runtime: mark sigtramp as TOPFRAME

Currently throw() in the signal handler results in "fatal error: unknown
return pc from runtime.sigreturn ...".

Marking sigtramp as TOPFRAME allows gentraceback to stop tracebacks at
the end of a signal handler, since there is not much beyond sigtramp.

This is just done on Linux for now, but may apply to other Unix systems
as well.

Change-Id: I96edcb945283f417a5bfe00ce2fb2b1a0d578692
Reviewed-on: https://go-review.googlesource.com/c/go/+/402190
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

9 files changed, 9 insertions, 9 deletions

diff --git a/src/runtime/sys_linux_386.s b/src/runtime/sys_linux_386.s
index fef68d51dc..4942f21e4f 100644
--- a/src/runtime/sys_linux_386.s
+++ b/src/runtime/sys_linux_386.s
@@ -433,7 +433,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$12-16
 	RET
 
 // Called using C ABI.
-TEXT runtime·sigtramp(SB),NOSPLIT,$28
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$28
 	// Save callee-saved C registers, since the caller may be a C signal handler.
 	MOVL	BX, bx-4(SP)
 	MOVL	BP, bp-8(SP)
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
index f2dfbbb70c..ca6ecb13eb 100644
--- a/src/runtime/sys_linux_amd64.s
+++ b/src/runtime/sys_linux_amd64.s
@@ -339,7 +339,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
 	RET
 
 // Called using C ABI.
-TEXT runtime·sigtramp(SB),NOSPLIT,$0
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$0
 	// Transition from C ABI to Go ABI.
 	PUSH_REGS_HOST_TO_ABI0()
 
diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
index 201940b4e6..66bf40328e 100644
--- a/src/runtime/sys_linux_arm.s
+++ b/src/runtime/sys_linux_arm.s
@@ -566,7 +566,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-16
 	MOVW	R4, R13
 	RET
 
-TEXT runtime·sigtramp(SB),NOSPLIT,$0
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$0
 	// Reserve space for callee-save registers and arguments.
 	MOVM.DB.W [R4-R11], (R13)
 	SUB	$16, R13
diff --git a/src/runtime/sys_linux_arm64.s b/src/runtime/sys_linux_arm64.s
index 8e7cbf7d11..b47b6fd0a0 100644
--- a/src/runtime/sys_linux_arm64.s
+++ b/src/runtime/sys_linux_arm64.s
@@ -445,7 +445,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
 	RET
 
 // Called from c-abi, R0: sig, R1: info, R2: cxt
-TEXT runtime·sigtramp(SB),NOSPLIT,$176
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$176
 	// Save callee-save registers in the case of signal forwarding.
 	// Please refer to https://golang.org/issue/31827 .
 	SAVE_R19_TO_R28(8*4)
diff --git a/src/runtime/sys_linux_mips64x.s b/src/runtime/sys_linux_mips64x.s
index 3c7f0e7307..06d54dff78 100644
--- a/src/runtime/sys_linux_mips64x.s
+++ b/src/runtime/sys_linux_mips64x.s
@@ -405,7 +405,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
 	JAL	(R25)
 	RET
 
-TEXT runtime·sigtramp(SB),NOSPLIT,$64
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$64
 	// initialize REGSB = PC&0xffffffff00000000
 	BGEZAL	R0, 1(PC)
 	SRLV	$32, R31, RSB
diff --git a/src/runtime/sys_linux_mipsx.s b/src/runtime/sys_linux_mipsx.s
index ab4e976ee4..e70edcc0e2 100644
--- a/src/runtime/sys_linux_mipsx.s
+++ b/src/runtime/sys_linux_mipsx.s
@@ -311,7 +311,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-16
 	MOVW	R22, R29
 	RET
 
-TEXT runtime·sigtramp(SB),NOSPLIT,$12
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$12
 	// this might be called in external code context,
 	// where g is not set.
 	MOVB	runtime·iscgo(SB), R1
diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
index 48f9334795..2913a05f56 100644
--- a/src/runtime/sys_linux_ppc64x.s
+++ b/src/runtime/sys_linux_ppc64x.s
@@ -459,7 +459,7 @@ TEXT runtime·sigtramp(SB),NOSPLIT|NOFRAME,$0
 	DWORD	$sigtramp<>(SB)
 	DWORD	$0
 	DWORD	$0
-TEXT sigtramp<>(SB),NOSPLIT|NOFRAME,$0
+TEXT sigtramp<>(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
 #endif
 	// Start with standard C stack frame layout and linkage.
 	MOVD    LR, R0
diff --git a/src/runtime/sys_linux_riscv64.s b/src/runtime/sys_linux_riscv64.s
index 8dde29eb92..afb2d11da9 100644
--- a/src/runtime/sys_linux_riscv64.s
+++ b/src/runtime/sys_linux_riscv64.s
@@ -417,7 +417,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
 	RET
 
 // func sigtramp(signo, ureg, ctxt unsafe.Pointer)
-TEXT runtime·sigtramp(SB),NOSPLIT,$64
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$64
 	MOVW	A0, 8(X2)
 	MOV	A1, 16(X2)
 	MOV	A2, 24(X2)
diff --git a/src/runtime/sys_linux_s390x.s b/src/runtime/sys_linux_s390x.s
index 03ec7f03fd..91ce1b3c8d 100644
--- a/src/runtime/sys_linux_s390x.s
+++ b/src/runtime/sys_linux_s390x.s
@@ -272,7 +272,7 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
 TEXT runtime·sigreturn(SB),NOSPLIT,$0-0
 	RET
 
-TEXT runtime·sigtramp(SB),NOSPLIT,$64
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$64
 	// initialize essential registers (just in case)
 	XOR	R0, R0