target/riscv: Remove CSRs that set/clear an IMSIC interrupt file bits

Based on architecture review committee feedback, the [m|s|vs]seteienum,
[m|s|vs]clreienum, [m|s|vs]seteipnum, and [m|s|vs]clreipnum CSRs are
removed in the latest AIA draft v0.3.0 specification.
(Refer, https://github.com/riscv/riscv-aia/releases/tag/0.3.0-draft.31)

These CSRs were mostly for software convenience and software can always
use [m|s|vs]iselect and [m|s|vs]ireg CSRs to update the IMSIC interrupt
file bits.

We update the IMSIC CSR emulation as-per above to match the latest AIA
draft specification.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220616031543.953776-2-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

2 files changed, 6 insertions, 168 deletions

diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index b3f7fa7..157d706 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -174,14 +174,8 @@
 #define CSR_MIREG           0x351
 
 /* Machine-Level Interrupts (AIA) */
-#define CSR_MTOPI           0xfb0
-
-/* Machine-Level IMSIC Interface (AIA) */
-#define CSR_MSETEIPNUM      0x358
-#define CSR_MCLREIPNUM      0x359
-#define CSR_MSETEIENUM      0x35a
-#define CSR_MCLREIENUM      0x35b
 #define CSR_MTOPEI          0x35c
+#define CSR_MTOPI           0xfb0
 
 /* Virtual Interrupts for Supervisor Level (AIA) */
 #define CSR_MVIEN           0x308
@@ -221,14 +215,8 @@
 #define CSR_SIREG           0x151
 
 /* Supervisor-Level Interrupts (AIA) */
-#define CSR_STOPI           0xdb0
-
-/* Supervisor-Level IMSIC Interface (AIA) */
-#define CSR_SSETEIPNUM      0x158
-#define CSR_SCLREIPNUM      0x159
-#define CSR_SSETEIENUM      0x15a
-#define CSR_SCLREIENUM      0x15b
 #define CSR_STOPEI          0x15c
+#define CSR_STOPI           0xdb0
 
 /* Supervisor-Level High-Half CSRs (AIA) */
 #define CSR_SIEH            0x114
@@ -279,14 +267,8 @@
 #define CSR_VSIREG          0x251
 
 /* VS-Level Interrupts (H-extension with AIA) */
-#define CSR_VSTOPI          0xeb0
-
-/* VS-Level IMSIC Interface (H-extension with AIA) */
-#define CSR_VSSETEIPNUM     0x258
-#define CSR_VSCLREIPNUM     0x259
-#define CSR_VSSETEIENUM     0x25a
-#define CSR_VSCLREIENUM     0x25b
 #define CSR_VSTOPEI         0x25c
+#define CSR_VSTOPI          0xeb0
 
 /* Hypervisor and VS-Level High-Half CSRs (H-extension with AIA) */
 #define CSR_HIDELEGH        0x613
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 4982e98..235f2a0 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -1257,14 +1257,6 @@ 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:
@@ -1419,124 +1411,6 @@ 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)
 {
@@ -3658,14 +3532,8 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_MIREG]    = { "mireg",    aia_any,   NULL, NULL,    rmw_xireg },
 
     /* 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 },
+    [CSR_MTOPI]    = { "mtopi",    aia_any,   read_mtopi },
 
     /* Virtual Interrupts for Supervisor Level (AIA) */
     [CSR_MVIEN]      = { "mvien", aia_any, read_zero, write_ignore },
@@ -3713,14 +3581,8 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_SIREG]      = { "sireg",      aia_smode, NULL, NULL, rmw_xireg },
 
     /* 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 },
+    [CSR_STOPI]      = { "stopi",      aia_smode, read_stopi },
 
     /* Supervisor-Level High-Half CSRs (AIA) */
     [CSR_SIEH]       = { "sieh",   aia_smode32, NULL, NULL, rmw_sieh },
@@ -3792,14 +3654,8 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_VSIREG]      = { "vsireg",      aia_hmode, NULL, NULL,      rmw_xireg },
 
     /* 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 },
+    [CSR_VSTOPI]      = { "vstopi",      aia_hmode, read_vstopi },
 
     /* Hypervisor and VS-Level High-Half CSRs (H-extension with AIA) */
     [CSR_HIDELEGH]    = { "hidelegh",    aia_hmode32, NULL, NULL, rmw_hidelegh },