From 6998a7866b8428fd49c31506795c9f8154826d13 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Wed, 27 Feb 2019 05:05:44 +0100
Subject: [PATCH] runtime: use CLOCK_BOOTTIME in nanotime on Linux

This makes timers account for having expired while a computer was
asleep, which is quite common on mobile devices. Note that BOOTTIME is
identical to MONOTONIC, except that it takes into account time spent
in suspend. In Linux 4.17, the kernel will actually make MONOTONIC act
like BOOTTIME anyway, so this switch will additionally unify the
timer behavior across kernels.

BOOTTIME was introduced into Linux 2.6.39-rc1 with 70a08cca1227d in
2011.

Fixes #24595

Change-Id: I7b2a6ca0c5bc5fce57ec0eeafe7b68270b429321
---
 src/runtime/sys_linux_386.s     | 4 ++--
 src/runtime/sys_linux_amd64.s   | 2 +-
 src/runtime/sys_linux_arm.s     | 4 ++--
 src/runtime/sys_linux_arm64.s   | 4 ++--
 src/runtime/sys_linux_mips64x.s | 2 +-
 src/runtime/sys_linux_mipsx.s   | 2 +-
 src/runtime/sys_linux_ppc64x.s  | 2 +-
 src/runtime/sys_linux_s390x.s   | 2 +-
 8 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/runtime/sys_linux_386.s b/src/runtime/sys_linux_386.s
index 40b55a67eb..6105780ff4 100644
--- a/src/runtime/sys_linux_386.s
+++ b/src/runtime/sys_linux_386.s
@@ -288,13 +288,13 @@ noswitch:
 
 	LEAL	8(SP), BX	// &ts (struct timespec)
 	MOVL	BX, 4(SP)
-	MOVL	$1, 0(SP)	// CLOCK_MONOTONIC
+	MOVL	$7, 0(SP)	// CLOCK_BOOTTIME
 	CALL	AX
 	JMP finish
 
 fallback:
 	MOVL	$SYS_clock_gettime, AX
-	MOVL	$1, BX		// CLOCK_MONOTONIC
+	MOVL	$7, BX		// CLOCK_BOOTTIME
 	LEAL	8(SP), CX
 	INVOKE_SYSCALL
 
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
index b709f77060..18a1f1d43a 100644
--- a/src/runtime/sys_linux_amd64.s
+++ b/src/runtime/sys_linux_amd64.s
@@ -261,7 +261,7 @@ noswitch:
 	MOVQ	runtime·vdsoClockgettimeSym(SB), AX
 	CMPQ	AX, $0
 	JEQ	fallback
-	MOVL	$1, DI // CLOCK_MONOTONIC
+	MOVL	$7, DI // CLOCK_BOOTTIME
 	LEAQ	0(SP), SI
 	CALL	AX
 	MOVQ	0(SP), AX	// sec
diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
index 43a58335c8..8b93635f4f 100644
--- a/src/runtime/sys_linux_arm.s
+++ b/src/runtime/sys_linux_arm.s
@@ -11,7 +11,7 @@
 #include "textflag.h"
 
 #define CLOCK_REALTIME	0
-#define CLOCK_MONOTONIC	1
+#define CLOCK_BOOTTIME	7
 
 // for EABI, as we don't support OABI
 #define SYS_BASE 0x0
@@ -291,7 +291,7 @@ noswitch:
 	SUB	$24, R13	// Space for results
 	BIC	$0x7, R13	// Align for C code
 
-	MOVW	$CLOCK_MONOTONIC, R0
+	MOVW	$CLOCK_BOOTTIME, R0
 	MOVW	$8(R13), R1	// timespec
 	MOVW	runtime·vdsoClockgettimeSym(SB), R11
 	CMP	$0, R11
diff --git a/src/runtime/sys_linux_arm64.s b/src/runtime/sys_linux_arm64.s
index 8b344be8f8..daf142fba0 100644
--- a/src/runtime/sys_linux_arm64.s
+++ b/src/runtime/sys_linux_arm64.s
@@ -13,7 +13,7 @@
 #define AT_FDCWD -100
 
 #define CLOCK_REALTIME 0
-#define CLOCK_MONOTONIC 1
+#define CLOCK_BOOTTIME 7
 
 #define SYS_exit		93
 #define SYS_read		63
@@ -247,7 +247,7 @@ noswitch:
 	BIC	$15, R1
 	MOVD	R1, RSP
 
-	MOVW	$CLOCK_MONOTONIC, R0
+	MOVW	$CLOCK_BOOTTIME, R0
 	MOVD	runtime·vdsoClockgettimeSym(SB), R2
 	CBZ	R2, fallback
 	BL	(R2)
diff --git a/src/runtime/sys_linux_mips64x.s b/src/runtime/sys_linux_mips64x.s
index c45703d228..9842b596e7 100644
--- a/src/runtime/sys_linux_mips64x.s
+++ b/src/runtime/sys_linux_mips64x.s
@@ -189,7 +189,7 @@ TEXT runtime·walltime(SB),NOSPLIT,$16
 	RET
 
 TEXT runtime·nanotime(SB),NOSPLIT,$16
-	MOVW	$1, R4 // CLOCK_MONOTONIC
+	MOVW	$7, R4 // CLOCK_BOOTTIME
 	MOVV	$0(R29), R5
 	MOVV	$SYS_clock_gettime, R2
 	SYSCALL
diff --git a/src/runtime/sys_linux_mipsx.s b/src/runtime/sys_linux_mipsx.s
index f362b0f3f1..5ab866e047 100644
--- a/src/runtime/sys_linux_mipsx.s
+++ b/src/runtime/sys_linux_mipsx.s
@@ -193,7 +193,7 @@ TEXT runtime·walltime(SB),NOSPLIT,$8-12
 	RET
 
 TEXT runtime·nanotime(SB),NOSPLIT,$8-8
-	MOVW	$1, R4	// CLOCK_MONOTONIC
+	MOVW	$7, R4	// CLOCK_BOOTTIME
 	MOVW	$4(R29), R5
 	MOVW	$SYS_clock_gettime, R2
 	SYSCALL
diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
index 6835f434de..46618b2d91 100644
--- a/src/runtime/sys_linux_ppc64x.s
+++ b/src/runtime/sys_linux_ppc64x.s
@@ -204,7 +204,7 @@ fallback:
 	JMP	finish
 
 TEXT runtime·nanotime(SB),NOSPLIT,$16
-	MOVD	$1, R3		// CLOCK_MONOTONIC
+	MOVD	$7, R3		// CLOCK_BOOTTIME
 
 	MOVD	R1, R15		// R15 is unchanged by C code
 	MOVD	g_m(g), R21	// R21 = m
diff --git a/src/runtime/sys_linux_s390x.s b/src/runtime/sys_linux_s390x.s
index c79ceea751..44e3258e60 100644
--- a/src/runtime/sys_linux_s390x.s
+++ b/src/runtime/sys_linux_s390x.s
@@ -180,7 +180,7 @@ TEXT runtime·walltime(SB),NOSPLIT,$16
 	RET
 
 TEXT runtime·nanotime(SB),NOSPLIT,$16
-	MOVW	$1, R2 // CLOCK_MONOTONIC
+	MOVW	$7, R2 // CLOCK_BOOTTIME
 	MOVD	$tp-16(SP), R3
 	MOVW	$SYS_clock_gettime, R1
 	SYSCALL
-- 
2.20.1