| Colin Cross | 7bb052a | 2015-02-03 12:59:37 -0800 | [diff] [blame^] | 1 | // Copyright 2009 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | #include "textflag.h" |
| 6 | |
| 7 | TEXT _rt0_arm_linux(SB),NOSPLIT,$-4 |
| 8 | MOVW (R13), R0 // argc |
| 9 | MOVW $4(R13), R1 // argv |
| 10 | MOVW $_rt0_arm_linux1(SB), R4 |
| 11 | B (R4) |
| 12 | |
| 13 | TEXT _rt0_arm_linux1(SB),NOSPLIT,$-4 |
| 14 | // We first need to detect the kernel ABI, and warn the user |
| 15 | // if the system only supports OABI |
| 16 | // The strategy here is to call some EABI syscall to see if |
| 17 | // SIGILL is received. |
| 18 | // To catch SIGILL, we have to first setup sigaction, this is |
| 19 | // a chicken-and-egg problem, because we can't do syscall if |
| 20 | // we don't know the kernel ABI... Oh, not really, we can do |
| 21 | // syscall in Thumb mode. |
| 22 | |
| 23 | // Save argc and argv |
| 24 | MOVM.DB.W [R0-R1], (R13) |
| 25 | |
| 26 | // Thumb mode OABI check disabled because there are some |
| 27 | // EABI systems that do not support Thumb execution. |
| 28 | // We can run on them except for this check! |
| 29 | |
| 30 | // // set up sa_handler |
| 31 | // MOVW $bad_abi<>(SB), R0 // sa_handler |
| 32 | // MOVW $0, R1 // sa_flags |
| 33 | // MOVW $0, R2 // sa_restorer |
| 34 | // MOVW $0, R3 // sa_mask |
| 35 | // MOVM.DB.W [R0-R3], (R13) |
| 36 | // MOVW $4, R0 // SIGILL |
| 37 | // MOVW R13, R1 // sa |
| 38 | // SUB $16, R13 |
| 39 | // MOVW R13, R2 // old_sa |
| 40 | // MOVW $8, R3 // c |
| 41 | // MOVW $174, R7 // sys_sigaction |
| 42 | // BL oabi_syscall<>(SB) |
| 43 | |
| 44 | // do an EABI syscall |
| 45 | MOVW $20, R7 // sys_getpid |
| 46 | SWI $0 // this will trigger SIGILL on OABI systems |
| 47 | |
| 48 | // MOVW $4, R0 // SIGILL |
| 49 | // MOVW R13, R1 // sa |
| 50 | // MOVW $0, R2 // old_sa |
| 51 | // MOVW $8, R3 // c |
| 52 | // MOVW $174, R7 // sys_sigaction |
| 53 | // SWI $0 // restore signal handler |
| 54 | // ADD $32, R13 |
| 55 | |
| 56 | SUB $4, R13 // fake a stack frame for runtime·setup_auxv |
| 57 | BL runtime·setup_auxv(SB) |
| 58 | ADD $4, R13 |
| 59 | B runtime·rt0_go(SB) |
| 60 | |
| 61 | TEXT bad_abi<>(SB),NOSPLIT,$-4 |
| 62 | // give diagnosis and exit |
| 63 | MOVW $2, R0 // stderr |
| 64 | MOVW $bad_abi_msg(SB), R1 // data |
| 65 | MOVW $45, R2 // len |
| 66 | MOVW $4, R7 // sys_write |
| 67 | BL oabi_syscall<>(SB) |
| 68 | MOVW $1, R0 |
| 69 | MOVW $1, R7 // sys_exit |
| 70 | BL oabi_syscall<>(SB) |
| 71 | B 0(PC) |
| 72 | |
| 73 | DATA bad_abi_msg+0x00(SB)/8, $"This pro" |
| 74 | DATA bad_abi_msg+0x08(SB)/8, $"gram can" |
| 75 | DATA bad_abi_msg+0x10(SB)/8, $" only be" |
| 76 | DATA bad_abi_msg+0x18(SB)/8, $" run on " |
| 77 | DATA bad_abi_msg+0x20(SB)/8, $"EABI ker" |
| 78 | DATA bad_abi_msg+0x28(SB)/4, $"nels" |
| 79 | DATA bad_abi_msg+0x2c(SB)/1, $0xa |
| 80 | GLOBL bad_abi_msg(SB), RODATA, $45 |
| 81 | |
| 82 | TEXT oabi_syscall<>(SB),NOSPLIT,$-4 |
| 83 | ADD $1, PC, R4 |
| 84 | WORD $0xe12fff14 //BX (R4) // enter thumb mode |
| 85 | // TODO(minux): only supports little-endian CPUs |
| 86 | WORD $0x4770df01 // swi $1; bx lr |
| 87 | |
| 88 | TEXT main(SB),NOSPLIT,$-4 |
| 89 | MOVW $_rt0_arm_linux1(SB), R4 |
| 90 | B (R4) |
| 91 | |