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Slightly rework CHERI PTE to add CapDirty flag

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Permissions are consistently checked before dirty flags, now, too.
This commit is contained in:
Nathaniel Filardo
2020-09-30 15:40:50 +01:00
parent 00ffdd7228
commit d4308f0f03
1 changed files with 24 additions and 13 deletions
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37
src_Core/RISCY_OOO/procs/lib/TlbTypes.bsv
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@@ -69,11 +69,12 @@ typedef struct {
typedef struct {
Bool cap_writable;
Bool cap_readable;
Bool cap_dirty;
} PTEUpperType deriving (Bits, Eq, FShow);
typedef struct {
PTEUpperType pteUpperType;
Bit#(8) reserved;
Bit#(7) reserved;
Ppn ppn;
Bit#(2) reserved_sw; // reserved for supervisor software
PTEType pteType;
@@ -183,6 +184,14 @@ typedef struct {
Bool allowCap; // Whether we can load caps
} TlbPermissionCheck deriving(Bits, Eq, FShow);
function Exception tlbExcCode(TlbAccessType access, Bool cap);
if (access == DataStore) begin
return cap ? excStoreCapPageFault : excStorePageFault;
end else begin
return excLoadPageFault;
end
endfunction
function TlbPermissionCheck hasVMPermission(
VMInfo vm_info,
PTEType pte_type, PTEUpperType pte_upper_type,
@@ -241,28 +250,30 @@ function TlbPermissionCheck hasVMPermission(
if(!(pte_type.readable && pte_type.writable)) begin
fault = True;
end
if(cap && !pte_upper_type.cap_writable) begin
fault = True;
end
end
endcase
TlbPermissionCheck ret = TlbPermissionCheck {
allowed: !fault,
excCode: access == DataStore ? excStorePageFault : excLoadPageFault,
excCode: tlbExcCode(access, cap),
allowCap: pte_upper_type.cap_readable};
if (!fault) begin
if (cap && access == DataStore && !pte_upper_type.cap_writable) begin
// check if accessed or dirty bit needs to be set
if(cap && access == DataStore && !pte_upper_type.cap_dirty) begin
ret.allowed = False;
ret.excCode = excStoreCapPageFault;
end else begin
// check if accessed or dirty bit needs to be set
if(!pte_type.accessed) begin
ret.allowed = False;
ret.excCode = access == DataStore ? excStorePageFault : excLoadPageFault;
end
if(access == DataStore && !pte_type.dirty) begin
ret.allowed = False;
ret.excCode = access == DataStore ? excStorePageFault : excLoadPageFault;
end
end
if(access == DataStore && !pte_type.dirty) begin
ret.allowed = False;
ret.excCode = excStorePageFault;
end
if(!pte_type.accessed) begin
ret.allowed = False;
ret.excCode = access == DataStore ? excStorePageFault : excLoadPageFault;
end
end