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Fixed bug decoding svinval instructions and checking TVM

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David Harris 2025-06-05 16:54:15 -07:00
parent 55df24f00b
commit d7c30f5f1f
2 changed files with 18 additions and 10 deletions
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26
src/privileged/privdec.sv
View file

@ -31,7 +31,7 @@
module privdec import cvw::*; #(parameter cvw_t P) (
input logic clk, reset,
input logic StallW, FlushW,
input logic [31:15] InstrM, // privileged instruction function field
input logic [31:7 ] InstrM, // privileged instruction function field
input logic PrivilegedM, // is this a privileged instruction (from IEU controller)
input logic IllegalIEUFPUInstrM, // Not a legal IEU instruction
input logic IllegalCSRAccessM, // Not a legal CSR access
@ -43,26 +43,31 @@ module privdec import cvw::*; #(parameter cvw_t P) (
output logic wfiM, wfiW, sfencevmaM // wfi / sfence.vma / sinval.vma instructions
);
logic rs1zeroM; // rs1 field = 0
logic rs1zeroM, rdzeroM; // rs1 / rd field = 0
logic IllegalPrivilegedInstrM; // privileged instruction isn't a legal one or in legal mode
logic WFITimeoutM; // WFI reaches timeout threshold
logic ebreakM, ecallM; // ebreak / ecall instructions
logic sinvalvmaM; // sinval.vma
logic presfencevmaM; // sfence.vma before checking privilege mode
logic sfencewinvalM, sfenceinvalirM; // sfence.w.inval, sfence.inval.ir
logic invalM; // any of the svinval instructions
logic vmaM; // sfence.vma or sinval.vma
logic fenceinvalM; // sfence.w.inval or sfence.inval.ir
///////////////////////////////////////////
// Decode privileged instructions
///////////////////////////////////////////
assign rs1zeroM = InstrM[19:15] == 5'b0;
assign rdzeroM = InstrM[11:7] == 5'b0;
// svinval instructions
// any svinval instruction is treated as sfence.vma on Wally
assign sinvalvmaM = (InstrM[31:25] == 7'b0001011);
assign sfencewinvalM = (InstrM[31:20] == 12'b000110000000) & rs1zeroM;
assign sfenceinvalirM = (InstrM[31:20] == 12'b000110000001) & rs1zeroM;
assign invalM = P.SVINVAL_SUPPORTED & (sinvalvmaM | sfencewinvalM | sfenceinvalirM);
assign sinvalvmaM = (InstrM[31:25] == 7'b0001011) & rdzeroM;
assign sfencewinvalM = (InstrM[31:20] == 12'b000110000000) & rs1zeroM & rdzeroM;
assign sfenceinvalirM = (InstrM[31:20] == 12'b000110000001) & rs1zeroM & rdzeroM;
assign presfencevmaM = (InstrM[31:25] == 7'b0001001) & rdzeroM;
assign vmaM = presfencevmaM | (sinvalvmaM & P.SVINVAL_SUPPORTED); // sfence.vma or sinval.vma
assign fenceinvalM = (sfencewinvalM | sfenceinvalirM) & P.SVINVAL_SUPPORTED; // sfence.w.inval or sfence.inval.ir
assign sretM = PrivilegedM & (InstrM[31:20] == 12'b000100000010) & rs1zeroM & P.S_SUPPORTED &
(PrivilegeModeW == P.M_MODE | PrivilegeModeW == P.S_MODE & ~STATUS_TSR);
@ -71,8 +76,11 @@ module privdec import cvw::*; #(parameter cvw_t P) (
assign ecallM = PrivilegedM & (InstrM[31:20] == 12'b000000000000) & rs1zeroM;
assign ebreakM = PrivilegedM & (InstrM[31:20] == 12'b000000000001) & rs1zeroM;
assign wfiM = PrivilegedM & (InstrM[31:20] == 12'b000100000101) & rs1zeroM;
assign sfencevmaM = PrivilegedM & (InstrM[31:25] == 7'b0001001 | invalM) &
(PrivilegeModeW == P.M_MODE | (PrivilegeModeW == P.S_MODE & ~STATUS_TVM)) & P.VIRTMEM_SUPPORTED;
// all of sinval.vma, sfence.w.inval, sfence.inval.ir are treated as sfence.vma
assign sfencevmaM = PrivilegedM & P.VIRTMEM_SUPPORTED &
((PrivilegeModeW == P.M_MODE & (vmaM | fenceinvalM)) |
(PrivilegeModeW == P.S_MODE & (vmaM & ~STATUS_TVM | fenceinvalM))); // sfence.w.inval & sfence.inval.ir not affected by TVM
///////////////////////////////////////////
// WFI timeout Privileged Spec 3.1.6.5

2
src/privileged/privileged.sv
View file

@ -127,7 +127,7 @@ module privileged import cvw::*; #(parameter cvw_t P) (
.STATUS_MPP, .STATUS_SPP, .NextPrivilegeModeM, .PrivilegeModeW);
// decode privileged instructions
privdec #(P) pmd(.clk, .reset, .StallW, .FlushW, .InstrM(InstrM[31:15]),
privdec #(P) pmd(.clk, .reset, .StallW, .FlushW, .InstrM(InstrM[31:7]),
.PrivilegedM, .IllegalIEUFPUInstrM, .IllegalCSRAccessM,
.PrivilegeModeW, .STATUS_TSR, .STATUS_TVM, .STATUS_TW, .IllegalInstrFaultM,
.EcallFaultM, .BreakpointFaultM, .sretM, .mretM, .RetM, .wfiM, .wfiW, .sfencevmaM);