The branch main has been updated by andrew:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=591c7a08bf8addce4b047ef9c8033c33099e4688

commit 591c7a08bf8addce4b047ef9c8033c33099e4688
Author:     Sarah Walker <[email protected]>
AuthorDate: 2026-01-13 14:18:31 +0000
Commit:     Andrew Turner <[email protected]>
CommitDate: 2026-01-13 15:28:03 +0000

    arm64: Enable MOPS in userspace
    
    Detect presence of FEAT_MOPS, and enable instruction set and set HWCAP2 flag
    if present.
    
    Add handler for MOE exceptions.
    
    Reviewed by:    andrew
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D54558
---
 sys/arm64/arm64/identcpu.c |  8 +++++-
 sys/arm64/arm64/machdep.c  | 35 +++++++++++++++++++++++++
 sys/arm64/arm64/trap.c     | 64 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/sys/arm64/arm64/identcpu.c b/sys/arm64/arm64/identcpu.c
index 2d07420bcdb0..e37c9813582b 100644
--- a/sys/arm64/arm64/identcpu.c
+++ b/sys/arm64/arm64/identcpu.c
@@ -1094,6 +1094,11 @@ static const struct mrs_field_value id_aa64isar2_mops[] 
= {
        MRS_FIELD_VALUE_END,
 };
 
+static const struct mrs_field_hwcap id_aa64isar2_mops_caps[] = {
+       MRS_HWCAP(2, HWCAP2_MOPS, ID_AA64ISAR2_MOPS_IMPL),
+       MRS_HWCAP_END
+};
+
 static const struct mrs_field_value id_aa64isar2_apa3[] = {
        MRS_FIELD_VALUE(ID_AA64ISAR2_APA3_NONE, ""),
        MRS_FIELD_VALUE(ID_AA64ISAR2_APA3_PAC, "APA3 PAC"),
@@ -1149,7 +1154,8 @@ static const struct mrs_field id_aa64isar2_fields[] = {
        MRS_FIELD(ID_AA64ISAR2, PAC_frac, false, MRS_LOWER, 0,
            id_aa64isar2_pac_frac),
        MRS_FIELD(ID_AA64ISAR2, BC, false, MRS_LOWER, 0, id_aa64isar2_bc),
-       MRS_FIELD(ID_AA64ISAR2, MOPS, false, MRS_LOWER, 0, id_aa64isar2_mops),
+       MRS_FIELD_HWCAP(ID_AA64ISAR2, MOPS, false, MRS_LOWER, MRS_USERSPACE,
+           id_aa64isar2_mops, id_aa64isar2_mops_caps),
        MRS_FIELD_HWCAP(ID_AA64ISAR2, APA3, false, MRS_LOWER, MRS_USERSPACE,
            id_aa64isar2_apa3, id_aa64isar2_apa3_caps),
        MRS_FIELD_HWCAP(ID_AA64ISAR2, GPA3, false, MRS_LOWER, MRS_USERSPACE,
diff --git a/sys/arm64/arm64/machdep.c b/sys/arm64/arm64/machdep.c
index 322bad273a08..6790f47a0f82 100644
--- a/sys/arm64/arm64/machdep.c
+++ b/sys/arm64/arm64/machdep.c
@@ -219,6 +219,41 @@ CPU_FEAT(feat_pan, "Privileged access never",
     pan_check, NULL, pan_enable, pan_disabled,
     CPU_FEAT_AFTER_DEV | CPU_FEAT_PER_CPU);
 
+static cpu_feat_en
+mops_check(const struct cpu_feat *feat __unused, u_int midr __unused)
+{
+       uint64_t id_aa64isar2;
+
+       if (!get_kernel_reg(ID_AA64ISAR2_EL1, &id_aa64isar2))
+               return (FEAT_ALWAYS_DISABLE);
+       if (ID_AA64ISAR2_MOPS_VAL(id_aa64isar2) == ID_AA64ISAR2_MOPS_NONE)
+               return (FEAT_ALWAYS_DISABLE);
+
+       return (FEAT_DEFAULT_ENABLE);
+}
+
+static bool
+mops_enable(const struct cpu_feat *feat __unused,
+    cpu_feat_errata errata_status __unused, u_int *errata_list __unused,
+    u_int errata_count __unused)
+{
+       WRITE_SPECIALREG(sctlr_el1, READ_SPECIALREG(sctlr_el1) | SCTLR_MSCEn);
+       isb();
+
+       return (true);
+}
+
+static void
+mops_disabled(const struct cpu_feat *feat __unused)
+{
+       WRITE_SPECIALREG(sctlr_el1, READ_SPECIALREG(sctlr_el1) & ~SCTLR_MSCEn);
+       isb();
+}
+
+CPU_FEAT(feat_mops, "MOPS",
+    mops_check, NULL, mops_enable, mops_disabled,
+    CPU_FEAT_AFTER_DEV | CPU_FEAT_PER_CPU);
+
 bool
 has_hyp(void)
 {
diff --git a/sys/arm64/arm64/trap.c b/sys/arm64/arm64/trap.c
index 75c9b5f87892..3de56187657c 100644
--- a/sys/arm64/arm64/trap.c
+++ b/sys/arm64/arm64/trap.c
@@ -597,6 +597,66 @@ do_el1h_sync(struct thread *td, struct trapframe *frame)
        }
 }
 
+static void
+handle_moe(struct thread *td, struct trapframe *frame, uint64_t esr)
+{
+       uint64_t src;
+       uint64_t dest;
+       uint64_t size;
+       int src_reg;
+       int dest_reg;
+       int size_reg;
+       int format_option;
+
+       format_option = esr & ISS_MOE_FORMAT_OPTION_MASK;
+       dest_reg = (esr & ISS_MOE_DESTREG_MASK) >> ISS_MOE_DESTREG_SHIFT;
+       size_reg = (esr & ISS_MOE_SIZEREG_MASK) >> ISS_MOE_SIZEREG_SHIFT;
+       dest = frame->tf_x[dest_reg];
+       size = frame->tf_x[size_reg];
+
+       /*
+        * Put the registers back in the original format suitable for a
+        * prologue instruction, using the generic return routine from the
+        * Arm ARM (DDI 0487I.a) rules CNTMJ and MWFQH.
+        */
+       if (esr & ISS_MOE_MEMINST) {
+               /* SET* instruction */
+               if (format_option == ISS_MOE_FORMAT_OPTION_A ||
+                   format_option == ISS_MOE_FORMAT_OPTION_A2) {
+                       /* Format is from Option A; forward set */
+                       frame->tf_x[dest_reg] = dest + size;
+                       frame->tf_x[size_reg] = -size;
+               }
+       } else {
+               /* CPY* instruction */
+               src_reg = (esr & ISS_MOE_SRCREG_MASK) >> ISS_MOE_SRCREG_SHIFT;
+               src = frame->tf_x[src_reg];
+
+               if (format_option == ISS_MOE_FORMAT_OPTION_B ||
+                   format_option == ISS_MOE_FORMAT_OPTION_B2) {
+                       /* Format is from Option B */
+                       if (frame->tf_spsr & PSR_N) {
+                               /* Backward copy */
+                               frame->tf_x[dest_reg] = dest - size;
+                               frame->tf_x[src_reg] = src + size;
+                       }
+               } else {
+                       /* Format is from Option A */
+                       if (frame->tf_x[size_reg] & (1UL << 63)) {
+                               /* Forward copy */
+                               frame->tf_x[dest_reg] = dest + size;
+                               frame->tf_x[src_reg] = src + size;
+                               frame->tf_x[size_reg] = -size;
+                       }
+               }
+       }
+
+       if (esr & ISS_MOE_FROM_EPILOGUE)
+               frame->tf_elr -= 8;
+       else
+               frame->tf_elr -= 4;
+}
+
 void
 do_el0_sync(struct thread *td, struct trapframe *frame)
 {
@@ -738,6 +798,10 @@ do_el0_sync(struct thread *td, struct trapframe *frame)
                    exception);
                userret(td, frame);
                break;
+       case EXCP_MOE:
+               handle_moe(td, frame, esr);
+               userret(td, frame);
+               break;
        default:
                call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr,
                    exception);

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