go-patches: read nanotime in 1 instruction on 64bit

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

3 files changed, 200 insertions, 6 deletions

diff --git a/go-patches/0001-runtime-allow-builtin-write-function-to-be-redirecte.patch b/go-patches/0001-runtime-allow-builtin-write-function-to-be-redirecte.patch
index b72675bd..3b44b363 100644
--- a/go-patches/0001-runtime-allow-builtin-write-function-to-be-redirecte.patch
+++ b/go-patches/0001-runtime-allow-builtin-write-function-to-be-redirecte.patch
@@ -54,6 +54,3 @@ index 5a4ceaf43d..68c01805a5 100644
 +	}
  	return write1(fd, p, n)
  }
--- 
-2.33.0
-
diff --git a/go-patches/0002-release-branch.go1.17-cmd-compile-speed-up-unsafe.Sl.patch b/go-patches/0002-release-branch.go1.17-cmd-compile-speed-up-unsafe.Sl.patch
index 42a71f88..0dac195a 100644
--- a/go-patches/0002-release-branch.go1.17-cmd-compile-speed-up-unsafe.Sl.patch
+++ b/go-patches/0002-release-branch.go1.17-cmd-compile-speed-up-unsafe.Sl.patch
@@ -326,6 +326,3 @@ index 4c940aa855..d613088827 100644
 -	}()
 -	f()
 -}
--- 
-2.33.0
-
diff --git a/go-patches/0003-runtime-on-windows-read-nanotime-with-one-instructio.patch b/go-patches/0003-runtime-on-windows-read-nanotime-with-one-instructio.patch
new file mode 100644
index 00000000..2ff79368
--- /dev/null
+++ b/go-patches/0003-runtime-on-windows-read-nanotime-with-one-instructio.patch
@@ -0,0 +1,200 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+Date: Wed, 3 Nov 2021 18:19:04 +0100
+Subject: [PATCH] runtime: on windows, read nanotime with one instruction or
+ issue barrier
+
+On 64-bit, this is more efficient, and on ARM64, this prevents the time
+from moving backwards due to the weaker memory model. On ARM32 due to
+the weaker memory model, we issue a memory barrier.
+
+Updates #48072.
+
+Change-Id: If4695716c3039d8af14e14808af217f5c99fc93a
+Reviewed-on: https://go-review.googlesource.com/c/go/+/361057
+Trust: Jason A. Donenfeld <Jason@zx2c4.com>
+Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
+TryBot-Result: Go Bot <gobot@golang.org>
+Reviewed-by: Austin Clements <austin@google.com>
+---
+ src/runtime/sys_windows_amd64.s  | 13 +++----------
+ src/runtime/sys_windows_arm.s    |  2 ++
+ src/runtime/sys_windows_arm64.s  | 10 +---------
+ src/runtime/time_windows.h       |  1 +
+ src/runtime/time_windows_amd64.s | 19 +++----------------
+ src/runtime/time_windows_arm.s   |  4 ++++
+ src/runtime/time_windows_arm64.s | 22 +++-------------------
+ 7 files changed, 17 insertions(+), 54 deletions(-)
+
+diff --git a/src/runtime/sys_windows_amd64.s b/src/runtime/sys_windows_amd64.s
+index e7782846b2..64fa6791f4 100644
+--- a/src/runtime/sys_windows_amd64.s
++++ b/src/runtime/sys_windows_amd64.s
+@@ -348,16 +348,9 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$0-8
+ 	CMPB	runtime·useQPCTime(SB), $0
+ 	JNE	useQPC
+ 	MOVQ	$_INTERRUPT_TIME, DI
+-loop:
+-	MOVL	time_hi1(DI), AX
+-	MOVL	time_lo(DI), BX
+-	MOVL	time_hi2(DI), CX
+-	CMPL	AX, CX
+-	JNE	loop
+-	SHLQ	$32, CX
+-	ORQ	BX, CX
+-	IMULQ	$100, CX
+-	MOVQ	CX, ret+0(FP)
++	MOVQ	time_lo(DI), AX
++	IMULQ	$100, AX
++	MOVQ	AX, ret+0(FP)
+ 	RET
+ useQPC:
+ 	JMP	runtime·nanotimeQPC(SB)
+diff --git a/src/runtime/sys_windows_arm.s b/src/runtime/sys_windows_arm.s
+index 48f8c7dedf..d7ad244161 100644
+--- a/src/runtime/sys_windows_arm.s
++++ b/src/runtime/sys_windows_arm.s
+@@ -350,7 +350,9 @@ TEXT runtime·nanotime1(SB),NOSPLIT|NOFRAME,$0-8
+ 	MOVW	$_INTERRUPT_TIME, R3
+ loop:
+ 	MOVW	time_hi1(R3), R1
++	DMB	MB_ISH
+ 	MOVW	time_lo(R3), R0
++	DMB	MB_ISH
+ 	MOVW	time_hi2(R3), R2
+ 	CMP	R1, R2
+ 	BNE	loop
+diff --git a/src/runtime/sys_windows_arm64.s b/src/runtime/sys_windows_arm64.s
+index 7a2e11f5ae..183128dd09 100644
+--- a/src/runtime/sys_windows_arm64.s
++++ b/src/runtime/sys_windows_arm64.s
+@@ -415,15 +415,7 @@ TEXT runtime·nanotime1(SB),NOSPLIT|NOFRAME,$0-8
+ 	CMP	$0, R0
+ 	BNE	useQPC
+ 	MOVD	$_INTERRUPT_TIME, R3
+-loop:
+-	MOVWU	time_hi1(R3), R1
+-	MOVWU	time_lo(R3), R0
+-	MOVWU	time_hi2(R3), R2
+-	CMP	R1, R2
+-	BNE	loop
+-
+-	// wintime = R1:R0, multiply by 100
+-	ORR	R1<<32, R0
++	MOVD	time_lo(R3), R0
+ 	MOVD	$100, R1
+ 	MUL	R1, R0
+ 	MOVD	R0, ret+0(FP)
+diff --git a/src/runtime/time_windows.h b/src/runtime/time_windows.h
+index cd16fd163b..7c2e65c328 100644
+--- a/src/runtime/time_windows.h
++++ b/src/runtime/time_windows.h
+@@ -9,6 +9,7 @@
+ // http://web.archive.org/web/20210411000829/https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
+ 
+ // Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2.
++// Or, on 64-bit, just read lo:hi1 all at once atomically.
+ #define _INTERRUPT_TIME 0x7ffe0008
+ #define _SYSTEM_TIME 0x7ffe0014
+ #define time_lo 0
+diff --git a/src/runtime/time_windows_amd64.s b/src/runtime/time_windows_amd64.s
+index 93ab960b06..045f64eb46 100644
+--- a/src/runtime/time_windows_amd64.s
++++ b/src/runtime/time_windows_amd64.s
+@@ -12,27 +12,14 @@
+ TEXT time·now(SB),NOSPLIT,$0-24
+ 	CMPB	runtime·useQPCTime(SB), $0
+ 	JNE	useQPC
++
+ 	MOVQ	$_INTERRUPT_TIME, DI
+-loop:
+-	MOVL	time_hi1(DI), AX
+-	MOVL	time_lo(DI), BX
+-	MOVL	time_hi2(DI), CX
+-	CMPL	AX, CX
+-	JNE	loop
+-	SHLQ	$32, AX
+-	ORQ	BX, AX
++	MOVQ	time_lo(DI), AX
+ 	IMULQ	$100, AX
+ 	MOVQ	AX, mono+16(FP)
+ 
+ 	MOVQ	$_SYSTEM_TIME, DI
+-wall:
+-	MOVL	time_hi1(DI), AX
+-	MOVL	time_lo(DI), BX
+-	MOVL	time_hi2(DI), CX
+-	CMPL	AX, CX
+-	JNE	wall
+-	SHLQ	$32, AX
+-	ORQ	BX, AX
++	MOVQ	time_lo(DI), AX
+ 	MOVQ	$116444736000000000, DI
+ 	SUBQ	DI, AX
+ 	IMULQ	$100, AX
+diff --git a/src/runtime/time_windows_arm.s b/src/runtime/time_windows_arm.s
+index 7c763b66ed..6552d75ff1 100644
+--- a/src/runtime/time_windows_arm.s
++++ b/src/runtime/time_windows_arm.s
+@@ -17,7 +17,9 @@ TEXT time·now(SB),NOSPLIT|NOFRAME,$0-20
+ 	MOVW	$_INTERRUPT_TIME, R3
+ loop:
+ 	MOVW	time_hi1(R3), R1
++	DMB	MB_ISH
+ 	MOVW	time_lo(R3), R0
++	DMB	MB_ISH
+ 	MOVW	time_hi2(R3), R2
+ 	CMP	R1, R2
+ 	BNE	loop
+@@ -34,7 +36,9 @@ loop:
+ 	MOVW	$_SYSTEM_TIME, R3
+ wall:
+ 	MOVW	time_hi1(R3), R1
++	DMB	MB_ISH
+ 	MOVW	time_lo(R3), R0
++	DMB	MB_ISH
+ 	MOVW	time_hi2(R3), R2
+ 	CMP	R1, R2
+ 	BNE	wall
+diff --git a/src/runtime/time_windows_arm64.s b/src/runtime/time_windows_arm64.s
+index ef52ce4c99..e8a0eb2f93 100644
+--- a/src/runtime/time_windows_arm64.s
++++ b/src/runtime/time_windows_arm64.s
+@@ -13,34 +13,18 @@ TEXT time·now(SB),NOSPLIT|NOFRAME,$0-24
+ 	MOVB    runtime·useQPCTime(SB), R0
+ 	CMP	$0, R0
+ 	BNE	useQPC
+-	MOVD	$_INTERRUPT_TIME, R3
+-loop:
+-	MOVWU	time_hi1(R3), R1
+-	MOVWU	time_lo(R3), R0
+-	MOVWU	time_hi2(R3), R2
+-	CMP	R1, R2
+-	BNE	loop
+ 
+-	// wintime = R1:R0, multiply by 100
+-	ORR	R1<<32, R0
++	MOVD	$_INTERRUPT_TIME, R3
++	MOVD	time_lo(R3), R0
+ 	MOVD	$100, R1
+ 	MUL	R1, R0
+ 	MOVD	R0, mono+16(FP)
+ 
+ 	MOVD	$_SYSTEM_TIME, R3
+-wall:
+-	MOVWU	time_hi1(R3), R1
+-	MOVWU	time_lo(R3), R0
+-	MOVWU	time_hi2(R3), R2
+-	CMP	R1, R2
+-	BNE	wall
+-
+-	// w = R1:R0 in 100ns units
++	MOVD	time_lo(R3), R0
+ 	// convert to Unix epoch (but still 100ns units)
+ 	#define delta 116444736000000000
+-	ORR	R1<<32, R0
+ 	SUB	$delta, R0
+-
+ 	// Convert to nSec
+ 	MOVD	$100, R1
+ 	MUL	R1, R0