runtime: remove OABI check from ARM startup

The code in question is trying to print a nice error message
when a Go EABI binary runs on an OABI machine.
Unfortunately, the only way to do that is to use
ARM Thumb instructions, which we otherwise don't use.

There exist ARM EABI machines that do not support Thumb.
We could run on them if not for this OABI check, so disable it.

Fixes #5685.

R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/13234050
This commit is contained in:
Russ Cox 2013-09-09 15:06:05 -04:00
parent 9c21ce54dd
commit 6252b41981

View File

@ -22,31 +22,36 @@ TEXT _rt0_arm_linux1(SB),NOSPLIT,$-4
// Save argc and argv
MOVM.DB.W [R0-R1], (R13)
// set up sa_handler
MOVW $bad_abi<>(SB), R0 // sa_handler
MOVW $0, R1 // sa_flags
MOVW $0, R2 // sa_restorer
MOVW $0, R3 // sa_mask
MOVM.DB.W [R0-R3], (R13)
MOVW $4, R0 // SIGILL
MOVW R13, R1 // sa
SUB $16, R13
MOVW R13, R2 // old_sa
MOVW $8, R3 // c
MOVW $174, R7 // sys_sigaction
BL oabi_syscall<>(SB)
// Thumb mode OABI check disabled because there are some
// EABI systems that do not support Thumb execution.
// We can run on them except for this check!
// // set up sa_handler
// MOVW $bad_abi<>(SB), R0 // sa_handler
// MOVW $0, R1 // sa_flags
// MOVW $0, R2 // sa_restorer
// MOVW $0, R3 // sa_mask
// MOVM.DB.W [R0-R3], (R13)
// MOVW $4, R0 // SIGILL
// MOVW R13, R1 // sa
// SUB $16, R13
// MOVW R13, R2 // old_sa
// MOVW $8, R3 // c
// MOVW $174, R7 // sys_sigaction
// BL oabi_syscall<>(SB)
// do an EABI syscall
MOVW $20, R7 // sys_getpid
SWI $0 // this will trigger SIGILL on OABI systems
MOVW $4, R0 // SIGILL
MOVW R13, R1 // sa
MOVW $0, R2 // old_sa
MOVW $8, R3 // c
MOVW $174, R7 // sys_sigaction
SWI $0 // restore signal handler
ADD $32, R13
// MOVW $4, R0 // SIGILL
// MOVW R13, R1 // sa
// MOVW $0, R2 // old_sa
// MOVW $8, R3 // c
// MOVW $174, R7 // sys_sigaction
// SWI $0 // restore signal handler
// ADD $32, R13
SUB $4, R13 // fake a stack frame for runtime·setup_auxv
BL runtime·setup_auxv(SB)