ref: a54fcac01609be9438f6fb05b4da4be01c303383
dir: /sys/src/9/pc64/apbootstrap.s/
/* * Start an Application Processor. This must be placed on a 4KB boundary * somewhere in the 1st MB of conventional memory (APBOOTSTRAP). However, * due to some shortcuts below it's restricted further to within the 1st * 64KB. The AP starts in real-mode, with * CS selector set to the startup memory address/16; * CS base set to startup memory address; * CS limit set to 64KB; * CPL and IP set to 0. */ #include "mem.h" #define NOP BYTE $0x90 /* NOP */ #define pFARJMP32(s, o) BYTE $0xea; /* far jmp ptr32:16 */ \ LONG $o; WORD $s #define rFARJMP16(s, o) BYTE $0xea; /* far jump ptr16:16 */ \ WORD $o; WORD $s; #define rFARJMP32(s, o) BYTE $0x66; /* far jump ptr32:16 */ \ pFARJMP32(s, o) #define rLGDT(gdtptr) BYTE $0x0f; /* LGDT */ \ BYTE $0x01; BYTE $0x16; \ WORD $gdtptr #define rMOVAX(i) BYTE $0xb8; /* i -> AX */ \ WORD $i; #define DELAY BYTE $0xEB; /* JMP .+2 */ \ BYTE $0x00 MODE $16 TEXT apbootstrap(SB), 1, $-4 rFARJMP16(0, _apbootstrap-KZERO(SB)) NOP; NOP; NOP; TEXT _apvector(SB), 1, $-4 /* address APBOOTSTRAP+0x08 */ QUAD $0 TEXT _appml4(SB), 1, $-4 /* address APBOOTSTRAP+0x10 */ QUAD $0 TEXT _apapic(SB), 1, $-4 /* address APBOOTSTRAP+0x18 */ QUAD $0 TEXT _apmach(SB), 1, $-4 /* address APBOOTSTRAP+0x20 */ QUAD $0 TEXT _apefer(SB), 1, $-4 QUAD $0x100 /* Long Mode Enable */ TEXT _apbootstrap(SB), 1, $-4 MOVW CS, AX MOVW AX, DS /* initialise DS */ rLGDT(_gdtptr32p<>-KZERO(SB)) /* load a basic gdt */ MOVL CR0, AX ORL $1, AX MOVL AX, CR0 /* turn on protected mode */ DELAY /* JMP .+2 */ rFARJMP16(SELECTOR(3, SELGDT, 0), _ap32-KZERO(SB)) /* * Enable and activate Long Mode. From the manual: * make sure Page Size Extentions are off, and Page Global * Extensions and Physical Address Extensions are on in CR4; * set Long Mode Enable in the Extended Feature Enable MSR; * set Paging Enable in CR0; * make an inter-segment jump to the Long Mode code. * It's all in 32-bit mode until the jump is made. */ MODE $32 TEXT _ap32(SB), 1, $-4 MOVW $SELECTOR(2, SELGDT, 0), AX MOVW AX, DS MOVW AX, ES MOVW AX, FS MOVW AX, GS MOVW AX, SS MOVL _appml4-KZERO(SB), AX /* physical address of PML4 */ MOVL AX, CR3 /* load the mmu */ DELAY MOVL CR4, AX ANDL $~0x00000010, AX /* Page Size */ ORL $0x000000A0, AX /* Page Global, Phys. Address */ MOVL AX, CR4 MOVL $0xc0000080, CX /* Extended Feature Enable */ RDMSR ORL _apefer-KZERO(SB), AX WRMSR MOVL CR0, DX ANDL $~0x6000000a, DX ORL $0x80010000, DX /* Paging Enable, Write Protect */ MOVL DX, CR0 pFARJMP32(SELECTOR(KESEG, SELGDT, 0), _ap64-KZERO(SB)) /* * Long mode. Welcome to 2003. * Jump out of the identity map space; * load a proper long mode GDT; * initialise the stack and call the * C startup code in m->splpc. */ MODE $64 TEXT _ap64(SB), 1, $-4 MOVQ $_gdtptr64v<>(SB), AX MOVL (AX), GDTR XORQ AX, AX MOVW AX, DS /* not used in long mode */ MOVW AX, ES /* not used in long mode */ MOVW AX, FS MOVW AX, GS MOVW AX, SS /* not used in long mode */ MOVW AX, LDTR MOVQ _apmach(SB), SP MOVQ AX, RUSER /* up = 0; */ MOVQ SP, RMACH /* m = apmach */ ADDQ $MACHSIZE, SP PUSHQ AX /* clear flags */ POPFQ MOVQ _apvector(SB), AX MOVQ _apapic(SB), RARG PUSHQ RARG CALL *AX _halt: HLT JMP _halt TEXT _gdt<>(SB), 1, $-4 /* null descriptor */ LONG $0 LONG $0 /* (KESEG) 64 bit long mode exec segment */ LONG $(0xFFFF) LONG $(SEGL|SEGG|SEGP|(0xF<<16)|SEGPL(0)|SEGEXEC|SEGR) /* 32 bit data segment descriptor for 4 gigabytes (PL 0) */ LONG $(0xFFFF) LONG $(SEGG|SEGB|(0xF<<16)|SEGP|SEGPL(0)|SEGDATA|SEGW) /* 32 bit exec segment descriptor for 4 gigabytes (PL 0) */ LONG $(0xFFFF) LONG $(SEGG|SEGD|(0xF<<16)|SEGP|SEGPL(0)|SEGEXEC|SEGR) TEXT _gdtptr32p<>(SB), 1, $-4 WORD $(4*8-1) LONG $_gdt<>-KZERO(SB) TEXT _gdtptr64p<>(SB), 1, $-4 WORD $(4*8-1) QUAD $_gdt<>-KZERO(SB) TEXT _gdtptr64v<>(SB), 1, $-4 WORD $(4*8-1) QUAD $_gdt<>(SB)