runtime: make racereadrange ABIinternal

CL 266638 marked racewriterange (and some other race functions) as
ABIinternal but missed racereadrange.

arm64 and ppc64le (the other two register ABI platforms at the moment)
already have racereadrange marked as such.

The other two instrumented calls are to racefuncenter/racefuncexit.
Do you think they would need this treatment as well? arm64 already does,
but amd64 and ppc64le do not.

Fixes #51459

Change-Id: I3f54e1298433b6d67bfe18120d9f86205ff66a73
Reviewed-on: https://go-review.googlesource.com/c/go/+/393154
Reviewed-by: Than McIntosh <[email protected]>
Run-TryBot: Keith Randall <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Keith Randall <[email protected]>

src/runtime/race_amd64.s

@@ -94,9 +94,11 @@ TEXT	runtime·racewritepc(SB), NOSPLIT, $0-24
 
 // func runtime·racereadrange(addr, size uintptr)
 // Called from instrumented code.
-TEXT	runtime·racereadrange(SB), NOSPLIT, $0-16
-	MOVQ	addr+0(FP), RARG1
-	MOVQ	size+8(FP), RARG2
+// Defined as ABIInternal so as to avoid introducing a wrapper,
+// which would render runtime.getcallerpc ineffective.
+TEXT	runtime·racereadrange<ABIInternal>(SB), NOSPLIT, $0-16
+	MOVQ	AX, RARG1
+	MOVQ	BX, RARG2
 	MOVQ	(SP), RARG3
 	// void __tsan_read_range(ThreadState *thr, void *addr, uintptr size, void *pc);
 	MOVQ	$__tsan_read_range(SB), AX