runtime: use explicit NOFRAME on linux/amd64

This CL marks some linux assembly functions as NOFRAME to avoid relying on the implicit amd64 NOFRAME heuristic, where NOSPLIT functions without stack were also marked as NOFRAME. Updates #58378 Change-Id: I7792cff4f6e539bfa56c02868f2965088ca1975a Reviewed-on: https://go-review.googlesource.com/c/go/+/466316 Reviewed-by: Than McIntosh <[email protected]> Reviewed-by: Cherry Mui <[email protected]> Run-TryBot: Quim Muntal <[email protected]> TryBot-Result: Gopher Robot <[email protected]>
golang · Feb 22, 2023 · 521d261 · 521d261
1 parent 133e0bc
commit 521d261
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Showing 3 changed files with 17 additions and 12 deletions.
diff --git a/src/cmd/internal/obj/x86/obj6.go b/src/cmd/internal/obj/x86/obj6.go
@@ -611,17 +611,23 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 		}
 	}
 
+	var usefpheuristic bool
+	switch ctxt.Headtype {
+	case objabi.Hwindows, objabi.Hdarwin, objabi.Hlinux:
+	default:
+		usefpheuristic = true
+	}
+
 	var bpsize int
 	if ctxt.Arch.Family == sys.AMD64 &&
 		!p.From.Sym.NoFrame() && // (1) below
-		!(autoffset == 0 && p.From.Sym.NoSplit() && ctxt.Headtype != objabi.Hwindows && ctxt.Headtype != objabi.Hdarwin) && // (2) below
+		!(autoffset == 0 && p.From.Sym.NoSplit() && usefpheuristic) && // (2) below
 		!(autoffset == 0 && !hasCall) { // (3) below
 		// Make room to save a base pointer.
 		// There are 2 cases we must avoid:
 		// 1) If noframe is set (which we do for functions which tail call).
 		// 2) Scary runtime internals which would be all messed up by frame pointers.
 		//    We detect these using a heuristic: frameless nosplit functions.
-		//    Windows and Darwin do not use this heuristic anymore.
 		//    TODO: Maybe someday we label them all with NOFRAME and get rid of this heuristic.
 		// For performance, we also want to avoid:
 		// 3) Frameless leaf functions

diff --git a/src/cmd/link/internal/ld/testdata/stackcheck/main.s b/src/cmd/link/internal/ld/testdata/stackcheck/main.s
@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 #define NOSPLIT 7
+#define NOFRAME 512
 
 TEXT ·asmMain(SB),0,$0-0
 	CALL ·startSelf(SB)
@@ -32,9 +33,9 @@ TEXT ·chainEnd(SB),NOSPLIT,$1000-0 // Should be reported twice
 	RET
 
 // Test reporting of rootless recursion
-TEXT ·startRec(SB),NOSPLIT,$0-0
+TEXT ·startRec(SB),NOSPLIT|NOFRAME,$0-0
 	CALL ·startRec0(SB)
 	RET
-TEXT ·startRec0(SB),NOSPLIT,$0-0
+TEXT ·startRec0(SB),NOSPLIT|NOFRAME,$0-0
 	CALL ·startRec(SB)
 	RET
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
@@ -325,16 +325,14 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
 	MOVL	sig+8(FP),   DI
 	MOVQ	info+16(FP), SI
 	MOVQ	ctx+24(FP),  DX
-	PUSHQ	BP
-	MOVQ	SP, BP
+	MOVQ	SP, BX		// callee-saved
 	ANDQ	$~15, SP     // alignment for x86_64 ABI
 	CALL	AX
-	MOVQ	BP, SP
-	POPQ	BP
+	MOVQ	BX, SP
 	RET
 
 // Called using C ABI.
-TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$0
+TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME|NOFRAME,$0
 	// Transition from C ABI to Go ABI.
 	PUSH_REGS_HOST_TO_ABI0()
 
@@ -359,7 +357,7 @@ TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$0
 	RET
 
 // Called using C ABI.
-TEXT runtime·sigprofNonGoWrapper<>(SB),NOSPLIT,$0
+TEXT runtime·sigprofNonGoWrapper<>(SB),NOSPLIT|NOFRAME,$0
 	// Transition from C ABI to Go ABI.
 	PUSH_REGS_HOST_TO_ABI0()
 
@@ -556,7 +554,7 @@ TEXT runtime·futex(SB),NOSPLIT,$0
 	RET
 
 // int32 clone(int32 flags, void *stk, M *mp, G *gp, void (*fn)(void));
-TEXT runtime·clone(SB),NOSPLIT,$0
+TEXT runtime·clone(SB),NOSPLIT|NOFRAME,$0
 	MOVL	flags+0(FP), DI
 	MOVQ	stk+8(FP), SI
 	MOVQ	$0, DX
@@ -620,7 +618,7 @@ nog2:
 	SYSCALL
 	JMP	-3(PC)	// keep exiting
 
-TEXT runtime·sigaltstack(SB),NOSPLIT,$-8
+TEXT runtime·sigaltstack(SB),NOSPLIT,$0
 	MOVQ	new+0(FP), DI
 	MOVQ	old+8(FP), SI
 	MOVQ	$SYS_sigaltstack, AX