riscv/rocket-chip
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Correct CSR privilege logic

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This commit is contained in:
Andrew Waterman 2014-01-31 01:03:17 -08:00
parent 0266c1f76a
commit febd26f505
1 changed files with 8 additions and 5 deletions
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13
rocket/src/main/scala/ctrl.scala
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@ -410,16 +410,18 @@ class Control(implicit conf: RocketConfiguration) extends Module
val id_csr_en = id_csr != CSR.N
val id_csr_fp = Bool(conf.fpu) && id_csr_en && DecodeLogic(id_csr_addr, fp_csrs, CSRs.all.toSet -- fp_csrs)
val id_csr_wen = id_raddr1 != UInt(0) || !Vec(CSR.S, CSR.C).contains(id_csr)
val id_csr_privileged = id_csr_en &&
(id_csr_addr(9,8) != UInt(0) ||
id_csr_addr(11,10) != UInt(0) && id_csr_wen)
val id_csr_invalid = id_csr_en && !Vec(legal_csrs.map(UInt(_))).contains(id_csr_addr)
val id_csr_privileged = id_csr_en &&
(id_csr_addr(11,10) === UInt(3) && id_csr_wen ||
id_csr_addr(11,10) === UInt(2) ||
id_csr_addr(11,10) === UInt(1) && !io.dpath.status.s ||
id_csr_addr(9,8) >= UInt(2) ||
id_csr_addr(9,8) === UInt(1) && !io.dpath.status.s && id_csr_wen)
// flush pipeline on CSR writes that may have side effects
val id_csr_flush = {
val safe_csrs = CSRs.sup0 :: CSRs.sup1 :: CSRs.epc :: Nil
id_csr_en && id_csr_wen && !DecodeLogic(id_csr_addr, safe_csrs, legal_csrs -- safe_csrs)
}
val id_privileged = id_sret || id_csr_privileged
// stall decode for fences (now, for AMO.aq; later, for AMO.rl and FENCE)
val id_amo_aq = io.dpath.inst(26)
@ -436,7 +438,8 @@ class Control(implicit conf: RocketConfiguration) extends Module
(io.imem.resp.bits.xcpt_ma, UInt(Causes.misaligned_fetch)),
(io.imem.resp.bits.xcpt_if, UInt(Causes.fault_fetch)),
(!id_int_val || id_csr_invalid, UInt(Causes.illegal_instruction)),
(id_privileged && !io.dpath.status.s, UInt(Causes.privileged_instruction)),
(id_csr_privileged, UInt(Causes.privileged_instruction)),
(id_sret && !io.dpath.status.s, UInt(Causes.privileged_instruction)),
((id_fp_val || id_csr_fp) && !io.dpath.status.ef, UInt(Causes.fp_disabled)),
(id_syscall, UInt(Causes.syscall)),
(id_rocc_val && !io.dpath.status.er, UInt(Causes.accelerator_disabled))))