diff --git a/internal/fakecgo/trampolines_amd64.s b/internal/fakecgo/trampolines_amd64.s
index c9a3cc09..6deb374b 100644
--- a/internal/fakecgo/trampolines_amd64.s
+++ b/internal/fakecgo/trampolines_amd64.s
@@ -25,6 +25,7 @@ return value will be in AX
 */
 #include "textflag.h"
 #include "go_asm.h"
+#include "abi_amd64.h"
 
 // these trampolines map the gcc ABI to Go ABI and then calls into the Go equivalent functions.
 
@@ -73,11 +74,20 @@ TEXT ·setg_trampoline(SB), NOSPLIT, $0-16
 	CALL BX
 	RET
 
-TEXT threadentry_trampoline(SB), NOSPLIT, $16
+TEXT threadentry_trampoline(SB), NOSPLIT, $0
+	// See crosscall2.
+	PUSH_REGS_HOST_TO_ABI0()
+
+	// X15 is designated by Go as a fixed zero register.
+	// Calling directly into ABIInternal, ensure it is zero.
+	PXOR X15, X15
+
 	MOVQ DI, AX
 	MOVQ ·threadentry_call(SB), DX
 	MOVQ (DX), CX
 	CALL CX
+
+	POP_REGS_HOST_TO_ABI0()
 	RET
 
 TEXT ·call5(SB), NOSPLIT, $0-56
diff --git a/internal/fakecgo/trampolines_arm64.s b/internal/fakecgo/trampolines_arm64.s
index 9dbdbc01..ccee9a4a 100644
--- a/internal/fakecgo/trampolines_arm64.s
+++ b/internal/fakecgo/trampolines_arm64.s
@@ -5,6 +5,7 @@
 
 #include "textflag.h"
 #include "go_asm.h"
+#include "abi_arm64.h"
 
 // these trampolines map the gcc ABI to Go ABI and then calls into the Go equivalent functions.
 
@@ -53,11 +54,25 @@ TEXT ·setg_trampoline(SB), NOSPLIT, $0-16
 	RET
 
 TEXT threadentry_trampoline(SB), NOSPLIT, $0-0
-	MOVD R0, 8(RSP)
+	// See crosscall2.
+	SUB  $(8*24), RSP
+	STP  (R0, R1), (8*1)(RSP)
+	MOVD R3, (8*3)(RSP)
+
+	SAVE_R19_TO_R28(8*4)
+	SAVE_F8_TO_F15(8*14)
+	STP (R29, R30), (8*22)(RSP)
+
 	MOVD ·threadentry_call(SB), R26
 	MOVD (R26), R2
 	CALL (R2)
 	MOVD $0, R0                     // TODO: get the return value from threadentry
+
+	RESTORE_R19_TO_R28(8*4)
+	RESTORE_F8_TO_F15(8*14)
+	LDP (8*22)(RSP), (R29, R30)
+
+	ADD $(8*24), RSP
 	RET
 
 TEXT ·call5(SB), NOSPLIT, $0-0
diff --git a/internal/fakecgo/trampolines_loong64.s b/internal/fakecgo/trampolines_loong64.s
index 15b33543..a6faf687 100644
--- a/internal/fakecgo/trampolines_loong64.s
+++ b/internal/fakecgo/trampolines_loong64.s
@@ -5,6 +5,7 @@
 
 #include "textflag.h"
 #include "go_asm.h"
+#include "abi_loong64.h"
 
 // these trampolines map the gcc ABI to Go ABI and then calls into the Go equivalent functions.
 
@@ -52,11 +53,26 @@ TEXT ·setg_trampoline(SB), NOSPLIT, $0
 	CALL (R5)
 	RET
 
-TEXT threadentry_trampoline(SB), NOSPLIT, $16
-	MOVV R4, 8(R3)
+TEXT threadentry_trampoline(SB), NOSPLIT, $0
+	// See crosscall2.
+	ADDV $(-23*8), R3
+	MOVV R4, (1*8)(R3) // fn unsafe.Pointer
+	MOVV R5, (2*8)(R3) // a unsafe.Pointer
+	MOVV R7, (3*8)(R3) // ctxt uintptr
+
+	SAVE_R22_TO_R31((4*8))
+	SAVE_F24_TO_F31((14*8))
+	MOVV R1, (22*8)(R3)
+
 	MOVV ·threadentry_call(SB), R5
 	MOVV (R5), R6
 	CALL (R6)
+
+	RESTORE_R22_TO_R31((4*8))
+	RESTORE_F24_TO_F31((14*8))
+	MOVV (22*8)(R3), R1
+
+	ADDV $(23*8), R3
 	RET
 
 TEXT ·call5(SB), NOSPLIT, $0-0