Commit 32b770b2 authored by Keith Randall's avatar Keith Randall

runtime: jump to badmcall instead of calling it.

This replaces the mcall frame with the badmcall frame instead of
leaving the mcall frame on the stack and adding the badmcall frame.
Because mcall is no longer on the stack, traceback will now report what
called mcall, which is what we would like to see in this situation.

R=golang-dev, cshapiro
CC=golang-dev
https://golang.org/cl/13012044
parent 90351506
......@@ -181,14 +181,16 @@ TEXT runtime·mcall(SB), NOSPLIT, $0-4
MOVL m(CX), BX
MOVL m_g0(BX), SI
CMPL SI, AX // if g == m->g0 call badmcall
JNE 2(PC)
CALL runtime·badmcall(SB)
JNE 3(PC)
MOVL $runtime·badmcall(SB), AX
JMP AX
MOVL SI, g(CX) // g = m->g0
MOVL (g_sched+gobuf_sp)(SI), SP // sp = m->g0->sched.sp
PUSHL AX
CALL DI
POPL AX
CALL runtime·badmcall2(SB)
MOVL $runtime·badmcall2(SB), AX
JMP AX
RET
/*
......
......@@ -169,16 +169,16 @@ TEXT runtime·mcall(SB), NOSPLIT, $0-8
MOVQ m_g0(BX), SI
CMPQ SI, AX // if g == m->g0 call badmcall
JNE 3(PC)
ARGSIZE(0)
CALL runtime·badmcall(SB)
MOVQ $runtime·badmcall(SB), AX
JMP AX
MOVQ SI, g(CX) // g = m->g0
MOVQ (g_sched+gobuf_sp)(SI), SP // sp = m->g0->sched.sp
PUSHQ AX
ARGSIZE(8)
CALL DI
POPQ AX
ARGSIZE(0)
CALL runtime·badmcall2(SB)
MOVQ $runtime·badmcall2(SB), AX
JMP AX
RET
/*
......
......@@ -157,12 +157,13 @@ TEXT runtime·mcall(SB), NOSPLIT, $-4-4
MOVW g, R1
MOVW m_g0(m), g
CMP g, R1
BL.EQ runtime·badmcall(SB)
B.NE 2(PC)
B runtime·badmcall(SB)
MOVW (g_sched+gobuf_sp)(g), SP
SUB $8, SP
MOVW R1, 4(SP)
BL (R0)
BL runtime·badmcall2(SB)
B runtime·badmcall2(SB)
RET
/*
......
......@@ -1997,14 +1997,16 @@ runtime·mcount(void)
}
void
runtime·badmcall(void) // called from assembly
runtime·badmcall(void (*fn)(G*)) // called from assembly
{
USED(fn); // TODO: print fn?
runtime·throw("runtime: mcall called on m->g0 stack");
}
void
runtime·badmcall2(void) // called from assembly
runtime·badmcall2(void (*fn)(G*)) // called from assembly
{
USED(fn);
runtime·throw("runtime: mcall function returned");
}
......
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