BIOS function 0xE820 for memory map detection
- this function returns a ritcher description of available memory - is ACPI compliant, ACPI data structures are excluded from free memory list - available memory exported to Minix in a backwards compatible manner - fallback to the old method if this function not available (old hardware)
This commit is contained in:
Tomas Hruby
parent
a022f412b5
commit
c80138ac71
27
boot/boot.c
27
boot/boot.c
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@ -538,11 +538,30 @@ static void initialize(void)
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* done to get out of the way of Minix, and to put the data area
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* cleanly inside a 64K chunk if using BIOS I/O (no DMA problems).
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*/
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u32_t oldaddr= caddr;
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u32_t memend= mem[0].base + mem[0].size;
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u32_t newaddr= (memend - runsize) & ~0x0000FL;
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u32_t oldaddr;
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u32_t memend;
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u32_t newaddr;
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#if !DOS
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u32_t dma64k= (memend - 1) & ~0x0FFFFL;
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u32_t dma64k;
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#endif
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if (mem_entries) {
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int i, j;
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j = 0;
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for(i = 0; i < mem_entries ; i++) {
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if (j < 3 && emem[i].type == 1) {
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mem[j].base = emem[i].base_lo;
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mem[j].size = emem[i].size_lo;
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j++;
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}
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}
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}
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oldaddr= caddr;
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memend= mem[0].base + mem[0].size;
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newaddr= (memend - runsize) & ~0x0000FL;
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#if !DOS
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dma64k= (memend - 1) & ~0x0FFFFL;
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/* Check if data segment crosses a 64K boundary. */
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11
boot/boot.h
11
boot/boot.h
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@ -67,7 +67,18 @@ typedef struct { /* One chunk of free memory. */
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u32_t size; /* Number of bytes. */
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} memory;
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typedef struct { /* One chunk of free memory. */
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u32_t base_lo; /* Start byte. */
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u32_t base_hi;
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u32_t size_lo; /* Number of bytes. */
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u32_t size_hi; /* Number of bytes. */
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u32_t type;
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u32_t acpi_attrs;
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} e820_memory;
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EXTERN memory mem[3]; /* List of available memory. */
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EXTERN e820_memory emem[16]; /* List of available memory. */
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EXTERN int mem_entries;
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EXTERN int mon_return; /* Monitor stays in memory? */
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EXTERN int cdbooted; /* Did we boot from CD? (Set by boothead.s.) */
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@ -41,6 +41,8 @@
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.extern _rem_part ! To pass partition info
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.extern _k_flags ! Special kernel flags
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.extern _mem ! Free memory list
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.extern _emem ! Free memory list for E820
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.extern _mem_entries ! Free memory E820 list entries
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.extern _cdbooted ! Whether we booted from CD
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.extern _cddevice ! Whether we booted from CD
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@ -143,6 +145,64 @@ sepID:
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mov _runsize+0, ax
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mov _runsize+2, dx ! 32 bit size of this process
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!Determine memory using the 0xE820 BIOS function if available
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mov di, #_emem
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mov 20(di), #1 ! force a valid ACPI 3.X entry
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.data1 o32
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xor bx, bx ! zero EBX
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xor bp, bp !zero bp
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.data1 o32
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mov dx, e820_magic
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.data1 o32
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mov cx, const_24 ! request 24 bytes
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.data1 o32
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mov ax, const_0xe820
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int 0x15
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jc e820_failed
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.data1 o32
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mov dx, e820_magic
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.data1 o32
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cmp dx, ax
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jne e820_failed
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.data1 o32
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test bx, bx
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je e820_failed
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jmp e820_gotit
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e820_next:
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.data1 o32
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mov ax, const_0xe820
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mov 20(di), #1 ! force a valid ACPI 3.X entry
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.data1 o32
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mov cx, const_24 ! request 24 bytes
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int 0x15
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jc e820_done
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.data1 o32
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mov dx, e820_magic
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e820_gotit:
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jcxz e820_skip
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cmp bp, #16
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je e820_done ! we have only space for 16 entries
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inc bp
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add di, #24
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e820_skip:
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.data1 o32
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test bx, bx
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jne e820_next
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e820_done:
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mov _mem_entries, bp
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jmp memory_detected
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e820_failed:
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! Determine available memory as a list of (base,size) pairs as follows:
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! mem[0] = low memory, mem[1] = memory between 1M and 16M, mem[2] = memory
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! above 16M. Last two coalesced into mem[1] if adjacent.
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@ -185,6 +245,8 @@ adj_ext:
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add 14(di), bx ! Add ext mem above 16M to mem below 16M
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no_ext:
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memory_detected:
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! Time to switch to a higher level language (not much higher)
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call _boot
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@ -1534,6 +1596,15 @@ p_mcs_desc:
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.data2 0xFFFF, UNSET
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.data1 UNSET, 0x9A, 0x00, 0x00
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e820_magic:
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! .data1 0x53, 0x4D, 0x41, 0x50
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.data1 0x50, 0x41, 0x4D, 0x53
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const_24:
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.data1 0x18, 0x0, 0x0, 0x0
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const_0xe820:
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.data2 0xe820
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.bss
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.comm old_vid_mode, 2 ! Video mode at startup
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.comm cur_vid_mode, 2 ! Current video mode
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