[PATCH 0/1] x86_64: Fix stack aligment for x86-64 SysV ABI

[Matheus Pecoraro]

Thanks! Just for clarification, should I create a new ticket for this
specific bug and then add "Closes #XXXX" to the commit message?


On Sat, Mar 23, 2024 at 12:08 PM Joel Sherrill <joel at rtems.org> wrote:

> This is a great explanation. Would you mind filing a ticket with this
> explanatino and referencing the ticket in the commit message of the patch?
>
> When someone wonders about the change in the future, the ticket
> explanation will be useful
>
> On Fri, Mar 22, 2024 at 9:24 PM Matheus Pecoraro <matpecor at gmail.com>
> wrote:
>
>> I kept getting a general protection fault whenever attempting to
>> execute the amd64 BSP while preparing for my GSOC proposal.
>>
>> The GPF was being caused by an instruction attempting to move an SSE
>> register to an address on the stack not aligned to 16 bytes. After
>> some debugging I noticed that the code for setting up the stack frame
>> for a context would result in it being misaligned by 8 bytes as to
>> what is expected by the x86-64 SysV ABI, thus leading the compiler to
>> unknowingly cause the exception (when control is transferred to the
>> function entry point RSP+8 is supposed to be a multiple of 16, without
>> this patch RSP itself was a multiple of 16).
>>
>> After the fix I was able to run the hello test on the amd64 BSP both
>> while booting through the FreeBSD bootloader with no EFI boot services
>> as well as through GRUB with multiboot2 and EFI boot services.
>>
>> Matheus Pecoraro (1):
>>   x86_64: Fix stack aligment for x86-64 SysV ABI
>>
>>  bsps/x86_64/amd64/clock/eficlock.c            | 28 ++-----------------
>>  bsps/x86_64/amd64/start/start.S               |  1 -
>>  .../cpu/x86_64/x86_64-context-initialize.c    |  4 +--
>>  3 files changed, 5 insertions(+), 28 deletions(-)
>>
>> --
>> 2.43.0
>> _______________________________________________
>> devel mailing list
>> devel at rtems.org
>> http://lists.rtems.org/mailman/listinfo/devel
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.rtems.org/pipermail/devel/attachments/20240324/9f6c40b3/attachment.htm>