diff options
Diffstat (limited to 'src/runtime/sys_linux_386.s')
| -rw-r--r-- | src/runtime/sys_linux_386.s | 43 |
1 files changed, 39 insertions, 4 deletions
diff --git a/src/runtime/sys_linux_386.s b/src/runtime/sys_linux_386.s index 79985070f1..722d2ab2d3 100644 --- a/src/runtime/sys_linux_386.s +++ b/src/runtime/sys_linux_386.s @@ -203,12 +203,34 @@ TEXT runtime·mincore(SB),NOSPLIT,$0-16 RET // func walltime() (sec int64, nsec int32) -TEXT runtime·walltime(SB), NOSPLIT, $32 +TEXT runtime·walltime(SB), NOSPLIT, $16 + // Stack layout, depending on call path: + // x(SP) vDSO INVOKE_SYSCALL + // 12 ts.tv_nsec ts.tv_nsec + // 8 ts.tv_sec ts.tv_sec + // 4 &ts - + // 0 CLOCK_<id> - + // + // If we take the vDSO path, we're calling a function with gcc calling convention. + // We're guaranteed 128 bytes on entry. We've taken 16, and the call uses another 4, + // leaving 108 for __vdso_clock_gettime to use. + MOVL runtime·__vdso_clock_gettime_sym(SB), AX + CMPL AX, $0 + JEQ fallback + + LEAL 8(SP), BX // &ts (struct timespec) + MOVL BX, 4(SP) + MOVL $0, 0(SP) // CLOCK_REALTIME + CALL AX + JMP finish + +fallback: MOVL $SYS_clock_gettime, AX MOVL $0, BX // CLOCK_REALTIME LEAL 8(SP), CX - MOVL $0, DX INVOKE_SYSCALL + +finish: MOVL 8(SP), AX // sec MOVL 12(SP), BX // nsec @@ -220,12 +242,25 @@ TEXT runtime·walltime(SB), NOSPLIT, $32 // int64 nanotime(void) so really // void nanotime(int64 *nsec) -TEXT runtime·nanotime(SB), NOSPLIT, $32 +TEXT runtime·nanotime(SB), NOSPLIT, $16 + // See comments above in walltime() about stack space usage and layout. + MOVL runtime·__vdso_clock_gettime_sym(SB), AX + CMPL AX, $0 + JEQ fallback + + LEAL 8(SP), BX // &ts (struct timespec) + MOVL BX, 4(SP) + MOVL $1, 0(SP) // CLOCK_MONOTONIC + CALL AX + JMP finish + +fallback: MOVL $SYS_clock_gettime, AX MOVL $1, BX // CLOCK_MONOTONIC LEAL 8(SP), CX - MOVL $0, DX INVOKE_SYSCALL + +finish: MOVL 8(SP), AX // sec MOVL 12(SP), BX // nsec |