target/riscv: Implement AIA IMSIC interface CSRs

The AIA specification defines IMSIC interface CSRs for easy access
to the per-HART IMSIC registers without using indirect xiselect and
xireg CSRs. This patch implements the AIA IMSIC interface CSRs.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Message-id: 20220204174700.534953-16-anup@brainfault.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

1 files changed, 203 insertions, 0 deletions

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index a186b31..fe2c8dd 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -942,6 +942,16 @@ static int aia_xlate_vs_csrno(CPURISCVState *env, int csrno)
         return CSR_VSISELECT;
     case CSR_SIREG:
         return CSR_VSIREG;
+    case CSR_SSETEIPNUM:
+        return CSR_VSSETEIPNUM;
+    case CSR_SCLREIPNUM:
+        return CSR_VSCLREIPNUM;
+    case CSR_SSETEIENUM:
+        return CSR_VSSETEIENUM;
+    case CSR_SCLREIENUM:
+        return CSR_VSCLREIENUM;
+    case CSR_STOPEI:
+        return CSR_VSTOPEI;
     default:
         return csrno;
     };
@@ -1094,6 +1104,178 @@ done:
     return RISCV_EXCP_NONE;
 }
 
+static int rmw_xsetclreinum(CPURISCVState *env, int csrno, target_ulong *val,
+                            target_ulong new_val, target_ulong wr_mask)
+{
+    int ret = -EINVAL;
+    bool set, pend, virt;
+    target_ulong priv, isel, vgein, xlen, nval, wmask;
+
+    /* Translate CSR number for VS-mode */
+    csrno = aia_xlate_vs_csrno(env, csrno);
+
+    /* Decode register details from CSR number */
+    virt = set = pend = false;
+    switch (csrno) {
+    case CSR_MSETEIPNUM:
+        priv = PRV_M;
+        set = true;
+        pend = true;
+        break;
+    case CSR_MCLREIPNUM:
+        priv = PRV_M;
+        pend = true;
+        break;
+    case CSR_MSETEIENUM:
+        priv = PRV_M;
+        set = true;
+        break;
+    case CSR_MCLREIENUM:
+        priv = PRV_M;
+        break;
+    case CSR_SSETEIPNUM:
+        priv = PRV_S;
+        set = true;
+        pend = true;
+        break;
+    case CSR_SCLREIPNUM:
+        priv = PRV_S;
+        pend = true;
+        break;
+    case CSR_SSETEIENUM:
+        priv = PRV_S;
+        set = true;
+        break;
+    case CSR_SCLREIENUM:
+        priv = PRV_S;
+        break;
+    case CSR_VSSETEIPNUM:
+        priv = PRV_S;
+        virt = true;
+        set = true;
+        pend = true;
+        break;
+    case CSR_VSCLREIPNUM:
+        priv = PRV_S;
+        virt = true;
+        pend = true;
+        break;
+    case CSR_VSSETEIENUM:
+        priv = PRV_S;
+        virt = true;
+        set = true;
+        break;
+    case CSR_VSCLREIENUM:
+        priv = PRV_S;
+        virt = true;
+        break;
+    default:
+         goto done;
+    };
+
+    /* IMSIC CSRs only available when machine implements IMSIC. */
+    if (!env->aia_ireg_rmw_fn[priv]) {
+        goto done;
+    }
+
+    /* Find the selected guest interrupt file */
+    vgein = (virt) ? get_field(env->hstatus, HSTATUS_VGEIN) : 0;
+
+    /* Selected guest interrupt file should be valid */
+    if (virt && (!vgein || env->geilen < vgein)) {
+        goto done;
+    }
+
+    /* Set/Clear CSRs always read zero */
+    if (val) {
+        *val = 0;
+    }
+
+    if (wr_mask) {
+        /* Get interrupt number */
+        new_val &= wr_mask;
+
+        /* Find target interrupt pending/enable register */
+        xlen = riscv_cpu_mxl_bits(env);
+        isel = (new_val / xlen);
+        isel *= (xlen / IMSIC_EIPx_BITS);
+        isel += (pend) ? ISELECT_IMSIC_EIP0 : ISELECT_IMSIC_EIE0;
+
+        /* Find the interrupt bit to be set/clear */
+        wmask = ((target_ulong)1) << (new_val % xlen);
+        nval = (set) ? wmask : 0;
+
+        /* Call machine specific IMSIC register emulation */
+        ret = env->aia_ireg_rmw_fn[priv](env->aia_ireg_rmw_fn_arg[priv],
+                                         AIA_MAKE_IREG(isel, priv, virt,
+                                                       vgein, xlen),
+                                         NULL, nval, wmask);
+    } else {
+        ret = 0;
+    }
+
+done:
+    if (ret) {
+        return (riscv_cpu_virt_enabled(env) && virt) ?
+               RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
+    }
+    return RISCV_EXCP_NONE;
+}
+
+static int rmw_xtopei(CPURISCVState *env, int csrno, target_ulong *val,
+                      target_ulong new_val, target_ulong wr_mask)
+{
+    bool virt;
+    int ret = -EINVAL;
+    target_ulong priv, vgein;
+
+    /* Translate CSR number for VS-mode */
+    csrno = aia_xlate_vs_csrno(env, csrno);
+
+    /* Decode register details from CSR number */
+    virt = false;
+    switch (csrno) {
+    case CSR_MTOPEI:
+        priv = PRV_M;
+        break;
+    case CSR_STOPEI:
+        priv = PRV_S;
+        break;
+    case CSR_VSTOPEI:
+        priv = PRV_S;
+        virt = true;
+        break;
+    default:
+        goto done;
+    };
+
+    /* IMSIC CSRs only available when machine implements IMSIC. */
+    if (!env->aia_ireg_rmw_fn[priv]) {
+        goto done;
+    }
+
+    /* Find the selected guest interrupt file */
+    vgein = (virt) ? get_field(env->hstatus, HSTATUS_VGEIN) : 0;
+
+    /* Selected guest interrupt file should be valid */
+    if (virt && (!vgein || env->geilen < vgein)) {
+        goto done;
+    }
+
+    /* Call machine specific IMSIC register emulation for TOPEI */
+    ret = env->aia_ireg_rmw_fn[priv](env->aia_ireg_rmw_fn_arg[priv],
+                    AIA_MAKE_IREG(ISELECT_IMSIC_TOPEI, priv, virt, vgein,
+                                  riscv_cpu_mxl_bits(env)),
+                    val, new_val, wr_mask);
+
+done:
+    if (ret) {
+        return (riscv_cpu_virt_enabled(env) && virt) ?
+               RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
+    }
+    return RISCV_EXCP_NONE;
+}
+
 static RISCVException read_mtvec(CPURISCVState *env, int csrno,
                                  target_ulong *val)
 {
@@ -2930,6 +3112,13 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     /* Machine-Level Interrupts (AIA) */
     [CSR_MTOPI]    = { "mtopi",    aia_any,   read_mtopi },
 
+    /* Machine-Level IMSIC Interface (AIA) */
+    [CSR_MSETEIPNUM] = { "mseteipnum", aia_any, NULL, NULL, rmw_xsetclreinum },
+    [CSR_MCLREIPNUM] = { "mclreipnum", aia_any, NULL, NULL, rmw_xsetclreinum },
+    [CSR_MSETEIENUM] = { "mseteienum", aia_any, NULL, NULL, rmw_xsetclreinum },
+    [CSR_MCLREIENUM] = { "mclreienum", aia_any, NULL, NULL, rmw_xsetclreinum },
+    [CSR_MTOPEI]     = { "mtopei",     aia_any, NULL, NULL, rmw_xtopei },
+
     /* Virtual Interrupts for Supervisor Level (AIA) */
     [CSR_MVIEN]      = { "mvien", aia_any, read_zero, write_ignore },
     [CSR_MVIP]       = { "mvip",  aia_any, read_zero, write_ignore },
@@ -2966,6 +3155,13 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     /* Supervisor-Level Interrupts (AIA) */
     [CSR_STOPI]      = { "stopi",      aia_smode, read_stopi },
 
+    /* Supervisor-Level IMSIC Interface (AIA) */
+    [CSR_SSETEIPNUM] = { "sseteipnum", aia_smode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_SCLREIPNUM] = { "sclreipnum", aia_smode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_SSETEIENUM] = { "sseteienum", aia_smode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_SCLREIENUM] = { "sclreienum", aia_smode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_STOPEI]     = { "stopei",     aia_smode, NULL, NULL, rmw_xtopei },
+
     /* Supervisor-Level High-Half CSRs (AIA) */
     [CSR_SIEH]       = { "sieh",   aia_smode32, NULL, NULL, rmw_sieh },
     [CSR_SIPH]       = { "siph",   aia_smode32, NULL, NULL, rmw_siph },
@@ -3013,6 +3209,13 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     /* VS-Level Interrupts (H-extension with AIA) */
     [CSR_VSTOPI]      = { "vstopi",      aia_hmode, read_vstopi },
 
+    /* VS-Level IMSIC Interface (H-extension with AIA) */
+    [CSR_VSSETEIPNUM] = { "vsseteipnum", aia_hmode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_VSCLREIPNUM] = { "vsclreipnum", aia_hmode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_VSSETEIENUM] = { "vsseteienum", aia_hmode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_VSCLREIENUM] = { "vsclreienum", aia_hmode, NULL, NULL, rmw_xsetclreinum },
+    [CSR_VSTOPEI]     = { "vstopei",     aia_hmode, NULL, NULL, rmw_xtopei },
+
     /* Hypervisor and VS-Level High-Half CSRs (H-extension with AIA) */
     [CSR_HIDELEGH]    = { "hidelegh",    aia_hmode32, NULL, NULL, rmw_hidelegh },
     [CSR_HVIENH]      = { "hvienh",      aia_hmode32, read_zero, write_ignore },