-----Original Message----- From: Sebastian Huber <sebastian.hu...@embedded-brains.de> Sent: Saturday, November 14, 2020 06:24 To: Kinsey Moore <kinsey.mo...@oarcorp.com>; devel@rtems.org Subject: Re: [PATCH 2/2] spec/aarch64: Only apply SUBALIGN(4) to ILP32
>On 13/11/2020 15:53, Kinsey Moore wrote: > >>>> -----Original Message----- >>>> From: Sebastian Huber<sebastian.hu...@embedded-brains.de> >>>> Sent: Friday, November 13, 2020 04:26 >>>> To: Kinsey Moore<kinsey.mo...@oarcorp.com>;devel@rtems.org >>>> Subject: Re: [PATCH 2/2] spec/aarch64: Only apply SUBALIGN(4) to >>>> ILP32 >>>> >>>>> On 12/11/2020 14:32, Kinsey Moore wrote: >>>>> >>>>>> The SUBALIGN(4) required on rtemsroset and rtemsrwset for ILP32 >>>>>> builds was previously present on LP64 builds and causes no issues >>>>>> within RTEMS, but causes relocation/alignment issues when building >>>>>> libbsd. >>>>>> This restricts those alignment changes to ILP32 builds. >>>>> The SUBALIGN() is currently only used on aarch64 in RTEMS. Why is it >>>>> necessary? The PowerPC port for example uses a single linkcmds.base for >>>>> the 32-bit and 64-bit without a SUBALIGN(). >>>> The SUBALIGN was necessary because the default alignment was 8 bytes and >>>> the ILP32 code would fail during initialization while iterating over the >>>> linker sets since the upper half-word of every address was zeroed out and >>>> was being treated as another init call. Is there a preferred way to >>>> accomplish this that doesn't involve SUBALIGN? >>> Why can't you remove all the SUBALIGN() from the linker script? >>> >>> For example >>> >>> aarch64-rtems6-ld --verbose | grep SUBALIGN >>> >>> has no output. >> That output is specifically for LP64 AArch64. ILP32 linker scripts have >> different OUTPUT_ARCH and OUTPUT_FORMAT directives. I wasn't able to get >> aarch64-rtems6-ld to output an ILP32 default linker script. >What happens if you remove all the SUBALIGN() stuff from the linker script? The LP64 multilib variant works just fine, but the ILP32 variant crashes during init on a null pointer since the elements of the linker set are aligned on 8 byte boundaries and the iteration occurs for 4 byte pointers. Kinsey _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
