github.com/jspc/eggos@v0.5.1-0.20221028160421-556c75c878a5/kernel/syscall.s (about) 1 #include "textflag.h" 2 3 #define tls_my 0 4 #define tls_ax 8 5 #define m_kstack 40 6 #define ucode_idx 3 7 #define udata_idx 4 8 #define rpl_user 3 9 10 #define SYS_clockgettime 228 11 12 TEXT ·syscallEntry(SB), NOSPLIT, $0 13 // save AX 14 MOVQ AX, tls_ax(GS) 15 16 // AX == pointer of current thread 17 MOVQ tls_my(GS), AX 18 19 // AX == kernel stack 20 MOVQ m_kstack(AX), AX 21 22 // push regs like INT 0x80 23 SUBQ $40, AX 24 25 // CX store IP 26 MOVQ CX, 0(AX) 27 28 // save CS 29 MOVQ $ucode_idx<<3|rpl_user, 8(AX) 30 31 // R11 store FLAGS 32 MOVQ R11, 16(AX) 33 34 // save SP 35 MOVQ SP, 24(AX) 36 37 // save SS 38 MOVQ $udata_idx<<3|rpl_user, 32(AX) 39 40 // change SP 41 MOVQ AX, SP 42 43 // restore AX 44 MOVQ tls_ax(GS), AX 45 46 // jmp INT 0x80 47 JMP ·trap128(SB) 48 49 TEXT ·vdsoGettimeofday(SB), NOSPLIT, $0 50 MOVQ $SYS_clockgettime, AX 51 52 // DI store *TimeSpec, but clockgettime need SI 53 MOVQ DI, SI 54 MOVQ $0, DI 55 INT $0x80 56 RET 57