Re: [rust-dev] Problems cross-compiling to ARM9
Hi Tomi, > The prologue problem was fixed by adding "morestack: false," to the > linux ARM target specification, similar to how it is in the iOS > target. Right, my bad, that should be enough. > My device does not really benefit from the segmented stack, since it > has only 64MB RAM Segmented stacks in Rust for a long time are used only for catching a stack overflow. -- Valerii signature.asc Description: OpenPGP digital signature ___ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
Re: [rust-dev] Problems cross-compiling to ARM9
FWIW, we're just disabling segmented stack in zinc for now exactly because of the same problem. I have a patch for llvm but I didn't really push it upstream hard enough. On Tue, Dec 30, 2014 at 11:23 AM, Valerii Hiora wrote: > Hi Tomi, > > > Anyone have any idea if that's a larger problem, or simply something > > nobody has written the small handcoded ASMs needed for ARMv5 or v4? > > If latter, I might be able to wrap my head around this. > > The problem you've got is related to segmented stack support. It need > fix on 2 levels: > > - Rust - can be relatively easy fixed by providing (or patching) a > target and marking it as a target which doesn't support segmented > stacks, see example [1] > >Once it works you can play a bit to provide a correct implementation > in record_sp.S and morestack.S > > - LLVM - as I remember some time ago LLVM generated a function prologue > which uses the same instruction for any ARM device, may be that was > patched in upstream, may be not. You can also ask Vladimir Pouzanov and > zinc.rs [2] team, AFAIK they had the similar problem too and definitely > have a workaround. > > [1] > > https://github.com/rust-lang/rust/blob/master/src/librustc_back/target/arm_apple_ios.rs#L33 > [2] https://zinc.rs/ > > -- > > Valerii > > > ___ > Rust-dev mailing list > Rust-dev@mozilla.org > https://mail.mozilla.org/listinfo/rust-dev > > -- Sincerely, Vladimir "Farcaller" Pouzanov http://farcaller.net/ ___ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
Re: [rust-dev] Problems cross-compiling to ARM9
> - Rust - can be relatively easy fixed by providing (or patching) a > target and marking it as a target which doesn't support segmented > stacks, see example [1] > - LLVM - as I remember some time ago LLVM generated a function > prologue which uses the same instruction for any ARM device The prologue problem was fixed by adding "morestack: false," to the linux ARM target specification, similar to how it is in the iOS target. >Once it works you can play a bit to provide a correct >implementation in record_sp.S and morestack.S My device does not really benefit from the segmented stack, since it has only 64MB RAM, so I simply modified libstd/sys/common/stack.rs to define stubs for all ARMs, not just iOS. Not that I would have the skills to do it anyway. With these two modifications I got helloworld working! Thank you for the segmented stack on iOS hint. I'll now start programming what I originally wanted, and will report if I find any other problems. -- Tomi Pieviläinen, +358 400 487 504 A: Because it disrupts the natural way of thinking. Q: Why is top posting frowned upon? signature.asc Description: Digital signature ___ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
Re: [rust-dev] Problems cross-compiling to ARM9
Hi Tomi, > Anyone have any idea if that's a larger problem, or simply something > nobody has written the small handcoded ASMs needed for ARMv5 or v4? > If latter, I might be able to wrap my head around this. The problem you've got is related to segmented stack support. It need fix on 2 levels: - Rust - can be relatively easy fixed by providing (or patching) a target and marking it as a target which doesn't support segmented stacks, see example [1] Once it works you can play a bit to provide a correct implementation in record_sp.S and morestack.S - LLVM - as I remember some time ago LLVM generated a function prologue which uses the same instruction for any ARM device, may be that was patched in upstream, may be not. You can also ask Vladimir Pouzanov and zinc.rs [2] team, AFAIK they had the similar problem too and definitely have a workaround. [1] https://github.com/rust-lang/rust/blob/master/src/librustc_back/target/arm_apple_ios.rs#L33 [2] https://zinc.rs/ -- Valerii signature.asc Description: OpenPGP digital signature ___ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
Re: [rust-dev] Problems cross-compiling to ARM9
So far my best guess is that the problem is the Assmebly line
mrc 15, 0, r4, cr13, cr0, {3}
in main, which means that it's trying to read from coprocessor 15,
register 13, part 3. According to
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0360e/CACEAIHG.html
that's a thread ID that's read only for user processes. But that's for
ARM11, and the corresponding doc for ARM9 (926EJ-S, specifically)
http://infocenter.arm.com/help/topic/com.arm.doc.ddi0198e/I1002240.html
doesn't list thread registers at all. So I'm guessing it doesn't
exist, and trying to read from it naturally fails.
A friend noticed that
https://github.com/rust-lang/rust/blob/master/src/librustc_back/target/arm_unknown_linux_gnueabi.rs
specifies ARMv6 as the target, but either retargetting from command
line or recompiling with that file patched for v5te didn't help; the
resulting ASM is the same in that part.
I think the problem might be
https://github.com/rust-lang/rust/blob/master/src/rt/arch/arm/record_sp.S
which assumes a more modern architecture. So perhaps this means that
rust has stricter requirements than C gnueabi?
Anyone have any idea if that's a larger problem, or simply something
nobody has written the small handcoded ASMs needed for ARMv5 or v4? If
latter, I might be able to wrap my head around this.
--
Tomi Pieviläinen, +358 400 487 504
A: Because it disrupts the natural way of thinking.
Q: Why is top posting frowned upon?
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Re: [rust-dev] Problems cross-compiling to ARM9
> In the past when I've seen this error, it's because your C cross > toolchain is built for a slightly wrong architecture. Can you verify > that C programs cross compiled with your cross-gcc work correctly? Christmas is over, back to work. C works fine just by calling arm-linux-gnueabi-gcc. I hadn't tried an empty rust program, but that also stops with the same "illegal instructions". The other hints are a bit over my head right now, as I haven't done much anything this close to metal. I'll continue studying this and report on whatever I find. I'm still wondering if rustc is somehow creating "bad" IR, since LLVM doesn't like that. -- Tomi Pieviläinen, +358 400 487 504 A: Because it disrupts the natural way of thinking. Q: Why is top posting frowned upon? ___ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
Re: [rust-dev] Problems cross-compiling to ARM9
Tomi Pieviläinen wrote: > --target=arm-unknown-linux-gnueabi hello.rs`, but trying to run the > binary on the device just gives me "Illegal instruction". In the past when I've seen this error, it's because your C cross toolchain is built for a slightly wrong architecture. Can you verify that C programs cross compiled with your cross-gcc work correctly? -=rsw ___ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
