runtime: cleanup ppc64le/linux library startup code

Fix the argument passing to runtime.newosproc0, the ABI0 argument
storing must account for the fixed frame size.

Cleanup the _rt0_ppc64le_linux_lib definition, the assembler
should not generate a stack frame.  And convert it to use the
new ABI wrappers.

Change-Id: Ibc0be8b37f6522900781a19980fa018dd89ba7b3
Reviewed-on: https://go-review.googlesource.com/c/go/+/479796
Reviewed-by: Than McIntosh <[email protected]>
Run-TryBot: Paul Murphy <[email protected]>
Reviewed-by: David Chase <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Lynn Boger <[email protected]>

Author: pmur

src/runtime/rt0_linux_ppc64le.s

@@ -4,64 +4,22 @@
 
 #include "go_asm.h"
 #include "textflag.h"
+#include "asm_ppc64x.h"
+#include "cgo/abi_ppc64x.h"
 
 TEXT _rt0_ppc64le_linux(SB),NOSPLIT,$0
 	XOR R0, R0	  // Make sure R0 is zero before _main
 	BR _main<>(SB)
 
-TEXT _rt0_ppc64le_linux_lib(SB),NOSPLIT,$-8
-	// Start with standard C stack frame layout and linkage.
-	MOVD	LR, R0
-	MOVD	R0, 16(R1) // Save LR in caller's frame.
-	MOVW	CR, R0     // Save CR in caller's frame
-	MOVD	R0, 8(R1)
-	MOVDU	R1, -320(R1) // Allocate frame.
-
-	// Preserve callee-save registers.
-	MOVD	R14, 24(R1)
-	MOVD	R15, 32(R1)
-	MOVD	R16, 40(R1)
-	MOVD	R17, 48(R1)
-	MOVD	R18, 56(R1)
-	MOVD	R19, 64(R1)
-	MOVD	R20, 72(R1)
-	MOVD	R21, 80(R1)
-	MOVD	R22, 88(R1)
-	MOVD	R23, 96(R1)
-	MOVD	R24, 104(R1)
-	MOVD	R25, 112(R1)
-	MOVD	R26, 120(R1)
-	MOVD	R27, 128(R1)
-	MOVD	R28, 136(R1)
-	MOVD	R29, 144(R1)
-	MOVD	g, 152(R1) // R30
-	MOVD	R31, 160(R1)
-	FMOVD	F14, 168(R1)
-	FMOVD	F15, 176(R1)
-	FMOVD	F16, 184(R1)
-	FMOVD	F17, 192(R1)
-	FMOVD	F18, 200(R1)
-	FMOVD	F19, 208(R1)
-	FMOVD	F20, 216(R1)
-	FMOVD	F21, 224(R1)
-	FMOVD	F22, 232(R1)
-	FMOVD	F23, 240(R1)
-	FMOVD	F24, 248(R1)
-	FMOVD	F25, 256(R1)
-	FMOVD	F26, 264(R1)
-	FMOVD	F27, 272(R1)
-	FMOVD	F28, 280(R1)
-	FMOVD	F29, 288(R1)
-	FMOVD	F30, 296(R1)
-	FMOVD	F31, 304(R1)
+TEXT _rt0_ppc64le_linux_lib(SB),NOSPLIT|NOFRAME,$0
+	// This is called with ELFv2 calling conventions. Convert to Go.
+	// Allocate argument storage for call to newosproc0.
+	STACK_AND_SAVE_HOST_TO_GO_ABI(16)
 
 	MOVD	R3, _rt0_ppc64le_linux_lib_argc<>(SB)
 	MOVD	R4, _rt0_ppc64le_linux_lib_argv<>(SB)
 
 	// Synchronous initialization.
-	MOVD	$runtime·reginit(SB), R12
-	MOVD	R12, CTR
-	BL	(CTR)
 	MOVD	$runtime·libpreinit(SB), R12
 	MOVD	R12, CTR
 	BL	(CTR)
@@ -78,57 +36,16 @@ TEXT _rt0_ppc64le_linux_lib(SB),NOSPLIT,$-8
 
 nocgo:
 	MOVD	$0x800000, R12                     // stacksize = 8192KB
-	MOVD	R12, 8(R1)
+	MOVD	R12, 8+FIXED_FRAME(R1)
 	MOVD	$_rt0_ppc64le_linux_lib_go(SB), R12
-	MOVD	R12, 16(R1)
+	MOVD	R12, 16+FIXED_FRAME(R1)
 	MOVD	$runtime·newosproc0(SB),R12
 	MOVD	R12, CTR
 	BL	(CTR)
 
 done:
-	// Restore saved registers.
-	MOVD	24(R1), R14
-	MOVD	32(R1), R15
-	MOVD	40(R1), R16
-	MOVD	48(R1), R17
-	MOVD	56(R1), R18
-	MOVD	64(R1), R19
-	MOVD	72(R1), R20
-	MOVD	80(R1), R21
-	MOVD	88(R1), R22
-	MOVD	96(R1), R23
-	MOVD	104(R1), R24
-	MOVD	112(R1), R25
-	MOVD	120(R1), R26
-	MOVD	128(R1), R27
-	MOVD	136(R1), R28
-	MOVD	144(R1), R29
-	MOVD	152(R1), g // R30
-	MOVD	160(R1), R31
-	FMOVD	168(R1), F14
-	FMOVD	176(R1), F15
-	FMOVD	184(R1), F16
-	FMOVD	192(R1), F17
-	FMOVD	200(R1), F18
-	FMOVD	208(R1), F19
-	FMOVD	216(R1), F20
-	FMOVD	224(R1), F21
-	FMOVD	232(R1), F22
-	FMOVD	240(R1), F23
-	FMOVD	248(R1), F24
-	FMOVD	256(R1), F25
-	FMOVD	264(R1), F26
-	FMOVD	272(R1), F27
-	FMOVD	280(R1), F28
-	FMOVD	288(R1), F29
-	FMOVD	296(R1), F30
-	FMOVD	304(R1), F31
-
-	ADD	$320, R1
-	MOVD	8(R1), R0
-	MOVFL	R0, $0xff
-	MOVD	16(R1), R0
-	MOVD	R0, LR
+	// Restore and return to ELFv2 caller.
+	UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(16)
 	RET
 
 TEXT _rt0_ppc64le_linux_lib_go(SB),NOSPLIT,$0