diff options
Diffstat (limited to 'src/runtime/asm_arm.s')
| -rw-r--r-- | src/runtime/asm_arm.s | 76 |
1 files changed, 39 insertions, 37 deletions
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s index 23619b1408..9896ab4383 100644 --- a/src/runtime/asm_arm.s +++ b/src/runtime/asm_arm.s @@ -112,7 +112,7 @@ GLOBL _rt0_arm_lib_argv<>(SB),NOPTR,$4 // using NOFRAME means do not save LR on stack. // argc is in R0, argv is in R1. -TEXT runtime·rt0_go(SB),NOSPLIT|NOFRAME,$0 +TEXT runtime·rt0_go(SB),NOSPLIT|NOFRAME|TOPFRAME,$0 MOVW $0xcafebabe, R12 // copy arguments forward on an even stack @@ -202,27 +202,24 @@ TEXT runtime·asminit(SB),NOSPLIT,$0-0 WORD $0xeee1ba10 // vmsr fpscr, r11 RET +TEXT runtime·mstart(SB),NOSPLIT|TOPFRAME,$0 + BL runtime·mstart0(SB) + RET // not reached + /* * go-routine */ // void gogo(Gobuf*) // restore state from Gobuf; longjmp -TEXT runtime·gogo(SB),NOSPLIT,$8-4 +TEXT runtime·gogo(SB),NOSPLIT|NOFRAME,$0-4 MOVW buf+0(FP), R1 MOVW gobuf_g(R1), R0 - BL setg<>(SB) + MOVW 0(R0), R2 // make sure g != nil + B gogo<>(SB) - // NOTE: We updated g above, and we are about to update SP. - // Until LR and PC are also updated, the g/SP/LR/PC quadruple - // are out of sync and must not be used as the basis of a traceback. - // Sigprof skips the traceback when SP is not within g's bounds, - // and when the PC is inside this function, runtime.gogo. - // Since we are about to update SP, until we complete runtime.gogo - // we must not leave this function. In particular, no calls - // after this point: it must be straight-line code until the - // final B instruction. - // See large comment in sigprof for more details. +TEXT gogo<>(SB),NOSPLIT|NOFRAME,$0 + BL setg<>(SB) MOVW gobuf_sp(R1), R13 // restore SP==R13 MOVW gobuf_lr(R1), LR MOVW gobuf_ret(R1), R0 @@ -246,7 +243,6 @@ TEXT runtime·mcall(SB),NOSPLIT|NOFRAME,$0-4 MOVW LR, (g_sched+gobuf_pc)(g) MOVW $0, R11 MOVW R11, (g_sched+gobuf_lr)(g) - MOVW g, (g_sched+gobuf_g)(g) // Switch to m->g0 & its stack, call fn. MOVW g, R1 @@ -305,24 +301,14 @@ TEXT runtime·systemstack(SB),NOSPLIT,$0-4 switch: // save our state in g->sched. Pretend to // be systemstack_switch if the G stack is scanned. - MOVW $runtime·systemstack_switch(SB), R3 - ADD $4, R3, R3 // get past push {lr} - MOVW R3, (g_sched+gobuf_pc)(g) - MOVW R13, (g_sched+gobuf_sp)(g) - MOVW LR, (g_sched+gobuf_lr)(g) - MOVW g, (g_sched+gobuf_g)(g) + BL gosave_systemstack_switch<>(SB) // switch to g0 MOVW R0, R5 MOVW R2, R0 BL setg<>(SB) MOVW R5, R0 - MOVW (g_sched+gobuf_sp)(R2), R3 - // make it look like mstart called systemstack on g0, to stop traceback - SUB $4, R3, R3 - MOVW $runtime·mstart(SB), R4 - MOVW R4, 0(R3) - MOVW R3, R13 + MOVW (g_sched+gobuf_sp)(R2), R13 // call target function MOVW R0, R7 @@ -524,10 +510,6 @@ CALLFN(·call1073741824, 1073741824) // 1. grab stored LR for caller // 2. sub 4 bytes to get back to BL deferreturn // 3. B to fn -// TODO(rsc): Push things on stack and then use pop -// to load all registers simultaneously, so that a profiling -// interrupt can never see mismatched SP/LR/PC. -// (And double-check that pop is atomic in that way.) TEXT runtime·jmpdefer(SB),NOSPLIT,$0-8 MOVW 0(R13), LR MOVW $-4(LR), LR // BL deferreturn @@ -537,19 +519,39 @@ TEXT runtime·jmpdefer(SB),NOSPLIT,$0-8 MOVW 0(R7), R1 B (R1) -// Save state of caller into g->sched. Smashes R11. -TEXT gosave<>(SB),NOSPLIT|NOFRAME,$0 - MOVW LR, (g_sched+gobuf_pc)(g) +// Save state of caller into g->sched, +// but using fake PC from systemstack_switch. +// Must only be called from functions with no locals ($0) +// or else unwinding from systemstack_switch is incorrect. +// Smashes R11. +TEXT gosave_systemstack_switch<>(SB),NOSPLIT|NOFRAME,$0 + MOVW $runtime·systemstack_switch(SB), R11 + ADD $4, R11 // get past push {lr} + MOVW R11, (g_sched+gobuf_pc)(g) MOVW R13, (g_sched+gobuf_sp)(g) MOVW $0, R11 MOVW R11, (g_sched+gobuf_lr)(g) MOVW R11, (g_sched+gobuf_ret)(g) - MOVW R11, (g_sched+gobuf_ctxt)(g) // Assert ctxt is zero. See func save. MOVW (g_sched+gobuf_ctxt)(g), R11 - CMP $0, R11 + TST R11, R11 B.EQ 2(PC) - CALL runtime·badctxt(SB) + BL runtime·abort(SB) + RET + +// func asmcgocall_no_g(fn, arg unsafe.Pointer) +// Call fn(arg) aligned appropriately for the gcc ABI. +// Called on a system stack, and there may be no g yet (during needm). +TEXT ·asmcgocall_no_g(SB),NOSPLIT,$0-8 + MOVW fn+0(FP), R1 + MOVW arg+4(FP), R0 + MOVW R13, R2 + SUB $32, R13 + BIC $0x7, R13 // alignment for gcc ABI + MOVW R2, 8(R13) + BL (R1) + MOVW 8(R13), R2 + MOVW R2, R13 RET // func asmcgocall(fn, arg unsafe.Pointer) int32 @@ -575,7 +577,7 @@ TEXT ·asmcgocall(SB),NOSPLIT,$0-12 MOVW m_g0(R8), R3 CMP R3, g BEQ nosave - BL gosave<>(SB) + BL gosave_systemstack_switch<>(SB) MOVW R0, R5 MOVW R3, R0 BL setg<>(SB) |