runtime: fix ppc64le race code

This code is not currently compiling, the asm vet checks fail. When running race.bash on ppc64le, I get:

runtime/race_ppc64le.s:104:1: [ppc64le] RaceReadRange: wrong argument size 24; expected $...-16
runtime/race_ppc64le.s:514:1: [ppc64le] racecallbackthunk: unknown variable cmd; offset 0 is arg+0(FP)
runtime/race_ppc64le.s:515:1: [ppc64le] racecallbackthunk: unknown variable ctx

I'm also not sure why it ever worked; it looks like it is writing
the arguments to racecallback in the wrong place (the race detector
itself probably still works, it would just have trouble symbolizing
any resulting race report).

At a meta-level, we should really add a ppc64le/race builder.
Otherwise this code will rot, as evidenced by the rot this CL fixes :)

Update #33309

Change-Id: I3b49c2442aa78538fbb631a143a757389a1368fd
Reviewed-on: https://go-review.googlesource.com/c/go/+/197337
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/runtime/race_ppc64le.s

@@ -8,6 +8,7 @@
 #include "go_tls.h"
 #include "funcdata.h"
 #include "textflag.h"
+#include "asm_ppc64x.h"
 
 // The following functions allow calling the clang-compiled race runtime directly
 // from Go code without going all the way through cgo.
@@ -101,7 +102,7 @@ TEXT	runtime·racereadrangepc1(SB), NOSPLIT, $0-24
 	MOVD    $__tsan_read_range(SB), R8
 	BR	racecalladdr<>(SB)
 
-TEXT    runtime·RaceReadRange(SB), NOSPLIT, $0-24
+TEXT    runtime·RaceReadRange(SB), NOSPLIT, $0-16
 	BR	runtime·racereadrange(SB)
 
 // func runtime·RaceWriteRange(addr, size uintptr)
@@ -467,9 +468,9 @@ rest:
 	MOVD	R10, 16(R1)
 	MOVW	CR, R10
 	MOVW	R10, 8(R1)
-	MOVDU   R1, -336(R1) // Allocate frame needed for register save area
+	MOVDU   R1, -336(R1) // Allocate frame needed for outargs and register save area
 
-	MOVD    R14, 40(R1)
+	MOVD    R14, 328(R1)
 	MOVD    R15, 48(R1)
 	MOVD    R16, 56(R1)
 	MOVD    R17, 64(R1)
@@ -511,8 +512,8 @@ rest:
 
 	MOVD	g_m(g), R7
 	MOVD	m_g0(R7), g // set g = m-> g0
-	MOVD	R3, cmd+0(FP) // can't use R1 here ?? use input args and assumer caller expects those?
-	MOVD	R4, ctx+8(FP) // can't use R1 here ??
+	MOVD	R3, FIXED_FRAME+0(R1)
+	MOVD	R4, FIXED_FRAME+8(R1)
 	BL	runtime·racecallback(SB)
 	// All registers are clobbered after Go code, reload.
 	MOVD    runtime·tls_g(SB), R10
@@ -520,7 +521,7 @@ rest:
 
 	MOVD	g_m(g), R7
 	MOVD	m_curg(R7), g // restore g = m->curg
-	MOVD    40(R1), R14
+	MOVD    328(R1), R14
 	MOVD    48(R1), R15
 	MOVD    56(R1), R16
 	MOVD    64(R1), R17