// Copyright 2009 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. // // System calls and other sys.stuff for ARM, OpenBSD // /usr/src/sys/kern/syscalls.master for syscall numbers. // #include "go_asm.h" #include "go_tls.h" #include "textflag.h" #define CLOCK_REALTIME $0 #define CLOCK_MONOTONIC $3 // With OpenBSD 6.7 onwards, an armv7 syscall returns two instructions // after the SWI instruction, to allow for a speculative execution // barrier to be placed after the SWI without impacting performance. // For now use hardware no-ops as this works with both older and newer // kernels. After OpenBSD 6.8 is released this should be changed to // speculation barriers. #define NOOP MOVW R0, R0 #define INVOKE_SYSCALL \ SWI $0; \ NOOP; \ NOOP // mstart_stub is the first function executed on a new thread started by pthread_create. // It just does some low-level setup and then calls mstart. // Note: called with the C calling convention. TEXT runtime·mstart_stub(SB),NOSPLIT,$0 // R0 points to the m. // We are already on m's g0 stack. // Save callee-save registers. MOVM.DB.W [R4-R11], (R13) MOVW m_g0(R0), g BL runtime·save_g(SB) BL runtime·mstart(SB) // Restore callee-save registers. MOVM.IA.W (R13), [R4-R11] // Go is all done with this OS thread. // Tell pthread everything is ok (we never join with this thread, so // the value here doesn't really matter). MOVW $0, R0 RET TEXT runtime·sigfwd(SB),NOSPLIT,$0-16 MOVW sig+4(FP), R0 MOVW info+8(FP), R1 MOVW ctx+12(FP), R2 MOVW fn+0(FP), R3 MOVW R13, R9 SUB $24, R13 BIC $0x7, R13 // alignment for ELF ABI BL (R3) MOVW R9, R13 RET TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$0 // Reserve space for callee-save registers and arguments. MOVM.DB.W [R4-R11], (R13) SUB $16, R13 // If called from an external code context, g will not be set. // Save R0, since runtime·load_g will clobber it. MOVW R0, 4(R13) // signum BL runtime·load_g(SB) MOVW R1, 8(R13) MOVW R2, 12(R13) BL runtime·sigtrampgo(SB) // Restore callee-save registers. ADD $16, R13 MOVM.IA.W (R13), [R4-R11] RET TEXT ·publicationBarrier(SB),NOSPLIT|NOFRAME,$0-0 B runtime·armPublicationBarrier(SB) // TODO(jsing): OpenBSD only supports GOARM=7 machines... this // should not be needed, however the linker still allows GOARM=5 // on this platform. TEXT runtime·read_tls_fallback(SB),NOSPLIT|NOFRAME,$0 MOVM.WP [R1, R2, R3, R12], (R13) MOVW $330, R12 // sys___get_tcb INVOKE_SYSCALL MOVM.IAW (R13), [R1, R2, R3, R12] RET // These trampolines help convert from Go calling convention to C calling convention. // They should be called with asmcgocall - note that while asmcgocall does // stack alignment, creation of a frame undoes it again. // A pointer to the arguments is passed in R0. // A single int32 result is returned in R0. // (For more results, make an args/results structure.) TEXT runtime·pthread_attr_init_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 0(R0), R0 // arg 1 attr CALL libc_pthread_attr_init(SB) MOVW R9, R13 RET TEXT runtime·pthread_attr_destroy_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 0(R0), R0 // arg 1 attr CALL libc_pthread_attr_destroy(SB) MOVW R9, R13 RET TEXT runtime·pthread_attr_getstacksize_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 size MOVW 0(R0), R0 // arg 1 attr CALL libc_pthread_attr_getstacksize(SB) MOVW R9, R13 RET TEXT runtime·pthread_attr_setdetachstate_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 state MOVW 0(R0), R0 // arg 1 attr CALL libc_pthread_attr_setdetachstate(SB) MOVW R9, R13 RET TEXT runtime·pthread_create_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 SUB $16, R13 BIC $0x7, R13 // align for ELF ABI MOVW 0(R0), R1 // arg 2 attr MOVW 4(R0), R2 // arg 3 start MOVW 8(R0), R3 // arg 4 arg MOVW R13, R0 // arg 1 &threadid (discarded) CALL libc_pthread_create(SB) MOVW R9, R13 RET TEXT runtime·thrkill_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 - signal MOVW $0, R2 // arg 3 - tcb MOVW 0(R0), R0 // arg 1 - tid CALL libc_thrkill(SB) MOVW R9, R13 RET TEXT runtime·thrsleep_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 SUB $16, R13 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 - clock_id MOVW 8(R0), R2 // arg 3 - abstime MOVW 12(R0), R3 // arg 4 - lock MOVW 16(R0), R4 // arg 5 - abort (on stack) MOVW R4, 0(R13) MOVW 0(R0), R0 // arg 1 - id CALL libc_thrsleep(SB) MOVW R9, R13 RET TEXT runtime·thrwakeup_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 - count MOVW 0(R0), R0 // arg 1 - id CALL libc_thrwakeup(SB) MOVW R9, R13 RET TEXT runtime·exit_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 0(R0), R0 // arg 1 exit status BL libc_exit(SB) MOVW $0, R8 // crash on failure MOVW R8, (R8) MOVW R9, R13 RET TEXT runtime·getthrid_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 MOVW R0, R8 BIC $0x7, R13 // align for ELF ABI BL libc_getthrid(SB) MOVW R0, 0(R8) MOVW R9, R13 RET TEXT runtime·raiseproc_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW R0, R4 BL libc_getpid(SB) // arg 1 pid MOVW R4, R1 // arg 2 signal BL libc_kill(SB) MOVW R9, R13 RET TEXT runtime·sched_yield_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI BL libc_sched_yield(SB) MOVW R9, R13 RET TEXT runtime·mmap_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 SUB $16, R13 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW 4(R0), R1 // arg 2 len MOVW 8(R0), R2 // arg 3 prot MOVW 12(R0), R3 // arg 4 flags MOVW 16(R0), R4 // arg 5 fid (on stack) MOVW R4, 0(R13) MOVW $0, R5 // pad (on stack) MOVW R5, 4(R13) MOVW 20(R0), R6 // arg 6 offset (on stack) MOVW R6, 8(R13) // low 32 bits MOVW $0, R7 MOVW R7, 12(R13) // high 32 bits MOVW 0(R0), R0 // arg 1 addr BL libc_mmap(SB) MOVW $0, R1 CMP $-1, R0 BNE ok BL libc_errno(SB) MOVW (R0), R1 // errno MOVW $0, R0 ok: MOVW R0, 24(R8) MOVW R1, 28(R8) MOVW R9, R13 RET TEXT runtime·munmap_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 len MOVW 0(R0), R0 // arg 1 addr BL libc_munmap(SB) CMP $-1, R0 BNE 3(PC) MOVW $0, R8 // crash on failure MOVW R8, (R8) MOVW R9, R13 RET TEXT runtime·madvise_trampoline(SB), NOSPLIT, $0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 len MOVW 8(R0), R2 // arg 3 advice MOVW 0(R0), R0 // arg 1 addr BL libc_madvise(SB) // ignore failure - maybe pages are locked MOVW R9, R13 RET TEXT runtime·open_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 SUB $8, R13 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 - flags MOVW 8(R0), R2 // arg 3 - mode (vararg, on stack) MOVW R2, 0(R13) MOVW 0(R0), R0 // arg 1 - path MOVW R13, R4 BIC $0x7, R13 // align for ELF ABI BL libc_open(SB) MOVW R9, R13 RET TEXT runtime·close_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 0(R0), R0 // arg 1 - fd BL libc_close(SB) MOVW R9, R13 RET TEXT runtime·read_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 - buf MOVW 8(R0), R2 // arg 3 - count MOVW 0(R0), R0 // arg 1 - fd BL libc_read(SB) CMP $-1, R0 BNE noerr BL libc_errno(SB) MOVW (R0), R0 // errno RSB.CS $0, R0 // caller expects negative errno noerr: MOVW R9, R13 RET TEXT runtime·write_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 buf MOVW 8(R0), R2 // arg 3 count MOVW 0(R0), R0 // arg 1 fd BL libc_write(SB) CMP $-1, R0 BNE noerr BL libc_errno(SB) MOVW (R0), R0 // errno RSB.CS $0, R0 // caller expects negative errno noerr: MOVW R9, R13 RET TEXT runtime·pipe2_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 flags MOVW 0(R0), R0 // arg 1 filedes BL libc_pipe2(SB) CMP $-1, R0 BNE 3(PC) BL libc_errno(SB) MOVW (R0), R0 // errno RSB.CS $0, R0 // caller expects negative errno MOVW R9, R13 RET TEXT runtime·setitimer_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 new MOVW 8(R0), R2 // arg 3 old MOVW 0(R0), R0 // arg 1 which BL libc_setitimer(SB) MOVW R9, R13 RET TEXT runtime·usleep_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 0(R0), R0 // arg 1 usec BL libc_usleep(SB) MOVW R9, R13 RET TEXT runtime·sysctl_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 SUB $8, R13 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 miblen MOVW 8(R0), R2 // arg 3 out MOVW 12(R0), R3 // arg 4 size MOVW 16(R0), R4 // arg 5 dst (on stack) MOVW R4, 0(R13) MOVW 20(R0), R5 // arg 6 ndst (on stack) MOVW R5, 4(R13) MOVW 0(R0), R0 // arg 1 mib BL libc_sysctl(SB) MOVW R9, R13 RET TEXT runtime·kqueue_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI BL libc_kqueue(SB) MOVW R9, R13 RET TEXT runtime·kevent_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 SUB $8, R13 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 keventt MOVW 8(R0), R2 // arg 3 nch MOVW 12(R0), R3 // arg 4 ev MOVW 16(R0), R4 // arg 5 nev (on stack) MOVW R4, 0(R13) MOVW 20(R0), R5 // arg 6 ts (on stack) MOVW R5, 4(R13) MOVW 0(R0), R0 // arg 1 kq BL libc_kevent(SB) CMP $-1, R0 BNE ok BL libc_errno(SB) MOVW (R0), R0 // errno RSB.CS $0, R0 // caller expects negative errno ok: MOVW R9, R13 RET TEXT runtime·clock_gettime_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 tp MOVW 0(R0), R0 // arg 1 clock_id BL libc_clock_gettime(SB) CMP $-1, R0 BNE noerr BL libc_errno(SB) MOVW (R0), R0 // errno RSB.CS $0, R0 // caller expects negative errno noerr: MOVW R9, R13 RET TEXT runtime·fcntl_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 SUB $8, R13 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW 0(R8), R0 // arg 1 fd MOVW 4(R8), R1 // arg 2 cmd MOVW 8(R8), R2 // arg 3 arg (vararg, on stack) MOVW R2, 0(R13) BL libc_fcntl(SB) MOVW $0, R1 CMP $-1, R0 BNE noerr BL libc_errno(SB) MOVW (R0), R1 MOVW $-1, R0 noerr: MOVW R0, 12(R8) MOVW R1, 16(R8) MOVW R9, R13 RET TEXT runtime·sigaction_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 new MOVW 8(R0), R2 // arg 3 old MOVW 0(R0), R0 // arg 1 sig BL libc_sigaction(SB) CMP $-1, R0 BNE 3(PC) MOVW $0, R8 // crash on failure MOVW R8, (R8) MOVW R9, R13 RET TEXT runtime·sigprocmask_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 new MOVW 8(R0), R2 // arg 3 old MOVW 0(R0), R0 // arg 1 how BL libc_pthread_sigmask(SB) CMP $-1, R0 BNE 3(PC) MOVW $0, R8 // crash on failure MOVW R8, (R8) MOVW R9, R13 RET TEXT runtime·sigaltstack_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW 4(R0), R1 // arg 2 old MOVW 0(R0), R0 // arg 1 new BL libc_sigaltstack(SB) CMP $-1, R0 BNE 3(PC) MOVW $0, R8 // crash on failure MOVW R8, (R8) MOVW R9, R13 RET // syscall calls a function in libc on behalf of the syscall package. // syscall takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall must be called on the g0 stack with the // C calling convention (use libcCall). // // syscall expects a 32-bit result and tests for 32-bit -1 // to decide there was an error. TEXT runtime·syscall(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW (0*4)(R8), R7 // fn MOVW (1*4)(R8), R0 // a1 MOVW (2*4)(R8), R1 // a2 MOVW (3*4)(R8), R2 // a3 BL (R7) MOVW R0, (4*4)(R8) // r1 MOVW R1, (5*4)(R8) // r2 // Standard libc functions return -1 on error and set errno. CMP $-1, R0 BNE ok // Get error code from libc. BL libc_errno(SB) MOVW (R0), R1 MOVW R1, (6*4)(R8) // err ok: MOVW $0, R0 // no error (it's ignored anyway) MOVW R9, R13 RET // syscallX calls a function in libc on behalf of the syscall package. // syscallX takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscallX must be called on the g0 stack with the // C calling convention (use libcCall). // // syscallX is like syscall but expects a 64-bit result // and tests for 64-bit -1 to decide there was an error. TEXT runtime·syscallX(SB),NOSPLIT,$0 MOVW R13, R9 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW (0*4)(R8), R7 // fn MOVW (1*4)(R8), R0 // a1 MOVW (2*4)(R8), R1 // a2 MOVW (3*4)(R8), R2 // a3 BL (R7) MOVW R0, (4*4)(R8) // r1 MOVW R1, (5*4)(R8) // r2 // Standard libc functions return -1 on error and set errno. CMP $-1, R0 BNE ok CMP $-1, R1 BNE ok // Get error code from libc. BL libc_errno(SB) MOVW (R0), R1 MOVW R1, (6*4)(R8) // err ok: MOVW $0, R0 // no error (it's ignored anyway) MOVW R9, R13 RET // syscall6 calls a function in libc on behalf of the syscall package. // syscall6 takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // a4 uintptr // a5 uintptr // a6 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall6 must be called on the g0 stack with the // C calling convention (use libcCall). // // syscall6 expects a 32-bit result and tests for 32-bit -1 // to decide there was an error. TEXT runtime·syscall6(SB),NOSPLIT,$0 MOVW R13, R9 SUB $8, R13 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW (0*4)(R8), R7 // fn MOVW (1*4)(R8), R0 // a1 MOVW (2*4)(R8), R1 // a2 MOVW (3*4)(R8), R2 // a3 MOVW (4*4)(R8), R3 // a4 MOVW (5*4)(R8), R4 // a5 MOVW R4, 0(R13) MOVW (6*4)(R8), R5 // a6 MOVW R5, 4(R13) BL (R7) MOVW R0, (7*4)(R8) // r1 MOVW R1, (8*4)(R8) // r2 // Standard libc functions return -1 on error and set errno. CMP $-1, R0 BNE ok // Get error code from libc. BL libc_errno(SB) MOVW (R0), R1 MOVW R1, (9*4)(R8) // err ok: MOVW $0, R0 // no error (it's ignored anyway) MOVW R9, R13 RET // syscall6X calls a function in libc on behalf of the syscall package. // syscall6X takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // a4 uintptr // a5 uintptr // a6 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall6X must be called on the g0 stack with the // C calling convention (use libcCall). // // syscall6X is like syscall6 but expects a 64-bit result // and tests for 64-bit -1 to decide there was an error. TEXT runtime·syscall6X(SB),NOSPLIT,$0 MOVW R13, R9 SUB $8, R13 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW (0*4)(R8), R7 // fn MOVW (1*4)(R8), R0 // a1 MOVW (2*4)(R8), R1 // a2 MOVW (3*4)(R8), R2 // a3 MOVW (4*4)(R8), R3 // a4 MOVW (5*4)(R8), R4 // a5 MOVW R4, 0(R13) MOVW (6*4)(R8), R5 // a6 MOVW R5, 4(R13) BL (R7) MOVW R0, (7*4)(R8) // r1 MOVW R1, (8*4)(R8) // r2 // Standard libc functions return -1 on error and set errno. CMP $-1, R0 BNE ok CMP $-1, R1 BNE ok // Get error code from libc. BL libc_errno(SB) MOVW (R0), R1 MOVW R1, (9*4)(R8) // err ok: MOVW $0, R0 // no error (it's ignored anyway) MOVW R9, R13 RET // syscall10 calls a function in libc on behalf of the syscall package. // syscall10 takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // a4 uintptr // a5 uintptr // a6 uintptr // a7 uintptr // a8 uintptr // a9 uintptr // a10 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall10 must be called on the g0 stack with the // C calling convention (use libcCall). TEXT runtime·syscall10(SB),NOSPLIT,$0 MOVW R13, R9 SUB $24, R13 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW (0*4)(R8), R7 // fn MOVW (1*4)(R8), R0 // a1 MOVW (2*4)(R8), R1 // a2 MOVW (3*4)(R8), R2 // a3 MOVW (4*4)(R8), R3 // a4 MOVW (5*4)(R8), R4 // a5 MOVW R4, 0(R13) MOVW (6*4)(R8), R5 // a6 MOVW R5, 4(R13) MOVW (7*4)(R8), R6 // a7 MOVW R6, 8(R13) MOVW (8*4)(R8), R4 // a8 MOVW R4, 12(R13) MOVW (9*4)(R8), R5 // a9 MOVW R5, 16(R13) MOVW (10*4)(R8), R6 // a10 MOVW R6, 20(R13) BL (R7) MOVW R0, (11*4)(R8) // r1 MOVW R1, (12*4)(R8) // r2 // Standard libc functions return -1 on error and set errno. CMP $-1, R0 BNE ok // Get error code from libc. BL libc_errno(SB) MOVW (R0), R1 MOVW R1, (13*4)(R8) // err ok: MOVW $0, R0 // no error (it's ignored anyway) MOVW R9, R13 RET // syscall10X calls a function in libc on behalf of the syscall package. // syscall10X takes a pointer to a struct like: // struct { // fn uintptr // a1 uintptr // a2 uintptr // a3 uintptr // a4 uintptr // a5 uintptr // a6 uintptr // a7 uintptr // a8 uintptr // a9 uintptr // a10 uintptr // r1 uintptr // r2 uintptr // err uintptr // } // syscall10X must be called on the g0 stack with the // C calling convention (use libcCall). // // syscall10X is like syscall10 but expects a 64-bit result // and tests for 64-bit -1 to decide there was an error. TEXT runtime·syscall10X(SB),NOSPLIT,$0 MOVW R13, R9 SUB $24, R13 BIC $0x7, R13 // align for ELF ABI MOVW R0, R8 MOVW (0*4)(R8), R7 // fn MOVW (1*4)(R8), R0 // a1 MOVW (2*4)(R8), R1 // a2 MOVW (3*4)(R8), R2 // a3 MOVW (4*4)(R8), R3 // a4 MOVW (5*4)(R8), R4 // a5 MOVW R4, 0(R13) MOVW (6*4)(R8), R5 // a6 MOVW R5, 4(R13) MOVW (7*4)(R8), R6 // a7 MOVW R6, 8(R13) MOVW (8*4)(R8), R4 // a8 MOVW R4, 12(R13) MOVW (9*4)(R8), R5 // a9 MOVW R5, 16(R13) MOVW (10*4)(R8), R6 // a10 MOVW R6, 20(R13) BL (R7) MOVW R0, (11*4)(R8) // r1 MOVW R1, (12*4)(R8) // r2 // Standard libc functions return -1 on error and set errno. CMP $-1, R0 BNE ok CMP $-1, R1 BNE ok // Get error code from libc. BL libc_errno(SB) MOVW (R0), R1 MOVW R1, (13*4)(R8) // err ok: MOVW $0, R0 // no error (it's ignored anyway) MOVW R9, R13 RET TEXT runtime·issetugid_trampoline(SB),NOSPLIT,$0 MOVW R13, R9 MOVW R0, R8 BIC $0x7, R13 // align for ELF ABI BL libc_issetugid(SB) MOVW R0, 0(R8) MOVW R9, R13 RET