diff options
Diffstat (limited to 'src/runtime/sys_linux_amd64.s')
| -rw-r--r-- | src/runtime/sys_linux_amd64.s | 57 |
1 files changed, 49 insertions, 8 deletions
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s index e0dc3e1264..79e110f15a 100644 --- a/src/runtime/sys_linux_amd64.s +++ b/src/runtime/sys_linux_amd64.s @@ -139,11 +139,31 @@ TEXT runtime·mincore(SB),NOSPLIT,$0-28 RET // func walltime() (sec int64, nsec int32) -TEXT runtime·walltime(SB),NOSPLIT,$16 - // Be careful. We're calling a function with gcc calling convention here. - // We're guaranteed 128 bytes on entry, and we've taken 16, and the - // call uses another 8. - // That leaves 104 for the gettime code to use. Hope that's enough! +TEXT runtime·walltime(SB),NOSPLIT,$0-12 + // We don't know how much stack space the VDSO code will need, + // so switch to g0. + // In particular, a kernel configured with CONFIG_OPTIMIZE_INLINING=n + // and hardening can use a full page of stack space in gettime_sym + // due to stack probes inserted to avoid stack/heap collisions. + // See issue #20427. + + MOVQ SP, BP // Save old SP; BP unchanged by C code. + + get_tls(CX) + MOVQ g(CX), AX + MOVQ g_m(AX), CX + MOVQ m_curg(CX), DX + + CMPQ AX, DX // Only switch if on curg. + JNE noswitch + + MOVQ m_g0(CX), DX + MOVQ (g_sched+gobuf_sp)(DX), SP // Set SP to g0 stack + +noswitch: + SUBQ $16, SP // Space for results + ANDQ $~15, SP // Align for C code + MOVQ runtime·__vdso_clock_gettime_sym(SB), AX CMPQ AX, $0 JEQ fallback @@ -152,6 +172,7 @@ TEXT runtime·walltime(SB),NOSPLIT,$16 CALL AX MOVQ 0(SP), AX // sec MOVQ 8(SP), DX // nsec + MOVQ BP, SP // Restore real SP MOVQ AX, sec+0(FP) MOVL DX, nsec+8(FP) RET @@ -163,13 +184,31 @@ fallback: MOVQ 0(SP), AX // sec MOVL 8(SP), DX // usec IMULQ $1000, DX + MOVQ BP, SP // Restore real SP MOVQ AX, sec+0(FP) MOVL DX, nsec+8(FP) RET -TEXT runtime·nanotime(SB),NOSPLIT,$16 - // Duplicate time.now here to avoid using up precious stack space. - // See comment above in time.now. +TEXT runtime·nanotime(SB),NOSPLIT,$0-8 + // Switch to g0 stack. See comment above in runtime·walltime. + + MOVQ SP, BP // Save old SP; BX unchanged by C code. + + get_tls(CX) + MOVQ g(CX), AX + MOVQ g_m(AX), CX + MOVQ m_curg(CX), DX + + CMPQ AX, DX // Only switch if on curg. + JNE noswitch + + MOVQ m_g0(CX), DX + MOVQ (g_sched+gobuf_sp)(DX), SP // Set SP to g0 stack + +noswitch: + SUBQ $16, SP // Space for results + ANDQ $~15, SP // Align for C code + MOVQ runtime·__vdso_clock_gettime_sym(SB), AX CMPQ AX, $0 JEQ fallback @@ -178,6 +217,7 @@ TEXT runtime·nanotime(SB),NOSPLIT,$16 CALL AX MOVQ 0(SP), AX // sec MOVQ 8(SP), DX // nsec + MOVQ BP, SP // Restore real SP // sec is in AX, nsec in DX // return nsec in AX IMULQ $1000000000, AX @@ -191,6 +231,7 @@ fallback: CALL AX MOVQ 0(SP), AX // sec MOVL 8(SP), DX // usec + MOVQ BP, SP // Restore real SP IMULQ $1000, DX // sec is in AX, nsec in DX // return nsec in AX |