nested = false;
 
-       if (WARN_ON(!has_vector()))
+       if (WARN_ON(!has_vector(ZVE32X)))
                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(ZVE32X)))
                return;
 
        riscv_v_disable();
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 92922dbd5b5c..919e72f9fff6 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -178,7 +178,7 @@ 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(ZVE32X))
                riscv_v_thread_free(tsk);
 }
 
@@ -225,7 +225,7 @@ 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(ZVE32X))
                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 501e66debf69..a96e6e969a3f 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -188,7 +188,7 @@ 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(ZVE32X) || !riscv_v_vstate_query(regs) 
||
                            size != riscv_v_sc_size)
                                return -EINVAL;
 
@@ -210,7 +210,7 @@ static size_t get_rt_frame_size(bool cal_all)
 
        frame_size = sizeof(*frame);
 
-       if (has_vector()) {
+       if (has_vector(ZVE32X)) {
                if (cal_all || riscv_v_vstate_query(task_pt_regs(current)))
                        total_context_size += riscv_v_sc_size;
        }
@@ -283,7 +283,7 @@ 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(ZVE32X) && 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/smpboot.c b/arch/riscv/kernel/smpboot.c
index 673437ccc13d..7252666ce0da 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -214,7 +214,7 @@ asmlinkage __visible void smp_callin(void)
        struct mm_struct *mm = &init_mm;
        unsigned int curr_cpuid = smp_processor_id();
 
-       if (has_vector()) {
+       if (has_vector(ZVE32X)) {
                /*
                 * Return as early as possible so the hart with a mismatching
                 * vlen won't boot.
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index c8219b82fbfc..e7c3fcac62a1 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -69,7 +69,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
        if (riscv_isa_extension_available(NULL, c))
                pair->value |= RISCV_HWPROBE_IMA_C;
 
-       if (has_vector())
+       if (has_vector(v))
                pair->value |= RISCV_HWPROBE_IMA_V;
 
        /*
@@ -112,7 +112,11 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
                EXT_KEY(ZACAS);
                EXT_KEY(ZICOND);
 
-               if (has_vector()) {
+               /*
+                *  Vector crypto and ZVE* extensions are supported only if
+                *  kernel has minimum V support of ZVE32X.
+                */
+               if (has_vector(ZVE32X)) {
                        EXT_KEY(ZVE32X);
                        EXT_KEY(ZVE32F);
                        EXT_KEY(ZVE64X);
diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
index 6727d1d3b8f2..e8a47fa72351 100644
--- a/arch/riscv/kernel/vector.c
+++ b/arch/riscv/kernel/vector.c
@@ -53,7 +53,7 @@ int riscv_v_setup_vsize(void)
 
 void __init riscv_v_setup_ctx_cache(void)
 {
-       if (!has_vector())
+       if (!has_vector(ZVE32X))
                return;
 
        riscv_v_user_cachep = kmem_cache_create_usercopy("riscv_vector_ctx",
@@ -173,8 +173,11 @@ bool riscv_v_first_use_handler(struct pt_regs *regs)
        u32 __user *epc = (u32 __user *)regs->epc;
        u32 insn = (u32)regs->badaddr;
 
+       if (!has_vector(ZVE32X))
+               return false;
+
        /* Do not handle if V is not supported, or disabled */
-       if (!(ELF_HWCAP & COMPAT_HWCAP_ISA_V))
+       if (!riscv_v_vstate_ctrl_user_allowed())
                return false;
 
        /* If V has been enabled then it is not the first-use trap */
@@ -213,7 +216,7 @@ void riscv_v_vstate_ctrl_init(struct task_struct *tsk)
        bool inherit;
        int cur, next;
 
-       if (!has_vector())
+       if (!has_vector(ZVE32X))
                return;
 
        next = riscv_v_ctrl_get_next(tsk);
@@ -235,7 +238,7 @@ void riscv_v_vstate_ctrl_init(struct task_struct *tsk)
 
 long riscv_v_vstate_ctrl_get_current(void)
 {
-       if (!has_vector())
+       if (!has_vector(ZVE32X))
                return -EINVAL;
 
        return current->thread.vstate_ctrl & PR_RISCV_V_VSTATE_CTRL_MASK;
@@ -246,7 +249,7 @@ long riscv_v_vstate_ctrl_set_current(unsigned long arg)
        bool inherit;
        int cur, next;
 
-       if (!has_vector())
+       if (!has_vector(ZVE32X))
                return -EINVAL;
 
        if (arg & ~PR_RISCV_V_VSTATE_CTRL_MASK)
@@ -296,7 +299,7 @@ static struct ctl_table riscv_v_default_vstate_table[] = {
 
 static int __init riscv_v_sysctl_init(void)
 {
-       if (has_vector())
+       if (has_vector(ZVE32X))
                if (!register_sysctl("abi", riscv_v_default_vstate_table))
                        return -EINVAL;
        return 0;
diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S
index bc22c078aba8..bbe143bb32a0 100644
--- a/arch/riscv/lib/uaccess.S
+++ b/arch/riscv/lib/uaccess.S
@@ -14,7 +14,7 @@
 
 SYM_FUNC_START(__asm_copy_to_user)
 #ifdef CONFIG_RISCV_ISA_V
-       ALTERNATIVE("j fallback_scalar_usercopy", "nop", 0, RISCV_ISA_EXT_v, 
CONFIG_RISCV_ISA_V)
+       ALTERNATIVE("j fallback_scalar_usercopy", "nop", 0, 
RISCV_ISA_EXT_ZVE32X, CONFIG_RISCV_ISA_V)
        REG_L   t0, riscv_v_usercopy_threshold
        bltu    a2, t0, fallback_scalar_usercopy
        tail enter_vector_usercopy

-- 
2.44.0.rc2


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