runtime: use pselect6 for usleep on linux/amd64 and linux/arm

Android O black-lists the select system call because its libc, Bionic,
does not use this system call. Replace our use of select with pselect6
(which is allowed) on the platforms that support targeting Android.
linux/arm64 already uses pselect6 because there is no select on arm64,
so only linux/amd64 and linux/arm need changing. pselect6 has been
available since Linux 2.6.16, which is before Go's minimum
requirement.

Fixes #20409.

Change-Id: Ic526b5b259a9e01d2f145a1f4d2e76e8c49ce809
Reviewed-on: https://go-review.googlesource.com/43641
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
index c2b1376fa9c98beb48e831522045e018e0ff95af..bf539aa0da7f6ae8733f28ca75304387d54dec1a 100644 (file)
--- a/src/runtime/sys_linux_amd64.s
+++ b/src/runtime/sys_linux_amd64.s
@@ -82,15 +82,18 @@ TEXT runtime·usleep(SB),NOSPLIT,$16
        MOVL    $1000000, CX
        DIVL    CX
        MOVQ    AX, 0(SP)
-       MOVQ    DX, 8(SP)
+       MOVL    $1000, AX       // usec to nsec
+       MULL    DX
+       MOVQ    AX, 8(SP)
 
-       // select(0, 0, 0, 0, &tv)
+       // pselect6(0, 0, 0, 0, &ts, 0)
        MOVL    $0, DI
        MOVL    $0, SI
        MOVL    $0, DX
        MOVL    $0, R10
        MOVQ    SP, R8
-       MOVL    $23, AX
+       MOVL    $0, R9
+       MOVL    $270, AX
        SYSCALL
        RET
 

diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
index 0244613e67642ab0e1abead2df043880c0ebd50e..64beed8f68e999efe1da244a63d464caeac5377f 100644 (file)
--- a/src/runtime/sys_linux_arm.s
+++ b/src/runtime/sys_linux_arm.s
@@ -36,7 +36,7 @@
 #define SYS_gettid (SYS_BASE + 224)
 #define SYS_tkill (SYS_BASE + 238)
 #define SYS_sched_yield (SYS_BASE + 158)
-#define SYS_select (SYS_BASE + 142) // newselect
+#define SYS_pselect6 (SYS_BASE + 335)
 #define SYS_ugetrlimit (SYS_BASE + 191)
 #define SYS_sched_getaffinity (SYS_BASE + 242)
 #define SYS_clock_gettime (SYS_BASE + 263)
@@ -388,13 +388,16 @@ TEXT runtime·usleep(SB),NOSPLIT,$12
        MOVW    usec+0(FP), R0
        CALL    runtime·usplitR0(SB)
        MOVW    R0, 4(R13)
+       MOVW    $1000, R0       // usec to nsec
+       MUL     R0, R1
        MOVW    R1, 8(R13)
        MOVW    $0, R0
        MOVW    $0, R1
        MOVW    $0, R2
        MOVW    $0, R3
        MOVW    $4(R13), R4
-       MOVW    $SYS_select, R7
+       MOVW    $0, R5
+       MOVW    $SYS_pselect6, R7
        SWI     $0
        RET