Fix segment ACCESSED tracking
This commit is contained in:
Jeff Parsons
jeffpar
parent
42a7bb049a
commit
42cf78b8e0
5 changed files with 121 additions and 74 deletions
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@ -64,6 +64,7 @@ CSEG_REAL equ 0xf000
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CSEG_PROT16 equ 0x0008
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CSEG_PROT32 equ 0x0010
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DSEG_PROT16 equ 0x0018
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DSEG_PROT32 equ 0x0020
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;
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; The "defDesc" macro defines a descriptor, given a name (%1), base (%2), limit (%3), type (%4), and ext (%5)
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@ -96,9 +97,9 @@ DSEG_PROT16 equ 0x0018
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%assign selDesc selDesc+8
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%endmacro
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start: cli
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start: nop
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;
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; Test unsigned 32-bit multiplication and division
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; Quick test of unsigned 32-bit multiplication and division
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;
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mov eax,0x44332211
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mov ebx,eax
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@ -111,7 +112,7 @@ start: cli
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xor dx,dx
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mov ds,dx ; DS -> 0x0000
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;
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; Test moving a segment register to a 32-bit register
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; Quick test of moving a segment register to a 32-bit register
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;
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mov eax,ds
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test eax,eax
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@ -153,6 +154,7 @@ myGDT: defDesc NULL,0 ; the first descriptor in any descriptor table is always
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defDesc CSEG_PROT16,0x000f0000,0x0000ffff,ACC_TYPE_CODE_READABLE,EXT_NONE
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defDesc CSEG_PROT32,0x000f0000,0x0000ffff,ACC_TYPE_CODE_READABLE,EXT_BIG
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defDesc DSEG_PROT16,0x00000000,0x000fffff,ACC_TYPE_DATA_WRITABLE,EXT_NONE
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defDesc DSEG_PROT32,0x00000000,0x000fffff,ACC_TYPE_DATA_WRITABLE,EXT_BIG
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myGDTEnd:
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initGDT:
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@ -166,6 +168,7 @@ initGDT:
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setDesc CSEG_PROT16,eax,0x0000ffff,ACC_TYPE_CODE_READABLE,EXT_NONE
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setDesc CSEG_PROT32,eax,0x0000ffff,ACC_TYPE_CODE_READABLE,EXT_BIG
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setDesc DSEG_PROT16,0x0,0x000fffff,ACC_TYPE_DATA_WRITABLE,EXT_NONE
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setDesc DSEG_PROT32,0x0,0x000fffff,ACC_TYPE_DATA_WRITABLE,EXT_BIG
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sub edi,RAM_GDT
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dec edi
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mov [RAM_GDTR],di
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@ -244,10 +247,10 @@ initPages:
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mov es,ax
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xor edi,edi
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;
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; Build a page directory at ES:EDI with only 1 valid PDE (the first one)
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; Build a page directory at ES:EDI with only 1 valid PDE (the first one),
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; because we're not going to access any memory outside the first 4Mb.
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;
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cld
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cli ; make sure interrupts are still off (in case any DOS calls turned them back on)
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mov eax,esi
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add eax,0x1000 ; EAX == page frame address (of the next page)
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or eax,PTE_USER | PTE_READWRITE | PTE_PRESENT
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@ -256,7 +259,7 @@ initPages:
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sub eax,eax
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rep stosd
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;
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; Build a page table at EDI with only 256 (out of 1024) valid PTEs, which will map the first 1Mb of the
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; Build a page table at EDI with 256 (out of 1024) valid PTEs, mapping the first 1Mb of the
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; first 4Mb as linear == physical.
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;
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mov eax,PTE_USER | PTE_READWRITE | PTE_PRESENT
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@ -268,7 +271,9 @@ initPT: stosd
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sub eax,eax
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rep stosd
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goProt: o32 lgdt [cs:addrGDT]
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goProt:
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cli ; make sure interrupts are off now, since we've not initialized the IDT yet
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o32 lgdt [cs:addrGDT]
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mov cr3,esi
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mov eax,cr0
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%if PAGING
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@ -286,6 +291,45 @@ toProt32:
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mov ds,ax
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mov es,ax
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;
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; Of the 64Kb of scratch memory we allocated, the first 8Kb (0x2000) is being used for a
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; page directory and a single page table, so we have at least another 52Kb, at ESI+0x2000,
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; to play with (I'm rounding down by 4Kb to be safe).
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;
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; Let's use the top of that memory, ESI+0xd000, as the top of our stack. Note, however, that
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; that guarantees ESI will be be greater than 0xffff, so as long as SS contains a 16-bit data
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; segment, pushes will NOT be occurring where you expect.
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;
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add esi,0x2000 ; ESI -> bottom of scratch memory
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mov ss,ax
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lea esp,[esi+0xe000] ; set ESP to bottom of scratch + 52K
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lea ebp,[esp-4]
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and ebp,0xffff ; EBP now mirrors SP instead of ESP
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mov edx,[ebp]
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mov eax,0x11223344
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push eax
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cmp [ebp],eax ; did the push use SP instead of ESP?
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jne near error ; no, error
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pop eax
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push ax
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cmp [ebp+2],ax
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jne near error
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pop ax
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mov [ebp+2],edx ; restore dword trashed by the above pushes
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mov ax,DSEG_PROT32
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mov ss,ax
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lea esp,[esi+0xe000] ; SS:ESP should now be a valid 32-bit pointer
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lea ebp,[esp-4]
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mov edx,[ebp]
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mov eax,0x11223344
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push eax
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cmp [ebp],eax ; did the push use ESP instead of SP?
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jne near error ; no, error
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pop eax
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push ax
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cmp [ebp+2],ax
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jne near error
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pop ax
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;
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; Test moving a segment register to a 32-bit memory location
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;
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test1: mov edx,[0x0000] ; save the DWORD at 0x0000:0x0000 in EDX
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@ -294,11 +338,11 @@ test1: mov edx,[0x0000] ; save the DWORD at 0x0000:0x0000 in EDX
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mov [0x0000],ds
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mov ax,ds
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cmp eax,[0x0000]
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jne error
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jne near error
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mov eax,ds
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xor eax,0xffff0000
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cmp eax,[0x0000]
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jne error
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jne near error
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mov [0x0000],edx ; restore the DWORD at 0x0000:0x0000 from EDX
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jmp test2
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;
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