Re: [PATCH] Do arm_abi detection for ELFOSABI_GNU binaries

[Kyle Huey <me@kylehuey.com>]

On Fri, Mar 27, 2015 at 1:55 PM, Kyle Huey <me@kylehuey.com> wrote:
> On ARM systems, gdb must determine which style of breakpoint to use
> (see the comments at the beginning of gdb/arm-linux-tdep.c).  In
> arm_gdbarch_init we only attempt to extract the eabi version from the
> ELF binary if it is a ELFOSABI_NONE binary.  If the binary is
> ELFOSABI_GNU instead, we end up defaulting to the old style OABI
> syscall breakpoint instruction.  On a Linux kernel built without
> CONFIG_OABI_COMPAT, this triggers a SIGILL in ld when attempting to
> execute any ELFOSABI_GNU program.  (e.g.
> https://github.com/raspberrypi/linux/issues/766)
>
> gdb/ChangeLog:
>     * gdb/arm-tdep.c (arm_gdbarch_init): Perform arm_abi detection on
> ELFOSABI_GNU binaries.
> ---
>  gdb/arm-tdep.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
> index 630a207..830739e 100644
> --- a/gdb/arm-tdep.c
> +++ b/gdb/arm-tdep.c
> @@ -9948,17 +9948,17 @@ arm_gdbarch_init (struct gdbarch_info info,
> struct gdbarch_list *arches)
>
>        if (ei_osabi == ELFOSABI_ARM)
>          {
>            /* GNU tools used to use this value, but do not for EABI
>           objects.  There's nowhere to tag an EABI version
>           anyway, so assume APCS.  */
>            arm_abi = ARM_ABI_APCS;
>          }
> -      else if (ei_osabi == ELFOSABI_NONE)
> +      else if (ei_osabi == ELFOSABI_NONE || ei_osabi == ELFOSABI_GNU)
>          {
>            int eabi_ver = EF_ARM_EABI_VERSION (e_flags);
>            int attr_arch, attr_profile;
>
>            switch (eabi_ver)
>          {
>          case EF_ARM_EABI_UNKNOWN:
>            /* Assume GNU tools.  */

Bump.  Has anyone had a chance to review this?

- Kyle