13 files changed, 25 insertions, 221 deletions
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index dd2ea458cc..11c60309f4 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -582,26 +582,6 @@ TEXT ·publicationBarrier(SB),NOSPLIT,$0-0
 	// compile barrier.
 	RET
 
-// void jmpdefer(fn, sp);
-// called from deferreturn.
-// 1. pop the caller
-// 2. sub 5 bytes (the length of CALL & a 32 bit displacement) from the callers
-//    return (when building for shared libraries, subtract 16 bytes -- 5 bytes
-//    for CALL & displacement to call __x86.get_pc_thunk.cx, 6 bytes for the
-//    LEAL to load the offset into BX, and finally 5 for the call & displacement)
-// 3. jmp to the argument
-TEXT runtime·jmpdefer(SB), NOSPLIT, $0-8
-	MOVL	fv+0(FP), DX	// fn
-	MOVL	argp+4(FP), BX	// caller sp
-	LEAL	-4(BX), SP	// caller sp after CALL
-#ifdef GOBUILDMODE_shared
-	SUBL	$16, (SP)	// return to CALL again
-#else
-	SUBL	$5, (SP)	// return to CALL again
-#endif
-	MOVL	0(DX), BX
-	JMP	BX	// but first run the deferred function
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index 0f719b2664..2d8f4c2412 100644
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -662,21 +662,6 @@ TEXT ·publicationBarrier(SB),NOSPLIT,$0-0
 	// compile barrier.
 	RET
 
-// func jmpdefer(fv func(), argp uintptr)
-// argp is a caller SP.
-// called from deferreturn.
-// 1. pop the caller
-// 2. sub 5 bytes from the callers return
-// 3. jmp to the argument
-TEXT runtime·jmpdefer(SB), NOSPLIT, $0-16
-	MOVQ	fv+0(FP), DX	// fn
-	MOVQ	argp+8(FP), BX	// caller sp
-	LEAQ	-8(BX), SP	// caller sp after CALL
-	MOVQ	-8(SP), BP	// restore BP as if deferreturn returned (harmless if framepointers not in use)
-	SUBQ	$5, (SP)	// return to CALL again
-	MOVQ	0(DX), BX
-	JMP	BX	// but first run the deferred function
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s
index 5c2bc00fe8..a1164781d2 100644
--- a/src/runtime/asm_arm.s
+++ b/src/runtime/asm_arm.s
@@ -506,20 +506,6 @@ CALLFN(·call268435456, 268435456)
 CALLFN(·call536870912, 536870912)
 CALLFN(·call1073741824, 1073741824)
 
-// void jmpdefer(fn, sp);
-// called from deferreturn.
-// 1. grab stored LR for caller
-// 2. sub 4 bytes to get back to BL deferreturn
-// 3. B to fn
-TEXT runtime·jmpdefer(SB),NOSPLIT,$0-8
-	MOVW	0(R13), LR
-	MOVW	$-4(LR), LR	// BL deferreturn
-	MOVW	fv+0(FP), R7
-	MOVW	argp+4(FP), R13
-	MOVW	$-4(R13), R13	// SP is 4 below argp, due to saved LR
-	MOVW	0(R7), R1
-	B	(R1)
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index e7c5fa3225..e51ce2f831 100644
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -982,23 +982,6 @@ again:
 	CBNZ	R0, again
 	RET
 
-// void jmpdefer(fv, sp);
-// called from deferreturn.
-// 1. grab stored LR for caller
-// 2. sub 4 bytes to get back to BL deferreturn
-// 3. BR to fn
-TEXT runtime·jmpdefer(SB), NOSPLIT|NOFRAME, $0-16
-	MOVD	0(RSP), R0
-	SUB	$4, R0
-	MOVD	R0, LR
-
-	MOVD	fv+0(FP), R26
-	MOVD	argp+8(FP), R0
-	MOVD	R0, RSP
-	SUB	$8, RSP
-	MOVD	0(R26), R3
-	B	(R3)
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_mips64x.s b/src/runtime/asm_mips64x.s
index f3ac453d99..b2e2384c36 100644
--- a/src/runtime/asm_mips64x.s
+++ b/src/runtime/asm_mips64x.s
@@ -384,22 +384,6 @@ CALLFN(·call1073741824, 1073741824)
 TEXT runtime·procyield(SB),NOSPLIT,$0-0
 	RET
 
-// void jmpdefer(fv, sp);
-// called from deferreturn.
-// 1. grab stored LR for caller
-// 2. sub 8 bytes to get back to JAL deferreturn
-// 3. JMP to fn
-TEXT runtime·jmpdefer(SB), NOSPLIT|NOFRAME, $0-16
-	MOVV	0(R29), R31
-	ADDV	$-8, R31
-
-	MOVV	fv+0(FP), REGCTXT
-	MOVV	argp+8(FP), R29
-	ADDV	$-8, R29
-	NOR	R0, R0	// prevent scheduling
-	MOVV	0(REGCTXT), R4
-	JMP	(R4)
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_mipsx.s b/src/runtime/asm_mipsx.s
index 4dc165849e..87a1344e8f 100644
--- a/src/runtime/asm_mipsx.s
+++ b/src/runtime/asm_mipsx.s
@@ -382,22 +382,6 @@ CALLFN(·call1073741824, 1073741824)
 TEXT runtime·procyield(SB),NOSPLIT,$0-4
 	RET
 
-// void jmpdefer(fv, sp);
-// called from deferreturn.
-// 1. grab stored LR for caller
-// 2. sub 8 bytes to get back to JAL deferreturn
-// 3. JMP to fn
-TEXT runtime·jmpdefer(SB),NOSPLIT,$0-8
-	MOVW	0(R29), R31
-	ADDU	$-8, R31
-
-	MOVW	fv+0(FP), REGCTXT
-	MOVW	argp+4(FP), R29
-	ADDU	$-4, R29
-	NOR	R0, R0	// prevent scheduling
-	MOVW	0(REGCTXT), R4
-	JMP	(R4)
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index a789d041e4..5dc96c5947 100644
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -503,34 +503,6 @@ again:
 	OR	R6, R6, R6	// Set PPR priority back to medium-low
 	RET
 
-// void jmpdefer(fv, sp);
-// called from deferreturn.
-// 1. grab stored LR for caller
-// 2. sub 8 bytes to get back to either nop or toc reload before deferreturn
-// 3. BR to fn
-// When dynamically linking Go, it is not sufficient to rewind to the BL
-// deferreturn -- we might be jumping between modules and so we need to reset
-// the TOC pointer in r2. To do this, codegen inserts MOVD 24(R1), R2 *before*
-// the BL deferreturn and jmpdefer rewinds to that.
-TEXT runtime·jmpdefer(SB), NOSPLIT|NOFRAME, $0-16
-	MOVD	0(R1), R31
-	SUB     $8, R31
-	MOVD	R31, LR
-
-	MOVD	fv+0(FP), R11
-	MOVD	argp+8(FP), R1
-	SUB	$FIXED_FRAME, R1
-#ifdef GOOS_aix
-	// AIX won't trigger a SIGSEGV if R11 = nil
-	// So it manually triggers it
-	CMP	R0, R11
-	BNE	2(PC)
-	MOVD	R0, 0(R0)
-#endif
-	MOVD	0(R11), R12
-	MOVD	R12, CTR
-	BR	(CTR)
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_riscv64.s b/src/runtime/asm_riscv64.s
index 9957ae201b..9927a817f7 100644
--- a/src/runtime/asm_riscv64.s
+++ b/src/runtime/asm_riscv64.s
@@ -248,21 +248,6 @@ TEXT gogo<>(SB), NOSPLIT|NOFRAME, $0
 	MOV	gobuf_pc(T0), T0
 	JALR	ZERO, T0
 
-// func jmpdefer(fv func(), argp uintptr)
-// called from deferreturn
-// 1. grab stored return address from the caller's frame
-// 2. sub 8 bytes to get back to JAL deferreturn
-// 3. JMP to fn
-TEXT runtime·jmpdefer(SB), NOSPLIT|NOFRAME, $0-16
-	MOV	0(X2), RA
-	ADD	$-8, RA
-
-	MOV	fv+0(FP), CTXT
-	MOV	argp+8(FP), X2
-	ADD	$-8, X2
-	MOV	0(CTXT), T0
-	JALR	ZERO, T0
-
 // func procyield(cycles uint32)
 TEXT runtime·procyield(SB),NOSPLIT,$0-0
 	RET
diff --git a/src/runtime/asm_s390x.s b/src/runtime/asm_s390x.s
index 534cb6112c..d4110d563f 100644
--- a/src/runtime/asm_s390x.s
+++ b/src/runtime/asm_s390x.s
@@ -480,21 +480,6 @@ TEXT callfnMVC<>(SB),NOSPLIT|NOFRAME,$0-0
 TEXT runtime·procyield(SB),NOSPLIT,$0-0
 	RET
 
-// void jmpdefer(fv, sp);
-// called from deferreturn.
-// 1. grab stored LR for caller
-// 2. sub 6 bytes to get back to BL deferreturn (size of BRASL instruction)
-// 3. BR to fn
-TEXT runtime·jmpdefer(SB),NOSPLIT|NOFRAME,$0-16
-	MOVD	0(R15), R1
-	SUB	$6, R1, LR
-
-	MOVD	fv+0(FP), R12
-	MOVD	argp+8(FP), R15
-	SUB	$8, R15
-	MOVD	0(R12), R3
-	BR	(R3)
-
 // Save state of caller into g->sched,
 // but using fake PC from systemstack_switch.
 // Must only be called from functions with no locals ($0)
diff --git a/src/runtime/asm_wasm.s b/src/runtime/asm_wasm.s
index 53c271aa70..d885da6e70 100644
--- a/src/runtime/asm_wasm.s
+++ b/src/runtime/asm_wasm.s
@@ -193,35 +193,6 @@ TEXT runtime·return0(SB), NOSPLIT, $0-0
 	MOVD $0, RET0
 	RET
 
-TEXT runtime·jmpdefer(SB), NOSPLIT, $0-16
-	MOVD fv+0(FP), CTXT
-
-	Get CTXT
-	I64Eqz
-	If
-		CALLNORESUME runtime·sigpanic<ABIInternal>(SB)
-	End
-
-	// caller sp after CALL
-	I64Load argp+8(FP)
-	I64Const $8
-	I64Sub
-	I32WrapI64
-	Set SP
-
-	// decrease PC_B by 1 to CALL again
-	Get SP
-	I32Load16U (SP)
-	I32Const $1
-	I32Sub
-	I32Store16 $0
-
-	// but first run the deferred function
-	Get CTXT
-	I32WrapI64
-	I64Load $0
-	JMP
-
 TEXT runtime·asminit(SB), NOSPLIT, $0-0
 	// No per-thread init.
 	RET
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index e66fe27be0..4b8bca6c56 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -396,47 +396,39 @@ func freedeferfn() {
 	throw("freedefer with d.fn != nil")
 }
 
-// Run a deferred function if there is one.
+// deferreturn runs deferred functions for the caller's frame.
 // The compiler inserts a call to this at the end of any
 // function which calls defer.
-// If there is a deferred function, this will call runtime·jmpdefer,
-// which will jump to the deferred function such that it appears
-// to have been called by the caller of deferreturn at the point
-// just before deferreturn was called. The effect is that deferreturn
-// is called again and again until there are no more deferred functions.
 func deferreturn() {
 	gp := getg()
-	d := gp._defer
-	if d == nil {
-		return
-	}
-	sp := getcallersp()
-	if d.sp != sp {
-		return
-	}
-	if d.openDefer {
-		done := runOpenDeferFrame(gp, d)
-		if !done {
-			throw("unfinished open-coded defers in deferreturn")
+	for {
+		d := gp._defer
+		if d == nil {
+			return
 		}
+		sp := getcallersp()
+		if d.sp != sp {
+			return
+		}
+		if d.openDefer {
+			done := runOpenDeferFrame(gp, d)
+			if !done {
+				throw("unfinished open-coded defers in deferreturn")
+			}
+			gp._defer = d.link
+			freedefer(d)
+			// If this frame uses open defers, then this
+			// must be the only defer record for the
+			// frame, so we can just return.
+			return
+		}
+
+		fn := d.fn
+		d.fn = nil
 		gp._defer = d.link
 		freedefer(d)
-		return
+		fn()
 	}
-
-	fn := d.fn
-	d.fn = nil
-	gp._defer = d.link
-	freedefer(d)
-	// If the defer function pointer is nil, force the seg fault to happen
-	// here rather than in jmpdefer. gentraceback() throws an error if it is
-	// called with a callback on an LR architecture and jmpdefer is on the
-	// stack, because jmpdefer manipulates SP (see issue #8153).
-	_ = **(**funcval)(unsafe.Pointer(&fn))
-	// We must not split the stack between computing argp and
-	// calling jmpdefer because argp is a uintptr stack pointer.
-	argp := getcallersp() + sys.MinFrameSize
-	jmpdefer(fn, argp)
 }
 
 // Goexit terminates the goroutine that calls it. No other goroutine is affected.
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go
index b94acdea1f..fc29a1bac3 100644
--- a/src/runtime/stubs.go
+++ b/src/runtime/stubs.go
@@ -176,8 +176,6 @@ func cgocallback(fn, frame, ctxt uintptr)
 
 func gogo(buf *gobuf)
 
-//go:noescape
-func jmpdefer(fv func(), argp uintptr)
 func asminit()
 func setg(gg *g)
 func breakpoint()
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go
index 44ea0710c6..d08aa0b320 100644
--- a/src/runtime/symtab.go
+++ b/src/runtime/symtab.go
@@ -331,7 +331,6 @@ const (
 	funcID_gogo
 	funcID_gopanic
 	funcID_handleAsyncEvent
-	funcID_jmpdefer
 	funcID_mcall
 	funcID_morestack
 	funcID_mstart