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Re: [PATCH 2/3] Use PTRACE_PEEKUSER to get fs_base/gs_base for x32
> Date: Tue, 26 Jun 2012 05:48:09 -0700
> From: "H.J. Lu" <hjl.tools@gmail.com>
>
> On Tue, Jun 26, 2012 at 4:31 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> >> Date: Thu, 21 Jun 2012 11:59:36 -0700
> >> From: "H.J. Lu" <hongjiu.lu@intel.com>
> >>
> >> On Thu, Jun 21, 2012 at 11:15:29AM -0700, H.J. Lu wrote:
> >> > PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the fs_base and gs_base
> >> > fields of user_regs_struct can be used directly. ?Since x32 support was
> >> > added to kernel 3.4.0 and PTRACE_ARCH_PRCTL support was removed for x32,
> >> > we should always use fs_base/gs_base for x32. ?OK to install? We
> >> >
> >> > Thanks.
> >>
> >> Here is a better patch to use the fs_base and gs_base fields of
> >> struct user_regs_struct to get fs/gs base. ?OK to install?
> >>
> >> Thanks.
> >>
> >>
> >> H.J.
> >> ---
> >> 2012-06-16 ?Roland McGrath ?<roland@hack.frob.com>
> >> ? ? ? ? ? H.J. Lu ?<hongjiu.lu@intel.com>
> >>
> >> ? ? ? * amd64-linux-nat.c: Include <sys/user.h> if
> >> ? ? ? HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE or
> >> ? ? ? HAVE_STRUCT_USER_REGS_STRUCT_GS_BASE is defined.
> >> ? ? ? (ps_get_thread_area): Use PTRACE_PEEKUSER to get fs_base/gs_base
> >> ? ? ? if HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE or
> >> ? ? ? HAVE_STRUCT_USER_REGS_STRUCT_GS_BASE is defined.
> >>
> >> ? ? ? * configure.ac: Check if the fs_base and gs_base members of
> >> ? ? ? `struct user_regs_struct' exist.
> >> ? ? ? * config.in: Regenerated.
> >> ? ? ? * configure: Likewise.
> >>
> >> diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
> >> index 23eadbd..781456f 100644
> >> --- a/gdb/amd64-linux-nat.c
> >> +++ b/gdb/amd64-linux-nat.c
> >> @@ -34,6 +34,10 @@
> >> ?#include <sys/debugreg.h>
> >> ?#include <sys/syscall.h>
> >> ?#include <sys/procfs.h>
> >> +#if defined HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE \
> >> + ? ?|| defined HAVE_STRUCT_USER_REGS_STRUCT_GS_BASE
> >> +#include <sys/user.h>
> >> +#endif
> >
> > Any reason to not just unconditionally include <sys/user.h>?
> >
>
> I can include <sys/user.h> unconditionally. OK to install
> with this change?
Yes.