Hello World App crashes with 'Illegal Instruction' in 32-bit environment on a 64-bit SoC

[venkag]

I am trying to build Hello World Application and run on a cortex-a53 based processor. The userspace environment is 32-bit (with the all libraries, binaries built in 32-bit mode). The Kernel however, is built in 64-bit mode.

Code:

$ cat hello.rs
fn main() {
println!("Hello World!");
}

Compile

$ rustc --target arm-unknown-linux-gnueabi -C target-cpu=cortex-a53 hello.rs

The output is that the string 'Hello World!' prints and crashes during the cleanup phase with 'illegal instruction'. gdb points to atomic_sub. I am suspecting that there is alignment issue with the memory pointers. One example of the GDB backtrace is:

gdb Backtrace

#0 atomic_sub () at /rustc/9fda7c2237db910e41d6a712e9a2139b352e558b/src/libcore/sync/atomic.rs:2077
2077 /rustc/9fda7c2237db910e41d6a712e9a2139b352e558b/src/libcore/sync/atomic.rs: No such file or directory.
(gdb) quit

[parched]

Can you print the instruction that is failing and dump the registers with GDB?

Does it happen when you don't specify the target-cpu?

What linux distribution and architecture are you using? armv7-unknown-linux-gnueabihf is possibly the target you really want.

[venkag]

It happens even when taret-cpu is not set.

Linux Distribution is OpenWRT and Procerros has Brahma53 processor module that implements ARMv8-A complaint architecture.

(gdb) info all-registers
r0 0x0 0
r1 0x1 1
r2 0xab18a020 2870517792
r3 0x0 0
r4 0x0 0
r5 0x0 0
r6 0xab172c74 2870422644
r7 0x0 0
r8 0xffe911f0 4293464560
r9 0xab18a550 2870519120
r10 0xab188e40 2870513216
r11 0xffe91288 4293464712
r12 0x1 1
sp 0xffe911f0 0xffe911f0
lr 0x1 1
pc 0xab159834 0xab159834 std::io::stdio::_print::hca3615e2c19cbb93+500
cpsr 0x60000010 1610612752
d0 value not available
d1 value not available
... value not available

(gdb) backtrace
#0 atomic_sub () at /rustc/9fda7c2237db910e41d6a712e9a2139b352e558b/src/libcore/sync/atomic.rs:2077
#1 fetch_sub () at /rustc/9fda7c2237db910e41d6a712e9a2139b352e558b/src/libcore/sync/atomic.rs:1519
#2 drop<std::sys_common::remutex::ReentrantMutex<core::cell::RefCell<std::io::buffered::LineWriter<std::io::stdio::Maybestd::io::stdio::StdoutRaw>>>> () at /rustc/9fda7c2237db910e41d6a712e9a2139b352e558b/src/liballoc/sync.rs:960
#3 real_drop_in_place<alloc::sync::Arc<std::sys_common::remutex::ReentrantMutex<core::cell::RefCell<std::io::buffered::LineWriter<std::io::stdio::Maybestd::io::stdio::StdoutRaw>>>>> ()
at /rustc/9fda7c2237db910e41d6a712e9a2139b352e558b/src/libcore/ptr.rs:204
#4 real_drop_in_placestd::io::stdio::Stdout () at /rustc/9fda7c2237db910e41d6a712e9a2139b352e558b/src/libcore/ptr.rs:204
#5 {{closure}}std::io::stdio::Stdout () at src/libstd/io/stdio.rs:695
#6 try_with<core::cell::RefCell<core::option::Option<alloc::boxed::Box>>,closure,core::result::Result<(), std::io::error::Error>> () at src/libstd/thread/local.rs:309
#7 print_tostd::io::stdio::Stdout () at src/libstd/io/stdio.rs:688
#8 std::io::stdio::print::hca3615e2c19cbb93 () at src/libstd/io/stdio.rs:709
#9 0xab154c5c in hello::main::h5570a636a13636e8 ()
#10 0xab154ae4 in std::rt::lang_start::$u7b$$u7b$closure$u7d$$u7d$::h654985c2b7f96540 ()
#11 0xab15fb6c in {{closure}} () at src/libstd/rt.rs:59
#12 std::panicking::try::do_call::hf93a787b72e1d226 () at src/libstd/panicking.rs:310
#13 0xab16984c in __rust_maybe_catch_panic () at src/libpanic_unwind/lib.rs:102
#14 0xab160498 in try<i32,closure> () at src/libstd/panicking.rs:289
#15 catch_unwind<closure,i32> () at src/libstd/panic.rs:398
#16 std::rt::lang_start_internal::h7b3bd8c78881c37d () at src/libstd/rt.rs:58
#17 0xab154abc in std::rt::lang_start::h0268d04b9985a2bf ()
#18 0xab154c9c in main ()
(gdb)

[parched]

Ok, and when you type disassemble in gdb what do you get?

[venkag]

Here is the disassemble output:

(gdb) disassemble
Dump of assembler code for function std::io::stdio::print::hca3615e2c19cbb93:
0xab159640 <+0>: push {r4, r5, r6, r7, r8, r9, r11, lr}
0xab159644 <+4>: sub sp, sp, #88 ; 0x58
0xab159648 <+8>: ldm r0, {r2, r3, r4, r5, r6, r7}
0xab15964c <+12>: mov r8, sp
0xab159650 <+16>: mov r1, r8
0xab159654 <+20>: mov r0, #6
0xab159658 <+24>: stm r1, {r2, r3, r4, r5, r6, r7}
0xab15965c <+28>: str r0, [sp, #28]
0xab159660 <+32>: ldr r0, [pc, #1040] ; 0xab159a78 std::io::stdio::_print::hca3615e2c19cbb93+1080
0xab159664 <+36>: add r0, pc, r0
0xab159668 <+40>: str r0, [sp, #24]
0xab15966c <+44>: ldr r0, [pc, #976] ; 0xab159a44 std::io::stdio::_print::hca3615e2c19cbb93+1028
0xab159670 <+48>: add r0, pc, r0
0xab159674 <+52>: bl 0xab154798
0xab159678 <+56>: ldrb r0, [r0, #17]
0xab15967c <+60>: cmp r0, #0
0xab159680 <+64>: beq 0xab159698 std::io::stdio::_print::hca3615e2c19cbb93+88
0xab159684 <+68>: mov r0, #0
0xab159688 <+72>: str r0, [sp, #44] ; 0x2c
0xab15968c <+76>: mov r0, #4
0xab159690 <+80>: str r0, [sp, #40] ; 0x28
0xab159694 <+84>: b 0xab159880 std::io::stdio::_print::hca3615e2c19cbb93+576
0xab159698 <+88>: ldr r0, [pc, #936] ; 0xab159a48 std::io::stdio::_print::hca3615e2c19cbb93+1032
0xab15969c <+92>: add r0, pc, r0
0xab1596a0 <+96>: bl 0xab154798
0xab1596a4 <+100>: ldrb r0, [r0, #16]
0xab1596a8 <+104>: cmp r0, #0
0xab1596ac <+108>: bne 0xab159714 std::io::stdio::_print::hca3615e2c19cbb93+212
0xab1596b0 <+112>: ldr r0, [pc, #964] ; 0xab159a7c std::io::stdio::_print::hca3615e2c19cbb93+1084
0xab1596b4 <+116>: ldr r0, [pc, r0]
0xab1596b8 <+120>: cmp r0, #0
0xab1596bc <+124>: beq 0xab1596e8 std::io::stdio::_print::hca3615e2c19cbb93+168
0xab1596c0 <+128>: ldr r0, [pc, #904] ; 0xab159a50 std::io::stdio::_print::hca3615e2c19cbb93+1040
0xab1596c4 <+132>: add r0, pc, r0
0xab1596c8 <+136>: bl 0xab154798
0xab1596cc <+140>: mov r1, r0
0xab1596d0 <+144>: ldr r0, [pc, #936] ; 0xab159a80 std::io::stdio::_print::hca3615e2c19cbb93+1088
0xab1596d4 <+148>: ldr r2, [pc, #936] ; 0xab159a84 std::io::stdio::_print::hca3615e2c19cbb93+1092
0xab1596d8 <+152>: add r0, pc, r0
0xab1596dc <+156>: add r2, pc, r2
0xab1596e0 <+160>: bl 0xab154504
0xab1596e4 <+164>: b 0xab159700 std::io::stdio::_print::hca3615e2c19cbb93+192
0xab1596e8 <+168>: ldr r0, [pc, #860] ; 0xab159a4c std::io::stdio::_print::hca3615e2c19cbb93+1036
0xab1596ec <+172>: add r0, pc, r0
0xab1596f0 <+176>: bl 0xab154798
0xab1596f4 <+180>: ldr r1, [pc, #908] ; 0xab159a88 std::io::stdio::_print::hca3615e2c19cbb93+1096
0xab1596f8 <+184>: add r1, pc, r1
0xab1596fc <+188>: bl 0xab15eba0 std::sys_common::thread_local::register_dtor_fallback::h94e34bf3c42c0f50
0xab159700 <+192>: ldr r0, [pc, #844] ; 0xab159a54 std::io::stdio::_print::hca3615e2c19cbb93+1044
0xab159704 <+196>: add r0, pc, r0
0xab159708 <+200>: bl 0xab154798
0xab15970c <+204>: mov r1, #1
0xab159710 <+208>: strb r1, [r0, #16]
0xab159714 <+212>: ldr r0, [pc, #828] ; 0xab159a58 std::io::stdio::_print::hca3615e2c19cbb93+1048
0xab159718 <+216>: add r0, pc, r0
0xab15971c <+220>: bl 0xab154798
0xab159720 <+224>: ldr r0, [r0]
0xab159724 <+228>: cmp r0, #1
0xab159728 <+232>: bne 0xab159758 std::io::stdio::_print::hca3615e2c19cbb93+280
0xab15972c <+236>: ldr r0, [pc, #812] ; 0xab159a60 std::io::stdio::_print::hca3615e2c19cbb93+1056
0xab159730 <+240>: add r0, pc, r0
0xab159734 <+244>: bl 0xab154798
0xab159738 <+248>: ldr r0, [r0, #4]
0xab15973c <+252>: cmp r0, #0
0xab159740 <+256>: bne 0xab159804 std::io::stdio::_print::hca3615e2c19cbb93+452
0xab159744 <+260>: ldr r0, [pc, #792] ; 0xab159a64 std::io::stdio::_print::hca3615e2c19cbb93+1060
0xab159748 <+264>: add r0, pc, r0
0xab15974c <+268>: bl 0xab154798
0xab159750 <+272>: ldr r9, [r0, #8]
0xab159754 <+276>: b 0xab159778 std::io::stdio::_print::hca3615e2c19cbb93+312
0xab159758 <+280>: ldr r0, [pc, #764] ; 0xab159a5c std::io::stdio::_print::hca3615e2c19cbb93+1052
0xab15975c <+284>: add r0, pc, r0
0xab159760 <+288>: bl 0xab154798
0xab159764 <+292>: mov r9, #0
0xab159768 <+296>: mov r1, #1
0xab15976c <+300>: stm r0, {r1, r9}
0xab159770 <+304>: str r9, [r0, #8]
0xab159774 <+308>: str r9, [r0, #12]
0xab159778 <+312>: ldr r0, [pc, #744] ; 0xab159a68 std::io::stdio::_print::hca3615e2c19cbb93+1064
0xab15977c <+316>: add r0, pc, r0
0xab159780 <+320>: bl 0xab154798
0xab159784 <+324>: mvn r1, #0
0xab159788 <+328>: cmp r9, #0
0xab15978c <+332>: str r1, [r0, #4]!
0xab159790 <+336>: str r0, [sp, #44] ; 0x2c
0xab159794 <+340>: add r0, r0, #4
0xab159798 <+344>: str r0, [sp, #40] ; 0x28
0xab15979c <+348>: beq 0xab1597f0 std::io::stdio::_print::hca3615e2c19cbb93+432
0xab1597a0 <+352>: ldr r0, [pc, #708] ; 0xab159a6c std::io::stdio::_print::hca3615e2c19cbb93+1068
0xab1597a4 <+356>: add r0, pc, r0
0xab1597a8 <+360>: bl 0xab154798
0xab1597ac <+364>: mov r3, r8
0xab1597b0 <+368>: ldr r12, [r0, #12]
0xab1597b4 <+372>: add r2, sp, #64 ; 0x40
0xab1597b8 <+376>: ldm r3, {r0, r1, r4, r5, r6, r7}
0xab1597bc <+380>: mov lr, r2
0xab1597c0 <+384>: stm lr, {r0, r1, r4, r5, r6, r7}
0xab1597c4 <+388>: ldr r3, [r12, #24]
0xab1597c8 <+392>: add r0, sp, #56 ; 0x38
0xab1597cc <+396>: mov r1, r9
0xab1597d0 <+400>: blx r3
0xab1597d4 <+404>: ldr r0, [pc, #660] ; 0xab159a70 std::io::stdio::_print::hca3615e2c19cbb93+1072
0xab1597d8 <+408>: add r0, pc, r0
0xab1597dc <+412>: bl 0xab154798
0xab1597e0 <+416>: ldr r1, [r0, #4]
0xab1597e4 <+420>: add r1, r1, #1
0xab1597e8 <+424>: str r1, [r0, #4]
0xab1597ec <+428>: b 0xab159864 std::io::stdio::_print::hca3615e2c19cbb93+548
0xab1597f0 <+432>: ldr r0, [pc, #636] ; 0xab159a74 std::io::stdio::_print::hca3615e2c19cbb93+1076
0xab1597f4 <+436>: add r0, pc, r0
0xab1597f8 <+440>: bl 0xab154798
0xab1597fc <+444>: mov r1, #0
0xab159800 <+448>: str r1, [r0, #4]
0xab159804 <+452>: bl 0xab158e50 std::io::stdio::stdout::h0afc55fe207cb8dc
0xab159808 <+456>: str r0, [sp, #40] ; 0x28
0xab15980c <+460>: mov r12, r8
0xab159810 <+464>: mov r9, r0
0xab159814 <+468>: add r2, sp, #64 ; 0x40
0xab159818 <+472>: ldm r12, {r0, r3, r4, r5, r6, r7}
0xab15981c <+476>: mov r1, r2
0xab159820 <+480>: stm r1, {r0, r3, r4, r5, r6, r7}
0xab159824 <+484>: add r0, sp, #56 ; 0x38
0xab159828 <+488>: add r1, sp, #40 ; 0x28
0xab15982c <+492>: bl 0xab1590d0 <$LT$std..io..stdio..Stdout$u20$as$u20$std..io..Write$GT$::write_fmt::h5d8cf71a7da5ae57>
0xab159830 <+496>: mov r0, #0
=> 0xab159834 <+500>: mcr 15, 0, r0, cr7, cr10, {5}
0xab159838 <+504>: ldrex r0, [r9]
0xab15983c <+508>: sub r1, r0, #1
0xab159840 <+512>: strex r2, r1, [r9]
0xab159844 <+516>: cmp r2, #0
0xab159848 <+520>: bne 0xab159838 std::io::stdio::_print::hca3615e2c19cbb93+504
0xab15984c <+524>: cmp r0, #1
0xab159850 <+528>: bne 0xab159864 std::io::stdio::_print::hca3615e2c19cbb93+548
0xab159854 <+532>: mov r0, #0
0xab159858 <+536>: mcr 15, 0, r0, cr7, cr10, {5}
0xab15985c <+540>: add r0, sp, #40 ; 0x28
0xab159860 <+544>: bl 0xab154f8c <$LT$alloc..sync..Arc$LT$T$GT$$GT$::drop_slow::h2ecc4c27b36f3959>
0xab159864 <+548>: ldr r0, [sp, #56] ; 0x38
0xab159868 <+552>: ldr r1, [sp, #60] ; 0x3c
0xab15986c <+556>: str r1, [sp, #44] ; 0x2c
0xab159870 <+560>: uxtb r2, r0
0xab159874 <+564>: cmp r2, #4
0xab159878 <+568>: str r0, [sp, #40] ; 0x28
0xab15987c <+572>: bne 0xab159934 std::io::stdio::_print::hca3615e2c19cbb93+756
0xab159880 <+576>: bl 0xab158e50 std::io::stdio::stdout::h0afc55fe207cb8dc
0xab159884 <+580>: str r0, [sp, #56] ; 0x38
0xab159888 <+584>: add r2, sp, #64 ; 0x40
0xab15988c <+588>: ldm r8, {r1, r3, r4, r5, r6, r7}
0xab159890 <+592>: mov r9, r0
0xab159894 <+596>: mov r0, r2
0xab159898 <+600>: stm r0, {r1, r3, r4, r5, r6, r7}
0xab15989c <+604>: add r0, sp, #32
0xab1598a0 <+608>: add r1, sp, #56 ; 0x38
0xab1598a4 <+612>: bl 0xab1590d0 <$LT$std..io..stdio..Stdout$u20$as$u20$std..io..Write$GT$::write_fmt::h5d8cf71a7da5ae57>
0xab1598a8 <+616>: mov r0, #0
0xab1598ac <+620>: mcr 15, 0, r0, cr7, cr10, {5}
0xab1598b0 <+624>: ldrex r0, [r9]
0xab1598b4 <+628>: sub r1, r0, #1
0xab1598b8 <+632>: strex r2, r1, [r9]
0xab1598bc <+636>: cmp r2, #0
0xab1598c0 <+640>: bne 0xab1598b0 std::io::stdio::_print::hca3615e2c19cbb93+624
0xab1598c4 <+644>: cmp r0, #1
0xab1598c8 <+648>: bne 0xab1598dc std::io::stdio::_print::hca3615e2c19cbb93+668
0xab1598cc <+652>: mov r0, #0
0xab1598d0 <+656>: mcr 15, 0, r0, cr7, cr10, {5}
0xab1598d4 <+660>: add r0, sp, #56 ; 0x38
0xab1598d8 <+664>: bl 0xab154f8c <_$LT$alloc..sync..Arc$LT$T$GT$$GT$::drop_slow::h2ecc4c27b36f3959>
0xab1598dc <+668>: ldrb r0, [sp, #40] ; 0x28
0xab1598e0 <+672>: and r1, r0, #7
0xab1598e4 <+676>: cmp r1, #4
0xab1598e8 <+680>: bhi 0xab1598f4 std::io::stdio::_print::hca3615e2c19cbb93+692
0xab1598ec <+684>: cmp r0, #2
0xab1598f0 <+688>: bne 0xab15993c std::io::stdio::_print::hca3615e2c19cbb93+764
0xab1598f4 <+692>: ldr r5, [sp, #44] ; 0x2c
0xab1598f8 <+696>: ldm r5, {r0, r1}
0xab1598fc <+700>: ldr r1, [r1]
0xab159900 <+704>: blx r1
0xab159904 <+708>: ldr r0, [r5, #4]
0xab159908 <+712>: ldr r1, [r0, #4]
0xab15990c <+716>: cmp r1, #0
0xab159910 <+720>: beq 0xab159920 std::io::stdio::_print::hca3615e2c19cbb93+736
0xab159914 <+724>: ldr r2, [r0, #8]
0xab159918 <+728>: ldr r0, [r5]
0xab15991c <+732>: bl 0xab154cac <__rust_dealloc>
0xab159920 <+736>: mov r0, r5
0xab159924 <+740>: mov r1, #12
0xab159928 <+744>: mov r2, #4
0xab15992c <+748>: bl 0xab154cac <__rust_dealloc>
0xab159930 <+752>: b 0xab15993c std::io::stdio::_print::hca3615e2c19cbb93+764
0xab159934 <+756>: str r0, [sp, #32]
0xab159938 <+760>: str r1, [sp, #36] ; 0x24
0xab15993c <+764>: ldrb r0, [sp, #32]
0xab159940 <+768>: cmp r0, #3
0xab159944 <+772>: addeq sp, sp, #88 ; 0x58
0xab159948 <+776>: popeq {r4, r5, r6, r7, r8, r9, r11, pc}
0xab15994c <+780>: ldr r0, [sp, #32]
0xab159950 <+784>: ldr r1, [sp, #36] ; 0x24
0xab159954 <+788>: str r1, [sp, #60] ; 0x3c
0xab159958 <+792>: add r1, sp, #40 ; 0x28
0xab15995c <+796>: str r0, [sp, #56] ; 0x38
0xab159960 <+800>: ldr r0, [pc, #292] ; 0xab159a8c std::io::stdio::_print::hca3615e2c19cbb93+1100
0xab159964 <+804>: ldr r0, [pc, r0]
0xab159968 <+808>: str r0, [sp, #52] ; 0x34
0xab15996c <+812>: add r0, sp, #56 ; 0x38
0xab159970 <+816>: str r0, [sp, #48] ; 0x30
0xab159974 <+820>: ldr r0, [pc, #276] ; 0xab159a90 std::io::stdio::_print::hca3615e2c19cbb93+1104
0xab159978 <+824>: add r0, pc, r0
0xab15997c <+828>: str r0, [sp, #44] ; 0x2c
0xab159980 <+832>: add r0, sp, #24
0xab159984 <+836>: str r0, [sp, #40] ; 0x28
0xab159988 <+840>: mov r0, #2
0xab15998c <+844>: str r0, [sp, #84] ; 0x54
0xab159990 <+848>: str r1, [sp, #80] ; 0x50
0xab159994 <+852>: str r0, [sp, #76] ; 0x4c
0xab159998 <+856>: ldr r1, [pc, #244] ; 0xab159a94 std::io::stdio::_print::hca3615e2c19cbb93+1108
0xab15999c <+860>: add r1, pc, r1
0xab1599a0 <+864>: str r1, [sp, #72] ; 0x48
0xab1599a4 <+868>: str r0, [sp, #68] ; 0x44
0xab1599a8 <+872>: ldr r0, [pc, #232] ; 0xab159a98 std::io::stdio::_print::hca3615e2c19cbb93+1112
0xab1599ac <+876>: add r0, pc, r0
0xab1599b0 <+880>: str r0, [sp, #64] ; 0x40
0xab1599b4 <+884>: ldr r1, [pc, #224] ; 0xab159a9c std::io::stdio::_print::hca3615e2c19cbb93+1116
0xab1599b8 <+888>: add r0, sp, #64 ; 0x40
0xab1599bc <+892>: add r1, pc, r1
0xab1599c0 <+896>: bl 0xab15fb80 std::panicking::begin_panic_fmt::hf946e5e7aa3496df
0xab1599c4 <+900>: ; instruction: 0xe7ffdefe
0xab1599c8 <+904>: mov r4, r0
0xab1599cc <+908>: ldm r5, {r0, r1}
0xab1599d0 <+912>: bl 0xab1568f4 alloc::alloc::box_free::h03cc9cb92030d653
0xab1599d4 <+916>: mov r0, r5
0xab1599d8 <+920>: bl 0xab15690c alloc::alloc::box_free::h2765089cb184fe8b
0xab1599dc <+924>: b 0xab159a38 std::io::stdio::_print::hca3615e2c19cbb93+1016
0xab1599e0 <+928>: mov r4, r0
0xab1599e4 <+932>: add r0, sp, #40 ; 0x28
0xab1599e8 <+936>: bl 0xab1556e8 core::ptr::real_drop_in_place::h2c4cafce33700501
0xab1599ec <+940>: b 0xab159a38 std::io::stdio::_print::hca3615e2c19cbb93+1016
0xab1599f0 <+944>: mov r4, r0
0xab1599f4 <+948>: add r0, sp, #40 ; 0x28
0xab1599f8 <+952>: bl 0xab155930 core::ptr::real_drop_in_place::h7f4ebdf459ff0fe9
0xab1599fc <+956>: b 0xab159a38 std::io::stdio::_print::hca3615e2c19cbb93+1016
0xab159a00 <+960>: mov r4, r0
0xab159a04 <+964>: add r0, sp, #56 ; 0x38
0xab159a08 <+968>: bl 0xab155930 core::ptr::real_drop_in_place::h7f4ebdf459ff0fe9
0xab159a0c <+972>: b 0xab159a38 std::io::stdio::_print::hca3615e2c19cbb93+1016
0xab159a10 <+976>: mov r4, r0
0xab159a14 <+980>: add r0, sp, #56 ; 0x38
0xab159a18 <+984>: bl 0xab155b84 core::ptr::real_drop_in_place::hfa10616964a6f4d1
0xab159a1c <+988>: b 0xab159a38 std::io::stdio::_print::hca3615e2c19cbb93+1016
0xab159a20 <+992>: mov r4, r0
0xab159a24 <+996>: ldrb r0, [sp, #40] ; 0x28
0xab159a28 <+1000>: cmp r0, #4
0xab159a2c <+1004>: beq 0xab159a38 std::io::stdio::_print::hca3615e2c19cbb93+1016
0xab159a30 <+1008>: add r0, sp, #40 ; 0x28
0xab159a34 <+1012>: bl 0xab15563c core::ptr::real_drop_in_place::h217bb8fbabcc2511
0xab159a38 <+1016>: mov r0, r4
0xab159a3c <+1020>: bl 0xab1547b0
0xab159a40 <+1024>: ; instruction: 0xe7ffdefe
0xab159a44 <+1028>: andeq pc, r2, r12, lsl #18
0xab159a48 <+1032>: andeq pc, r2, r0, ror #17
0xab159a4c <+1036>: muleq r2, r0, r8
0xab159a50 <+1040>: ; instruction: 0x0002f8b8
0xab159a54 <+1044>: andeq pc, r2, r8, ror r8 ;
0xab159a58 <+1048>: andeq pc, r2, r4, ror #16
0xab159a5c <+1052>: andeq pc, r2, r0, lsr #16
0xab159a60 <+1056>: andeq pc, r2, r12, asr #16
0xab159a64 <+1060>: andeq pc, r2, r4, lsr r8 ;
0xab159a68 <+1064>: andeq pc, r2, r0, lsl #16
0xab159a6c <+1068>: ldrdeq pc, [r2], -r8
0xab159a70 <+1072>: andeq pc, r2, r4, lsr #15
0xab159a74 <+1076>: andeq pc, r2, r8, lsl #15
0xab159a78 <+1080>: andeq r9, r1, r7, lsl #29
0xab159a7c <+1084>: strdeq pc, [r2], -r8
0xab159a80 <+1088>: ; instruction: 0xffffdf6c
0xab159a84 <+1092>: andeq pc, r2, r12, lsr #18
0xab159a88 <+1096>: ; instruction: 0xffffdf4c
0xab159a8c <+1100>: andeq pc, r2, r8, ror #12
0xab159a90 <+1104>: ; instruction: 0xffffb868
0xab159a94 <+1108>: ldrdeq r9, [r1], -r0
0xab159a98 <+1112>: andeq lr, r2, r12, lsl r1
0xab159a9c <+1116>: andeq lr, r2, r12, lsl r1
End of assembler dump.
(gdb)
(gdb)

Thanks!

[parched]

Ok yes, it's an old CP15 barrier, you should be fine if you just use armv7-unknown-linux-gnueabihf then.

[huydng]

Instead of using armv7-unknown-linux-gnueabihf, we opted to enable CP15 barrier emulation in the kernel and it no longer crashes. Do you see any problem with this approach?

Thanks for your help!

[parched]

The float ABIs are different so if your c libraries are built with the hard float ABI you will have issues. You'll also have a less optimal Rust std library with arm-unknown-linux-gnueabi because that will only have Armv6 instructions.

[sanxiyn]

CP15 barrier emulation should be enabled in the kernel if you are using CP15 barrier target. Closing.